The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis, i.e., stroke and myocardial infarction are definable but not the plaque burden. Platelet indices including platelet count and mean platelet volume (MPV) and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities, e.g., altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plaque stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1bα, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation and atherosclerosis. Despite the increasing knowledge about the intricate pathogenesis of atherosclerosis our therapeutic achievements have not much further evolved since the approval of statins. Various cell types and numerous mediators have been identified to contribute in exacerbating or resolving atherosclerotic lesions and are thus principally to be considered as potential targets  are kept in α-granules. Some chemokines such as CXCL4 and CXCL7, are amongst the highest expressed proteins in platelets and are detectable in other cell types only in low amounts under physiologic conditions  is a vital and well-studied chemokine, which is expressed by various cell types and stored in platelet α-granules. As key mediator of regenerative processes CXCL12 binds and regulates homeostasis, localization and trafficking of endothelial and smooth muscle progenitor cells via CXCR4 and CXCR7. Using the regenerative properties of CXCL12 has been envisioned to be applicable in myocardial infarction and arterial injury  on chromosome 10q11 near the CXCL12 gene as a powerful predictor for the susceptibility of coronary atherosclerosis and myocardial infarction in association with higher CXCL12 plasma levels   plasma and tissue levels are increased during atherogenesis in apoEThe cytokine macrophage migration inhibitory factor (MIF) is structurally and functionally related to the chemokine family as it resembles the CXCL8-dimer and binds and activates CXC chemokine receptors playing an aggravating role in atherogenesis -receptor GP1bα is required to a large part, too. Blocking or genetic deficiency of either one resulted in a considerable reduction of atherosclerosis by reduced monocyte recruitment  is a central player in platelet adhesion and its absence in mice completely prevents platelet adhesion to the carotid artery of apoEConflicting results exist in addition whether GPIIb/IIIa inhibitors are able to reduce the formation of atherogenic platelet-leukocyte complexes , Bernard Soulier Syndrome (GPIbα) and von Willebrand disease (VWD). From studies of Glanzmann patients we know that the absence of GPIIb/IIIa does not fully protect from atherosclerosis since ultrasound of the carotid bifurcation revealed plaques in 4 of 7 patients  is a transmembrane protein of the TNF-family and one of the best characterized co-stimulatory molecules. CD40L activates CD40 thereby stimulating atherogenic immune responses  are small phospholipid-vesicles loaded with bioactive substances being shed from aged or activated platelets  and P2Y1 associating with Gq as well as the ATP activated ion channel P2X1. P2Y1 signaling activates phospholipase C, which will be followed by platelet shape change, whereas activation of the P2Y12R triggers platelet aggregation via GPIIb/IIIa and is the target of well-established antagonists such as clopidogrel, prasugrel, and ticagrelor that are applied in the prevention of arterial thrombosis . The development of PAR knockout mice has provided the unique opportunity to identify and characterize the members of this family of GPCRs, to evaluate the interaction of PARs jointly expressed in common cells and tissues, and better understand the role of PARs in thrombosis, restenosis, vascular remodeling, angiogenesis, and inflammation . Beyond anticoagulation, heparin and its variants play a role in atherosclerosis, preferably adhering at the endothelial cell lining and inhibiting platelet endothelial cell interactions, preventing lipid uptake, and increasing lipoprotein-lipase A2 activity  is the standard drug in the secondary prevention of myocardial infarction and stroke. It acts in the usually applied low doses as an irreversible inhibitor of cyclooxygenase (COX-1), an enzyme required for the synthesis of prostaglandins such as thromboxane A2, which mediates platelet thromboxane receptor amplifying platelet aggregation  failed to show a protective effect on myocardial infarction, which might be due to inhibiting cyclooxygenase reversibly in contrast to the irreversible binding of aspirin , decreased the overall rate of recurrent ischemic events in patients with stroke and were overall protective at the expense of increased intracranial hemorrhage  and later a reduction in adverse cardiac events. Due to the short time frame a lipid lowering effect was not yet effective, implying pleiotropic effects  and ultimately platelet isoprostanes and thromboxane  upon activation preventing in a negative feedback loop further platelet activation and recruitment  activate platelets , which is well-expressed in platelets . The answers that can be obtained are as good as the models of atherosclerosis that are available, typically apoE- or LDLR- deficient mice put on cholesterol rich diet, which copy some but not all of the characteristics of human atherosclerosis. We have to acknowledge that our understanding of human atherogenesis is still very limited, which is in part due to the technical difficulty in assessing reliably, non-invasively and with reasonable efforts the atherosclerotic burden over time in humans leading to the employment of sometimes weak surrogate parameters such as Intima-Media thickness and soft end points. Hard endpoints, however, do not tell us whether beneficial effects by antiplatelet drugs on cardiovascular mortality, stroke and myocardial infarction derive from fewer plaque ruptures due to alterations in the size and stability of atherosclerotic lesions or rather from mere thrombotic and hemostatic inhibition. Examples are the oral GPIIb/IIIa antagonists that failed to keep their promises or the side effects of PAR-1 antagonists demonstrating the difficulty to separate clearly antithrombotic and anti-inflammatory properties from antihemostatic effects. An increase in understanding and dissecting the specific role of platelets in atherosclerosis compared to thrombosis has to be envisioned to result in novel anti-platelet targets and therapies, which are clearly needed to improve the prevention of atherosclerotic complications.Philipp von Hundelshausen is shareholder of Carolus Therapeutics Inc. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Breast cancer is currently the most frequent, fatal cancer of women in western countries. While estrogens have a widely understood involvement in breast cancer, a significant but not yet fully understood role for androgens has also been suggested. The principal androgen, testosterone, is the obligate steroidal precursor of estradiol, but can equally be metabolized into dihydrotestosterone, a more potent, pure androgen. Both androgens exert their distinctive biological effects via the androgen receptor, which is coexpressed with estrogen receptor alpha in 80 to 90% of breast cancers. The hormonal control of breast development and pathology has been examined experimentally through the use of animal models, notably mice and rats. This review summarizes the data from experimental rodent models on the effects of androgens in experimental breast cancer, aiming to address the importance of androgens and the androgen receptor in the origins and pathogenesis of breast cancers, as well as to discuss potential biomarker and therapeutic opportunities arising from novel insights based on the experimental research. Breast cancer is currently among the most frequent and fatal cancers afflicting women worldwide. The strongest epidemiological clues to the hormonal origins of breast cancer arise from the recognition of lifetime endogenous estrogen exposure comprising early menarche, incessant ovulation, and late first lactation and menopause. While estrogens have a widely understood involvement, we  and otheThis review summarizes the experimental data using rodent models on the effects of androgens in experimental breast cancer, aiming to highlight the role of androgens and androgen receptor (AR)-mediated androgen effects in experimental breast cancers. In addition, the review aims to lay a solid foundation for a consensus, as well as guidance for future research into novel biomarkers and therapeutic targets arising from novel insights acquired from experimental research. Owing to increased interest in androgen actions in breast cancer, we will cover the historical aspects briefly, but concentrate on the most recent literature focusing on the role of androgens in experimental rodent breast tumorigenesis. This focus on experimental animal models aims to provide a complementary view to recent reviews of androgens and breast cancer, which concentrate on clinical data and human breast cancer cell lines ,3]..3].2) acting via estrogen receptor (ER) signaling or can be reduced (via 5?-reductases) within target tissues to the nonaromatizable androgen DHT, which has higher androgenic bioactivity than testosterone and is associated with a higher affinity for AR . Bu. Bu16]. N-nitroso-N-methylurea is a direct-acting carcinogen that does not require metabolic activation. This carcinogen can be advantageous in experiments that involve co-treatments or genetic modification, which may influence CYP activation -[57-[5752]-, but not2 is co-administered 50% develop tumors within 26?weeks -[79-[7960]-, found tAdministration of the nonaromatizable androgen drostanolone  propionate  to rats had no effect on DMBA-induced or MCA-induced mammary tumors . Yet botThe anti-androgen flutamide has been used to investigate the role of androgens in chemical carcinogen-induced mammary tumors ,78]. Su. Su78]. Ar gene with most of the human Ar exon 1 CAG repeat length variant  but butAr ge2 concentrations in both rodents ,, and rodents . Althougpression -93]. Ho. Ho2 conpression ,[87] ? hpression . Hence, 1 as well as E2 in the 1940s was a landmark in the investigation of hormone-dependent breast cancer . Th. Th1 as 1 and TP in Noble rats significantly increased the incidence of mammary tumors compared with E1 treatment alone , a, a1 and Specific rat and mouse lines that develop spontaneous mammary tumors have been used to investigate the role of androgens in the incidence of these tumors, as well as their growth as tumor transplants Table?. Growth Most studies ,102],1,1102],-108], b, b108], 2,-108], 2,-108], Ar allele in mammary epithelium demonstrated that reduced epithelial AR expression also promoted the early onset of Neu (ERBB2) proto-oncogene tumors . I. I114]. In conclusion, while androgens are assumed inhibitory and estrogens stimulatory for mammary cell proliferation in experimental settings, it is possible that the ratios of these hormones and/or their respective receptors may regulate the optimal balance in tissue maintenance and if disturbed will lead to pathological/malignant growth. As the AR is one of the most abundant steroid receptors present in breast cancers, more research is warranted to understand androgen actions via the AR in breast tissue as a regulator for optimal hormonal balance and to provide opportunities for novel therapeutic targets and prognostic biomarkers for this lethal disease.


