In this review we discuss the major chemical classes of LMW molecules targeting the FSHR, and document their activity profiles and current status of development, in addition to discussing potential clinical applications.The follicle-stimulating hormone receptor (FSHR) has been targeted therapeutically for decades, due to its pivotal role in reproduction. To date, only purified and recombinant/biosimilar FSH have been used to target FSHR in assisted reproduction, with the exception of corifollitropin alfa; a modified gonadotropin in which the FSH beta subunit is joined to the C-terminal peptide of the human choriogonadotropin beta subunit, to extend serum half-life. Assisted reproduction protocols usually entail the trauma of multiple injections of FSH to initiate and promote folliculogenesis, which has prompted the development of a number of orally-available low molecular weight (LMW) chemical scaffolds targeting the FSHR. Furthermore, the recently documented roles of the FSHR in diverse extragonadal tissues, including cancer, fat metabolism, and bone density regulation, has highlighted the potential utility of LMW modulators of FSHR activity. Despite these chemical scaffolds encompassing a spectrum of  The hypothalamic-pituitary-gonadal axis comprises hypothalamic kisspeptin and neurokinin B (NKB) driving the secretion of gonadotropin-releasing hormone (GnRH). GnRH subsequently stimulates the pituitary secretion of the gonadotropin hormones luteinizing hormone (LH) and follicle stimulating hormone (FSH), into the general circulation, resulting in gonadal steroidogenesis, and pubertal development via activation of their cognate gonadotropin receptors, FSH receptor (FSHR), and LH receptor (LHR/LHCGR). In this article we review the development and potential clinical application of small molecule/low molecular weight (LMW) modulators of FSHR activity.s class of intracellular G proteins, resulting in adenylyl cyclase stimulation, and a subsequent increase in the second messenger cyclic adenosine monophosphate (cAMP). cAMP then binds to and modulates the activity of a number of cyclic nucleotide-binding proteins, including cAMP-dependent protein kinases, and ion channels.The FSHR is a G protein-coupled receptor (GPCR) that belongs to the glycoprotein hormone receptor sub-family of GPCRs that also includes the luteinizing hormone receptor (LHR/LHCGR), and the thyroid-stimulating hormone receptor (TSHR). These GPCRs are characterized by the presence of large extracellular N-terminal ectodomains (ECDs) that bind the heterodimeric glycoprotein hormones, in addition to the classical seven transmembrane domain region (TMD) characteristic of the GPCR superfamily. FSHR predominantly couples to and activates the Gαs is considered the main effector of FSHR-mediated signaling, Gαq-mediated signaling, and β-arrestin mediated (G protein-independent) signaling have also been observed  are emerging with selective signaling profiles . These molecules have greatly informed as to the pathways involved (and required) for successful gonadal steroidogenesis, while simultaneously highlighting the inherent dangers of Despite the successful application of corifollitropin, which comprises a hybrid molecule in which the FSHβ subunit is fused to the C-terminal 24 amino acids of the human chorionic gonadotropin β subunit (hCGβ) to increase serum half-life (marketed under the trade name Elonva) in assisted reproduction –8. The dConcluding remarks and future perspectives).In addition to these potential advantages, orally bioavailable LMW FSH antagonists may have potential as oral contraceptives. Current sex steroid-based contraceptives are administered at supra physiological doses to inhibit ovulation which can increase the risk of side effects, such as cardiovascular thrombosis events associated with estradiol-based contraceptives . It is aDespite the theoretical therapeutic potential of LMW modulators of FSHR, a number of substantial challenges needed to be overcome. The FSHR is a leucine-rich repeat containing GPCR, belonging to the glycoprotein hormone receptor family, which also includes the TSHR, and LHR. In addition, there are other GPCRs containing leucine-rich-repeat motifs. These GPCRs share high degrees of sequence conservation with the FSHR suggesting that drug cross-reactivity/specificity could be a potential problem. Moreover, the gonadotropins are large dimeric proteins that contact the gonadotropin receptors via multiple residues that include the glycan moieties, in addition to having a complex mechanism of receptor activation that includes structural movements within the extracellular domain (ECD) and the transmembrane (TM) domains of the receptor. As a result, it appeared that a LMW molecule might not fulfill the requirements of both receptor binding and activation. Nevertheless, these challenges could be successfully addressed in the development of both LHR and FSHR orthosteric agonists and antagonists , and allosteric analogs which interact with the receptor at a site distinct from the orthosteric ligand binding site .Allosteric GPCR modulators can be categorized based on measures of gonadotropin receptor signaling activity , and fall into three groups; allosteric agonists  and positive and negative allosteric modulators (PAMs and NAMs). Allosteric agonists have agonist activity, in the absence of gonadotropin, in contrast to PAMs and NAMs whose activity can only be demonstrated in the presence of agonist, usually via modulation of orthosteric hormone binding affinity or altering the ability of the receptor to interact with intracellular signal transducers. In this way, PAMs and NAMs can either augment or diminish the response to orthosteric agonists, respectively. PAMs and NAMs have garnered much interest in the pharmaceutical industry, as these classes of allosteric modulators only have activity in the presence of co-bound endogenous ligand meaning that GPCR activation is limited to the spatio-temporal release of endogenous ligands. This is extremely advantageous, as many of the reproductive neuroendocrine hormones are released/secreted in cyclical patterns or pulses .Structural modeling has been successfully utilized to identify allosteric sites in GPCRs for LMW compounds. Gonadotropin receptor TM domains have been modeled using adenosine receptor crystal structures, and identified two putative allosteric sites within the TM domains, positioned adjacent to the ECL loops , 15. Thein vitro and in vivo, with allo-agonists, NAMs, and PAMs identified. While LMW compounds targeting the closely-related, LHR have been identified, most endeavor has been directed toward developing LMW molecules targeting the FSHR. This is predictable, given that ovarian hyperstimulation requires multiple injections of FSH, in contrast to the single administration of LH/hCG  needed to induce ovulation. Despite considerable progress in the development of LMW FSH analogs, none have yet entered the clinic. In many cases, this is a result of in vitro activity failing to translate into in vivo activity, off-target effects/toxicity, synthesis issues, and frequently termination of research programs following pharmaceutical company acquisitions, and differing priorities of the acquiring company. These issues have been previously reviewed in detail  with an EC50 of 32 nM   core scaffolds have previously been utilized in a number of successful GPCR drug discovery programs, and offer a flexible and versatile platform for compound development . Affymaxof 32 nM . This leynthesis , 22. A p(1–6 nM) . Subsequ(1–6 nM) . A compo(1–6 nM) . In vivos) through to NAMs which inhibited estradiol production in rat granulosa cells via Gαi activation  and Organon  screened a large diketopiperazine compound library. A number of biaryl agonists were identified, with the most potent compounds containing heterocyclic diketopiperazine substituents . Lead opagonists .in vitro CRE-luciferase reporter gene assay, and subsequently a hexahydroquinoline LMW allosteric agonist at the FSHR, Org 214444-0 was described  as FSHR activators , 30. Theescribed  . Lead compounds were shown to have low nanomolar potency sa cells .max of approximately 1.5 and 0.5 h respectively) compared to recombinant FSH [half-life approximately 24–48 h sulfonic acid, (bis)benzamide FSHR antagonists were identified, with moderate potencies of activation in a number of o assays . While so assays . Concurro assays  that nono assays . In addio assays . This wa animals . Issues profiles . Modificprofiles .50's  (A tetrahydroquinoline (THQ) scaffold containing an amino group at position 6 with modest micromolar FSHR agonistic activity and an efficacy of 85% relative to FSH, was identified by Organon using a CRE-luciferase reporter assay. In a similar vein to the TZD agonists, minor modification of the core structure, in this case introduction of an aromatic group at position 6 of the THQ scaffold, resulted in compounds with completely different pharmacologies. Aromatic groups incorporated at position 6 resulted in a switch from full agonists to full antagonists, with nanomolar ICllicles) .50 0.7 μM with 55% inhibition of FSH EC80). Interestingly, ADX61623 inhibited cAMP and progesterone production in the presence of FSH in vitro in a dose-dependent manner, and conversely stimulated estradiol production at high concentrations (Introduction). In an in vivo setting, administration of 50 mg/kg ADX61623 s.c. was ineffective in completely inhibiting folliculogenesis and ovulation in rats following sequential treatment with pituitary FSH and hCG, as measured by number of oocytes recovered and ovarian weight  used a homogenous time resolved fluorescence (HTRF) screening assay to screen for FSHR NAMs, and identified a benzamide compound  but they failed to effectively inhibit ovulation and spermatogenesis in Wistar rats . To deteNatural and recombinant gonadotropins have been the mainstay of infertility treatment in men and women for decades, and are still an essential component of assisted reproductive technologies which have impressively addressed the needs of infertile patients world-wide. However, there is a perceived need to develop gonadotropin analogs and orally-available LMW compounds with gonadotropin receptor activity which would obviate current multiple injection protocols, and importantly, reduce OHSS risk. Modulation of relative FSH and LH activities would also have application in women's health conditions such as polycystic ovarian syndrome (PCOS) and would possibly offer a novel method of contraception. Other potential applications of gonadotropin receptor modulators could include the management of animal reproduction, both as contraceptives in population control, and utilization in assisted reproduction for animal husbandry purposes and in endangered animals. With regards to the latter, IVF and cryopreservation protocols have been applied with varying degrees of success in endangered ungulates, and felid species –63.Although several promising FSHR LMW agonists and antagonists have been shown to have desirable properties in animal models, none have shown efficacy in human clinical studies. This is in contrast to LHR LMW molecules which have been demonstrated to be efficacious in stimulating ovulation in women. One example is MK-8389 (developed by MSD) which had promising activity in a rat model but when tested in an ascending dose study on pituitary-suppressed females, showed an effect on thyroid function, despite no effect on follicular development, or estradiol production . Thus, fin vitro activity has been highly successful with the impressive development of dozens of allosteric compounds with appropriate properties. The majority of these LMW compounds have arisen from a relatively limited