Each patient received CRP for BPPV involving the hypoactive canal or, in case of normal VOR-gain, the assumed affected canal. Each subject exhibiting VOR-gain reduction for the involved canal developed normalization of vHIT data after proper repositioning (p < 0.001), proving a close relationship with otoliths altering high-frequency cupular responses. According to our results, overall vHIT sensitivity in detecting the affected SC was 72.9%, increasing up to 88.6% when considering only cases with persistent pDBN where an incomplete canal plug is more likely to occur. vHIT should be routinely used in patients with pDBN as it may enable to localize otoconia within the labyrinth, providing further insights to the pathophysiology of peripheral pDBN.Positional downbeat nystagmus (pDBN) represents a relatively frequent finding. Its possible peripheral origin has been widely ascertained. Nevertheless, distinguishing features of peripheral positional nystagmus, including latency, paroxysm and torsional components, may be missing, resulting in challenging differential diagnosis with central pDBN. Moreover, in case of benign paroxysmal positional vertigo (BPPV), detection of the affected canal may be challenging as involvement of the non-ampullary arm of posterior semicircular canal (PSC) results in the same oculomotor responses generated by contralateral anterior canal (ASC)-canalolithiasis. Recent acquisitions suggest that patients with persistent pDBN due to vertical canal-BPPV may exhibit impaired vestibulo-ocular reflex (VOR) for the involved canal on video-head impulse test (vHIT). Since canal hypofunction normalizes following proper canalith repositioning procedures (CRP), an incomplete canalith jam acting as a “low-pass filter” for the affected ampullary receptor has been hypothesized. This study aims to determine the sensitivity of vHIT in detecting canal involvement in patients presenting with pDBN due to vertical canal-BPPV. We retrospectively reviewed the clinical records of 59 consecutive subjects presenting with peripheral pDBN. All patients were tested with video-Frenzel examination and vHIT at presentation and after resolution of symptoms or transformation in typical BPPV-variant. BPPV involving non-ampullary tract of PSC was diagnosed in 78%, ASC-BPPV in 11.9% whereas in 6 cases the involved canal remained unidentified. Presenting VOR-gain values for the affected canal were greatly impaired in cases with persistent pDBN compared to subjects with paroxysmal/transitory nystagmus ( Positional downbeat nystagmus (pDBN) represents one of the most common findings related to central nervous system (CNS) disorders involving brainstem and cerebellum. As the main function of central vestibular system is to estimate the angular velocity, gravity orientation, and inertia processing peripheral vestibular afferents within the velocity-storage circuit, any lesions disrupting this network can generate pDBN , 2. ThouThis study was approved by our Institutional Review Boards  and was conducted according to the tenets of the Declaration of Helsinki. We performed a retrospective review of clinical-instrumental data of a cohort of 93 patients presenting with pDBN who were evaluated at our centers between June 2019 and May 2020. Overall subjects were admitted either to the outpatient units or to the emergency units. In order to select only patients with peripheral pDBN due to vertical SC-BPPV, subjects exhibiting oculomotor central signs  or abnormal findings on gadolinium-enhanced magnetic resonance imaging (MRI) were excluded from the analysis. Likewise, patients with past history of vestibular pathologies potentially resulting in pDBN or possible VOR-gain abnormalities for vertical SCs [i.e., Meniere's disease , vestibuAny of the following strategies were used for the identification of the SC involved by BPPV:Detection of the SC with impaired VOR-gain values on vHIT with either covert or overt saccades.In case of pDBN with torsional components, recent history of BPPV with paroxysmal positional nystagmus documented with Video-Frenzel goggles addressed the diagnosis toward a specific SC .In cases lacking of the above-mentioned findings, detection of the affected canal could only be provided after physical treatment, basing on the following findings:Resolution of pDBN after proper CRP designed to release a specific SC from debris, as therapeutic maneuvers, though effective in moving debris, would not result in restoring BPPV affecting other SCs.Conversion of pDBN in classical paroxysmal positional nystagmus involving either ipsilateral PSC  or horizontal SC (HSC)  after any CRP performed, consistently with otoconial switch from the affected canal either to other ipsilateral SCs or to another tract of the same affected SC .All patients underwent specific physical therapy aimed to move debris back to the utricle from the assumed affected vertical SC. In cases with BPPV involving the non-ampullary tract of PSC, DS maneuver was mainly used, followed by the 45°-FPP in case of persistence of symptoms following DS . WhereasIn cases with ASC involvement, patients were mostly treated with Yacovino's technique , followeIn cases where affected SC could not be ascertained due to the lack of the aforementioned findings, several CRP were pursued according to examiner's experience to obtain a canal switch, to move otoconia toward another tract of the involved SC or to directly free the affected canal.Each subject was checked within 3–4 days. In case of persistence of pDBN, additional CRP were pursued with following check within further 3–4 days, and so on until a complete recovery or a canal switch was achieved. Physical therapy outcome was considered as successful either if patients were free from symptom and signs or if they exhibited a conversion into a typical form of BPPV. In case debris moved to the ampullary tract of PSC, Epley's or Semont's maneuvers were performed according to examiner's preference or patient's compliance, whereas proper CRP for geotropic and apogeotropic variants of HSC-BPPV were used , 48 in cEye movements were analyzed with video-Frenzel goggles or video-oculography (VOG). Horizontal, vertical and torsional nystagmus were qualitatively assessed. Horizontal (right/leftbeating), vertical (up/downbeating) directions of nystagmus and torsional components  were described from the patient's point of view. Bedside-examination included assessment of spontaneous and positional nystagmus evoked by both DH and SHH positionings. Once evaluated any spontaneous DBN , positional nystagmus was checked for latency (with/without), direction , inhibition with visual fixation (yes/no), duration and temporal trend  and reversal when returning upright following positionings (with/without).Vestibulo-ocular reflex (VOR) gains for all three SCs were tested on both sides in response to high-frequency head stimuli on vHIT, an ICS video-oculographic system . At least 15 impulses were delivered for stimulating each SC and averaged to get corresponding mean VOR-gains. Vertical SC were considered hypoactive if VOR-gains were <0.7 with at least either covert or overt saccades , 30. AllCervical and ocular vestibular-evoked myogenic potentials  for air-conducted sounds were recorded using 2-channel evoked potential acquisition systems  with surface electrodes placed according to standardized criteria . PotentiU-test was employed for pairwise comparisons between subgroups. Results were considered statistically significant if p < 0.05. Statistical analyses were performed using IBM SPSS ver. 20.0 .Quantitative variables were checked for normal distribution using both Kolmogorov-Smirnov and Shapiro-Wilk tests. Continuous variables were described by mean ± 1 standard deviation for normally distributed variables or by median, interquartile range and range for non-normally distributed variables. Diagnostic sensitivity of vHIT in detecting the involved SC in BPPV with pDBN was calculated as the ratio of cases with hypoactive SC to overall patients. Conversely, diagnostic sensitivity of vHIT for persistent pDBN was calculated as the ratio of cases with persistent pDBN exhibiting a deficient SC to overall cases with persistent pDBN, whereas vHIT sensitivity for transitory/paroxysmal pDBN was derived dividing the number of cases with transitory/paroxysmal pDBN presenting with a hypoactive SC for overall cases exhibiting transitory/paroxysmal pDBN. Fisher's exact test was used for categorical comparisons. Spearman's rank correlation was used to correlate patient's age with SCs VOR-gains. Wilcoxon signed-rank test was used to compare pre- and post-treatment vHIT data for all six SCs. Mann-Whitney Fifty-four patients  with pDBN due to vertical SC-BPPV were included in the study. Recurrence of pDBN due to BPPV involving the same SC was recorded in a case and it was considered twice in the analysis. Similarly, four patients  were considered twice as they exhibited either simultaneous or newly sequential BPPV involving other vertical SCs with pDBN. Therefore, clinical and instrumental data concerning 59 cases with pDBN due to vertical SC-BPPV were finally analyzed. Detailed information about overall 59 cases included in the study can be found in p = 0.039) compared to ASC involvement. Conversely, it exhibited transitory and typical paroxysmal crescendo-decrescendo course in most cases with ASC-BPPV  and in half of patients where the affected SC was not identified , ASC-BPPV in 11.9% of cases  whereas in 6 cases (10.1%) neither the involved SC nor the pathologic side could be ascertained . Recent entified . The vasentified . No signentified . Despiten. 