Drosophila, the vertebrate and mammalian equivalent of the pathway has been studied extensively for its role in cancer development and progression. As this pathway regulates key target genes involved in development, its action also allows for the modulation of the microenvironment to prepare a tumor-suitable niche by manipulating tumor cell growth, differentiation, and immune regulation, thus creating an enabling environment for progression and metastasis. In this review, we will summarize recent scientific discoveries reporting the impact of the Hedgehog signaling pathway on the tumor initiation process and metastatic cascade, shedding light on the ability of the tumor to take over a mechanism crucially intended for development and normal function.Cancer poses a serious health problem in society and is increasingly surpassing cardiovascular disease as the leading cause of mortality in the United States. Current therapeutic strategies for cancer are extreme and harsh to patients and often have limited success; the danger of cancer is intensified as it metastasizes to secondary locations such as lung, bone, and liver, posing a dire threat to patient treatment and survival. Hedgehog signaling is an important pathway for normal development. Initially identified in  In order for tumor initiation and metastasis to occur, tumors usurp several signaling pathways that contribute to normal growth and tissue repair. The normal development of mammalian embryos involves multiple signaling pathways that regulate cell proliferation, survival, and differentiation such as the Hedgehog (Hh) , Wnt 2]2], TGF-βHh signaling involves a complex network of molecules. The canonical Hh signaling pathway can be initiated by three ligands: Desert hedgehog (DHH), Indian hedgehog (IHH) or Sonic hedgehog (SHH). These bind to the 12-pass transmembrane protein receptors Patched1 (PTCH1) and Patched 2 (PTCH2), which were initially found to form a complex with single pass co-receptor proteins: Cell adhesion molecule-related/downregulated by oncogenes (CDON) and Brother of Cdo (BOC) , 12. TheIn the nucleus, the GLI transcription factors bind DNA and modulate the transcription of a multitude of genes including Fox, Myc, and cyclin D among others that are involved in tissue development, differentiation, epithelial-mesenchymal transition (EMT), and stem cell maintenance. Recently, GLI1 protein transcript was found to undergo alternative splicing establishing two isoforms with different functions: an N-terminal deletion and a truncated GLI1 variant . The trunon-classically as a result of crosstalk between diverse intracellular signaling networks.Although the Hh signaling pathway is normally activated upon ligand binding to the receptor, multiple mechanisms have been involved in enhancing GLI protein activity in the absence of Hh ligands. In breast cancer, TGF-β signaling was shown to activate GLI2 target genes culminating in enhanced bone metastasis . In basaThe Hh signaling pathway must be strictly controlled in order to prevent aberrant activation. The Hh signaling pathway can be activated by four different mechanisms. And though the downstream effects of Hh activation are ultimately proliferation and differentiation, it is notable that its mode of activation differs depending on the cancer type , 27.The Hh signaling pathway can be activated classically through ligand binding or non-classically in the absence of the ligand , both ofThe non-classical mode of activation is, as mentioned above, independent of Hh ligand presence, which occurs irrespective of PTCH receptors loss of function or gain of function of SMO; this mode is found in BCC , and canThe first identified naturally occurring Hh blocker is cyclopamine, which causes developmental abnormalities in animals. The Beachy group first reported the inhibitory effect of cyclopamine on Hh signaling to occur by directly binding and inhibiting SMO . HoweverThe first FDA approved Hh inhibitor for clinical use is vismodegib (Genentech) marketed as Erivedge . ApproveCurrently, there are several Hh inhibitors employed in clinical trials for multiple types of cancers. For example, sonidegib is being tested on patients with advanced hepatocellular carcinoma  and in cIn the ensuing paragraphs, we will summarize recent scientific discoveries reporting the impact of the Hh signaling pathway on the tumor initiation process and metastatic cascade, shedding light on the ability of tumors to takeover a mechanism crucially intended for development and normal function. We have specifically focused on the recent advances and knowledge garnered to address novel tumor properties that pertain to creating a favorable microenvironment known as the updated hallmarks of cancer as described by Hanahan and Weinberg Fig. .Fig. 2ThThe most pronounced characteristic of cancer is the unrestricted proliferation of cells. As the main function of Hh signaling is to promote fetal development and patterning, it is expected that signaling through the pathway would upregulate genes involved in cellular proliferation and survival, a function that tumors manipulate. Not only does Hh signaling promote the over-proliferation of cancer cells themselves, but it also modulates cells found in the local microenvironment. Wilkinson and colleagues found that human prostate cancer associated fibroblasts (CAFs) have the capability of forming primary cilia; this was associated with upregulation of canonical Hh signaling . AdditioCancer by definition is the uncontrolled replication of cells. Cancers successfully employ telomeric activation to maintain maximum replication; this is supported by the Hh pathway’s ability to upregulate telomerase activity. As the normal function of Hh signaling pathway is to promote embryonic development, it essentially controls and influences cellular division allowing its implication in various cancers as a driver for telomerase activity. The telomerase subunit is made up of telomerase reverse transcriptase (TERT) and telomerase RNA component, both of which make up the complex that drives cell replication . RecentlIt is widely accepted that tumors adapt to hypoxic environments and survive by upregulating genes that promote anaerobic metabolism such as hypoxia-inducible factor-1α (HIF-1α) ; this isHelicobacter pylori-driven gastritis that progressed to gastric metaplasia, Gli1 was found to drive myeloid cell differentiation and upregulation of IL-6, IL-1β, and TNFα, three important cytokines for activating STAT3 signaling, the main promoter of the inflammatory response [Cancer has long been associated with inflammatory responses , 83. Infresponse . These eresponse . In gastThe formation of new limbs as development progresses requires the creation of blood vessels through the induction of pro-angiogenic factors such as vascular endothelial growth factors (VEGF) and fibroblast growth factors (FGF). Both VEGF and FGF are direct transcriptional targets of the Hh signaling pathway . In an iAlthough the majority of published literature largely associates Hh signaling with increased angiogenesis, several reports have emerged in pancreatic cancer models showing increased vascularization enhancing drug delivery upon the inhibition of paracrine Hh signaling in pancreatic stroma using SMO inhibitors –96. ThusAlthough the human immune system is fully capable of eliminating foreign matter and abnormal cells, cancer cells evade the immune system through various mechanisms . Cancer One of the most important mechanisms by which cancers support their growth and immune system evasion is through avoiding apoptosis , 108. ApThe ability of tumor cells to metastasize is permitted through the flexibility of the cells to alter their shape and function, break through the basement membrane, extravasate into lymph and blood vessels, and travel to distant locations where they occupy a distinct microenvironment , 115. SeHh signaling and cancer stem cells: Given the role of Hh signaling during development when there is a dynamic shift between cellular phenotypes from epithelial and mesenchymal type, it comes as no surprise that this is recapitulated in cancer progression [gression . Stainingression . A more gression . Likewisgression . p63, a gression . Also ingression . Also ingression . The invThe progression of cells through the cell cycle in order to undergo replication requires the successful advancement through many checkpoints which would suppress growth if cells are experiencing chemical and physical stress or DNA damage. Cancer cells though defective in structure and function, employ different signaling pathways, including the Hh pathway, to bypass those regulatory checkpoints . AberranA possible mechanism by which tumors can evade cell growth suppression other than cell cycle checkpoints is their ability to regulate autophagy. Autophagy is the process by which cells get degraded and their components recycled as a result of cellular stress or infections . In streIn addition to the impact of Hh signaling on profoundly influencing several cancer processes, it also desensitizes cancer to therapies. In breast cancer, the OPN oncoprotein was shown to activate non-classical Hh signaling and GLI transcription, resulting in the upregulation of multidrug resistance genes viz. ATP-binding cassette transporters (ABCB1) and ATP-binding cassette sub-family G member 2 (ABCG2). Treatment of cells with GLI inhibitor GANT-61 or silencing GLI1 expression abrogated this effect . In prosHh signaling also desensitizes tumor cells to radiotherapy. In hepatocellular carcinoma, SHH-driven signaling induced PTCH1 and Gli1 expression; this protected cells against ionizing radiation (IR) . The useIt is evident from the presented compilation of literature that the Hh signaling pathway is extensively studied and significantly linked to several cancer types. Aberrations in almost all molecular members of the pathway have been reported across multiple malignancies. The pathway’s ability to promote replicative immortality, evade genomic instability and growth suppression, sustain proliferative signaling, and switch cellular energetics are crucial for the tumor cells’ ability to grow uncontrollably, avoiding multiple levels of homeostatic cellular regulation that prevent damaged cells from surviving. As the tumors establish in their niche, they employ Hh signaling to induce angiogenesis, take advantage of tumor promoting inflammation and escape immune system surveillance to facilitate tissue invasion and metastasis.Derris glabrescens plant, Glabrescione B is among the newly identified, naturally occurring small molecule inhibitor, functioning in a similar mechanism to GLI inhibitors GANT-58 and 61 [In closing, Hh signaling is activated across multiple cancer types in many different ways: through mutations or through non-classical ligand-independent or through non-canonical modes. Hh signaling influences every aspect of a tumor cell: initiation, establishment and its metastatic journey. With the promising success of inhibitors of this pathway in the clinic, the pathway continues to offer the scope to direct and design inhibitors to function at multiple levels. At present, a large cadre of chemically modified pharmacological inhibitors has been developed to target SMO. In order to pursue the elimination of the rapidly-evolving tumor and its associated milieu, it is necessary to continue efforts to target this pathway at all levels. Avenues to target and block the activity of ligands, block co-receptors Boc, Cdo, and Gas1 and interfere with the activity of GLI transcription factors are currently being explored by many laboratories. Discovered in the 8 and 61 . The rec8 and 61 . With th