number of core scaffolds, each with distinctive chemistries, and an array of interesting properties. Amongst these allosteric compounds are NAMs and PAMs which have unique properties for exploitation, such as biased-activity profiles, which may be of value in differential stimulation or inhibition of estradiol and progesterone. In view of the diverse structures of molecular scaffolds utilized it is highly likely that following sufficient investment and development, several of these would have the appropriate characteristics and safety profile to be therapeutics.Despite these setbacks, the pursuit of FSHR LMW compounds with The acquisition of reproductive health companies by big pharma may have played a significant role in the termination of LMW gonadotropin analog development, due to differing research priorities. For example, the acquisition of Wyeth by Pfizer may have halted development of the TZD FSHR agonist. Encouragingly, a number of small biotech companies are still focussing on the development of LMW modulators of FSHR activity, and we may yet see compounds entering the clinic for a diversity of applications.An exciting new development in the arena of LMW gonadotropin analogs is the discovery that some of these compounds have gonadotropin receptor “pharmacological chaperone” or “pharmacoperone” activity. These pharmacoperone compounds can restore plasma membrane localization and function to intracellularly-retained GPCRs harboring mutations that result in misfolding and intracellular retention/degradation. LMW LHR allosteric agonists have been shown to act as pharmacoperones, “rescuing” cell surface expression of intracellularly retained mutant LHRs  an outc. We and in vivo studies. The intimate relationship between FSH/FSHR and estradiol frequently confuse and confound the interpretation of data, in addition to the complicated often-opposed effects of the two hormones such as on osteoclasts . Another area of potential FSHR LMW analog application is in oncology. Reported proliferative effects of FSH and FSHR in prostatic and ovarian cancers alludes to other novel applications for FSHR LMW agonists and antagonists (It has been suggested that the FSHR is expressed in a number of extragonadal tissues, and current research implies that these receptors may be physiologically important. Indeed, the utilization of LMW gonadotropin analogs targeting the FSHR may extend beyond the current remit of assisted reproduction and may yet herald a new era of gonadotropic therapeutics , 69. Foragonists –73, althAll authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.RM undertakes consultancy work for company KaNDy Therapeutics Ltd. The remaining 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.


Oxidative stress is recognized as a cancer-initiating stress response in the digestive system. It is produced through mitochondrial respiration and induces DNA damage, resulting in cancer cell transformation. However, recent findings indicate that oxidative stress is also a necessary anticancer response for destroying cancer cells. The oxidative stress response has also been reported to be an important step in increasing the anticancer response of newly developed molecular targeted agents. Oxidative stress might therefore be a cancer-initiating response that should be downregulated in the precancerous stage in patients at risk of cancer but an anticancer cell response that should not be downregulated in the postcancerous stage when cancer cells are still present. Many commercial antioxidant agents are marketed as “cancer-eliminating agents” or as products to improve one’s health, so cancer patients often take these antioxidant agents. However, care should be taken to avoid harming the anticancerous oxidative stress response. In this review, we will highlight the paradoxical effects of oxidative stress and antioxidant agents in the digestive system before and after carcinogenesis. Helicobacter pylori; H. pylori) and chronic hepatitis (hepatitis B and C viruses), are decreasing with the advent of antimicrobial treatments, while the rates of other etiology-related diseases are increasing. Representative non-infection-related chronic inflammatory digestive diseases include IBD, chronic pancreatitis and nonalcoholic fatty liver disease (NAFLD) .,51.50,51Pre-colon cancer state: ROS is an important initiator for colon cancer. In sporadic-type CRC, life-style related stressors such as smoking, alcohol, and obesity have been reported to induce colon carcinogenesis. In colitic cancer, chronic inflammation due to inflammatory bowel disease (IBD) can induce ROS.Colon cancer state: The level of oxidative stress has been shown to be elevated in cancer cells in comparison to normal cells. Nontumor tissue has been shown to produce high levels of antioxidant enzymes, possibly to defend against cancer-producing oxidative stress. The expression of antioxidant-related enzymes, such as MnSOD, in stage III and IV CRC tumor samples was shown to be increased, and the expression of several antioxidant enzymes, including catalase and GPx, was also increased in adjacent nontumor tissues. The effect of high-dose ascorbic acid on CRC cell lines is dependent on the expression of a tumor suppressor p53. CRC cells carrying mutant oncogenes of KRAS or BRAF were killed with high dose ascorbic acid. Dehydroascorbate (DHA), the oxidized form of ascorbic acid, was transported into CRC cells via glucose transporter GLUT1, which was overexpressed in KRAS or BRAF mutant CRC. The increased uptake of DHA caused oxidative stress as intracellular DHA was reduced due to ascorbic acid, which depleted glutathione. Vitamin E analogue erased the cancer cell toxic response of ascorbic acid via the recovery of the TCA cycle and ATP production.Most CRC is sporadic-type, which is believed to be correlated with lifestyle. Thus, exogenous factors, such as food, alcohol consumption, and smoking, are major risk factors. The gastrointestinal (GI) tract is a key source of oxidative stress. As the GI tract is constantly exposed to ingested materials and pathogens, including bacteria, oxidative stress can be induced by an individual’s personal environment . In sporOxidative stress has been shown to affect DNA methylation, resulting in the activation of several carcinogenesis-related genes . ROS-indPatients with genetically driven CRC, such as in familial adenomatous polyposis (FAP), have been shown to have lower whole blood ROS levels in comparison to patients with sporadic CRC . These rChronic inflammation is a major risk factor for carcinogenesis, and roughly 15–20% of cases of carcinogenesis are reported to occur as a result of chronic inflammation . IBD is Oxidative stress is an important factor associated with the development of colitis-associated CRC; however, the detailed mechanism of carcinogenesis in IBD remain unclear. Further studies on the relationship between colitis-associated CRC and oxidative stress are needed.Several reports have described the effects of antioxidants, such as vitamin E and selenium, in preventing tumorigenesis. The Linxian trial may have been the first study to investigate the putative prevention of cancer through the use of antioxidants with negative impacts on CRC prevention . HoweverOxidative stress-related molecules have been shown to be involved in colon cancer development, and Nox organizer 1 knockout was shown to reduce tumor-forming ability of colon cancer cells . These fGiven that oxidative stress can lead to the preferential killing of cancer cells, the application of oxidants has been considered as a new approach to CRC therapy. The promotion of oxidative stress overload might be an important strategy to consider in the development of new anticancer drugs. In fact, numerous anticancer drugs used for CRC patients are involved in oxidative stress production . One expThese contradictory reports have important implications for potential anticancer strategies that aim to modulate oxidative stress levels. Thus, further studies are needed to fully elucidate the mechanisms through which antioxidants exert their effects in different types of CRC.While HBV- and HCV-related chronic hepatitis variants have long been the main background of hepatocarcinogenesis, the incidence of nonalcoholic steatohepatitis (NASH)-related HCC is increasing.Oxidative stress is one of the features induced by chronic hepatic inflammation in chronic liver disease. As the liver is a mitochondria-rich organ, the damage induces a large amount of ROS; thus, oxidative stress can even be detected in a patient’s serum .Pre-liver cancer state: Hepatitis B virus (HBV), hepatitis C virus (HCV), and lipid in the liver of nonalcoholic fatty liver disease (NAFLD) induce ROS resulting in chronic inflammation, liver fibrosis, and hepatocarcinogenesis. HBx protein can upregulate oncogenes, such as Ras/Raf/MAPK and PI3K/Akt, and can also disrupt tumor suppressor p53 indicating its oncogenic potential. The HCV core protein could directly interact with the mitochondria resulting in the oxidization of the glutathione pool and reduced NADPH content resulting in increased ROS generation. The fatty acid in NAFLD can induce ROS. Adenosine monophosphate-activated protein kinase (AMPK) which is a heterodimeric serine-threonine kinase that functions as a bridge for energy homeostasis to cellular proliferation, survival and carcinogenesis is one of the key molecules involved in NAFLD progression.Liver cancer state: A recently established anti hepatocellular carcinoma agent, Sorafenib, is a multikinase inhibitor that can inhibit tumor cell proliferation and angiogenesis through the inactivation of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), c-kit receptor, and the serine-threonine kinase Raf-1. Advanced glycation end products (AGEs) are produced under high sustained glucose conditions and the receptor for AGE (RAGE) has been shown to be overexpressed in HCC. RAGE has been shown to induce sorafenib resistance in in vitro and in vivo xenograft models and the reduction of RAGE was shown to result in an increase in autophagy and a reduction of sorafenib resistance via the activation of the AMPK pathway.Since HBV and HCV are not cytopathic viruses, immune reactions play a central role in the development of chronic hepatitis ,71. The Recent progress in antiviral treatments has enabled the control of viral hepatitis, creating a condition of inactive hepatitis. Furthermore, HCV can be eradicated in almost all patients using presently available direct-acting antiviral agents (DAAs). In these patients, hepatocarcinogenesis can be induced by remnant fibrosis as well as environmental factors, such as concomitant fatty liver. Oxidative stress is involved in chronic hepatitis, irrespective of HBV or HCV infection; however, each virus has specific mechanisms that are correlated with the carcinogenic response.HBV is a DNA virus containing a relaxed circular DNA genome enclosed by an envelope protein ,78. AfteHBx can upregulate oncogenes such as Ras/Raf/MAPK, PI3K/Akt and can also disrupt tumor suppressor p53 indicating its oncogenic potential ,81. A loReports on HBV genome sequencing have shown several mutations that might be associated with hepatocarcinogenesis ,88,89,90HCV is an RNA virus coded into structural proteins and nonstructural proteins that have been shown to be oncogenic under some experimental conditions, although these effects might not be strong enough to be clinically evident, as HCV-related HCC is usually found in patients with cirrhosis. HCV antigens, especially core protein, play major roles in pathogenesis and hepatocarcinogenesis of patients with chronic hepatitis C . In HCV One of the environmental factors that induce oxidative stress is the iron-related