53) was performed prior to investigating VOR-gain behavior among different subgroups, to ensure lack of consistent age-related bias involving canal activity (p = 0.043) and for the contralateral SC other than the canal coupled with the affected SC  was found  in subjects with defined affected SC (activity . Only a as found .In 43/59 cases (72.9%) an isolated vertical SC hypofunction could be identified without statistically significant difference between apogeotropic PSC  and ASC-BPPV  . In all p < 0.001; When dividing overall cohort of patients according to pDBN duration, subgroup of patients presenting with persistent positional nystagmus (44/59) exhibited a significantly higher rate of cases with VOR-gain impairment (88.6%) compared to patients in which positionings elicited a transient/paroxysmal pDBN (26.7%) (p < 0.001), for its coupled contralateral canal (p < 0.001) and for the other contralateral vertical SC  and with spontaneous DBN (p = 0.002) than subjects exhibiting transient/paroxysmal pDBN and lacking of spontaneous nystagmus, respectively , a significant functional improvement could be found for the affected SC  and with pDBN resolution after CRP (p = 0.035), respectively (Both cVEMPs and oVEMPs to air-conducted sounds were performed only in 26/59 patients (44%) to test saccular and utricular function, respectively. Whereas, no significant difference in utricular function could be found among subgroups , cases wectively .canalolithiasis) or adhere to the cupula (cupulolithiasis)   , 54, it ith jam) , 56. Sinith jam) , 58, otoThe distinguishing feature of the typical variant of PSC-canalolithiasis (involving its ampullary arm) is represented by paroxysmal upbeat nystagmus with torsional components beating toward the undermost ear, referring to the upper corneal poles, evoked by ipsilateral DH maneuver. Geotropic upbeat nystagmus is disconjugated, with a weaker downward and stronger intorsional slow component in the eye of the pathologic side and a stronger downward and weaker extorsional slow component in the opposite eye, resulting from the transitory activation of ipsilateral PSC-ampulla, since debris within the ampullary arm move away from the cupula during diagnostic maneuvers . ResultiNevertheless, most authors have advocated BPPV involving ASC ampullary arm as underlying mechanism for pDBN . In thisAccording to our original series of 93 patients, most pDBN recognize a peripheral origin confirming previous studies , 9, 15. Despite specific rehabilitative treatments for these BPPV-variants have been designed reporting good results , 68, 69,The importance of a precise detection of the affected SC is reflected in higher number of CRP needed to restore patients with undefined affected SC compared to cases with identified pathologic canal in our series , with obincomplete canalith jam  while impeding the ampullary receptor to respond to high-frequency inputs (head impulses leading to impaired vHIT data). Partial embedment of debris within narrower portion of membranous duct may also account for the usual persistent course of pDBN with smaller frequency compared to typical PSC-canalolithiasis. In fact, hypothesizing that otoconia could remain incompletely entrapped in these canal tracts, a small amount of endolymphatic reflux is expected and fluid column may continue to press against ampullary receptor, resulting in a slower return of the ampullary crest to the resting position than typical BPPV  could likely account for different behavior of pDBN and affected SC activity in these BPPV variants, explaining also how vertical SCs function could have been normal in a series of patient diagnosed with AC-BPPV presenting with mainly transitory pDBN  evoked in DH or SHH positions has been related to PSC-cupulolithiasis –62 or toregular canalolithiasis vs. incomplete jam vs. complete canalith jam) accounting for different patterns of pDBN due to BPPV and vHIT measurements with corresponding assumed pathomechanism is summarized.Finally, when considering different VOR behavior for the affected canal between cases exhibiting spontaneous DBN or not, the former group presented with highly reduced function compared to the latter . This daDespite our instrumental assessment included both cervical and ocular-VEMPs to air-conducted sounds, they were neither routinely performed to search for possible AR differences among patients nor they were routinely tested both before and after CRP to look for amplitudes changes following proper repositioning. Moreover, due to the lack of bone-conducted stimuli in our equipment, a reliable measurement of both saccular and utricular function could not be obtained. On the other and, analysis of variations in VEMPs amplitudes among BPPV patients would have gone beyond the aim of our investigations. These methodological bias could likely account for the lack of statistically significant results among VEMPs data , 12.Our investigation presents some other limitations. First of all, being a multicentre investigation, each involved otoneurologist collected data by him/herself, and an inter-observer agreement for ambiguous cases  was never used. Then, despite corrective saccades were always checked to avoid artifacts inclusion in hypoactive VOR-gain plots, our analysis on vHIT data focused almost solely on SC VOR-gain values, whereas morphological study of saccades  was not pursued, being beyond the aims of this study. Moreover, we considered as deficient only VOR-gains below normative data without considering gain asymmetry between coupled pairs of SC. In addition, the subgroup of patients with ASC involvement was significantly smaller than population with apogeotropic PSC-BPPV, leading to possible misleading conclusions when comparing subsamples data. The inclusion in the analysis of 6 subject where the affected SC could not be identified could also have altered final results of our investigation. Though they presented with pDBN exhibiting the same characteristics of the remainder of cases with BPPV and restored with positionings, it could not be excluded they were not affected by vertical SC-BPPV. Finally, despite our cohort size with pDBN collected in a 1-year period was similar to others series, the small-sized sample analyzed does not permit to achieve definitive conclusions on the sensitivity of vHIT in detecting the affected canal in these patients. Further prospective investigations with a more significant number of subjects with pDBN will be needed to better determine the role of vHIT in vertical canals BPPV presenting with pDBN.incomplete jam is likely to occur. Unlike complete canalith jam, where otoconia are thought to plug the entire canal lumen impeding endolymphatic flows for both high- and low-frequency domains due to a continuous pressure exerted by the clot on a persistently displaced cupula, in these conditions particles partially entrapped within a narrow portion of the canal likely behave as a “low-pass filter” for the ampullary receptor. This phenomenon may actually impair high-frequency dynamic responses for the affected canal while allowing low-frequency endolymphatic movements, thus explaining reduced VOR-gain for the affected SC on vHIT despite pDBN, respectively, and normalization of head impulse data following symptoms resolution or pDBN conversion into a typical paroxysmal nystagmus. These findings should encourage clinicians to routinely use the vHIT in case of pDBN, including high-frequency testing of canal function in the test battery for these patients, particularly in cases lacking of torsional components, where detection of the affected canal and differential diagnosis with CNS disorders may be challenging.According to our data, vHIT may play a key role in the diagnosis of the affected canal in BPPV involving vertical SC presenting with pDBN. In fact, conversely to typical BPPV with paroxysmal positional nystagmus, where particles are free to move along the membranous ducts, in case of persistent pDBN an All datasets generated for this study are included in the article/The studies involving human participants were reviewed and approved by Area Vasta Nord Emilia Romagna Institutional Review Committee. The patients/participants provided their written informed consent to participate in this study.AC, PM, and SM led the conception of the study and conducted most data acquisition, interpretation and made significant contributions to the writing, and editing of the manuscript. AC conducted data analysis and creation of figures. CB and MR were involved in project conception and manuscript editing. SD, SQ, ER, and EA contributed to data acquisition and manuscript review. EA, MM, AG, and GL were involved in manuscript review. All authors approved the final version 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.