Phytohormones and reactive oxygen species (ROS) are major determinants of the regulation of development and stress responses in plants. During life cycle of these organisms, signaling networks of plant growth regulators and ROS interact in order to render an appropriate developmental and environmental response. In plant’s photosynthetic  and non-photosynthetic  tissues, enhanced and suboptimal ROS production is usually associated with stress, which in extreme cases can be lethal to cells, a whole organ or even an organism. However, controlled production of ROS is appreciated for cellular signaling. Despite the current progress that has been made in plant biology and increasing number of findings that have revealed roles of ROS and hormonal signaling in germination, some questions still arise, e.g., what are the downstream protein targets modified by ROS enabling stimulus-specific cellular responses of the seed? Or which molecular regulators allow ROS/phytohormones interactions and what is their function in seed life? In this particular review the role of some transcription factors, kinases and phosphatases is discussed, especially those which usually known to be involved in ROS and hormonal signal transduction under stress in plants, may also play a role in the regulation of processes occurring in seeds. The summarized recent findings regarding particular ROS- and phytohormones-related regulatory proteins, as well as their integration, allowed to propose a novel, possible model of action of LESION SIMULATING DISEASE 1, ENHANCED DISEASE SUSCEPTIBILITY 1, and PHYTOALEXIN DEFICIENT 4 functioning during seeds life. Arabidopsis thaliana, ends with the visible protrusion of covering layers  by an elongated radicle. Depending on the interaction between the weakened endosperm surrounding the radicle and on factors controlling embryo growth potential , proper seedling establishment either occurs or not , ein2-2 (ethylene insensitive 2-2), aao3-4 , and sid2 (SA induction deficient) indicated that the mechanism of action of SA in various developmental processes of plants, involved its interactions with other phytohormones , as well as with ROS (The role of abscisic acid (ABA) in dormancy onset during seed development is well documented by genetic and physiological studies. A dynamic balance in the metabolism of ABA and its antagonists – gibberellins (GA), as well as their signaling pathways interacting with ROS-induced signals determines whether an imbibed seed will complete germination or remain dormant. Another phytohormone counteracting ABA effect is ethylene (ET). Studies using inhibitors of ET biosynthesis or action indicated the involvement of this phytohormone in the regulation of germination and dormancy  cyanide , 2009. Awith ROS .Figure 1).Despite the current progress that has been made in plant science and cellular signaling, there is still far from complete understanding of biological functions of several regulatory proteins involved in signaling network of plant growth regulators and ROS occurring in non-photosynthetic (seeds) and photosynthetic (foliar) cells. Hence this review presents: (i) shortly summarized role of ROS and phytohormones in seeds and (ii) discussed novel findings about particular molecular regulators of ROS and phytohormone signaling with previously defined roles in plants acclimation and defense, which can also be involved in the regulation of germination. In addition, possible models of action of regulatory proteins integrating signals induced by ROS and phytohormones  in germinating seeds and plants exposed to optimal and/or suboptimal conditions are presented (•OH) radicals and singlet oxygen (1O2), that have a very short half-life-time and can be sensed at the production site, as well as 2) relatively stable with longer life-span hydrogen peroxide (H2O2) that can diffuse within and between cells and can be sensed remotely  superoxide  and of GA-inducible genes . Interestingly, authors also suggested that changes in this type of seeds triggered by ROS did not engage the interaction with ABA signaling, even if a small increase in ABA content was observed. Moreover, it is known that in cereals ROS play a role in phytohormone-regulated programmed cell death (PCD) of aleurone cells. This process is stimulated by GA which induces ROS accumulation, whereas ABA maintains low ROS concentrations through activation of the alternative oxidase pathway and the ROS-scavenging systems  plants. Moreover, in the natural field WT and lsd1 performed similarly. Such specific conditional differences were also reflected at gene expression levels. Based on that results it was suggested that LSD1/EDS1/PAD4 constitute a regulatory hub of transcription factors integrating photosynthesis, water use efficiency, ROS/hormonal cellular homeostasis with seed yield during plant growth and development in the field  and ROS operating in: non-photosynthetic (seed)  and photosynthetic tissues (plant) , exposed to optimal  and/or suboptimal conditions . It is emphasized that the same regulatory proteins may act differentially, in the manner dependent on the type of tissue as well as environmental conditions. Hence, it is highlighted that the mechanism of LSD1 and EDS1–PAD4 action as molecular regulators is conditional .Taking into consideration an up-to-date knowledge about functions of PCD-related regulators in seeds and plants the novel, possible model of its action is proposed in this review and presented on the via protein phosphorylation and de-phosphorylation in response to different stimuli. The various evidences confirm that mitogen-activated protein kinases (MAPK) and phosphatases are important regulators of these processes. The increasing number of evidences emphasize the role of both types of enzymes in directing cellular responses to a diverse array of stimuli, especially in the context of the response of photosynthetic tissue to stress conditions. Interestingly, the last decade brought discoveries indicating that MAPK also play a role in modulation of processes occurring in non-photosynthetic plant organs such as seeds. The MAPK are serine/threonine kinases that can phosphorylate a wide range of protein targets, including transcription factors and/or other kinases. It was shown that phosphorylation of the MYB44 transcription factor by MPK3 and MPK6 (MITOGEN ACTIVATED PROTEIN KINASE 3 and 6) was necessary for its function as a negative regulator of GA- and ABA-mediated control of seed germination . It is interesting that A. thaliana mpk4 null mutant is semi-lethal and does not produce seeds. Other lines of evidences obtained in biochemical and genetic studies have indicated that protein post-translational modifications  play a role in the regulation of the physiological status of the cell, gene expression and seed germination (MPK1 (MITOGEN ACTIVATED PROTEIN KINASE 1) in the release of Helianthus annuus embryo dormancy was reported  was differentially affected by dormancy alleviation either during after-ripening or by cyanide treatment in H. annuus embryos  mutant has been associated with changes in seed germination in response to ABA . Since ROS and phytohormones have been suggested to be involved in modulation of endosperm weakening and radicle growth during germination  which have been suggested to control various aspects of plant development, stress adaptation and are intricately linked to ROS/redox signaling . The phec stress , and thee to ABA . Moreovemination , the del mutants .Figure 1). The authors concluded that at least one of these kinases was necessary to protect seeds during desiccation and to maintain quiescent. While discussing plant-specific kinases involved in plant response to abiotic stresses and ABA-dependent plant development, it is important to mention the SnRK2 family members. The SNF1-RELATED PROTEIN KINASE 2s (members of SnRK2), together with the PYRABACTIN RESISTANCE/PYRABACTIN-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORS (PYR/PYL/RCAR), PP2C5 are core components of ABA signaling in plant photosynthetic tissues and in seeds. The redundant ABA-activated protein kinases such as: SRK2D/SnRK2.2, SRK2E/SnRK2.6/OST1, and SRK2I/SnRK2.3, were shown to control gene expression through the phosphorylation of ABI5 and the other transcription factors, such as AREB3 (ABA-RESPONSIVE ELEMENT BINDING PROTEIN 3), during seed development and dormancy  (Figure Indicated herein examples of kinases and phosphatases the most often recognized as key molecular regulators of stress response, highlight their role also in the establishment of ROS and hormonal signaling homeostasis in seeds-related events.Figure 1.The findings presented and discussed above demonstrate that regulatory genes encoding various kinases, phosphatases and transcription factors with previously defined roles in the regulation of ROS and phytohormone signaling for PCD as well as abiotic stress responses are also involved in the regulation of seed germination. The roles and function of these protein regulators were almost exclusively defined in fully developed leaves, which are not representative of other organs, tissues or types of cells. These limitations have been recently addressed in several studies and indicated that plants evolved a highly complex ROS and hormonal signaling and regulatory system. However, the precise function and role of this system depends on plant organs, tissue or type of cells and plant developmental status as well as on environmental conditions. In this review it is discussed that LSD1 and EDS1–PAD4 which regulate immune defenses, light acclimation, photosynthesis and transpiration are also involved in the regulation of seed germination as summarized in All authors listed, have made substantial, direct and intellectual contribution to the work, and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Glaucoma is characterized by chronic optic neuropathy resulting in progressive vision loss. Not only is glaucoma considered as a condition of elevated intraocular pressure (IOP), but also other risk factors may play a role in the pathogenesis of glaucomatous optic nerve damage. Vascular dysregulation in ocular blood flow and oxidative stress are currently suggested as important risk factors for glaucomatous retinal ganglion cell loss. New treatment modalities that improve ocular blood flow and reduce oxidative stress have been investigated in many studies. Magnesium (Mg) is thought to be one of the molecules that has a treatment potential in glaucoma. Mg has been shown to improve blood flow by modifying endothelial function via endothelin-1 (ET-1) and endothelial nitric oxide (NO) pathways. Mg also exhibits neuroprotective role by blocking N-methyl-D-aspartate (NMDA) receptor-related calcium influx and by inhibiting the release of glutamate, and hence protects the cell against oxidative stress and apoptosis. Both improvement in ocular blood flow and prevention of ganglion cell loss would make magnesium a good candidate for glaucoma management. Further studies on the effect of Mg may open a new therapeutic era in glaucoma. Glaucoma is characterized by chronic optic neuropathy resulting in progressive vision loss . IOP hasDisturbed ocular blood flow and oxidative stress are the suggested concomitant risk factors that may contribute to GON , 3. BlooMg is involved in many metabolic processes such as maintenance of normal cell membrane function, energy metabolism, and synthesis of nucleic acids . AdditioMg is the second most abundant intracellular cation and has been recognized as a cofactor in more than 300 enzymatic reactions in the body. Approximately 50% of Mg is present in bones, 50% in tissues and organs, and 1% in the blood stream . Some ofNormal serum Mg level ranges between 1.7 and 2.2 mg/dL, and approximately 20% of this cation is bound to albumin in the intravascular compartment. Under basal conditions, small intestine absorbs 30–50% of Mg intake and although 80% of serum Mg is filtered at the glomerulus, only 3% is finally excreted in the urine . Mg therIn experimental animal studies, it has been shown that Mg has a vital role in the development and normal functioning of the eye. Mg deficiency has been associated with multifocal necrosis in the retinal pigment epithelium of rats  and hypoVascular dysregulation, an imbalance between vasoconstriction and vasodilatation at microcirculatory level and general dysfunction of endothelium and autonomic nervous system, was believed to be a contributing factor for GON . ReductiWhen autoregulation is disturbed, even normal IOP or normal blood flow fluctuation leads to ocular blood flow fluctuation outside the normal limits, contributing to optic nerve damage . The balOcular perfusion instability occurs especially when IOP or blood pressure fluctuates and causes a repetitive reperfusion injury resulting in chronic oxidative stress, especially in mitochondrial level . It was Vascular tone is regulated locally by endothelium derived vasoactive agents such as ET-1 and endothelial NO. ET-1 causes the contraction of the retinal and optic nerve head vessels which is dependent on extracellular calcium influx through voltage-gated calcium channels, resulting in decreased ocular blood flow and ischemia . ET-1 maVascular dysregulation and repeated reperfusion injury does not only activate astrocytes and endothelin pathway but also lead to glutamate retention in retinal tissue as a result of increased oxidative stress . It is k+/K+ ATPase, which is responsible for the active transport of Na+ out of the cell membrane in exchange with K+ [+/K+ ATPase and causes intracellular Na+ accumulation and release of mitochondrial Ca++ ions which results in increased cytoplasmic Na+ and Ca++ [++ and Na+ further cause cellular swelling leading to retinal ganglion cell apoptosis. In summary, Mg may protect retinal ganglion cells from oxidative injury by combined effects on voltage-dependent calcium channels, glutathione synthesis, lipid peroxidation, and maintaining the regulation of many metabolic enzymatic reactions.As we discussed, Mg, as a physiological calcium channel blocker, may be a good candidate in the protection of retinal ganglion cells. Mg ions regulate the conductance of calcium channels and limit neuronal calcium influx. Additionally, Mg inhibits the release of glutamate and thereby may participate in the protection of retinal ganglion neuronal cells against oxidative stress and apoptosis . Further with K+ . Mg defiand Ca++ . IncreasMg supplementation-induced favourable vascular effects have been demonstrated in diabetic patients and patients with coronary artery disease , 69. TheIn conclusion, Mg is of critical importance in regulating cellular functions of the ocular tissues. The association of Mg levels with the pathogenesis of glaucoma may be attributed to Mg serving highly important roles as a cofactor for several enzymes involving membrane-associated ATPases, modulator of vessel smooth muscle contraction, and regulator in oxidative stress pathways. Therefore, Mg may have a great potential to come into clinical use in the management of glaucoma. The review of current literature supports the need of further investigations to evaluate the role of Mg as a supportive approach in glaucoma.