Fenton reaction, which produces a highly toxic forms of ROS: hydroxyl radicals. Because some investigators have reported that phlebotomy and a low-iron diet reduce the risk of HCC in patients with chronic hepatitis C infection, iron toxicity is thought to be involved in hepatocarcinogenesis ,98. The Most patients with NAFLD exhibit nonprogressive NAFL, while a certain proportion of patients progress to NASH, which is broadly defined by the presence of steatosis with inflammation, hepatocyte degeneration and liver fibrosis ,103, whiAdenosine monophosphate-activated protein kinase (AMPK) which is a heterodimeric serine-threonine kinase that functions as a bridge for energy homeostasis to cellular proliferation, survival and carcinogenesis is one of the key molecules involved in the progression . The synAs mentioned above, oxidative stress is linked to the progression from NAFLD to HCC. The correlation of AMPK and clinical conditions encourages us to control AMPK as a cancer regulator.Iron depletion improves not only iron overload but also insulin resistance, suggesting that iron toxicity is involved in several metabolic pathways .The guidelines for NAFLD recommend the use of antioxidant therapies, such as vitamin E, for NASH, however, whether this treatment reduces the risk for hepatocarcinogenesis is not clear ,118. ManAntidiabetic agents are recommended for patients whose condition is complicated by diabetes. Of the antidiabetic agents, metformin, pioglitazone, glucagon-like peptide 1 receptor agonists (GLP-1 RAs), and dipeptidyl-peptidase-4 inhibitors (DPP-4Is) have been shown to have favorable effects on NAFLD ,120. MetPioglitazone is a thiazolidinedione that activates peroxisome proliferator-activated receptor (PPAR) γ, improving insulin resistance. A six-month randomized study of pioglitazone revealed a histopathological reduction in liver necroinflammation with no reduction in fibrosis .The administration of L-carnitine  was reported to be associated with the histological improvement of NASH in a randomized controlled study .Silybum marianum) named silymarin used as an antioxidative agent [Flavonoids (heterogeneous polyphenols) have been shown to have an antioxidant function and to protect the liver from ROS-induced damage . A mixtuve agent . The maive agent . Silymarve agent .After the development of HCC, the role of oxidative stress changes. An adequate degree of oxidative stress should be maintained in order to regulate the progression of HCC. The ideal choice of agent for controlling chronic hepatitis or related hepatocarcinogenesis without suppressing the physiological roles of oxidative stress is difficult to determine.Sorafenib has been widely accepted as an effective oral chemotherapeutic agent for advanced HCC. Sorafenib is a multikinase inhibitor that can inhibit tumor cell proliferation and angiogenesis through the inactivation of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), c-kit receptor, and the serine-threonine kinase Raf-1 . RecentlOxidative stress inducing agents are a next candidate for improving the effects of sorafenib. Tetrandrine, a bisbenzylisoquinoline alkaloid that increases ROS, has been shown to exert synergistic antitumor activity with sorafenib . More daPancreaticobiliary malignancies exhibit poor prognoses . RecentlThe maintenance of homeostasis has recently been accepted as important for pancreatic cancer (PC) patients, as these patients often develop a cachexic status after pancreaticoduodenectomy surgery or toxic chemotherapies. Sufficient muscle mass has recently been indicated as an important factor that predicts good survival after pancreaticoduodenectomy . The musOxidative stress is strongly related to biliary tract carcinogenesis as well as PC. The risk factors for biliary carcinoma include parasitic infections, primary sclerosing cholangitis, biliary duct cysts, hepatolithiasis and toxin exposure. Other less-established potential risk factors include inflammatory bowel disease, HCV and HBV disease, liver cirrhosis, diabetes, obesity, alcohol consumption, and smoking . AlthougEpidemiological studies have recently shown that metformin use decreased incidence of pancreatic cancer . AlthougOxidative stress is a crucial factor in the cancer microenvironment, but oxidative stress management in pancreaticobiliary tract cancers remains controversial. The ability of several antioxidant agents to control oxidative stress for cancer prevention or treatment is being investigated in vitro and in vivo. Vitamin E is an antioxidant agent and a potential chemopreventive agent in cancer cells ,149. HusHowever, in order to administer antioxidants to cancer patients, we must carefully consider the oxidative stress-related environment. Several studies have indicated unfavorable outcomes of antioxidant vitamin A or E therapy . Thus, tRecently, mitochondria-targeted analogs of metformin have been shown to enhance antiproliferative and radiosensitizing effects in pancreatic cancer cells . One of The antioxidant molecule HO-1 was increased in pancreatic cancer tissue and the downregulation of HO-1 resulted in sensitization to gemcitabine treatment, indicating that oxidative stress is important for controlling pancreatic cancer . OxidatiOxidative stress is a disease-advancing reaction; however, as it also has an efficient anticancer function, this balance must be regulated with great care. The oxidative–antioxidative stress condition differs among cancers and chronic inflammatory diseases carrying a cancer risk. Determining the oxidative stress load via serum markers or histological analyses is an important method for assessing a patient’s condition. By evaluating a patient’s oxidative stress load, we can decide how to manage their condition-via either oxidative stress eliminators or antioxidants or through an alternative approach, such as the administration of high-dose ascorbic acid. However, there is no definite clinical data showing the favorable effects of antioxidant administration and there is no direct proof of the role of oxidants in tumor growth. We must therefore conclude that there is no solid proof of the causative role of ROS in carcinogenesis or tumor growth in human subjects.


Spatially heterogeneous flicker, characterized by probabilistic and locally independent luminance modulations, abounds in nature. It is generated by flames, water surfaces, rustling leaves, and so on, and it is pleasant to the senses. It affords spatiotemporal multistability that allows sensory activation conforming to the biases of the visual system, thereby generating the perception of spontaneous motion and likely facilitating the calibration of motion detectors. One may thus hypothesize that spatially heterogeneous flicker might potentially provide restoring stimuli to the visual system that engage fluent  and self-calibrating processes. Here, we present some converging behavioral and electrophysiological evidence consistent with this idea. Spatially heterogeneous (multistable) flicker  reduced posterior EEG  beta power implicated in long-range neural interactions that impose top-down influences on sensory processing. Further, the degree of spatiotemporal multistability, the amount of posterior beta-power reduction, and the aesthetic responses to flicker were closely associated. These results are consistent with the idea that the pleasantness of natural flicker may derive from its spatiotemporal multistability that affords fluent and self-calibrating visual processing. Flickering flames, rippling water surfaces, rustling leaves, and spattering rain drops are pleasant to the senses. Naturally occurring visual flicker such as these is spatially heterogeneous, characterized by probabilistic and locally independent dynamics of luminance modulations.A prominent perceptual characteristic of spatially heterogeneous flicker is its spatiotemporal multistability. To the extent that local luminance changes are probabilistic and spatially independent, they contain comparable motion energies in multiple directions, speeds, and spatial scales so that spontaneous motion can be seen according to the biases of motion detectors. For example, if leftward-tuned motion detectors happened to be more sensitive (less adapted) than those tuned to other directions, they would be most strongly activated so that a leftward motion would be seen in that region until the sensitive leftward-tuned motion detectors become adapted to be equivalently sensitive to motion detectors tuned to other directions . ThusDynamic visual signals often need to be spatially and/or feature-wise integrated to extract movements of behaviorally relevant surfaces and objects. Such integration processes entail long-range neural interactions involving feedback, reflected in the alpha/beta-band power of electrophysiological activity e.g., –5). For . For 5])If this line of reasoning is correct, spatially heterogeneous flicker, whose spatiotemporal multistability allows the activation of motion detectors according to their sensitivity biases, should also reduce central/posterior alpha/beta power. Further, if spatially heterogeneous flicker in nature is pleasant to the senses because the reward system prioritizes the benefit of multistability-based sensory calibration, the degree of multistability afforded by flicker, the amount of central/posterior alpha/beta-power reductions, and the aesthetic preferences for the flicker, should be closely associated. We tested these predictions using flicker displays that presented different degrees of spatiotemporal multistability.pchange, remained constant. The average flicker rate, pchange,f (except that the maximum flicker rate was 30Hz due to the use of a 60Hz display monitor). We chose this flicker-generating method partly because foveal luminance changes during a typical human experience follow a 1/f profile )How might spatially heterogeneous flicker provide visual signals that conform to the current biases of the visual system? Spatially heterogeneous flicker generates spatiotemporally multistable visual signals that simultaneously contain motion energies e.g., ,41) in m in m41])The fact that multistable flicker activates motion detectors according to their sensitivity differences suggests that it may have a restorative effect. Selective activation of motion detectors with greater sensitivity would calibrate the system-wide spatiotemporal sensitivity by selectively adapting the detectors with elevated sensitivities. It is plausible that such sensory calibration may be perceptually beneficial so that multistable flicker that facilitates it may engage the reward system. Consistent with this line of reasoning, multistable flicker was aesthetically preferred in the current study. In both experiments, flicker with the highest degree of multistability (with sixteen independent flickering regions) was strongly preferred, yielding the average aesthetic rating of ~3.5 . Further, although substantial evidence (primarily in the literature on flicker motion aftereffects) suggests that observing spatiotemporally multistable stimuli reduces motion sensitivity biases, future research needs to investigate how (or whether) this type of sensory calibration improves motion perception. Notwithstanding the need for these and other future investigations, we believe that it is worth disseminating the current results that may inspire a general hypothesis that spatiotemporal multistability may be a core principle underlying the neural, functional, and aesthetic impacts of experiencing visual dynamics in nature. Finally, our results extend the postulated link between posterior/central alpha/beta-band power reductions and reduced top-down controls in the context of experiencing multistable sensory stimulation.