Cardiac Implantable Electronic Devices (CIED)-associated infective endocarditis complicated by septic emboli and acute on chronic pulmonary hypertension is rare. We present a case where pulmonary thromboendarterectomy was required for treatment. A 55 year-old man with a history of myocardial infarction and ischemic cardiomyopathy status-post ICD placement 8 years prior presented with bacteremia, infected ICD, and tricuspid valve vegetation. He underwent CIED extraction along with the use of the AngioVac suction device to remove right ventricular and atrial vegetations. However the patient had persistent valvular vegetation and bilateral sub-massive pulmonary emboli. Pulmonary angiography showed filling defects in the lobar and segmental arteries. Percutaneous attempts at embolectomy were unsuccessful and he therefore underwent a pulmonary endarterectomy surgery (PTE).This case of CIED- associated endocarditis demonstrates the importance of early aggressive treatment of such infections. Guidelines recommend compete CIED system removal when there is associated infection. The AngioVac is a novel system for removal of right-sided vegetations and thrombi; however, complications such as distal embolization can occur. PTE surgery for septic emboli is rare. However, cases of such treatment as is presented here can be successful and may be necessary should percutaneous methods fail.  Cardiac Implantable Electronic Devices (CIED)-associated infective endocarditis complicated by septic emboli and acute on chronic pulmonary hypertension is rare. Here we present a case where pulmonary thromboendarterectomy (PTE) was required to successfully treat this uncommon complication.A 55 year-old man with a history of myocardial infarction and ischemic cardiomyopathy status-post ICD placement 8 years prior presented to an outside hospital with bacteremia. His original ICD placement was in 2005, with a Guidant FineLine atrial lead and a Guidant dual coil ICD lead. In 2008, an additional Guidant atrial lead was placed. He was transferred to our tertiary care center after 8 weeks of IV antibiotics and evidence of a large 5cm x 2cm, mobile tricuspid valve vegetation associated with the ICD lead Figure  seen on The patient was taken to the hybrid OR, placed under general anesthesia, and underwent pulse generator and lead extraction, along with AngioVac removal of RV and RA vegetations Figure . SignifiPost-procedure the patient remained febrile and with leukocytosis to 23,000. Post-procedure TEE showed persistent valve vegetation and a chest CT scan showed evidence of sub-massive pulmonary emboli. The patient had worsening fevers, chills, pleuritic pain, and dyspnea despite antibiotics. Right heart catheterization revealed normal right heart pressures and borderline pulmonary hypertension with a mean pulmonary artery pressure of 27 mmHg. Pulmonary angiography showed proximal filling defects of bilateral lobar and segmental branches. Percutaneous embolectomy was attempted but was unsuccessful as a wire was unable to be passed beyond the thrombus.The patient was therefore considered for pulmonary endarterectomy surgery. He underwent bilateral pulmonary endarterectomy under cardiopulmonary bypass and deep hypothermic circulatory arrest   lead management guidelines [The AngioVac system is a relatively novel method for removal of material from the vasculature using veno-venous bypass. Studies have shown it to be an effective method of percutaneous removal of thrombi and right-sided vegetations -4. ReporThere are a few reports of PTE for septic emboli in the literature -10; howeIn this case report, we demonstrate a successful treatment of a complicated case of CIED-associated infection and endocarditis. This patient did not undergo early device removal, and despite efforts at minimally invasive techniques of lead and vegetation removal, our patient eventually required an open surgery. This shows the importance of early antibiotic therapy to minimize the development and growth of vegetations, little delay in device removal, and close monitoring to determine when to proceed with an open extraction.


Upstream open reading frames (uORFs) are present in the 5’ leader sequences (or 5’ untranslated regions) upstream of the protein-coding main ORFs (mORFs) in eukaryotic polycistronic mRNA. It is well known that a uORF negatively affects translation of the mORF. Emerging ribosome profiling approaches have revealed that uORFs themselves, as well as downstream mORFs, can be translated. However, it has also been revealed that plants can fine-tune gene expression by modulating uORF-mediated regulation in some situations. This article reviews several proposed mechanisms that enable genes to escape from uORF-mediated negative regulation and gives insight into the application of uORF-mediated regulation for precisely controlling gene expression. Arabidopsis thaliana .,22.21,22s of NMD ,26. In os of NMD . Thus, uSome mechanisms for evading uORF-mediated negative regulation of gene expression have been proposed. This review explains not only well-known ones (leaky scanning and reinitiation) but also more recent ones, including those that have been experimentally proven and those that have yet to be. This includes alternative transcription start sites (TSSs) selection, splicing out of uORF initiation codons and initiation of cap-independent translation. In particular, alternative TSS and splicing can produce two mRNA variants, uORF+ and uORF–. Some plant stimuli result in shuffling the amount of variants by inducing a TSS positional shift or alternative splicing. Viruses often use leaky scanning by ribosomes and translational reinitiation to produce more than one kind of protein from their polycistronic RNAs . EukaryoTranslation generally starts by recruiting 40S ribosome subunits to the 5’ cap structures of the mRNAs. In canonical scanning, uORF is first recognized prior to the mORF. However, in leaky scanning, the 40S scanning ribosomal subunit in 48S preinitiation complexes passes over the initiation codon of the uORF avoiding uORF translation A. When tIn another case, after translation of a uORF, the translating ribosome is disassembled and the 60S subunit is released B. In traArabidopsis [bZIP11 mRNAs in a peptide sequence-dependent manner under high sucrose conditions, resulting in low translation of a bZIP-encoding mORF [GCN4 mRNA in yeast have also been well exemplified [Some events of leaky scanning or translational reinitiation have been reported in bidopsis . For exaing mORF ,31. Thismplified ,32. TakiThere are two types of uORF: one is an independent uORF that does not overlap with the mORF and the other is an overlapping uORF A. Leaky Arabidopsis [Approximately 75% of genes are estimated to use multiple TSSs in bidopsis ,34. The bidopsis ,35.Arabidopsis seedlings grown in dark were exposed to blue light [upf1 NMD-deficient mutants compared to wild-type plants, indicating they are targeted by NMD [Transcription from TSSs upstream of the uORF (uTSS) produces uORF+ mRNAs, while that from downstream TSSs (dTSSs) generates uORF– mRNAs ,36. It iue light . Ribosomd by NMD . Taken tAlternative TSS selection as described above can also overcome translational repression by uORFs overlapping with mORF initiation codons.In addition to alternative TSSs, alternative splicing is also one of the most important determinants of the 5’ leader sequence. Indeed, it has been reported that alternative splicing that occurs in the 5’ leader sequence also affects the translation efficiency of genes in plants .de novo initiation codon of a uORF at the splicing junction. Splicing out of introns containing the initiation codon of the uORF or a part of the uORF sequence from the 5’ leader sequence of pre-mRNAs produces mRNAs without uORFs or mRNAs with truncated uORFs, respectively B, while PHY2 gene in Ceratodon purpureus produces two splicing variants harboring different uORF sequences in a light-dependent manner [Medicago truncatula, alternative splicing of an intron containing uORFs in the HAP2-1 mRNA regulates root nodule development [However, at present, there have been a limited number of examples showing a possible link between splicing and uORFs ,38,39,40Alternative splicing events frequently occur in response to environmental changes in plants . It is eCap-independent translation is commonly driven by internal ribosomal entry sites (IRESs) that form dynamic RNA secondary structures. IRESs are widely used by viruses for producing proteins from their polycistronic mRNAs . In planA variety of endogenous IRESs or IRES-like structures have been discovered not only in viruses but also in eukaryotes including plants ,46,47,48WUSCHEL mRNA in Arabidopsis is enhanced by environmental hazard stress [N6-methyladenosine (m6A) methylation of 5’ leader sequences promotes cap-independent translation by IRESs in mammals [Although there have not been any examples illustrating such avoidance of translational repression C at leasd stress . In addi mammals ,50. Thus6A modification, it has also been reported that amino acid starvation induces demethylation at the m6A site within overlapping uORF on the mammalian ATF4 mRNA and increases mORF translation [ATF4 mORF may be cap-dependent but not cap-independent.Regarding mnslation . HoweverGGP2 gene encoding a key enzyme for vitamin C biosynthesis results in an increased amount of vitamin C through enhanced mORF translation in lettuce [Regulatory mechanisms of gene expression have often been modified and/or applied to expressing preferable genes under particular conditions. Application of transcriptional regulation using tissue-specific or stimulus-inducible promoters is the most popular. Recent papers have reported that translational fine-tuning by artificial modification of uORFs enables proper transgene expression to be achieved ,52. In p lettuce .This review proposes that there are various ways this regulation can be applied. A dynamic range of spatial and temporal gene expression is controlled at the transcriptional level. In the case where an appropriate level of gene expression is required, fine-tuning by translational regulatory elements such as uORFs can be applied to elicit the required function of the gene. Adjustment of gene expression may also be achieved by combining the use of both uORFs and IRESs. In particular, the uORF is an attractive candidate for controlling gene expression at the translational level.This review introduces several mechanisms that can overcome uORF-mediated translational repression of mORFs in polycistronic mRNAs. In particular, uORF shuffling by alternative TSS selection or alternative splicing may be a notable concept. It is expected that a growing body of future research will elucidate the unknown parts of the mechanisms. For this purpose, integrated analysis of multiple omics data derived from not only the transcriptome but also ribosome profiling and proteome will be required. As effectiveness of uORFs on mORF translation varies case by case and the action of IRESs is still obscure in plant biological processes, deeper understanding of the regulatory mechanisms of gene expression is necessary for their application in crops.