LMNA gene encoding the intermediate filament protein lamin A. Lamin A is a major component of the nuclear lamina, a scaffold structure at the nuclear envelope that defines mechanochemical properties of the nucleus and is involved in chromatin organization and epigenetic regulation. Lamin A is also present in the nuclear interior where it fulfills lamina-independent functions in cell signaling and gene regulation. The most common LMNA mutation linked to HGPS leads to mis-splicing of the LMNA mRNA and produces a mutant lamin A protein called progerin that tightly associates with the inner nuclear membrane and affects the dynamic properties of lamins. Progerin expression impairs many important cellular processes providing insight into potential disease mechanisms. These include changes in mechanosignaling, altered chromatin organization and impaired genome stability, and changes in signaling pathways, leading to impaired regulation of adult stem cells, defective extracellular matrix production and premature cell senescence. In this review, we discuss these pathways and their potential contribution to the disease pathologies as well as therapeutic approaches used in preclinical and clinical tests.Hutchinson–Gilford progeria syndrome (HGPS) is an extremely rare premature aging disease presenting many features resembling the normal aging process. HGPS patients die before the age of 20 years due to cardiovascular problems and heart failure. HGPS is linked to mutations in the  Aging is a universal process in biological organisms that is characterized by a time-dependent progressive decline in cellular and tissue function. At the molecular and cellular level, nine hallmarks have been proposed to contribute to the extremely complex, multifactorial process of aging: genomic instability and defects in nuclear architecture, telomere attrition, epigenetic alterations and chromatin remodeling, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion and altered intercellular communication  and restrictive dermopathy (RD) . A-type lamins are derived from a single LMNA gene by alternative splicing, which gives rise to the two major A-type isoforms  and two less abundant isoforms, the germ cell-specific lamin C2 and lamin AΔ10    that give rise to four major groups of diseases with overlapping pathologies, including striated muscle diseases, lipodystrophic syndromes, peripheral neuropathy and accelerated aging disorders  is an extremely rare sporadic autosomal-dominant genetic disorder affecting 1 in 4–8 million newborns and displays phenotypic features of premature aging  in exon 11 of Progerin is expressed in multiple tissues, mostly of mesenchymal origin including skin, bone, skeletal muscle, adipose tissue, heart and large and small arteries , a progeroid syndrome associated with neonatal death , a chromatin protein, which directly interacts with lamins and lamin-binding proteins and has been implicated in chromatin organization  that produces exclusively progerin but no wild-type lamin A and lamin C  develops progressive loss of vascular smooth muscle cells (VSMCs), a feature described also in HGPS patients, but did not show most of the other pathologies , also displayed phenotypes overlapping with HGPS  and produces progerin due to abnormal splicing of the endogenous Lmna mRNA like in HGPS patients  allowed tissue-specific and inducible expression of progerin by crossing them with transgenic mice expressing the transactivator in specific tissues  shows no progeroid phenotypes but develops severe cardiomyopathy  was generated by replacing the cysteine in the CaaX motif in the LmnaHG allele with a serine (CSIM → SSIM). Interestingly, homozygote and heterozygote LmnanHG mice showed similar, but less severe progeroid phenotypes than those described for LmnaHG mice . Surprisingly, LmnacsmHG mice showed no noticeable progeroid defects, suggesting that cysteine-to-serine substitution in the LmnanHG mouse model may be toxic, although the authors do not exclude the possibility that toxicity of progerin is linked to the 50 amino acid deletion in its C-terminus independent of farnesylation and the deletion of the isoleucine in CSIM may neutralize the toxicity of the protein   repair factors p53-binding protein 1 (53BP1) and Rad50 and Rad51 to the sites of DNA damage   NF-κB subunit, RelA+/−) or treatment of mice with the NF-κB inhibitor sodium salicylate extended life span and rescued skin and immunological phenotypes  a major regulator of cell proliferation  display decreased numbers and altered proliferative capacity of epidermal stem cells  and Zmpste24-proficient (mature lamin A-containing) cells in tissues  and statin (pravastatin) treatment, inhibiting farnesyl-pyrophosphatase synthase and the HMG-CoA reductase, respectively  antisense morpholino oligonucleotide that can sterically block the cryptic splice site in exon 11 of progerin pre-mRNA resulted in a concentration-dependent decrease in progerin mRNA and protein levels and in the reversion of cellular phenotypes in cultured HGPS cells (Scaffidi and Misteli Zmpste24−/− mice (Liu et al. Zmpste24−/− mice. Resveratrol enhances the binding of SIRT1 to A-type lamins, increases SIRT1 deacetylase activity and slows down body weight loss and significantly extends the life span of Zmpste24−/− mice (Liu et al. Finally, a few approaches have been described to target cellular HGPS phenotypes. Resveratrol, an activator of SIRT1, a deacetylase involved in many cellular processes (Lavu et al. LMNA is causally linked to the premature aging disease HGPS in 2003. Despite numerous cellular pathways that were identified to be affected by the expression of the mutant lamin A protein (Fig. The number of molecular biological studies aiming at the identification of lamin-mediated molecular disease mechanisms involved in HGPS increased tremendously following the surprising discovery that


Communication among cells via direct cell-cell contact by connexin gap junctions, or between cell and extracellular environment via pannexin channels or connexin hemichannels, is a key factor in cell function and tissue homeostasis. Upon malignant transformation in different cancer types, the dysregulation of these connexin and pannexin channels and their effect in cellular communication, can either enhance or suppress tumorigenesis and metastasis. In this review, we will highlight the latest reports on the role of the well characterized connexin family and its ability to form gap junctions and hemichannels in cancer. We will also introduce the more recently discovered family of pannexin channels and our current knowledge about their involvement in cancer progression. Intercellular communication between cells is realized through gap junction channels formed by connexins (Cx). In the last decade or so, connexin hemichannels were identified, which mediate the communication between intracellular and the extracellular microenvironment , 2. It iPannexin channels on the other hand , are a recently discovered family  of singl+, high intracellular Ca2+ and mechano-sensitive stimuli among others [Panx1 represents the best characterized member of the family. Panx1 is N-glycosylated at residue N254 in the second extracellular loop (EL2) , 24, andg others , 31. Pang others –34. Addig others .In the current review, we will highlight the most recent literature on the role of connexins in cancer, and introduce the more recently discovered pannexin channels and their proposed function in different cancer types.Cancer was one of the first pathologies found to be associated with gap junction channel impairment, and connexins have long been shown to possess tumor suppressive function . Cx43 asLoewenstein and Kanno first postulated that liver cancer cells were different from normal liver cells in that they lacked intercellular communication . Since tMany studies demonstrate that cancer cells lose their capability of communication through gap junctions, leading to the overall assumption that cancer cells do not communicate. However, the situation is more complicated than originally thought. Some cells completely lack cell coupling, whereas others exhibit a slight decrease compared to their normal counterparts . While iThe major effect of connexins and gap junctions on suppression of primary cancer growth is a result of inhibition of cell cycle progression; however, until now limited knowledge is gained regarding direct molecular mechanisms governing the cell cycle cell events in cancer cells. An earlier evidence of the effect of Cx43 on cell cycle is exemplified in C6 glioma cells, where the restoration of Cx43 inhibits their progression to the S phase of the cell cycle, owing in part to a reduction of cyclin E expression and thus, the rate of proliferation . InteresMore interestingly, recent studies show that epigenetic processes play an essential role in regulating connexin gene expression which includes histone modifications, DNA methylation and microRNA  A sThe major questions remain whether connexins are tumor suppressors or tumor promoters; the situation is much more complex, and no clear answer can be made thus far. There are many points to consider. The effect of connexins on tumor progression and behavior depends largely on endogenous connexin expressed or overexpression of exogenous connexins on the particular cells and tissue examined. Furthermore, the inconsistent evidence of connexins’ role in cancer reflects the complexity of developmental stages of cancer progression and metastasis. The existence of a correlation between connexin expression and the invasive potential, as opposed to the lack of connexin expression in the earlier proliferation period of cancer progression points to a specific function of connexins during cancer development and metastasis. For example, Cx43 has a multifaceted function depending upon the stages of