Epilepsy is one of the most devastating neurological diseases and despite significant efforts there is no cure available. Occurrence of spontaneous seizures in epilepsy is preceded by numerous functional and structural pathophysiological reorganizations in the brain—a process called epileptogenesis. Treatment strategies targeting this process may be efficient for preventing spontaneous recurrent seizures (SRS) in epilepsy, or for modification of disease progression. We have previously shown that (i) myoinositol (MI) pretreatment significantly decreases severity of acute seizures (status epilepticus: SE) induced by kainic acid (KA) in experimental animals and (ii) that daily post-SE administration of MI for 4 weeks prevents certain biochemical changes triggered by SE. However it was not established whether such MI treatment also exerts long-term effects on the frequency of SRS. In the present study we have shown that, in KA-induced post-SE epilepsy model in rats, MI treatment for 28 days reduces frequency and duration of behavioural SRS not only during the treatment, but also after its termination for the following 4 weeks. Moreover, MI has significant effects on molecular changes in the hippocampus, including mi-RNA expression spectrum, as well as mRNA levels of sodium-MI transporter and LRRC8A subunit of the volume regulated anionic channel. Taken together, these data suggest that molecular changes induced by MI treatment may counteract epileptogenesis. Thus, here we provide data indicating antiepileptogenic properties of MI, which further supports the idea of developing new antiepileptogenic and disease modifying drug that targets MI system. Epileptogenesis is a dynamic and multifactorial process of molecular, cellular, and functional reorganization in the brain that follows the precipitating events or insults that lead to epilepsy—a disease which is characterized by spontaneous recurrent seizures (SRS) . Approxi Ranunculacae family (that contains plant Aquilegia vulgaris) are widely used as antiepileptic and soporific medication . The coIn conclusion, our data could open the novel perspectives in MI treatment as a possible preventive strategy in epilepsy by altering the progress of epileptogenesis that warrants further translational studies on MI-based approaches


Prescriptions for Benzodiazepines (BZDs) have risen continually. According to national statistics, the combination of BZDs with opioids has increased since 1999. BZDs  work to calm or sedate a person by raising the level of the inhibitory neurotransmitter GABA in the brain. In terms of neurochemistry, BZDs act at the GABAA receptors to inhibit excitatory neurons, reducing VTA glutaminergic drive to reduce dopamine release at the Nucleus accumbens. Benzodiazepine Use Disorder (BUD) is very difficult to treat, partly because BZDs are used to reduce anxiety which paradoxically induces hypodopaminergia. Considering this, we are proposing a paradigm shift. Instead of simply targeting chloride channel direct GABAA receptors for replacement or substitution therapy, we propose the induction of dopamine homeostasis. Our rationale is supported by the well-established notion that the root cause of drug and non-drug addictions (i.e. Reward Deficiency Syndrome [RDS]), at least in adults, involve dopaminergic dysfunction and heightened stress. This proposition involves coupling the Genetic Addiction Risk Score (GARS) with a subsequent polymorphic matched genetic customized Pro-Dopamine Regulator known as KB220ZPBM . Induction of dopamine homeostasis will be clinically beneficial in attempts to combat BUD for at least three reasons: 1) During detoxification of alcoholism, the potential induction of dopamine regulation reduces the need for BZDs; 2) A major reason for BZD abuse is because people want to achieve stress reduction and subsequently, the potential induction of dopamine regulation acts as an anti-stress factor; and 3) BUD and OUD are known to reduce resting state functional connectivity, and as such, potential induction of dopamine regulation enhances resting state functional connectivity. Future randomized placebo-controlled studies will investigate this forward thinking proposed novel modality. Psych Central reports that in 2013, Xanax, a benzodiazepine, was the most commonly prescribed drug ), at least in adults, involve dopaminergic dysfunction and heightened stress; an epigenetic phenomenon.While Benzodiazepine Use Disorder (BUD) is very difficult to treat, partly because BZD are used to reduce anxiety and paradoxically induce a hypodopaminergia, we are proposing a paradigm shift. Instead of simply targeting chloride channel direct GABAThis proposition involves coupling the Genetic Addiction Risk Score (GARS) with a subsequent polymorphic matched genetic customized Pro-Dopamine Regulator known as KB220ZPBM. Induction of dopamine homeostasis will be clinically beneficial in attempts to combat BUD for at least three reasons: 1) During detoxification of alcoholism, the potential induction of dopamine regulation reduces the need for BZDs; 2) A major reason for BZD abuse is because people want to achieve stress reduction and subsequently, potential induction of dopamine regulation acts as an anti-stress factor, and; 3) BUD and OUD are known to reduce resting state functional connectivity, and as such, potential induction of dopamine regulation enhances resting state functional connectivity. The experimental support for the neuropharmacological and neurological basis of KB220 can be gleaned from the work of Blum et al. . Future


Social support serves as a protective factor, buffering stress in both adolescents and adults, however Socioemotional Selectivity Theory suggests developmental differences in stress reactivity and social support. It is unclear how modern forms of social contact, such as social media buffer stress, and the extent to which this differs across the lifespan. We utilized ecological momentary data to examine the moderating effects of age and two distinct types of social contacts the person had experienced in prior hours  on the association between daily stress and momentary mood. Participants were recruited initially through Amazon.com’s Mechanical Turk (adolescents referred by a parent). A total of 119 adolescent  and middle-aged/older adult participants  provided momentary data three times a day, on three consecutive days, every two weeks, for up to 12 weeks. Multi-level models showed significant 3-way interactions between stress appraisal of avoiding an argument, age group, and frequency of social contact via face-to-face  and social media . Older adults experienced better mood than adolescents. When avoiding an argument was appraised as more stressful, both age groups displayed worse mood. Whereas high levels of recent social contact  seemed to exacerbate the impact of this stressor on poorer mood for older persons, high levels of recent social contact, particularly social media, had stress-buffering benefits for adolescents.