Soft tissue fibrosis in important organs such as the heart, liver, lung, and kidney is a serious pathological process that is characterized by excessive connective tissue deposition. It is the result of chronic but progressive accumulation of fibroblasts and their production of extracellular matrix components such as collagens. Research on pathological scars, namely, hypertrophic scars and keloids, may provide important clues about the mechanisms that drive soft tissue fibrosis, in particular the vascular involvement. This is because these dermal fibrotic lesions bear all of the fibrotic characteristics seen in soft tissue fibrosis. Moreover, their location on the skin surface means they are readily observable and directly treatable and therefore more accessible to research. We will focus here on the roles that blood vessel-associated cells play in cutaneous scar pathology and assess from the literature whether these cells also contribute to other soft tissue fibroses. These cells include endothelial cells, which not only exhibit aberrant functions but also differentiate into mesenchymal cells in pathological scars. They also include pericytes, hepatic stellate cells, fibrocytes, and myofibroblasts. This article will review with broad strokes the roles that these cells play in the pathophysiology of different soft tissue fibroses. We hope that this brief but wide-ranging overview of the vascular involvement in fibrosis pathophysiology will aid research into the mechanisms underlying fibrosis and that this will eventually lead to the development of interventions that can prevent, reduce, or even reverse fibrosis formation and/or progression. Soft tissue fibrosis in important organs such as the heart, liver, lung, and kidney is a serious pathological process that is characterized by excessive connective tissue deposition. It is the result of chronic but progressive accumulation of fibroblasts and their production of extracellular matrix (ECM) components such as collagens. Soft tissue fibrosis decreases or obliterates organ function and can result in organ failure and death . Indeed,Research on pathological scars, namely, hypertrophic scars and keloids, may provide important clues about the mechanisms that drive soft tissue fibrosis. This is because these dermal fibrotic lesions bear all of the fibrotic characteristics seen in soft tissue fibrosis. Moreover, their location on the skin surface means they are readily observable and directly treatable and therefore more accessible to research.A particularly important focus in the field of cutaneous pathological scarring is the role of blood vessels: there is considerable evidence that suggests that these vessels and their dysfunctions contribute to the formation and progression of abnormally growing scars, as follows. First, pathological scars are characterized by chronic inflammation: this inflammation is particularly evident at the invasive edges of keloids and causes the erythematous and pruritic symptoms of these scars. This inflammation plays a key role in the development and progression of pathological scars, as demonstrated by the widely recognized beneficial effects of intralesional administration of anti-inflammatory drugs such as corticosteroid . It is lTo determine whether soft tissue fibrosis is also driven by abnormal vascular involvement, we will focus here on the cells and their functions that are known to participate in the abnormal vascular activity in cutaneous scar pathology. These cells include endothelial cells, which not only exhibit aberrant functions in pathological scars but also transdifferentiate into mesenchymal cells called myofibroblasts, which are highly contractile cells that produce large amounts of extracellular matrix (ECM). They also include cells that are in close communication with endothelial cells, namely, pericytes  and fibrocytes: as we still show below, these cells can also convert into myofibroblasts in profibrotic conditions . This arThe inner lining of blood vessels consists of monolayers of endothelial cells that are in direct contact with the cells and components of the blood. Consequently, these cells play a key role in vascular function, both as a barrier between the blood and the tissues and as an endocrine organ that actively regulates vascular dilation/constriction, immune responses, angiogenesis, and coagulation/fibrinolysis . EndotheEndothelial dysfunction refers to the impaired ability of endothelial cells to maintain vascular homeostasis ,10. ThisEndothelial dysfunction is a hallmark of skin fibrotic conditions such as pathological cutaneous scars and cystic fibrosis. For example, our logistic regression analysis showed that patients with keloids were significantly more likely than the non-keloid controls to have poor reactive hyperemia index and augmentation index values: both indices are measures of endothelial function . In fact4)-induced cirrhotic rat livers, the intrahepatic microcirculation relaxes poorly when exposed to acetylcholine. They also elucidated some of the molecular mechanisms that underlie this effect: they found that cirrhosis associated with excessive levels of thromboxane A2  for seven days before sacrifice and liver analysis. Fenofibrate is an agonist of peroxisome proliferator-activated receptor (PPAR)α, which can be expressed by endothelial cells in the liver and downregulates COX-1. The fenofibrate treatment significantly improved the vasodilatory response of the liver to acetylcholine and reduced hepatic fibrosis. These beneficial effects associated with a drop in COX-1 and TXA2 production in vivo. Notably, Rodríguez–Vilarrupla et al. also showed that when hepatic endothelial cells from CCl4 cirrhotic rats were treated with fenofibrate in vitro , the treatment increased nitric oxide (NO) bioavailability [4 cirrhotic rats with a soluble epoxide hydrolase inhibitor, these changes effectively improved hepatic endothelial dysfunction and liver fibrosis [2 and COX-1 are responsible for the endothelial dysfunction in liver fibrosis.There is also evidence that endothelial dysfunction participates in liver fibrosis: Graupera et al. showed that in carbon tetrachloride (CClfibrosis ) and thagenase-1 . These flability . In relafibrosis . These fSince we are discussing liver fibrosis here, we would like at this point to briefly digress to describe the highly specialized and differentiated endothelial cells that separate the blood cells in the sinusoidal lumen from the hepatocytes and hepatic stellate cells in the space of Disse . These lRenal fibrosis also involves endothelial dysfunction. For example, Wu et al. showed that lipopolysaccharide-induced kidney injury in mice markedly declined the peritubular capillary perfusion. They also found that this response associated with rapid upregulation of intercellular adhesion molecule-1 and vascular adhesion molecule-1: this suggests that when renal tubule cells are stressed, they quickly induce vascular inflammation that promotes endothelial dysfunction . In addiLipphardt et al. also showed recently that endothelial dysfunction after unilateral ureteral obstruction is responsible for the ensuing kidney fibrosis. Interestingly, they found that this effect was mediated by increased kidney expression of Syndecan-4. This is a membrane-spanning proteoglycan that consists of a short cytoplasmic domain and an ectodomain that bears heparan sulfate chains . It contAnother study that indicates the pivotal role of endothelial dysfunction in renal fibrosis is that of Ni et al. These authors examined the effect of FTY720 treatment on rats that had undergone 5/6 nephrectomy (a model of chronic kidney disease). FTY720 is an analog of sphingosine 1-phosphate that helps stabilize the endothelial barrier. When 5/6-nephrectomized rats underwent gavage with FTY720 a week after surgery, the treatment inhibited endothelial dysfunction in the renal microvasculature, thereby reducing renal fibrosis progression. These beneficial effects of FTY720 on renal endothelial function associated with improved endothelial NO bioavailability due to increased NO synthesis and increased expression of vascular endothelial growth factor (VEGF) and endothelial NO synthase, along with the reduced TGF-β1 expression .Balint et al. showed with a rat model that insular cortex ischemic stroke results in three histological features, namely, coronary microvascular endothelial dysfunction, myocardial inflammatory infiltration, and myocardial fibrosis. They also found that the fibrosis occurs downstream of the first two events . MoreoveMyofibroblasts, as the name indicates, combine the functions of ECM synthesis in fibroblasts and contraction in smooth muscle cells. These functions allow them to regulate connective tissue remodeling. Myofibroblast contracture is usually long-lasting, unlike the short and rapid contraction of smooth muscle cells . The hal+ fibrocytes, and from the phenotypic transition of various cells, including endothelial cells. This phenotypic transition causes the loss of the original features of the cell and the new production of mesenchymal features [Myofibroblasts in fibrotic diseases originate from several sources, including previously quiescent tissue fibroblasts, circulating bone marrow-derived CD34features . These tfeatures . In thisfeatures . The acqfeatures , its rolAs an aside, it should be noted that another source of myofibroblasts is epithelial cells: these cells transform into myofibroblasts via the well-known transdifferentiation process called the epithelial-mesenchymal transition (EMT). However, we will not discuss EMT-derived myofibroblasts further in this paper because recent cell fate-mapping studies in animal models show that EMT does not contribute directly to the pool of collagen-producing myofibroblasts during fibrosis in vivo ,47,48.