cancers; with low expression in primary tumor and high expression in metastasized tumor. Cx43 is involved in neural crest cell migration as a part of normal development and that impaired gap junction communication leads to reduced neural crest cell migration . ConsistIn contrast to the inhibitory effect of connexins in primary tumors, a promoting effect has been found in metastatic cancers. Some studies have found that increased gap junction coupling and Cx43 expression contribute to breast cancer adhesion and migration . The estCancer metastases could also be promoted with the aid of heterotypic gap junctions formed between the migrating cancer cells and the target tissue cells. For example, the formation of heterotypic gap junctions between a human breast cancer cell line and an osteoblast cell line has been demonstrated, where the degree of heterotypic gap junctions relative to homotypic ones correlated with breast cancer cell metastatic potential . This daThe tumor suppressive effect of connexins has also been demonstrated in several metastatic cancers. In a highly metastatic lung cancer cell line, Cx43 expression was undetected, whereas transfection of Cx43 inhibited the tumorigenicity of the cells . SimilarTumor microenvironment also impacts connexins and gap junctions in normal cells. It is known that interaction with mural cells causes endothelial cells of blood vessels to become quiescent. However, conditioned media collected from breast cancer cells diminishes gap junctional coupling between mural cells and endothelial cells, and downregulates Cx43 in mural cells . AdditioSeveral published studies suggest that connexin proteins influence cell cycle and signaling independently of their roles in forming gap junctions or hemichannels through its impact on cell cycle and signaling . A recenThe effect of Cx43 expression on the regulation of cell cycle was investigated in HeLa cells transfected with Cx43 and primary human foreskin fibroblasts (HFF) predominantly expressing Cx43 . 18-α-glGanoderma lucidum, an herbal mushroom increases Cx43 expression and inhibits growth of human ovarian cancer cells, and this growth inhibition was abrogated by knocking down Cx43 gene [There are several plausible strategies in the development of potential therapeutics. The initial attempts to reverse the lack of gap junctional communication known in tumorigenic cells were accomplished through chemical treatments, including retinoids, vitamin D, carotenoids, and cAMP . By takix43 gene . The biox43 gene . Severalx43 gene . All thex43 gene . Treatmex43 gene ; thus Cxx43 gene . Their rExpression of connexin subtypes are differentially regulated not only during metastasis but also during self-renewal of cancer cells. Among 131 cases of human astrocytic tumors, Cx43 was observed in 76.9 % of diffuse astrocytoma and in all cases of anaplastic astrocytoma and glioblastomas . Cx46 waDrug resistance is a major challenge for cancer treatment. Cisplatin is a commonly used chemotherapeutic agents for advanced non-small cell lung cancer, but prolonged treatment acquires resistant due to development of EMT . OverexpRecently, a new paradigm was proposed by Colin Green’s laboratory based on the data obtained in chronic inflammatory disorders and trauma in the eye that protecting, maintaining or restoring cancer vasculature leads to reduced tumor hypoxia and promotes the survival of normal cells . Given tThere are several examples of human diseases that are either directly or indirectly linked to pannexins, in particular, Panx1. This is not that surprising given that pannexins are involved in taste sensation, airway defense, viral infection (HIV), the immune response, ischemic cell death, seizures, apoptosis and the differentiation of keratinocytes, chondrocytes, and neurons , 140. PaPANX1 was reported in human biopsies from most cancer types according to the analysis of cross-cancer alterations in the 89 cancer studies included on the cBioPortal.org for Cancer Genomics [PANX1 deletions present in human biopsies, indicating that Panx1 expression could be regulated differently in specific cancer types. At the protein level, Panx1 expression is listed in 17 out of 20 tumour types , and up to 70 % of human melanoma tumours show high levels of Panx1 protein .Table 2Nature Cell Biology [C268T) results in a truncated protein Panx11–89that only contains the N-terminus, first trans-membrane domain and part of the first extracellular loop of Panx1. This mutant form is not functional on its own but when co-expressed with full-length Panx1 has a gain-of function effect on channel activity [The most recent report of the role of Panx1 in cancer was published by Furlow et al. in the journal of  Biology . In thisactivity . Interesactivity , 160. Fuactivity .Melanomas account for 80 % of all skin cancer-related deaths , and in 2 [2. Both IL-1β and PGE2 can be released from the cell to act on the microenvironment. The effects would include increased cell proliferation, angiogenesis, tumor invasiveness and growth, and recruitment of pro-inflammatory cells. Other mutations in the melanoma cell alter normal growth cycle feedback, and with this inflammasome activation, may continue to proliferate without control [Recently, two articles have highlighted the link between inflammation and melanoma, proposing the involvement of the Panx1/P2X7 complex as a key regulator , 173. Th2 . In the  control . A cavea control . In colo control . In concAs was mentioned before, even though the majority of reports in the literature to date point towards an over-expression or amplification of Panx1 in cancer cells and tumours, there are also important exceptions to this trend. In fact, one of the first papers involving Panx1 and cancer reported that while Panx1 mRNA was expressed in primary astrocytes, it was not expressed in the C6 rat glioma cell line. Paradoxically, the authors reported four human glioma cell lines  that were all positive for Panx1 at the transcript level, indicating that there might be some differences among species in terms of Panx1 expression in gliomas. Additionally, when Panx1-GFP was overexpressed in C6 glioma cells , 179, itA second case of downregulation of Panx1 in cancer tissues was reported in a review paper by Schalper et al.  where imThe third example of downregulation of pannexins in tumours was reported in non-melanoma skin cancer samples from human biopsies by our collaborators . While PIn the pannexin family, Panx2 and Panx3 are not as well characterized as their more popular and ubiquitously expressed sibling. Therefore, our understanding of the role of these two isoforms in cancer is limited. Panx3 plays a role in proliferation and differentiation of cells in skin, cartilage and bone , so we pLitvin et al. was the first to publish the initial evidence of a down-regulation of human Panx2 transcripts in Affymetrix chip analysis, particularly in astrocytomas, glioblastoma multiforme (GBM), and oligodendro-gliomas . AdditioLai et al.  describePANX2 as one of the methylated genes identified by expression profiling and DNA methylation arrays in hepatocellular carcinomas (HCC) [PANX2. Recently, Le Vasseur et al. demonstrated that Panx2 expression is not limited to the central nervous system as was originally proposed, and it was shown to be expressed in liver among many other organs and tissues [Consistent with a potential role as tumour suppressor, a recent publication listed as (HCC) . In HCC, tissues . TherefoAs we discussed earlier, Panx1 is commonly expressed and even upregulated in many cancer cells. An unexpected side effect of this Panx1 expression, other than its potential role in cancer progression, is the possibility that Panx1 channels in the presence of different chemotherapeutic drugs, can actually be exploited to enhance cancer cell death. One example of this was seen in prostate cancer PC-3 cells engineered by gene therapy to produce a variant of human thymidylate kinase (TMPK) that can potentiate the drug azido thymidine (AZT). Panx1 is necessary for this effective bystander cell killing of neighbouring cells after suicide gene therapy delivered by lentivirus . HoweverSome more clear examples of the role of Panx1 channels in the presence of chemotherapeutic drugs were reported by Boyd-Tressler et al.  and MartIt is encouraging to think that Panx1 could be used as a biomarker in different cancers, but also as a conduit of ATP that assists the process of cancer cell death by existing chemotherapies, and facilitates immune recognition of the targeted tumour.10Panx1 peptide [There are now several compounds that have been reported in the literature to efficiently block Panx1 channels that could be used as new therapeutic alternatives. Namely, probenecid (PBN) , 188, ca peptide , 197 and peptide  that havCancer is not a single disease but a term that includes many different and complex diseases. The role of cellular communication in cancer, facilitated by the connexin and pannexin families of channel-forming proteins is also of a complex nature. There are 21 connexins and 3 pannexins in the human genome, making it challenging to generalize about their overall function in cancer. In very general terms, the current literature would support a tumour suppressor role for connexins in early stages of cancer progression, with an opposing role in late-stage (or advanced) cancer and metastasis. On the pannexin side, the majority of reports point towards a tumour promoting effect of Panx1 expression. However, this effect may be different for the other pannexin members, and may also be tissue- and cancer- specific. Our developing knowledge of the mechanisms that regulate gap junctions, connexin hemichannels, and pannexin channels in the different cancer types will allow us to better target connexins and pannexins as new candidates for therapeutic intervention.