Different delivery mechanisms have been proposed in the literature for targeted therapies in the treatment of lymphedema. They vary from simple and direct injection to sophisticated induction of gene expression in a targeted tissue. We conducted a systematic review of publications assessing the use of viral vectors for gene transfer in lymphedema treatment. We hypothesized that viral vectors are an effective way to deliver targeted therapy in lymphedema treatment. We conducted a comprehensive systematic review of the published literature on targeted therapies associated with lymphedema surgery using the PubMed database. Eligibility criteria excluded papers that reported use of viral vectors for other medical conditions. Abstracts, presentations, reviews, meta-analyses, and non-English language articles were also excluded. From 21 potential articles found in the literature, fourteen fulfilled study eligibility criteria. Positive outcomes in terms of lymphangiogenesis were seen. The viral vectors used included adenovirus and recombinant adeno-associated virus. Most of the genes expressed were growth factors, but expression of dominant-negative transforming growth factor-β1 receptor-II or Prox1 was also proposed. Five studies targeted genetic expression on lymphedema tissue, five on transplanted lymph nodes, two on skeletal muscle, and one on adipose-derived stem cells. Publications assessing use of viral vectors for gene transfer in lymphedema treatment demonstrated that it is an effective mechanism of delivering targeted therapies. However, to date, all studies were experimental and further studies must be performed before translating these therapies into clinical practice. Lymphedema is a chronic lymphatic condition that affects 140 to 200 million people in the world -5.Development of targeted therapies has attracted the interest of investigators around the world. Those therapies have been proposed in two main groups: targeted therapies modulating inflammation, such as those that control Th2-inflammatory responses -8, and tDifferent delivery mechanisms for targeted therapies have been proposed in the literature. They vary from simple and direct injection to sophisticated induction of gene expression in a targeted tissue. The latter is possible through the use of viral vectors, such as adenovirus (short-term gene expression) and adeno-associated virus (long-term gene expression), encoding specific human genes . We condMaterials and MethodsSearch StrategyTwo reviewers  conducted independent searches using the PubMed database without timeframe limitations, initially through title and abstract screening, then by full-text review. Disagreements regarding article identification and final selection for inclusion of the literature were resolved by another reviewer (Antonio Forte). The search was conducted using the follow keywords: (((((((Adenovirus) OR Adenoviral) OR Adenovirally) OR Adenoviridae) OR Adenoviruses) OR Gene transfer vector)) AND ((Lymphedema) OR Breast Cancer Lymphedema). The bibliographies of those studies fulfilling eligibility criteria were also examined, looking for articles not present in our initial search. This study followed the guidelines outlined in the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA).Selection CriteriaEligibility criteria included studies reporting data on the use of viral vectors for gene transfer in lymphedema treatment. Therefore, we excluded papers that reported use of viral vectors for other medical conditions. Abstracts, presentations, reviews, meta-analyses, and non-English language publications were also excluded.Data Extraction and ProcessingExtracted data included study year, country, study type, viral vector, targeted tissue, gene expressed, and key findings. Data extraction from articles, tables, and figures was performed by two reviewers , with the accuracy of data entry confirmed by an additional reviewer (Antonio Jorge Forte).ResultsStudy CharacteristicsFrom 21 potential articles found in the literature, fourteen fulfilled study eligibility criteria  or endogenous, through gene expression induced by viral gene transfer. In this systematic literature review, we have shown that the use of viral vectors for gene transfer in lymphedema treatment was effective in several different experimental studies. Most studies had the rationale to induce lymphangiogenesis through gene transfer of growth factors, and VEGF-C was the most common gene transferred in the experiments. Moreover, different types of tissues and cells were targeted in the experiments, including lymphedema tissue, transplanted lymph nodes, skeletal muscles, and ADSCs. None of the studies described unintended consequences of injecting viral vectors, but experiments had a limited follow-up period. To our knowledge, this study is the first systematic literature review assessing the use of viral vectors for gene transfer in lymphedema treatment.We recognize several limitations to our study typical to systematic reviews, including the potential for bias in interpreting the data reported in each study. Moreover, we excluded non-English language publications, such as a study by Lu et al. from China, who conducted an experiment in which adenoviral VEGF-C was delivered to a transferred lymph node . NonetheThe publications assessing the use of viral vectors for gene transfer in lymphedema treatment demonstrated that it is an effective mechanism of delivering targeted therapies. To date, all experiments pursued gene transfer, and most used growth factors to induce lymphangiogenesis. Although encouraging outcomes were seen, all studies to date have been experimental, so further studies are necessary to translate those therapies into clinical practice.


Abnormalities and alterations in brain function are commonly associated with the etiology and maintenance of anorexia nervosa (AN). Different symptom categories of AN have been correlated with distinct neurobiological patterns in previous studies. The aim of this literature review is to provide a narrative overview of the investigations into neural correlates of disorder-specific stimuli in patients with AN. Although findings vary across studies, a summary of neuroimaging results according to stimulus category allows us to account for methodological differences in experimental paradigms. Based on the available evidence, the following conclusions can be made: (a) the neural processing of visual food cues is characterized by increased top-down control, which enables restrictive eating, (b) increased emotional and reward processing during gustatory stimulation triggers disorder-specific thought patterns, (c) hunger ceases to motivate food foraging but instead reinforces disorder-related behaviors, (d) body image processing is related to increased emotional and hedonic reactions, (e) emotional stimuli provoke increased saliency associated with decreased top-down control and (f) neural hypersensitivity during interoceptive processing reinforces avoidance behavior. Taken together, studies that investigated symptom-specific neural processing have contributed to a better understanding of the underlying mechanisms of AN.  Anorexia nervosa (AN) is a serious mental disorder characterized by self-induced starvation and excessive weight loss, fear of weight gain, body image concerns and food aversion . PsychiaFood restriction and avoidance are cornerstones of AN, since patients are able to limit food intake even in the presence of prolonged food deprivation. Although the causative mechanisms are not completely understood, a relation to increased inhibition, alterations in the rewarding effect of food and a conditioned relationship between food and aversive emotional states have all been proposed as possible explanations ,18. NumeThe majority of studies investigating the neural processing of food have employed visual depictions of food ,20. Visupassive viewing of visual food stimuli have yielded conflicting results, since a number different processes may be captured when passively viewing food stimuli [Previous studies employing  stimuli . However stimuli ,22,23. H stimuli  investigimagine eating the depicted food stimuli or to rate stimuli according to their pleasantness, patients with AN commonly display aberrant activation in different regions of the prefrontal cortex [When instructing participants to l cortex ,27,28,29l cortex ,21, hypol cortex ,31. The l cortex ,32,33. Fl cortex . Finallyl cortex ,31. choose between different visually depicted food items to assess the neural correlates of disorder-specific food choices in these patients. When choosing low-fat foods, patients with AN displayed an increased connectivity between the dorsal striatum and dorsolateral prefrontal cortex [Foerde and colleagues  asked pal cortex . Furtherl cortex . The autl cortex  and may l cortex . Howeverl cortex .Taken together, the results from studies investigating visual food stimuli note a pronounced top-down control mediated by medial prefrontal regions, which may override both somatosensory and hedonic-related brain signals.Studies employing real taste stimuli are able to probe disorder-specific neural reactions to food in a more natural setting. Behavioral investigations using gustatory stimulation have reported lower taste sensitivity in patients with AN , althougThe majority of studies using gustatory stimulation to investigate the neural processing of taste found altered activation profiles in patients with AN compared to healthy controls. Interestingly, with a few exceptions, , most sIncreased activation of reward-related brain regions during taste processing has been discussed as an increased salience attribution to taste stimuli and is considered a potential neural biomarker for AN . SimilarHorndasch et al.  used an Taken together, the results from studies investigating taste processing indicate an increased salience of taste stimuli in patients with AN, which appears to be strongly correlated with disorder-specific reactions to food stimuli, such as fear of weight gain and a drive for thinness.As stated above, since self-starvation allows the maintenance of the desired low body weight, this behavior develops rewarding qualities in patients with AN and reinforces the illness . Hunger visual depictions of food, Santel and colleagues [Using lleagues  observedlleagues  observedlleagues . The auttaste stimuli during both hunger and satiety, Vocks and colleagues [By presenting lleagues  found thlleagues . Togethelleagues ,55, the Taken together, studies investigating the effect of hunger on brain activation in patients with AN observe decreased activation in areas related to motivational processing and an interaction with emotional processing related to a fear of weight gain. However, these results relate exclusively to visual and gustatory food cues, since the influence of the satiety state on the processing of additional disorder-related stimuli remains to be investigated.Body image distortion is a hallmark feature of AN. The subjective perception of body weight or shape is disturbed, together with increased attention to particular details or parts of the body . Body impassive viewing of body images, patients with AN display reduced connectivity between the extrastriate and fusiform body areas and a negative correlation between the magnitude of connectivity and body size misjudgment [During the judgment . Vocks ajudgment . The autcompare their own body to slim, idealized female bodies, patients with AN display reduced activation in the rostral anterior cingulate cortex, but increased activation in the insula and premotor cortex [When asked to r cortex . Thus, br cortex . This chr cortex  employedown body digitally modified to be oversized, patients with AN show increased activation in the dorsolateral prefrontal cortex compared to healthy controls [When shown pictures of their controls . Furthercontrols ,71,72. Taken together, studies examining the passive viewing of body shapes, body comparison and modified images of one’s own body detected dysfunctional activation in neural body image networks and regions associated with interoception, and top-down control, as well as increased activation in regions associated with emotional processing and reward. Furthermore, the existing studies indicate a correlation between reduced top-down control and body-comparison in patients with AN, whereas the viewing of modified images of their own body is characterized by