+) cells in the dermal vasculature. It was thought that the remaining seven keloids did not coexpress these markers because their endothelial cells had already gone through EndoMT. In the same study, Lee et al. showed that Wnt-3a, , may drfibrosis .There is increasing evidence showing that EndoMT-derived myofibroblasts also play a key role in the tubulointerstitial fibrosis, tubular atrophy, and glomerulosclerosis that characterizes renal fibrosis . For exa+ or fibroblast-specific protein-1+) in murine myocardial fibrosis caused by pressure overload or chronic allograft rejection originate from endothelial cells. They also found that systemic administration of a recombinant human bone morphogenetic protein (BMP)-7 inhibited EndoMT and preserved the endothelial cell phenotype and thereby inhibited cardiac fibrosis progression [Cardiac fibrosis occurs after myocardial infarction and the resulting death of cardiomyocytes. Since the mammalian heart has little capacity to regenerate, the dead cardiomyocytes are replaced with ECM, which in turn disrupts the normal myocardial structure and function . Multiplgression .There is some, albeit limited, evidence that EndoMT participates in lung and liver fibrosis as well. Thus, in the bleomycin-induced lung fibrosis mouse model, immunofluorescence analyses of lung showed significantly increased mesenchymal marker α-SMA and decreased endothelial marker VE-cadherin. Moreover, when the microRNA MiR-155 (which is known to participate in lung fibrosis) was specifically deleted in endothelial cells, the bleomycin-induced EndoMT was alleviated along with the lung fibrotic response . RegardiLike endothelial cells, pericytes  can differentiate into myofibroblasts and play key roles in fibrogenesis. Pericytes are perivascular cells that are embedded in the microvascular basement membrane. They have rounded cell bodies that extend multiple long cytoplasmic processes along the length of the vessel, usually spanning several endothelial cells. The primary processes bear perpendicular secondary processes that partially encircle the vessel. Since these anatomical and morphological features can only be determined by electron microscopy, pericytes are generally identified on the basis of their general location and molecular markers such as nerve/glial antigen 2 , platelet-derived growth factor (PDGF) receptor β (PDGFRβ), and desmin. However, it should be noted that a single pericyte-specific marker has not yet been identified. Pericytes communicate closely with their neighboring endothelial cells, either directly via specialized peg-like cytoplasmic fingers that insert into endothelial socket-like invaginations or indirectly via juxtacrine or paracrine signaling . In term+ myofibroblasts in these scars originate from the PDGFRβ+ NG2+ perivascular subpopulation [A transmission electron microscopy study in 1982 showed that half of the 22 hypertrophic scars and keloids that were examined contained pericytes bearing an inner peripheral band of microfilaments: such pericytes were never observed in normal skin or mature scar samples and thus were termed pericapillary myofibroblasts. It was thought that these myofibroblastic pericytes migrate from their perivascular location to the interstitial region, where they then become a source of profibrotic fibroblasts. The same study also observed that the vast majority of microvessels in these pathological scars had occluded lumens. This pointed to a chronically hypoxic environment (which is well-known to promote fibrosis ). It waspulation . Moreovepulation .+ mesenchymal cells become adult CD73+ PDGFRβ+ α-SMA- pericytes, and that in fibrogenic conditions, these pericytes start expressing α-SMA. The study showed that the vast majority of the myofibroblasts in renal fibrosis were derived from the stromal precursors of pericytes. By contrast, EMT was not a source of myofibroblasts in kidney fibrosis [Kidney fibrosis also involves activated pericytes that transdifferentiate into myofibroblasts, detach from the capillaries, migrate into the interstitium, and produce ECM. These activities directly induce fibrosis and indirectly contribute to capillary fragility and rarefaction and hypoxia in the kidney . The linfibrosis .The molecular mechanisms behind the transdifferentiation of pericytes into myofibroblasts in still being explored. However, multiple studies show that in kidney fibrosis, pericytes transdifferentiate into myofibroblasts via the PDGFR, VEGF, TGF-β, connective tissue growth factor, Wnt/LRP6, Ephrin B, and Hedghog pathways . The ideInterestingly, numerous studies also suggest that renal pericytes may be the source of most of the body’s erythropoietin and that their transdifferentiation into myofibroblasts in kidney fibrosis impairs their eythropoietin production, thereby contributing to the anemia that characterizes advanced chronic kidney disease ,74,75.+ progenitor-derived pericytes expand and start expressing collagen I and α-SMA in fibrotic foci. It was concluded that pericytes are also the main source of myofibroblasts in pulmonary fibrosis [+ PDFGRβ+ pericyte-like cells did proliferate in bleomycin-induced pulmonary fibrosis, they did not change into α-SMA+ myofibroblasts. The authors argued that this discrepancy relative to other studies finding this transition in fibrotic lungs and other organs may reflect organ-specific differences in terms of fibrotic responses and the use of different markers to identify pericyte subpopulations [Hung et al. showed that after bleomycin-induced lung injury, FoxD1fibrosis . By contulations . WhateveDisse, namely, between the antiluminal side of the LSECs and the basolateral surface of the hepatocytes. When in a quiescent state, HSCs are vitamin A-storing hepatic pericytes. However, when activated, they transdifferentiate into vitamin A-depleted myofibroblasts and secrete ECM, thereby forming scars in the space of Disse [The pericytes in the liver are called hepatic stellate cells (HSCs) . We have placed these cells in a section of their own due to their unique functions and interactions with liver sinusoid endothelial cells (LSECs): note that the LSECs have been described briefly in of Disse .p < 0.01). Moreover, the ability of the LSECs to maintain HSC quiescence was lost when the LSECs had undergone capillarization: when previously quiescent HSCs were cultured with capillarized LSECs from cirrhotic rats, 81.2% of the HSCs started expressing α-SMA. A paracrine mechanism involving NO release by LSECs mediated the ability of LSECs to control HSC quiescence. Interestingly, HSCs that were activated by 3 days of homotypic culture reverted to a quiescent phenotype  when they were subsequently cultured with freshly isolated LSECs for another three days (days 3–6) in the presence of exogenous VEGF. This is notable because, in the normal liver, hepatocytes and HSCs secrete VEGF. However, this paracrine production of VEGF drops markedly after capillarization and before cirrhosis. Thus, it is likely that VEGF stimulates the NO production of LSECs that maintains HSCs in a quiescent state. These observations together show that loss of liver expression of VEGF and LSEC capillarization may permit HSC activation and the resulting fibrosis [The close physical proximity of HSCs and LSECs allows these two cell types to communicate readily. Indeed, HSCs and LSECs depend on each other to maintain a quiescent and differentiated state, respectively. Once that balance has been upended, liver fibrosis ensues. The mechanisms by which LSECs maintain and promote HSC quiescence, and HSCs control LSEC differentiation, have been investigated. Thus, LSECs control HSC quiescence by suppressing HSC expression of α-SMA: confocal microscopy showed that when quiescent HSCs and differentiated LSECs from rats were co-cultured for three days, only 29.6% of the HSCs expressed α-SMA. However, when the quiescent HSCs were cultured by themselves, 70.5% acquired this marker , they maintain well-defined fenestrae. By contrast, when they are cultured on stiff (36 kPa) collagen hydrogels that resemble the ECM produced by activated HSCs, they completely lose their fenestrae; they also start expressing CD31, which is normally not expressed by differentiated LSECs . Second,It should be noted that LSECs and HSCs also cooperate to maintain the homeostatic production/degradation of hepatic hyaluronic acid (HA), an ECM component: the HA in the liver is synthesized by HSCs and degraded by LSECs. This homeostatic relationship is disrupted in liver fibrosis and results in increasingly higher HA levels in the serum as liver fibrosis progresses .fibroblast’ and ‘leukocyte’, which reflects the fact that they are a small subpopulation of circulating leukocytes  differ from pericytes in that they surround arterioles and have no physical connection with endothelial cells . The teral blood ) that real blood ); notablal