The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed. Immune system is one of the crucial body systems that guard the body against infections and can be modified with genetic and environmental factors that may lead to certain pathogenic conditions. In the past few years, a significant increase in the studies related to immune system and its functioning has been noticed. But still the mechanism of regulation of immune system by hormones is not very clear. From the literature, it is apparent that immune system interacts with most of our body systems  and the Immune response is divided into two categories: nonspecific and specific. Nonspecific immune response is the innate or natural immune response that acts as the first line of defense against infections and recognizes structures like microbes. The components of nonspecific immune response are monocytes, macrophages, natural killer (NK) cells, dendritic cells, and granulocytes: neutrophils, eosinophils, and basophils. These cells attack microbes by phagocytosing them , by lysis of infected cells (NK cells), or by producing cytokines to enhance nonspecific immune and specific immune responses . DendritThe specific immune response is divided into two types, that is, cell mediated and humoral immune response. Cell mediated immune response does not include antibodies but active immune cell population, namely, phagocytes, antigen specific T lymphocytes, and various cytokines, whereas humoral immune response is mediated by macromolecules found in extracellular fluid such as antibodies. T lymphocyte population is divided into cytotoxic T lymphocytes (Tc cells) that kill foreign or infected cells and helper T lymphocytes (Th cells) that provide help to other immune cells by producing cytokines. These Th cells are further divided into subtypes, that is, the Th1 subset producing interferon (IFN) gamma that promotes cellular immune responses, the Th2 subset producing mainly interleukin-4 (IL-4), IL-13, and IL-5 to aid humoral immune responses, and the Th17 subset producing IL-17, which plays a crucial role in autoimmunity and allergen-specific immune responses. The third division of T lymphocytes is regulatory T cell (Treg) that is centre of immunoregulation and is capable of suppressing both Th1- and Th2-mediated specific immune responses . The comImmune system does not work in isolation as immune, endocrine, and central nervous systems are integrated through a network of signal molecules  that act on a common set of receptors. It is influenced by many other factors that may be neuroendocrine peptides, sex hormones, or other metabolites. The interaction of these systems is shown in Previous studies show the role of sex hormones in immune system functioning . The difSex hormones affect the immune system by increasing the number of circulating immune cells. Sex hormones either affect proliferation/apoptosis of the cells or induce production of new cells from the bone marrow. Sex hormones are steroids that are lipophilic in nature which facilitate their diffusion through cell membrane. This makes them affect the genetic material in the cell directly. Some workers described nongenomic effects of steroid hormones which are regulated via membrane receptors for these hormones on immunocytes . Due to Transcription of a number of genes is regulated by steroid hormones by interacting with intracellular receptors, which are modular proteins composed of a ligand binding domain, a DNA binding domain, and several transactivation functions distributed along the molecule. Regulation of gene expression by hormones involved an interaction of the DNA-bound receptors with transcription factors which was also studied to be mediated by coactivators and corepressors. Depending on the nature of these interactions, the final outcome could be induction or repression of transcription , 19.Effect of hormones on the immune response has been shown due to their effect on differentiation and maturation of immunocytes. Determination of the effect of antiestrogens on differentiation and maturation of dendritic cells was carried out by some workers. The authors observed the differentiation inhibitory effect of nonsteroidal antiestrogens (toremifene and tamoxifen) in the cultures of immature CD1a-positive DC in vitro from CD14-positive monocytes in the presence of interleukin-4 (IL-4) and granulocyte macrophage colony-stimulating factor. In the presence of antiestrogens the cells lost CD14 expression but remained CD1a-negative and have less dendritic processes than immature DC. Functionally, antiestrogen-treated cells were inferior to immature DC in inducing proliferation of allogeneic T cells and in producing IL-12 p70 protein after CD40 ligation. The expression of the costimulatory molecules CD80 and CD86 was differentially regulated by antiestrogens during DC differentiation. Antiestrogens were also able to inhibit the terminal maturation of DC .γ/δ TCR+ cells developed progesterone receptors. Progesterone binding resulted in the synthesis of a mediator protein named the progesterone-induced blocking factor (PIBF). PIBF by acting on the phospholipase A2 enzyme interfered with arachidonic acid metabolism leading to induction of Th2 biased immune response and by controlling NK activity exerted an antiabortive effect [While looking for the changes in the immune system during pregnancy an increased progesterone sensitivity of lymphocytes was observed which was due to activation-induced appearance of progesterone binding sites in the lymphocytes. Following recognition of fetus derived antigens e effect , 21.α and ER-β but only ER-α expression was enhanced by in vitro incubation with 17β-estradiol (10−8 mol/L). In vitro incubation of neutrophils from women with 17β-estradiol enhanced expression of both ER-α and ER-β subtypes [A subtype of estrogen receptor (ER) expressed in neutrophils from premenopausal women and in neutrophils from men under different estrogen conditions was identified in a study. The analysis was done on the association between the modifications in the expression of ER subtypes and neuronal nitric oxide synthase (nNOS) expression induced by estrogen. Neutrophils were isolated from premenopausal women during different stages of the menstrual cycle and from ten men for in vitro estrogen incubations. Outcomes showed that the neutrophils from premenopausal women expressed both ER-alpha and ER-beta subtypes which were increased in the ovulatory phase of the menstrual cycle. Neutrophils derived from men also expressed ER-subtypes .Peripheral blood constitutes about 65% of the leukocytes: 32% granulocytes, 5–10% monocytes, and 30% lymphocytes. In females an increase in white blood cells counts was observed in the luteal phase of ovarian cycle and during pregnancy. Number of studies showed a decrease in the number of monocytes in follicular phase of cyclic females when estrogen level is high as compared to an increase in males and postmenopausal females , 24.μg/100 gm body weight reduced the incidence and severity of the disease. Low doses of testosterone administered were also found to be beneficial to entire female rats. These results indicate that sex steroid hormones have an important modulatory influence on the genesis of autoimmune thyroiditis [An experiment was made on orchidectomized PVG/c strain male rats. It was observed that orchidectomy potentiated the development of autoimmune thyroiditis induced by thymectomy and irradiation in rats. Administration of testosterone to orchidectomized rats reduced the development of autoimmune disease. When given in varying quantities by injection in oil over a period of 15 weeks the inhibitory effect on the development of both thyroiditis and thyroglobulin autoantibodies was found to be directly related to dose. Levels of testosterone between 150 ng and 150 roiditis .Changes in immunophenotypic expression of lymphocytes from thymus, bone marrow, spleen, and blood were analysed in 3- and 10-week-old male mice at periodic intervals following agonist administration. Upon agonist administration, plasma testosterone levels were significantly increased in prepubertal mice but were significantly decreased in postpubertal males. Absolute thymic weights, thymocytes, and T subsets were significantly increased from the third week regardless of gonadal status. Blood lymphocyte subsets showed a decreasing trend after agonist administration in prepubertal males, whereas no differences were observed in postpubertal males. No significant differences were observed in spleen cells after agonist administration. This study indicated that GnRH agonist effects on the immune system were independent of steroid hormone levels .In one of the studies made to find out the effect of steroid exposure on immune function revealed that perinatal exposure to androgens transforms tissues like brain and genitalia permanently. The work showed the evidence suggesting a direct modification and regulation of immunocytes including Th1/Th2 balance through the interaction of androgen and estrogen and their receptors on developing immunocytes .Apseloff et al. examined the clinically relevant effects of menstruation on leukocyte count. Healthy female subjects with normal menstruation were taken for a complete blood count with differential on days 1, 2, 7, 10, 17, 22, 25, and 32. Levels of luteinizing hormone and estradiol were measured on days 11 and 16 to determine the day of ovulation. Evaluation of the data revealed a trend toward higher leukocyte counts and absolute neutrophil counts at the onset of menses .P < 0.05) during the periovulatory stage of the menstrual cycle. The work concluded that endogenous ovarian steroids regulate the ISC frequency [In order to determine the effect of the ovarian hormone cycle on immunity, immunoglobulin-secreting cell (ISC) frequency, and lymphocyte subsets in the blood, a study was made in healthy women. It was found that immunoglobulin A- (IgA-) secreting cells (IgA-ISC) were fourfold more frequent than IgG-ISC in peripheral blood mononuclear cells (PBMC). Further, the ISC frequency in PBMC was the highest -α producing monocytes and decreased percentage of IL-2 producing lymphocytes, that is, type 1 cytokine in men as compared to women. The results of the study suggested a gender difference in the balance between the specific and nonspecific immune response, that is, a more profound and higher state of excitation of the nonspecific immune response and relative suppression of the cellular immune response of the specific immune system in men as compared to women [Study was carried out to get insight into the sex differences of the basic nonspecific and specific immune responses. Intracellular types 1 and 2 cytokine production by stimulated male and female lymphocytes and monocytes in a whole blood preparation was measured by flow cytometry. The authors observed an increased percentage of interleukin-12 (IL-12), IL-1to women , 31.The impact of different phases of menstrual cycle on the blood leukocytes was examined in twenty-four healthy women in their reproductive age group and having regular menstrual cycle during menstrual, proliferative, and secretary phases of the cycle. Total leukocyte count, absolute and differential counts of neutrophils, lymphocytes, and mixed cells  were analyzed. The authors reported significant decrease in differential lymphocyte percentage in proliferative phase as compared to menstruation phase .Variations in the blood leucocytes during different phases of menstrual cycle were observed in forty healthy women in the age group of 18–25 years with regular menstrual cycles of 30 ± 2-day duration. Total leucocyte count (TLC), absolute eosinophil count (AEC), and differential leucocyte count (DLC) were analyzed during the menstrual phase and proliferative and secretory phase during a single cycle. Results are as follows: the authors showed a statistically significant increase in TLC during and a significant increase in the neutrophil percentage during secretory phase. Lymphocyte count increased during proliferative