increased top-down control. These results highlight the importance of disturbed body image processing in patients with AN, indicating that underweight body images possess a rewarding effect and an increased emotional relevance for patients with AN.Dysfunctional emotional processing is prevalent in patients with AN and is related to both the onset and prevalence of the disorder ,74. Dietaffective facial expressions, Fonville and colleagues [When assessing neural emotional processing in response to lleagues  observedlleagues  failed tlleagues  reportedlleagues  in weighlleagues  investiglleagues . Taken tsocial interactions also appears to be impaired in patients with AN. During positive social interactions in an economic exchange game, patients with AN and participants who had recovered from AN displayed diminished neural responses in the precuneus and right angular gyrus. However, only patients with current AN showed reduced activation in the fusiform gyrus during negative interactions [Neural processing during ractions . The autractions . Patientractions , Maier aractions  found thractions  observedractions . This firactions  and confractions ,99. active regulation of emotions has also been observed in patients with AN. According to Seidel and colleagues, when patients with AN are asked to “distance” themselves from aversive pictures, they display the same neural activation pattern as healthy controls, but increased activation of the amygdala and dorsolateral prefrontal cortex is detected when they passively view aversive pictures [Altered neural processing during the pictures . Howeverpictures  reportedTaken together, studies investigating neural activation related to the processing of emotions in patients with AN reported contradictory results, but suggest increased salience processing and a concurrent dysfunctional top-down control during emotional processing. However, heterogeneity in studies investigating emotion regulation in patients with AN might explain the fact that more than 55% of patients with AN exhibit at least one comorbid disorder , with apInteroception refers to the perception and integration of visceral and homeostatic signals representing internal physiological body states . Alteredinternal bodily sensations such as heartbeat or stomach distension, Kerr and colleagues [Employing an interoceptive attention task where participants must focus on lleagues  observedlleagues  investigpain in patients recovered from AN and observed increased activity in the insula and dorsolateral prefrontal cortex (DLPFC) during the anticipation of pain, whereas the experience of pain was associated with decreased insula but increased DLPFC activity. Increased insular activity during the anticipation of pain was also related to high levels of alexithymia. The authors concluded that the results suggest an abnormal integration of interoceptive signals, and the increase in DLPFC activity is an attempt to control the increased distress caused by the subsequent pain stimulation.Two studies have investigated neural processing during unpleasant bodily sensations in patients with AN. Strigo and colleagues  investiginspiratory breathing load paradigm, where participants’ breathing was intermittently restricted, causing mild discomfort [Similarly, Berner and colleagues assessed neural processing in women who had remitted from AN during an scomfort . When anpleasant affective touch task , where participants who had recovered from AN displayed an increased response in the right ventral mid-insula, but a decreased response in the same region during the anticipation of a pleasant touch [Bischoff-Grethe and colleagues investigated neural processing during a nt touch . These rnt touch . In summary, the results from studies investigating neural interoceptive processing have identified a pronounced relation between neural hypersensitivity to bodily sensations and concurrent avoidance behavior, which is partially mediated by dysfunctional prefrontal processing. Importantly, since all of the aforementioned studies recruited women who had recovered from AN, dysfunctional interoceptive processing might be a potential trait of AN.This narrative review aimed to provide a general overview of the neuroimaging literature investigating symptom-specific neural processing in patients with AN. In recent years, a number of studies have investigated the neural profiles of different symptom-categories in patients with AN using fMRI. While the obtained results sometimes differ and certain disorder-related stimuli have not yet been investigated, the findings provide a better understanding of the underlying neurobiological correlates of AN. Based on the reviewed literature, we provide the following summary of the different symptom categories.food cues in patients with AN is characterized by increased top-down control, enabling restrictive eating habits and a concurrent reduction in hedonic and somatosensory reactivity. On the other hand, studies using real tastants typically observe increased activation of brain areas related to saliency and reward processing, as well as emotional arousal, namely, a fear of weight gain and drive for thinness. Thus, although an increase in neural cognitive control in response to food cues allows patients to avoid food and consistently reduce their cravings for food, the actual consumption of food is associated with a number of disorder-specific neural reactions that collectively increase the saliency of food.Neural processing of visual hunger is associated with a decrease in neural motivational processing in response to food cues, and the observed activation patterns suggest an increase in emotional sensitivity related to a fear of weight gain. This finding is also consistent with the results from animal models suggesting that conditioned fear cues inhibit food consumption by food-deprived rats; therefore, signals from the amygdala may potentially override the homeostatic signaling of hunger in the hypothalamus and inhibit eating [In patients with AN, t eating . Therefot eating  has alsobody image, studies identified a number of aberrations in brain regions related to emotion and reward processing, as well as interoceptive processing and top-down control. Body images gain increased emotional relevance, and exposure to thin body figures can become rewarding. These results are consistent with the “reward contamination theory” proposed by Keating [When using stimuli related to  Keating , which h Keating . Further Keating .emotions in patients with AN is characterized by increased saliency processing and dysfunctional top-down control. These observations extend to visual depictions of emotional facial expressions, social interactions and emotion regulation but are more pronounced for negative emotional stimuli. Neural activation in corticolimbic regions during the processing of social stimuli and emotion regulation are related to treatment outcomes. However, a number of open questions related to emotional processing in patients with AN remain, such as the effect of the satiety state, since no neuroimaging study has yet investigated the specific interaction between the hunger state and neural emotional processing in patients with AN. An investigation of this interaction would be very interesting because dietary restriction represents an important method avoiding or reducing negative emotions in patients with AN [The processing of  with AN .interoception is related to a dysfunctional integration of interoceptive signals in the insula and an increased general neural sensitivity to interoceptive and somatosensory stimuli, which facilitates restrictive and avoidant behaviors in patients with AN. These results are consistent with previous studies showing that anxiety associated with food intake in patients with AN is related to intensified interoceptive sensations [The neural processing of nsations . visual food cues appears to enable restrictive eating; a concurrent increase in the activation of reward- and emotion related areas during gustatory stimulation triggers disorder-specific thought patterns, such as a fear of weight gain. Hunger loses its ability to motivate food foraging but instead reinforces disorder-related behaviors. Dysfunctional neural processing of body images is a central feature of AN, where increased emotional and hedonic processing are prevalent, and neural activation during emotional stimuli indicates decreased top-down control but increased salience, particularly for negative stimuli. Finally, dysfunctional interoceptive processing is a trait of AN, where neural hypersensitivity to bodily sensations promotes avoidance behavior.Taken together, studies using symptom provocation paradigms to assess disorder-specific neurobiological alterations in patients with AN observed a number of alterations in different brain networks. Some of these activation patterns are related to the acute phase of AN and some have been identified as state-independent risk factors. Specifically, an increase in top-down control observed in response to Studies investigating the neurobiological correlates of disorder-specific stimuli in patients with other psychiatric disorders might provide information about the pathophysiological mechanisms underlying shared symptomatology of psychiatric disorders. Given the high prevalence of comorbidities in patients with AN, studies investigating patients with anxiety disorders , affective disorders or substance abuse disorder can contribute to a better understanding of the psychopathology of AN. For example, patients with OCD show increased activation of fronto-striato-limbic regions and the amygdala upon exposure to symptom-provoking stimuli . The autConclusions drawn from neuroimaging data often remain ambiguous since using observed brain activation to infer conclusions about cognitive processes can be problematic. Specifically, reverse inference, or “reasoning backwards from brain activation to the engagement of a particular cognitive function”  is only Our conclusions are preliminary, since no systematic literature search or formal assessment of methodological quality was performed. However, the aim of this review was to reconcile findings derived from differing neural stimuli and to provide a parsimonious account of the underlying neurobiological alterations associated with AN. Alterations in brain networks subserving various functions jointly contribute to AN-specific symptoms and behaviors. Studies investigating symptom-specific neural processing will provide a better understanding of the mechanisms underlying AN and important suggestions for targets for neurobiologically informed treatments. In fact, treatment options integrating neurobiological contributions have already been described ,128.


Homelike research spaces provide a unique context for studying older adulthood by blurring the boundaries between the participant’s own home and traditional laboratories. Such intermediary spaces hold promise for developing measures of functional performance with increased ecological validity. While “home labs” are becoming more accessible at institutions around the world, the research design process in these spaces contains hidden challenges that can be a barrier to entry for the uninitiated. We identify and reflect on these challenges through the lens of a recent protocol built to assess upper-body performance among older adults during activities of daily living. The U-M HomeLab served as a proving ground for four example tasks: opening a water bottle, sorting pills, tying an apron, and hanging laundry. The evolution of each task is traced through ideation, testing, and refinement, culminating in a pilot among nine community-dwelling volunteers aged 61 to 72 with upper-body pain. Based on this experience, we recommend that designers of naturalistic tasks in homelike environments give special consideration to (1) feasibility, (2) scorability, and (3) safety while carefully balancing standardization against verisimilitude. In turn, each of these elements must be grounded not only in the context of the facility itself but also in the population using that facility. Among older adults with upper body pain, considerations included remaining cognizant of fall risk, anticipating and capturing compensatory behaviors, tailoring task difficulty for a wide range of physical ability, and accounting for the impact of historically gendered divisions of labor on task performance.


Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance. Actin is one of the most fundamental and abundant proteins in eukaryotic cells, comprising up to 20% of total protein mass in certain cell types. Its versatility is arguably unmatched amongst all cellular proteins, given actin’s diverse array of functions in maintaining cellular homeostasis. Until relatively recently, the role of actin in cell physiology was thought to be exclusively relegated to the cytoplasm, primarily functioning in motility, contraction, and scaffolding. However, a newly emerging field has begun to uncover integral roles for actin within the confines of the nucleus. It is now readily apparent that actin and the evolutionarily divergent actin-related proteins are critical to an assortment of nuclear processes, particularly in those modulating various aspects of chromatin dynamics. Herein, we discuss nuclear actin and actin-related proteins, detailing their involvement in nuclear complexes that regulate chromatin remodeling and histone modifications.Chromatin structure presents a formidable barrier to proteins and other factors that need to interact with DNA to induce various processes. Thus, accessibility to DNA is largely dependent upon intricate epigenetic control. Chromatin-modifying complexes comprise a crucial class of nuclear enzymatic complexes that affect DNA accessibility, allowing for critical processes such as transcription, replication, and repair. By modulating chromatin structure, chromatin-modifying complexes control the activation and repression of transcription at given regions on the chromosome. This modulation of chromatin structure is generally achieved through applying covalent histone modifications or altering histone composition .Chromatin-modifying complexes can broadly be categorized into chromatin remodelers and histone modifiers. Chromatin remodelers are principally responsible for nucleosome repositioning and reorganization, which is typically achieved in an ATP-dependent manner, as facilitated by the ATPase subunit of the complex . Meanwhiin vitro, and its presence is necessary for budding yeast viability in vivo, demonstrating the physiological significance of this domain  domain, which is a large helicase binding module present in a given subunit unique to each complex . For inss domain . Most suA number of human diseases are associated with defective chromatin remodeling. Various cancers, especially, are strongly correlated with deleterious mutations in chromatin remodeling complexes, particularly SWI/SNF. Indeed, approximately 20% of human cancers possess mutant SWI/SNF subunits . Given tXenopus oocyte nuclei using SDS-polyacrylamide gel migration, actin antiserum, DNase I-binding, and comparison of structural characteristics as tools for its identification  1 and 2 are each regulated by nuclear actin , furtherXenopus oocytes  are proteins that exhibit structural and functional similarities to conventional actin. Found in all eukaryotic cells, Arps are thought to have evolved from actin through a series of gene duplication events prior to the diversification of eukaryotic kingdoms . Each me animals .Unlike canonical actin, Arps do not polymerize into long filaments, instead residing as monomers in the nucleus, as revealed by the crystal and solution structures of Arp4 and Arp8 . ThroughXenopus egg extracts that Mre11 recruits the Arp2/3 complex to DNA double-strand break sites . Complexes that integrate both remodeling and acetyltransferase activity, such as p400 in humans, also possess actin and Arp subunits , together promoting structural integrity of the complex . This ArThe HSA domain serves as a binding platform not just for actin-Arp4 conjugates in chromatin-modifying complexes, but also for Arp-Arp conjugates as well, as is the case in the chromatin remodelers SWI/SNF and RSC . The HSAAs discussed earlier, Arps may also contribute to chromatin state regulation independently of their physical involvement in chromatin-modifying complexes, as several Arps directly interact with histones . PerhapsIn vitro experiments demonstrate that this sub-module is required for INO80 to interact with chromatin, greatly increasing affinity to DNA relative to each individual subunit’s DNA affinity . Budding yeast containing an A58T missense mutation in actin subdomain 2 exhibit hypersensitivity to hydroxyurea .The actin and Arp subunits of INO80 have been demonstrated to promote the remodeling complex’s response to DNA damage as well as to various cellular stresses in yeast, plants, and mammalian cells , INO80 may play a role in either responding to or mitigating oxidative DNA damage in addition to its better-defined roles in double-strand break repair. Perhaps future studies will implicate INO80 in an even wider array of pathways or stress responses that are actin- and/or Arp-dependent.SWR1 is another ATP-dependent chromatin remodeling complex, principally responsible for transcriptional regulation. By depositing H2A.Z histone variants within nucleosomes at specific locations on the chromatin, replacing the canonical histone H2A subunit, SWR1 effectively reconstructs the nucleosome structure. This process helps activate the transcription state . Actin, in vitro . In Arabidopsis, mutations in several SWR1 subunits, including Arp6, sensitize seedlings to a variety of DNA damaging agents, including γ-irradiation, bleomycin, mitomycin C, and hydroxyurea . Future research will need to discern the biological reasons attributable to these differences. Given that different organisms rely on homologous recombination to varying degrees over other double-strand break repair mechanisms, it is conceivable that this factor may contribute to the phenotypes observed in past studies. Alternatively, Arp6 or other SWR1 components may interact with varying factors in different organisms that in turn promote or suppress recombination.The Arp subunits of SWR1 also play key roles in promoting DNA double-strand break repair in somatic cells of certain species  subunit . Arp4/BAom actin . The comNuA4 is a yeast histone acetyltransferase that plays key roles in regulating gene transcription, cell cycle control, and certain DNA repair processes following acetylation of histone H4. NuA4 is highly similar in structure and function to the TIP60 histone acetyltransferase complex found in humans . NuA4/TIin vivo, where NuA4 acetylates histone H4 and helps facilitate the repair process . H2A phosphorylation at Ser129, an epigenetic mark indicative of DNA damage in yeast, is recognized by the Arp4 subunit of NuA4, thus enabling its recruitment to the damage site and promoting repair . In mammalian cells, TIP60 has key roles in promoting the Fanconi anemia pathway and homologous recombination in response to DNA interstrand crosslinks and double-strand breaks, respectively, in part by promoting expression of genes involved in both pathways, as well as through more direct means (Arp4 has been shown to recruit the NuA4 complex to DNA double-strand breaks  process  (Figure g repair . NuA4 ing repair  (Figure ct means . WhetherAfter a long-lasting and controversial debate on nuclear actin for the past several decades, it is now clear that at least a subset of actin can shuttle in and out of the nucleus in a highly regulated manner. Increasing sets of evidence suggest that nuclear actin plays a pivotal role in regulating different phases of transcription as part of RNA polymerase complexes, as well as a component of chromatin remodelers and histone modifiers. Recent evidence also points to actin’s key roles in other nuclear processes, such as the DNA damage response. The current area of research regarding nuclear actin is now focused on understanding its mechanistic involvement in various nuclear processes and in its different forms. Indeed, the presence of actin-binding proteins and other regulators may render the physical state and conformation of nuclear actin distinct from cytoplasmic actin. Moreover, in the context of chromatin-modifying complexes, nuclear actin relies on its monomeric state, indicating a unique functional role for the protein divergent from canonical actin filaments in the cytoplasm. Combinations of monomeric actin and nuclear Arps dimerize to constitute a key functional module within these complexes, which may facilitate interactions with nucleosomes and in turn promote new conformations that more directly promote catalytic functions of the complex. Exploring the structural and biochemical properties of these actin/Arp modules will likely offer new insights regarding the mechanisms by which these proteins promote chromatin remodeling and histone modification. Moreover, the post-translational modification status of actin remains poorly defined and may play important roles in distinguishing nuclear actin from its cytoplasmic counterpart. Studies in these directions will ultimately uncover the fundamental and highly conserved mechanisms of nuclear actin and Arps.Despite many recent advances in this rapidly emergent field, many important questions remain unanswered and require attention. How do the different combinations of actin and Arps present in a given chromatin-modifying complex specifically affect function? And does any functional redundancy exist amongst actin and Arps in terms of promoting certain nuclear processes? More broadly, how is actin’s monomeric state controlled within the confines of the nucleus? A more thorough understanding of how actin-binding proteins in the nucleus affect nuclear actin state and function will likely uncover clearer details regarding its regulation. Establishing a more refined notion of how Arps and perhaps nuclear actin cooperate with chromatin remodelers to control and maintain higher-order chromatin structure will also be particularly insightful. While we now are continuing to embark on understanding the role of monomeric actin in the context of chromatin remodelers and histone acetyltransferases, it would also be interesting to investigate the extent to which such complexes associate with actin filaments in the nucleus, as filamentous actin is known to regulate certain nuclear processes such as transcription and DNA double-strand break repair. Furthermore, given the importance of Arps, chromatin remodelers, and histone acetyltransferases in maintaining genomic integrity, it will be insightful to investigate how mutations in actin and Arps contribute to tumorigenesis and various cancers. As we begin to unravel the genetic and biochemical underpinnings associated with nuclear actin and Arps in chromatin-modifying complexes, it is likely that our understanding of how cells regulate processes such as gene transcription, replication, and repair will be greatly enhanced. Given the fundamental importance of actin, the emerging studies of nuclear actin and Arps will likely reveal a new world of actin biology, rivaling that of the cytoplasmic actin.NK-M wrote the manuscript. AK and YZ provided critical input. PK and XS provided expertise, advisement, and critical input.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.