blood  and the al blood .On cutaneous skin injury, peripheral blood fibrocytes migrate into the wound (together with other circulating inflammatory cells) and differentiate into fibroblasts/myofibroblasts . These fSeveral lines of evidence suggest that fibrocyte-derived fibroblasts in the skin can also differentiate further into fibrotic myofibroblasts that express α-SMA and promote pathological scarring. For example, keloid-derived fibroblasts bear fibrocyte markers (CD34 and CD86), which suggests that these pathological fibroblasts could be derived from fibrocytes . It shou+ CD45+ procollagen-1+) arrived in the wound/scar in two waves, namely, 2–4 days after wounding and later during scar formation and remodeling [+ N-terminal propeptide of type I collagen+) than mature scars . By contrast, normal skin lacks fibrocytes [+ 25F9+ MRP8/14+) than normal scars [There are also other lines of evidence that suggest fibrocytes participate in pathological scarring. Thus, Travis et al. showed that in a porcine hypertrophic scar model, fibrocytes  infiltrated as early as two days after bleomycin exposure. This is earlier than when significant collagen deposition is first detected (between 4 and 20 days). The fibrocyte numbers in the lungs peaked on day 8 and started to decrease by the last two observation time points (days 16 and 20) [+ Collagen I+) numbers in the lung dropped significantly on day 14 (p = 0.0097); this drop was mirrored by a fall in collagen content on day 28 (p = 0.0012) [Fibrocytes also contribute to the pathogenesis of pulmonary fibrosis. Immunofluorescence and confocal microscopy analyses show that the lungs of patients with idiopathic pulmonary fibrosis bear fibrocytes . Moreove and 20) . This de and 20) ,98. Nota and 20) . Similar 0.0012) .4 [4-induced liver fibrosis in mice [Fibrocytes also participate in liver, cardiac, and renal fibrosis. In terms of liver fibrosis, fibrocytes constitute 5%–6% of all collagen-expressing cells in livers that have been injured by bile-duct ligation or CCl4 ,101. Mor4 . By cont in mice . HoweverIn terms of cardiac fibrosis, Sopel et al. showed that when myocardial fibrosis is induced in rats by angiotensin II infusion, fibrocyte progenitor cells are quickly recruited to the myocardium and differentiate into myofibroblasts; these events occur before collagen deposition starts . The stuIn terms of kidney fibrosis, Sakai et al. showed that renal fibrosis involves angiotensin II and its two receptors, AT1R  and AT2R (which appears to counter the effects of AT1R and thus is organoprotective). First, the renal fibrosis caused by unilateral ureteral obstruction was reduced by valsartan-mediated blockade of AT1R and worsened by AT2R-knockout. The improvement caused by valsartan was mirrored by decreased fibrocyte infiltration and collagen deposition in the kidney. The opposite was observed when AT2R was knocked out. These findings were confirmed in another model of renal fibrosis, namely, the chronic angiotensin II-infusion model. The study suggested that AT1R/AT2R signaling shapes both the production of fibrocytes in the bone marrow and their fibrogenic activation .Myofibroblasts are pathogenic to endothelial cells. This can be seen in patients with idiopathic pulmonary arterial hypertension (PAH). Thus, Xu et al. first showed that the pulmonary artery endothelial cells in PAH exhibit decreased mitochondrial function . The in Conversely, endothelial cells can inhibit the formation of myofibroblasts. Thus, Yang et al. showed that when mice with unilateral ureteral obstruction-induced renal fibrosis were injected via the tail vein with putative endothelial progenitor cells (pEPCs), the mice were protected against renal fibrosis. This associated with significantly reduced expression of α-SMA and collagen IV in the kidneys. The pEPCs appeared to act by inhibiting pericyte detachment from endothelial cells and the pericyte-myofibroblast transition .Endothelial cells can also promote the healthy differentiation of fibroblasts into myofibroblasts: this was shown indirectly by the study of Miyazaki et al. on wound healing. This study used a dermal wound healing mouse model and found that calpastatin, an endogenous inhibitor of calpains, was enriched in pre-existing blood vessels in the wound but not in newly formed capillaries. When endothelial cells were transformed genetically to overexpress calpastatin, dermal wound healing was delayed. This effect associated with poor myofibroblast accumulation in vivo, which reduced the appropriate fibrogenic responses in the wound bed and slowed healing . Nieves This paper briefly and with broad strokes describes what is known about the vascular involvement in soft tissue fibrosis. Based on the lessons learned from pathological scar research, it focuses on the vascular cells that contribute directly in one way or another to fibrosis, namely, endothelial cells, pericytes , and fibrocytes. The studies reviewed in this paper suggest that these vascular cells not only play important roles in soft tissue fibroses, they also act in broadly similar ways: in particular, they can convert into heavily profibrotic myofibroblasts in response to the fibrotic stimulus. These studies also suggest that the spatial and structural proximity of the different vascular cells appear to potentiate their dynamic interactions and integral functional changes during fibrotic progression.4 treatment and protects these cells from oxidative stress: however, this defensive autophagic response is ultimately overcome and endothelial cell dedifferentiation and the resulting fibrogenic activation of hepatic stellate cells ensues [There are many questions that remain about vascular cell-mediated fibrosis. In particular, despite the broad similarities between the vascular cells in terms of their roles in fibrosis, these cells have distinctive functions and structures in specific organs: examples of this are the renal pericytes, which are the source of most of the body’s erythropoietin, and the LSECs, which are the only endothelial cells in the body that have non-diaphragmed fenestrae and no basement membrane. Further studies on how these organ-specific features shape the fibrotic process and destination and its deleterious effects are warranted. Another important question is the role of endothelial cell autophagy in fibrosis. Autophagy is the self-degradative process  . There is ensues . Converss ensues . Thus, as ensues . Sections ensues . Howevers ensues . ComparaWe hope that this brief but wide-ranging overview of the vascular involvement in fibrosis pathophysiology will aid research into the mechanisms underlying fibrosis and that this will eventually lead to the development of interventions that can prevent, reduce, or even reverse fibrosis formation and/or progression.


Bemisia tabaci) as a case study of a behaviorally-polymorphic migratory species lacking morphological or physiological differentiation. In addition, both adaptive and non-adaptive explanations for the empirically variable relationship between egg production and flight in wing-monomorphic insects are discussed. Finally, with respect to the largest order of insects (Hymenoptera), the role of sex determination mechanisms for haplodiploidy as a driver for natal dispersal (for inbreeding avoidance) versus philopatry  is discussed.Gains in our knowledge of dispersal and migration in insects have been largely limited to either wing-dimorphic species or current genetic model systems. Species belonging to these categories, however, represent only a tiny fraction of insect biodiversity, potentially making generalization problematic. In this perspective, I present three topics in which current and future research may lead to greater knowledge of these processes in wing-monomorphic insects with limited existing molecular tools. First, threshold genetic models are reviewed as testable hypotheses for the heritability of migratory traits, using the sweet potato whitefly ( In faDespite lagging behind other areas of entomological research, advances in molecular biology, physiology, and technology have substantially increased our understanding of insect movement biology. Recently, I reviewed these  and concDrosophila melanogaster , Drol system ), and a l system ,19). In Drosophila and monarch butterflies to reintroduce generalized quantitative genetic models that likely still have strong applicability to insects  gene: dominant “rovers” (forR) traverse a larger search area than recessive “sitters” (forS) [Helicoverpa armigera) indicate 215 candidate genes related to long versus short distance flight [Danaus plexippus), where migration is transgenerational and direction is reversed, epigenetic effects on migratory behavior are relatively easier to test for and illustrate strong environmental effects on direction switching in re-migrants [In ” (forS) ,23. Inte” (forS) . Such a e flight ; this ise flight ,25. In mmigrants ,27.Recent research into the genetics and epigenetics of migration has certainly increased our understanding of the phenomenon in model systems where such tools are readily available. Unfortunately, the broader application of these discoveries is problematic, as unique life history traits  that make these species ideal for studying migration are not necessarily representative of higher taxa . When reviewing genomic techniques