and secretory phase .It is apparent that females have better immune capabilities with higher immunoglobulin levels and stronger humoral and cell-mediated immune responses than males . StudiesA large amount of information supports the fact that hormones of the endocrine system are involved in the immunological dimorphism in males and females. Major hormones included are growth hormone (GH), gonadal steroids, adrenal glucocorticoids, and prolactins. Complex hormonal interactions affect both developing lymphocytes and regulate mature immune cells. Hormonal interactions leading to immunological dimorphism are the effects elicited by estrogen and progesterone in female ovary after puberty. Effect of elevated estrogen levels to growth hormone secretion along with an increase in prolactins and thymosin release on the development of lymphocytes and stimulate immune cell functions in females was studied. Interactions of hormonal regulatory axes involving the hypothalamus, pituitary, gonads, adrenals, and thymus were also thought to be involved. Factors like IL-1 and IL-2 are elaborated by activated immune cells. Genetic components were also considered relevant under conditions of pathological disequilibrium leading to autoimmune disease .Difference in the vulnerability to autoimmune diseases in two sexes supports the sex based immune dimorphism. Women have been shown to develop diseases such as rheumatoid arthritis and multiple sclerosis as compared to men. More prevalence to autoimmune diseases in women was believed to be dependent on the influence of sex hormones. Authors believed that the autoimmune diseases development depends upon estrogen-induced immune suppression both in human autoimmune diseases and the experimental animal model counterparts .Besides sexual differentiation and reproduction, sex hormones influence the immune system leading to immune dimorphism with females having higher immunoglobulin levels and mounting stronger immune responses than males. The greater immune responsiveness in females is also evident in their increased susceptibility to autoimmune diseases. Experimental studies reviewed described that normal mice show polyclonal B cell activation with increased expression of autoantibodies characteristic of autoimmune diseases by induction with estrogen treatment. Sex hormone levels in both humans and experimental models correlated with the activity of their cytokine-secreting cells indicating that sex hormones influence the cytokine milieu and suggesting that altered sex hormonal levels in autoimmune patients contribute to the skewed cytokine milieu characteristic of systemic lupus erythematosus , 39.α production was approximately 40% lower than postpartum values. At the same time, urinary cortisol and norepinephrine excretion and serum levels of 1, 25-dihydroxyvitamin D were 2 to 3-fold higher than postpartum values. Excessive production of IL-12 and TNF-α is linked to rheumatoid arthritis and multiple sclerosis. The study suggested that cortisol, norepinephrine, and 1, 25-dihydroxyvitamin D induced inhibition and subsequent rebound of IL-12 and TNF-α production may represent mechanism by which pregnancy and postpartum alter the course and susceptibility to various autoimmune disorders [Clinical observations of a study indicate that some autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis, frequently remit during pregnancy but worsen, or have their onset, in the postpartum period. The study was carried out in eighteen women with normal pregnancies in their third trimester and during the early postpartum period. It was reported that during the third trimester pregnancy, ex vivo monocytic IL-12 production was about 3-fold and TNF-isorders , 40.Natural killer cells are CD3-negative, CD56-positive, and/or CD16-positive cytotoxic lymphocytes mediating first-line defense against various types of target cells without prior immunization. To assess the effect of the menstrual cycle and gender on NK activity work was done in which evaluation of 30 healthy women  in follicular and luteal phases, 29 postmenopausal women , and 48 healthy men  was done. The authors noted lytic units in flow cytometry and expressed the results as lytic units per 107 cells. Also progesterone levels were determined in the luteal phase of the menstrual cycle of healthy women by chemiluminescence assay. Results indicated higher NK cytotoxicity in the follicular than in the luteal phase of the menstrual cycle, and postmenopausal women and men showed NK activity similar to women in the follicular phase but higher than women in the luteal phase of the menstrual cycle. No correlation between NK activity and levels of progesterone was noted. The data suggest that progesterone does not influence NK activity directly and that other factors may explain the reduction of NK activity in the luteal phase of the menstrual cycle .Gender has been a contributory factor in the incidence and progression of disorders associated with immune system. Evidence has suggested that gender may also play an important role in infectious disease susceptibility. It is well studied that females generate more robust and potentially protective humoral and cell-mediated immune responses following antigenic challenge than their male counterparts. The evidence for sexual dimorphism in innate immune responses to infectious organisms along with the recent studies providing mechanism underlying gender-based differences in infectious conditions such as bacterial sepsis is described and reviewed .Rheumatoid arthritis (RA) is an autoimmune disease that is more common in women than in men. The peak incidence in females coincides with menopause when the ovarian production of sex hormones drops markedly. RA is characterized by production of proinflammatory mediators leading to the inflammation in the joint and eventually to bone loss. Animal studies have revealed distinct beneficial effects of estrogens on arthritis. A positive effect of hormone replacement therapy has been reported in women with postmenopausal RA. This review will focus on the influence of female sex hormones in the pathogenesis and progression of RA .α/β) that are expressed on most immune cells. ERs are nuclear hormone receptors that can either directly bind to estrogen response elements in gene promoters or serve as cofactors with other transcription factors . Cytoplasmic ER and membrane associated ER impact specific kinase signaling pathways. ERs have prominent effects on immune function in both the innate and adaptive immune responses. Genetic deficiency of ERα in murine models of lupus resulted in significantly decreased disease and prolonged survival, while ERβ deficiency had minimal to no effect in autoimmune models. The protective effect of ERα in lupus is multifactoral. In arthritis models, ERα agonists appear to mediate a protective effect. The modulation of ERα function appears to be a potential target for therapy in autoimmunity [Due to the female predominance of autoimmune diseases, the role of gender and sex hormones in the immune system is of long-term interest. Estrogen's primary effects are mediated via estrogen receptors alpha and beta , and third during secretory phase (around 22nd to 24th days). Statistical analysis of all the samples showed that among women there was a significant high total WBC count during proliferative phase compared to menstrual phase and secretory phase. There is a significant high total WBC count and lymphocytes in all the phases of women compared to men .α (TNF-α), or interferon-γ (IFN-γ) was determined in vivo. Simultaneous assessment of serum hormone levels and cytokine secreting cell activity throughout the menstrual cycle showed that the number of peripheral blood mononuclear cells (PBMC) able to secrete IL-4 in response to stimulation correlated significantly with oestrogen levels and fluctuated with the menstrual cycle in premenopausal women. The activity of IFN-γ-secreting cells, on the other hand, varied as a function of serum DHEA-S levels in premenopausal women. Number of cells secreting IFN-γ in men correlated with serum DHEA-S levels. In contrast, postmenopausal women had fewer cells actively secreting cytokines and the activity of these cells did not correlate with sex hormone levels. These results suggested that sex hormones may modulate cytokine production in vivo and contributed to gender-related differences in normal and pathological immune responses [The correlation between serum levels of oestrogen, progesterone, and dehydroepiandrosterone sulphate (DHEA-S) and the number of human peripheral blood cells actively secreting interleukin-2 (IL-2), IL-4, IL-6, IL-10, tumour necrosis factor-esponses .β-estradiol (E2), progesterone (Pg), and dehydroepiandrosterone-sulphate (DHEAS) was monitored in sera from 128 lupus patients and 96 controls and correlated with the activity of their cytokine secreting cells. Study revealed that SLE patients had significantly fewer cells secreting IFN-γ, increased serum E2 and Pg levels, and reduced serum DHEAS levels compared to normal controls [Changes in the cytokine milieu of patients with systemic lupus erythematosus (SLE) in association with abnormal levels of sex hormone levels in serum were examined in a study. The concentration of 17controls .α (TNF-α), testosterone, estradiol, prolactin, procalcitonin, and sex hormone-binding globulin as well as the release of IL-6, TNF-a, and IL-10 after LPS ex vivo stimulation of whole blood in 26 patients without complications after major or minor abdominal surgery were measured. The study showed that therewas a gender-specific pattern of decreasing testosterone concentrations in men and increasing testosterone concentrations in women. Increasing estradiol concentrations were seen in both men and women. The ex vivo stimulated and systemic IL-6, IL-8, IL-10, and TNF-α cytokine release was not gender specific [A clinical study was conducted to evaluate the influence of gender on the release of proinflammatory and anti-inflammatory cytokines in the circulation and after lipopolysaccharide (LPS) ex vivo stimulation. The course of sex hormones in the acute phase response after surgery and assessed their correlation with cytokine release was also measured. The serum concentrations of interleukin-6 (IL-6), IL-8, IL-10, tumor necrosis factor-specific .α (TNF-α), interleukin-6 (IL-6), and IL-1β (IL1β) and of the acute-phase protein C-reactive protein (CRP) was measured. Both physiological and supraphysiological concentrations of testosterone reduced the expression and secretion of TNF-α and reduced the expression of IL-1β but did not affect the expression of IL6 or CRP. Estrogen caused a variable response in CRP expression that was positively associated with the plasma small dense LDL-cholesterol concentration of the donors [Role of inflammation in the development and progression of coronary heart disease (CHD) was studied by group of workers. For the study human monocyte-derived macrophages (HMDMs) were obtained from healthy normolipidemic men and postmenopausal women (age 50–70 years) and cultured in autologous serum along with both physiological and supraphysiological concentrations of estrogen or testosterone. HMDMs were stimulated with oxidized low-density lipoproteins, and the expression of the cytokines tumor necrosis factor e donors .Sex hormones have an impact on immune related diseases which results in immune dimorphism in males and females. Estrogen and testosterone are major regulators of immune system. The mechanism behind the sex hormone expression of immunocytes functions is attributed to the regulation through their interactions with the receptors on the immune cells which affects the production, maturation, differentiation, and ultimately the functioning of immune cells and molecules especially cytokines and development of immune related diseases. It is concluded that the modulation of cytokines production through hormones may help in future to design potential targets for therapy in sex hormones related inflammatory or autoimmune diseases.