A compulsive phenotype characterizes several neuropsychiatric illnesses – including but not limited to – schizophrenia and obsessive compulsive disorder. Because of its perceived etiological heterogeneity, it is challenging to disentangle the specific neurophysiology that precipitates compulsive behaving. Using polydipsia (or non-regulatory water drinking), we describe candidate neural substrates of compulsivity. We further postulate that aberrant neuroplasticity within cortically projecting structures  and circuits that encode homeostatic emotions  underlie compulsive drinking. By transducing an inaccurate signal that fails to represent true homeostatic state, cortical structures cannot select appropriate and adaptive actions. Additionally, augmented dopamine (DA) reactivity in striatal projections to and from the frontal cortex contribute to aberrant homeostatic signal propagation that ultimately biases cortex-dependent behavioral selection. Responding becomes rigid and corresponds with both erroneous, inflexible encoding in both bottom-up structures and in top-down pathways. How aberrant neuroplasticity in circuits that encode homeostatic emotion result in the genesis and maintenance of compulsive behaviors needs further investigation. Compulsivity can be a dominant and debilitating clinical feature of several psychiatric conditions including obsessive-compulsive disorder (OCD), schizophrenia, substance abuse, and other obsessive-compulsive spectrum disorders (OCSD) . CompulsBehavioral heterogeneity and symptom dimensionality observed across compulsive spectrum disorders complicates the search for a neurological trace of compulsivity. For instance, the “classical” compulsive behaviors seen in OCD are characterized by excessive repetition of intentional “normal” behaviors and/or mental acts in an attempt to soothe discomfort brought on by obsessions, the accompanying diagnostic feature of OCD. However, not all observed compulsions captured by this definition are associated with an OCD diagnosis. Primary polydipsia, or excessive, non-regulatory water drinking, is just one example of the clinical heterogeneity found in OCSD, a behavior that shares some of its core features with other psychiatric diagnoses including schizophrenia. By isolating and identifying common neurological substrates across diagnoses marked by compulsive behaving (including primary polydipsia associated with schizophrenia and OCD) we can highlight unique neurological features specific to compulsivity in psychiatric illness.To further characterize the neuropathophysiology of psychiatric disease states, we need appropriate animal models. Some preclinical models of compulsivity have been enormously useful in distilling discrete mechanisms and neural representations of pathological behavior . Among tDecades of research using the SIP protocol enables a full exploration of the hypothesis presented here, that disordered neuroplasticity underlying essential homeostatic emotions within limbic and cortical structures contributes to the compulsive phenotype observed in polydipsia. Because compulsive drinking  can be induced in humans as well as rodents, we further speculate that identified neural substrates [including the bed nucleus of the stria terminalis (BNST)] can apply to psychiatric populations, i.e., those with OCSD. Thus, herein, we synthesize the current understanding of the neurophysiology of compulsivity through the lens of polydipsia.Observationally, polydipsia is simply the overconsumption of fluid, and most often, water. Polydipsia can occur for several physiological reasons, for instance, in response to exaggerated thirst that results from disease states like diabetes insipidus. However, primary polydipsia or “psychogenic” polydipsia is non-physiologic and non-regulatory in nature, i.e., no underlying physiological condition can explain the individual’s need to overdrink. Polydipsia is maladaptive as over-drinking individuals seek and consume water despite the risk of severe life-threatening consequences . AdditioMaintaining adequate hydration is essential to an animal’s survival. Although most of our everyday drinking behavior is social, prandial, or habitual in nature and not in response to thirst, multiple fail-safe systems are in place to ensure that fluids lost are quickly replenished . One sucessential homeostatic “emotion.” This primal and essential emotion arises from interoceptive cues compiled by sensory circumventricular organs that sense dramatic shifts in water and energy homeostasis  and functional magnetic resonance imaging (fMRI) show that the anterior cingulate (ACC) and insular cortex are activated in subjects made thirsty, and that satiation of thirst by drinking quickly extinguished that activity . Upon weNevertheless, cortical regions including the ACC, insular, and OFC cortices have been implicated in many homeostatic emotions beyond thirst, including hunger and deep pain, reflecting an adverse condition within the body that requires immediate behavioral response . GeneralIn primary or “psychogenic” polydipsia, homeostatic emotions somehow become disassociated from appropriate behavioral selection. A person with polydipsia may either feel thirsty but is unable to encode satiety to stop drinking behavior or is not drinking in response to thirst in the first place. Whether compulsive over-drinking results from an altered perception of thirst and/or satiety is unconfirmed . HoweverThe significant incidence of psychogenic polydipsia in patients with severe chronic psychiatric illness  highlighNeurodegenerative processes may underlie some of the illness progression observed in schizophrenia  and may In part due to polydipsia’s temporal association with other repetitive behaviors , some suggest that polydipsia is related to the specific stereotypies and compulsions observed in OCSD or OCD itself . HoweverIndirect lines of evidence from imaging studies support a loss of brain matter across brain structures common to polydipsia, schizophrenia, and OCD . While lIn line with a view that reduced functional neuroplasticity in key networks contributes to OCSD, structural volume loss across fronto-cortico-striatal loops is consistently reported in both schizophrenia and OCD. In schizophrenia, reduced OFC and ACC volumes are linked with greater severity of formal thought disorder, low levels of insight, and a longer duration of the illness . RestingCumulative evidence suggests that schedule-induced polydipsia (SIP) is a valid animal model of compulsive water drinking . Good diAs the compulsion to overdrink in humans is postulated to be a behavioral manifestation of schizophrenia, some of the discrete neurobiology underlying the expression of polydipsia can be inferred from the neuropathology of schizophrenia itself. Currently, the etiology of schizophrenia continues to be debated, although it is generally conceptualized as a complex neurodevelopmental disorder with features of neurodegeneration and risk factors  predicting its onset ,b. HistoIn its original inception, the DA hypothesis proposed that schizophrenia results from DA overactivity within subcortical striatal structures . EvidencPsychogenic polydipsia in schizophrenia is temporally tied to psychosis, arguably a state of striatal hyperdopaminergia, where patients’ increased drinking behavior parallels psychotic exacerbation and is normalized when psychosis remits . This suBy inducing subtle but functionally significant augmentation of the DA system, compulsive drinking can be enhanced. We assessed the ability of amphetamine sensitization (subchronic AMPH), NMDA hypofunction (subchronic MK-801), and social isolation (from weaning) models of schizophrenia-like symptoms to augment striatal DA and “mimic” a schizophrenia-like state in rodents. Evidence suggests that repeated AMPH and MK-801 permanently increases DA transmission along the rat VTA-NAc pathway  for rev. ChronicCollectively, both animal and human data suggest that those with augmented, but intact, DA systems are prone to develop compulsive polydipsic behavior. In SIP, the temporal contiguity of the DA signal evoked by food stimuli precipitates a non-specific locomotor/approach behavior to an available drinking spout and facilitates acquisition of SIP . Rats wiSchedule-induced polydipsia is recognized as a valid model of compulsive behaving  in part due to the ability of serotonin reuptake inhibitors (SRIs) to disrupt SIP development and expression . The ame2A receptor binding in the mPFC  loops . For inscan precede an over reliance on habitual responding observed in compulsivity  male rats, low-frequency stimulation of ovBNST GABAergic synapses produces increases in inhibitory postsynaptic currents and promotes long-term potentiation (iLTP) in the majority of neurons recorded. Following acute food-restriction (24 h), however, GABAergic plasticity toggles to long-term depression (iLTD) via endocannabinoid dependent mechanisms  acts as an integrative hub to detect and signal exteroceptive and interoceptive shifts in the body. Subsequently, the BNST transduces homeostatic information onto circuits that assess contexts and invigorate behaviors to correct any physiological imbalance . Thus, inaccurate neural representation of interoceptive information within the BNST could have drastic behavioral impact. For instance, the reinstatement of bi-directional GABA plasticity  in the ovBNST following hunger-satiety could signal to the cortical structures a need to shift responding strategies to stop food-seeking behaviors. When iLTD persists despite homeostatic correction (feeding), cortical structures receive a “hunger” signal and continue to engage circuits that promote preparatory and consummatory behaviors, including locomotion and drinking. Convergent findings from animal and human research postulate that together with the mPFC , activitUsing compulsive drinking in humans (primary polydipsia) and rodents (schedule-induced polydipsia) we suggest a putative neurobiological framework for the etiology of compulsive behaviors. Thirst, hunger, and satiety constitute essential homeostatic emotions, or subjective feelings that drive motivated, goal-directed behavioral selection needed for survival. In polydipsia, homeostatic emotions fail to illicit appropriate adaptive behaviors. How the brain might switch from a state responsive to shifts in homeostasis to one that is unresponsive was surmised by identifying key over-lapping brain changes between polydipsia associated with schizophrenia, schizophrenia without polydipia, and obsessive compulsive disorder. Composite data suggest that DA-regulated neural plasticity within the striatum and regions of the cortex underlie compulsive phenotypes. Ecological and validated animal models of compulsive drinking, or SIP, confirm a role for increased striatal DA activity in compulsive behaving. Additionally, literature points toward aberrant (non-exclusive) monoamine  modulation of goal-directed and habitual behavior within cortico-limbic-striato-thalamic-cortical loops. Exciting new evidence suggests that non-representative encoding of homeostatic emotions (hunger/satiety) by a cluster of nuclei in the extended amygdala, promote the development of compulsions observed in SIP. The BNST’s role in valence attribution or “valence surveillance” and its extensive web of connectivity within the cognitive, affective, and reward-related circuits highlights the importance of accurate encoding and bottom-up (to the cortex) transduction of homeostatic emotions. Aberrant neuroplasticity within bottom-up and top-down circuits that support homeostatic emotion signaling likely contribute to maladaptive behavioral selection and inappropriate responding. Future research can explore our postulated mechanism of compulsive behaving.TB and EH equally contributed to the design, writing, and editing of the manuscript.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.