Cardiac arrest induces whole body ischemia, which causes damage to multiple organs particularly the heart and the brain. There is clinical and preclinical evidence that neurological injury is responsible for high mortality and morbidity of patients even after successful cardiopulmonary resuscitation. A better understanding of the metabolic alterations in the brain during ischemia will enable the development of better targeted resuscitation protocols that repair the ischemic damage and minimize the additional damage caused by reperfusion.A validated whole body model of rodent arrest followed by resuscitation was utilized; animals were randomized into three groups: control, 30 minute asphyxial arrest, or 30 minutes asphyxial arrest followed by 60 min cardiopulmonary bypass (CPB) resuscitation. Blood gases and hemodynamics were monitored during the procedures. An untargeted metabolic survey of heart and brain tissues following cardiac arrest and after CPB resuscitation was conducted to better define the alterations associated with each condition.After 30 min cardiac arrest and 60 min CPB, the rats exhibited no observable brain function and weakened heart function in a physiological assessment. Heart and brain tissues harvested following 30 min ischemia had significant changes in the concentration of metabolites in lipid and carbohydrate metabolism. In addition, the brain had increased lysophospholipid content. CPB resuscitation significantly normalized metabolite concentrations in the heart tissue, but not in the brain tissue.The observation that metabolic alterations are seen primarily during cardiac arrest suggests that the events of ischemia are the major cause of neurological damage in our rat model of asphyxia-CPB resuscitation. Impaired glycolysis and increased lysophospholipids observed only in the brain suggest that altered energy metabolism and phospholipid degradation may be a central mechanism in unresuscitatable brain damage. Cardiac arrest is one of the leading causes of death affecting over 300,000 people each year in the US To improve survival rates, various controlled resuscitation methods have been tested in animal models and in clinical studies Prior studies of post-ischemic dysfunction in cells and isolated organs have described important cellular disorders, such as ATP depletion, altered calcium and other ion gradients, and altered lipid/membrane function In this study, rats are subjected to 30 min asphyxia-induced cardiac arrest followed by CPB resuscitation. The system creates a reproducible ischemic injury The experimental protocol for the study was approved by the Institutional Animal Care and Use Committee of the University of Pennsylvania (protocol number 803328). Adult male Sprague–Dawley rats , housed in a rodent facility under 12 h light–dark cycle with unrestricted access to food and water, were used for the study. Chemicals used for this study were purchased from major chemical suppliers.2 between 35 and 45 mmHg. The left femoral artery and vein were separately cannulated for arterial and central venous pressure measurement. The right external jugular vein and the right femoral artery were cannulated for the venous outflow and arterial inflow ports. After surgical preparation, heparin (150 U) and vecuronium bromide (2 mg/kg IV) were administered and isoflurane was discontinued. Asphyxial cardiac arrest was induced by switching off the ventilator for 30 minutes. Mean arterial pressure below 20 mmHg was defined as cardiac arrest The detailed procedures were published elsewhere 2 of 35 to 45 mm Hg. Rats were sacrificed by decapitation either following 30 min cardiac arrest or 30 min cardiac arrest followed by 60 min resuscitation. Control rats were decapitated 7 min after administration of isoflurane. During the procedures, blood gas and hemodynamics were monitored.After 30 min of asphyxia, resuscitation was started with the initiation of CPB flow, which lasted 60 min. The customized CPB circuit designed for rodents consisted of a heat exchanger, an open venous reservoir, a membrane oxygenator, silicone tubing and a roller pump. For the oxygenator, 100% oxygen was used with a flow rate of 200 mL/min. Twenty mL of prime fluid and 20 mL of additional fluid (P-lyte) was added to the venous reservoir; the initial CPB flow rate was 70 mL/min and gradually decreased to ∼20 mL/min to meet venous outflow. With initiation of CPB, ventilation was resumed and subsequently adjusted to a PaCOHeart and brain cortex, harvested from control, post cardiac arrest, or post resuscitation rats, were pulverized in liquid nitrogen and stored at −80°C until a complete set of samples were collected. Five samples in each group were sent to Metabolon Inc.  for metabolomics analysis 2 pressure (PCO2) was increased from 35.0 to 103.4 mmHg (2) was decreased from 98.7 to 11.3 mmHg and the saturation level of oxygen in hemoglobin (SO2) was also decreased from 96.9 to 7.0%. HCO3 concentration and hematocrit level did not change. The concentration of lactate was increased from 0.99 to 9.6 mmol/L, indicating increased anaerobic metabolism. Overall, these data showed that 30 min of asphyxia generates respiratory acidosis and hypoxia, which are typical phenomena of ischemia 2, and PCO2 returned to the control levels  and 3-hydroxybutyryl CoA were significantly increased in heart tissue. Short-chain acyl carnitines and CoAs are derived from fatty acids or, in some cases from branched-chain amino acids, and represent incomplete mitochondrial oxidation products. Accumulation of these CoAs and carnitines are expected during ischemia-induced hypoxia due to the lack of oxygen to support operation of the mitochondrial oxidative phosphorylation 2+, Na+, and K+ ions Another group of molecules accumulated during cardiac arrest was organic osmolytes, such as mannitol, ribitol, and sorbitol . OrganicCarbohydrate metabolites were substantially decreased in the heart tissue, particularly metabolites in the glycolysis pathway , the pentose phosphate pathway (sedoheptulose 7-phosphate), and their precursors (mannose-6-phosphate and glucose-1-phosphate). Maltotriose, maltotetraose, maltopentaose, and maltohexaose (oligomeric forms of glucose) were also substantially decreased .These daThe metabolic and biochemical state of the heart tissues returned toward normal following 60 min CPB resuscitation; acyl carnitines and CoAs were decreased almost to the control level and carbohydrates were considerably increased compared to the cardiac arrest group. This observation is consistent with a resumption of cardiac function. However, the unchanged amounts of organic osmolytes suggest that more prolonged ionic or osmotic imbalances still existed following CPB.In brain tissue following cardiac arrest, the most remarkable metabolic change was an increase in lysophospholipids, particularly lysophosphatidylethanolamine and lysophosphatidylcholine species . The tisThe glucose level was decreased 90% relative to controls in brain tissue following cardiac arrest. However, other carbohydrates were not decreased as much as was observed in heart tissue; glucose-6-phosphate, sedoheptulose 7-phosphate, and mannose-6-phosphate were decreased by less than 50%. Changes in metabolites associated with glycolysis are examined in more detail below. Unlike the heart tissue, the metabolic disorder found in brain tissue following cardiac arrest remained fixed and did not improve toward normal levels following CPB resuscitation . ParticuAnaerobic glycolysis is the primary ATP generation pathway in the heart and the brain during ischemia. The levels of three intermediates in glycolysis, glucose-6-phosphate, fructose-6-phosphate, and 3-phosphoglycerate, were compared to assess the efficiency of glycolysis in these tissues. Glucose-6-phosphate and fructose-6-phosphate are intermediates in the early stage and 3-phosphoglycerate is in the late stage of glycolysis. In brain, glucose-6-phosphate was decreased by 50% and fructose-6-phosphate by 36% following cardiac arrest, whereas 3-phosphoglycerate was increased by 76%. Interestingly, the relative contents of these compounds were not changed with CPB. These data indicate that glycolysis in the brain is not as effective as in the heart during cardiac arrest and is not restored following CPB reperfusion.In vivo ischemia not only limits supply of oxygen and substrates but also prevents removal of cellular wastes Asphyxia-induced cardiac arrest is an excellent system to study the effect of ischemia in animal models. After 30 min asphyxial cardiac arrest, animals regained normal sinus rhythm on CPB support, with an average ROSC time of ∼8 min. For an injury model to be useful for developing resuscitation protocols, the injury must be severe enough that traditional resuscitation therapies would be unlikely to succeed while still keeping most organs viable. Viewed in this light, the achievement of ROSC shows that our injury model provides a good basis for investigations into the molecular mechanisms of injury caused by ischemia and reperfusion.Although interpretation on all the metabolites is beyond the scope of this study, some metabolic changes are clearly interpretable and expected under ischemic conditions. From ATP is essential for cellular viability during ischemia The levels of glucose and intermediates of glycolysis were significantly decreased, whereas the intermediates of fatty acid oxidation, acyl carnitines and CoAs, were increased . These dThe mechanism for the increase in lysophospholipids and free fatty acids is not clear. The most cited mechanism is increased phospholipase A2-mediated hydrolysis of phospholipid Alternatively, decreased reacylation of lysophospholipids rather than increased hydrolysis of phospholipid may be the cause for the accumulation of lysophospholipids. Acylation of lysophospholipids with free fatty acids as substrates requires ATP A more important aspect of the accumulation of lysophospholipids is the function of this event in the ischemic cascade. Studies have shown deleterious effect of increased lysophospholipids and acyl CoA, which may contribute to cellular damage during ischemia The direct cause for brain damage maybe other metabolic disorders that are also caused by the depletion of ATP. Impaired phospholipid metabolism may just be an indicator that the level of ATP is below the threshold required for cell viability. In any case, the impaired phospholipid metabolism is an important event; identifying the mechanism underlying the increase in lysophospholipids and free fatty acid will help to understand the significance of impaired phospholipid metabolism for progression of ischemic tissue damage in brain.Cellular mechanisms underlying ischemic tissue damage involve complex metabolic alterations and identification of the major cause responsible for irreversible tissue damage is highly challenging. Rats subjected to asphyxial cardiac arrest and CPB resuscitation develop biochemical phenotypes of ischemia and unresuscitatable brain damage, the critical pathology of human patients with cardiac arrest, thus this model is a valuable platform to link basic biochemical disorders to organ function in order to design better therapeutic applications for treatment of cardiac arrest.As shown in this study, the functional and biochemical responses of the heart are different than the responses of the brain to 30 min cardiac arrest followed by 60 min CPB resuscitation. Following CPB resuscitation, the rats exhibit no observable brain function but normal sinus rhythm on CPB support. These physiological outcomes are consistent with the observation that CPB significantly normalizes ischemia-induced metabolic alterations in the heart, but not in the brain. This result suggests that ischemia is the primary cause of brain damage observed following CPB resuscitation. In addition, brain tissue has the increased content of lysophospholipids, whereas this disorder is absent in the heart. This result further supports the notion that impaired phospholipid metabolism is an important phenomena for critical tissue damage during ischemia/reperfusion. However, it is not clear that the observed biochemical and lipid alterations in the brain tissue after CPB are evidence of irreversible brain damage or poor cerebral perfusion during CPB resuscitation.