in migration research on two focal species (blackcaps and monarch butterflies), Merlin and Liedvogel  addresse“Ultimately, the discovery of generalizable mechanisms, or lack thereof, will, however, require the diversification of strategically chosen migratory animal models across taxa.”Drosophila, clearly provide powerful tools for uncovering the proximate mechanisms underlying complex behavioral traits. A valid question, however, concerns the degree to which these findings can be generalized to the majority of understudied insect taxa. Given the increasing use of molecular techniques throughout the biological sciences, this type of work will no doubt continue to be the primary research effort towards a better understanding of migration and dispersal in insects. To increase the opportunity for generalization, however, I also advocate a complementary approach: extensively testing the assumptions of quantitative genetics models derived from first principles. Perhaps most ideal of these are threshold genetic models for dimorphic phenotypic traits [Insect genetic model systems, such as c traits ,29, whicc traits ), salmonc traits ), and inc traits ). One adc traits ,34,35). classical threshold genetic model assumes that the value of a trait is determined by either the additive action of two alleles at a single locus (Mendelian inheritance) or alleles at several loci  that varies by genotype, (2) is normally-distributed in the population, and (3) is sensitive to some key environmental variable  of the clade Middle East Asia Minor-1, sometimes referred to as the ‘B’-biotype or B. argentifolii, underwent a global invasion in the 1980s [B. tabaci in both the laboratory and field throughout the 1990s [Sweet potato whiteflies  an overhead 400-W skylight cue, which stimulates upward movement via positive phototaxis; and (2) a side-mounted green (ca. 550 nm) light cue that mimics the vegetative cues used by B. tabaci in foraging for host plants. A downward-oriented laminar air flow, controlled by the investigator, keeps the insect in a steady flying position. Foraging versus migratory flight behaviors are differentiated by the continued response, or lack thereof, of the insect to timed flashes of the green light cue. These studies indicate that approximately 6% of B. tabaci engage in flights fitting the behavioral definition of migration [The migratory capacity of echnique ,48,49. HB. tabaci show little or weak evidence of it possessing the morphological and/or life history traits consistent with a migratory ‘syndrome’ . With r’ . B. tabaci is relatively simple when compared to those of more well-studied migratory insect species. Like other sternorrhynchan hemipterans, it feeds exclusively on plant phloem via stylet penetration. Eggs are inserted directly into leaf tissue, and nymphal movement is restricted to the first instar (‘crawler’) stage [B. tabaci is likely not limited by host plant availability in either its endemic or invaded regions where year-round growing is common. This makes the species a strong choice for testing the assumptions of threshold genetic traits in a representative wing-monomorphic insect.The life history of ’) stage . As a geB. tabaci  B. tabaci is an exclusively fluid-feeding herbivore; and (3) scheduled defoliation is part of the standard growing practice of a major summer food source , the environmental variable chosen to underlie migratory decisions in the model is leaf moisture content. Genetically-determined migratory thresholds are assumed to be normally distributed, with the 6% of migrants detected in previous studies representing individuals from the right tail of the distribution  strong disruptive selection for (presumably) low and high migratory thresholds in response to leaf moisture content. B. tabaci populations can be exposed to cotton plants of common age with differing levels of water stress, creating a gradient of leaf moisture content exposure. Behavioral assessment in the vertical flight chamber would permit estimation of changes in the ratio of migrant to non-migrant B. tabaci as leaf moisture content declines, which can then be compared to the assumptions of normality. Should there be relatively small frequencies of migrants on healthy leaves and non-migrants on dry leaves, respectively, then individuals of each can be bred within type over successive generations and their flight chamber behavior assessed against the leaf moisture gradient. Post-selection increases in the average frequencies of migration or philopatry in the respective populations would largely support the environmental threshold model proposed here.Experiments designed to test the above model require two primary approaches: (1) establishment of the distribution of migratory responses to leaf moisture content in natural Entomologists have long been interested in the relationship between flight and reproductive timing in female insects, given the high energetic costs of both egg production and investment in the flight motor. Johnson  proposedEven if flight and egg production are not necessarily linked at the hormonal level, it is reasonable to expect that such expensive traits can result in an allocation trade-off, or that high egg loads can be aerodynamically unfavorable . Wing-diAssumptions of ubiquitous negative associations between flight and egg production ignore the possibility that natural selection could favor a different relationship under certain conditions. One example of this concerns the effects of time (or host) limitation on species with high early reproductive investment (measured by the ‘ovigeny index’ (OI), or proportion of lifetime fecundity available in the egg load at eclosion ,63,64). Amitus  and Encarsia , while the latter often harbor both aphidiine braconids (OI > 0.6) and Aphelinus  [The hypothesis that the reduced adult lifespans associated with higher OIs lead to more time-limited dispersal can be empirically tested in parasitoid wasps . IdeallyI < 0.1) . CompariTime limitation via early reproductive investment is not the only potential explanatory factor for a positive relationship between flight and egg production. For example, rapid reproduction could be favored immediately following emigration from poor habitats, leading to a ‘colonizer syndrome’ of high dispersal and reproductive effort . FurtherEupelmus vuilletti suggests that carbohydrate and protein feeding by adults staves off the use of lipid reserves for somatic maintenance instead of egg production . If suc breeder .Even if flight and egg production are actually competing for common resources in a wing-monomorphic species, the trade-off may not be detected empirically. The ‘Y-model’, a foundational principle in life history evolution, shows how this can occur in genetic correlations between traits . Let us Asplen et al.  show howHymenoptera likely constitutes the largest insect order, with the vast majority of this biodiversity classified as ‘micro-Hymenoptera’ and exhibiting the parasitoid life history strategy . GermaneFrom the ultimate perspective, a central hypothesis for high degrees of natal dispersal by one sex is inbreeding avoidance ,79,80,81One of the proposed adaptive benefits of haplodiploidy is the rapid purging of deleterious, recessive traits through haploid males, which can ameliorate inbreeding depression . This efNasonia vitripennis, sex determination appears to be under maternal control through a feminizing effect that is silenced in haploid offspring [While CSD has been confirmed in several hymenopteran species, and is likely the ancestral state in the order , its lacffspring . Nasonia vitripennis and Agaonidae within Chalcidoidea [Sclerodermus within Bethylidae [Cardiocondyla obscurior revealed only a single diploid male after seven generations of inbreeding [Cardiocondyla batesii, show strongly female-biased sex ratios and LMC, but also no evidence of diploid male production [Whereas natal dispersal functions as an outbreeding mechanism in CSD species, species engaging in LMC and sex-specific flightlessness are more commonly found in taxa that apparently lack CSD ; Sclthylidae ). Ants , ml-CSD , and lack of CSD (C. flavipes) [Cotesia species of known sex determination mechanism, with the expectation that unmated individuals with mechanisms expected to produce fewer diploid males  should exhibit lower flight levels than those bearing the highest risk of inbreeding depression .The braconid genus enoptera . All thrlavipes) ,99,100. Rather than an exhaustive review of genetic and physiological mechanisms underlying dispersal and migration in well-studied model organisms, this perspective examined relationships and hypotheses that may be more generalizable to Insecta as a whole . An important theme throughout is that, despite the theoretical attention paid to the ultimate consequences of dispersal and migratory behaviors, there is still much to learn about how they (1) are controlled genetically; (2) truly interact with other costly life history traits, such as egg production; and (3) may be driven by aspects of organismal biology that are not commonly associated with flight, such as sex determination mechanisms. The inclusion of wing-monomorphic species that are not seen as model systems for migratory/dispersal research  will hopefully stimulate research into taxa that may be more representative of “Citizen Insect”.


Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease worldwide and the major cause of renal failure among patients on hemodialysis. Numerous studies have demonstrated that transient activation of epidermal growth factor receptor (EGFR) pathway is required for promoting kidney recovery from acute injury whereas its persistent activation is involved in the progression of various chronic kidney diseases including DKD. EGFR-mediated pathogenesis of DKD is involved in hemodynamic alteration, metabolic disturbance, inflammatory response and parenchymal cellular dysfunction. Therapeutic intervention of this receptor has been available in the oncology setting. Targeting EGFR might also hold a therapeutic potential for DKD. Here we review the functional role of EGFR in the development of DKD, mechanisms involved and the perspective about use of EGFR inhibitors as a treatment for DKD. Diabetic kidney disease (DKD) is a complication of diabetes mellitus and one of the leading causes of end-stage renal disease (ESRD) worldwide. DKD places a heavy personal burden on the many people world-wide who need hemodialysis and heavy economic burden on health care systems. It is urgent to find ways to slow the progression of DKD. However, its pathogenesis is complex and the mechanism is still poorly understood.Increasing evidence indicates that various signaling pathways are activated and involved in the pathogenesis of DKD. Among them, the role of epidermal growth factor receptor (EGFR) has been extensively studied . The EGFActivation of EGFR signaling has been implicated in numerous physiological and pathophysiological processes, including embryonic development, cell proliferation, cell survival, and tumorigenesis. In the mammalian kidney, EGFR is widely expressed in glomeruli and proximal tubules, including renal epithelial cells, glomerular endothelial cells, podocytes, tubular cells, mesangial cells and medullary interstitial cells . In the 2 and ultimately reaches end-stage levels below 15 ml/min/1.73 m2  and the macroalbuminuria stage (>300 mg/day) . Protein/1.73 m2 . During /1.73 m2 .Renal EGFR phosphorylation levels were significantly increased in animal models of diabetes mellitus and in cultured cells treated with high glucose . EGFR inBesides direct activation by its ligands, EGFR transactivation has been recognized as another important mechanism for signal transduction. The process of EGFR transactivation is not mediated through direct ligand binding, but through other second messengers. Several stimuli known to be involved in the pathogenesis of DKD were found capable of transactivating EGFR, such as ROS, TGF-β and PKC. In streptozotocin-induced diabetes and in cultured cells exposed to high glucose, ROS inhibition with superoxide dismutase (SOD) or an NADPH oxidase inhibitor attenuated the upregulation of EGFR phosphorylation . EndotheThe pathogenesis of DKD is a complex process involving many factors, including hemodynamic alteration, metabolic disturbance, inflammatory response and parenchymal cellular dysfunction . EGFR trHemodynamic alteration plays an important role in the pathogenesis of DKD. Chronic hyperglycemia induces metabolic alteration and dysfunction in endothelial and vascular smooth muscle cells, leading to vascular dysfunction and hemodynamic alteration in kidneys and other organs . GlomeruIn diabetic animal models, treatment with EGFR inhibitors results in a significant normalization of the altered vasoconstrictor and vasodilator response without effecting blood glucose levels . MechaniDiabetic kidneys are highly sensitive to metabolic alteration. Patients with diabetes mellitus experience chronic hyperglycemia. Glucose was translocated into cells by various transporters including glucose transporter (GLUT)-1, GLUT-4, and sodium-glucose-linked transporters. Excess glucose influx into cells leads to glucose transport along various metabolic pathways, along with the generation of reactive oxygen species (ROS) and advanced glycation end product (AGEs) . These mp-eNOS expression and inhibiting Nox4 expression  . EndoMT Podocyte injury is an early event in DKD and is a hallmark of glomerulopathy. Studies have suggested that podocyte injury is associated with the early stage of proteinuria in patients with diabetes . As termThe tubular epithelial cell has been implicated in interstitial fibrosis. Tubular epithelial cells are also vulnerable to pathologic stress due to high glucose levels and can undergo epithelial-mesenchymal-transition and apoptosis . Upon inEGFR also participated in epithelial-mesenchymal transition (EMT). EMT, a process by which injured renal tubular cells undergo a phenotype change and acquire mesenchymal characteristics, is widely recognized as a critical mediator of fibrogenesis in chronic kidney diseases. EGFR has been thought to mediate EMT. Sustained EGFR activation in the tubule induces epithelial dedifferentiation and cell cycle arrest with an increase in the mesenchymal marker and decreases in the epithelial marker . AdminisTwo groups have reported that patients who suffered from non-small-cell lung cancer (NSCLC) experienced an improvement in diabetes after erlotinib (an EGFR inhibitor) treatment . This imOther EGFR tyrosine kinase family members, such as the ErbB2 and ErbB4, may also contribute to the progression of CKD and the pathogenesis of DKD . It reliin vitro studies have provided evidence that EGFR inhibition could attenuate or prevent development and progression of DKD. This effect may associate with improvement in β cell function and insulin resistance  was approved for clinical use in 2003 and was mostly used in patients with non-small-cell lung cancer (NSCLC) carrying EGFR-activating mutations and in patients with breast and pancreatic cancers. Nevertheless, EGFR-TKIs may cause adverse effects. Since EGFR plays a role in epithelial maintenance, the most frequent and severe side effects are dermatological reactions and diarrhea. Other adverse effects include hepatotoxicity, stomatitis, interstitial lung disease, ocular toxicity and hypomagnesaemia . Most ofIn vitro and in vivo studies have demonstrated that EGFR activation can initiate multiple pathological processes leading to DKD, such as hemodynamic and metabolic alterations, chronic inflammation, and multicellular dysfunction , the Branch Grant of National Key Grants of the Ministry of Science and Technology (2018YFA0108802 to SZ) and the US National Institutes of Health (1R01DK113256-01A1 to SZ).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.


Microscopic polyangiitis (MPA) is an idiopathic autoimmune disease characterized by systemic vasculitis. While the lungs and kidneys are the major organs affected by MPA, it is known to involve multiple organ systems throughout the body. Temporal artery involvement is a very rare finding in MPA. This report presents a patient whose initial presentation was consistent with giant cell arteritis but was ultimately found to have microscopic polyangiitis. It highlights the importance of considering alternative types of vasculitis in the differential diagnosis for patients with atypical temporal artery biopsy findings. Primary vasculitides are a diverse group of disorders characterized by an autoimmune response against host blood vessels that often leads to multisystem disease . These cMicroscopic polyangiitis (MPA) is an idiopathic autoimmune disease characterized by systemic vasculitis . It is aHere we report the case of a patient whose clinical picture was consistent with giant cell arteritis but was ultimately found to have microscopic polyangiitis. This case highlights the importance of identifying the proper diagnosis in these mixed vasculitides and provides the most up-to-date literature review in patients with temporal artery findings in MPA.An 81-year-old Caucasian male with hypertension and hyperlipidemia presented with one day of complete unilateral loss of vision in his right eye, along with jaw claudication, and bitemporal headaches. He reported 1 to 2 months of weight loss, worsening fatigue, decreased oral intake, and severe bilateral lower extremity pain and edema.On physical exam, the patient was cachectic and ill-appearing with severe anasarca. He exhibited bilateral tenderness to gentle temporomandibular joint palpation, and visual exam revealed complete unilateral right-sided vision loss. Initial labs showed elevated ESR (64 mm/hr) and serum creatinine (11.9 mg/dL) levels, while urinalysis revealed moderate hematuria (10–20 RBCs/hpf) and proteinuria (urine protein/creatinine ratio of 1.15). Further testing revealed high-titer p-ANCA anti-myeloperoxidase IgG  antibodies and weakly positive antinuclear antibody titers (1 : 80). C-ANCA anti-proteinase-3 (PR3) and complement levels  were within normal limits.Given these findings, the patient was started on pulsed steroids and began to exhibit signs of clinical improvement. A subsequent right temporal artery biopsy  identifiBased on these findings, the patient was diagnosed with microscopic polyangiitis with systemic involvement of the temporal and ophthalmic arteries. He was treated with three days of pulsed steroids and intermittent hemodialysis and was then transitioned to maintenance steroids. He received one dose of rituximab induction therapy in the hospital. Given his respiratory, cardiac, and hemodynamic instability, a renal biopsy was not obtained.During his hospitalization, the patient developed acute hypoxic respiratory failure requiring BiPAP ventilation, likely secondary to his interstitial lung disease. In addition, he experienced repeated episodes of supraventricular tachyarrhythmia that required treatment with a chronotropic therapy (diltiazem drip). As his condition worsened, he was transferred to the ICU and ultimately developed an acute right-sided cerebral infarct with left hemiparesis. Given his multiorgan failure (respiratory failure and kidney failure) and stroke, his family chose to transition him to comfort care and he passed away in the hospital.The size of affected vessels has long been used to classify the various types of systemic vasculitis . While tNotably, it is exceedingly rare for MPA to present with temporal artery involvement, as only a small handful of such cases have been reported to date –13. In oHere, we describe a patient whose clinical presentation appeared to be entirely consistent with GCA , but whose biopsy results and further diagnostic workup revealed the presence of ANCA-positive MPA. This case is an important example of a difficult clinical presentation of small vessel vasculitis with temporal artery involvement in an older adult with unilateral vision loss and acute renal failure. It highlights the importance of considering alternative types of vasculitis in the differential diagnosis for patients with atypical temporal artery biopsy findings.


Cardiovascular disease (CVD) is the leading cause of death worldwide. There are numerous factors involved in the development of CVD. Among these, lipids have an important role in maintaining the myocardial cell structure as well as cardiac function. Fatty acids (FA) are utilized for energy, but also contribute to the pathogenesis of CVD and heart failure. Advances in mass spectrometry methods have enabled the comprehensive analysis of a plethora of lipid species from a single sample comprised of a heterogeneous population of lipid molecules. Determining cardiac lipid alterations in different models of CVD identifies novel biomarkers as well as reveals molecular mechanisms that underlie disease development and progression. This information could inform the development of novel therapeutics in the treatment of CVD. Herein, we provide a review of recent studies of cardiac lipid profiles in myocardial infarction, obesity, and diabetic and dilated cardiomyopathy models of CVD by methods of mass spectrometry analysis. Cardiovascular disease (CVD) is the leading cause of death worldwide . CVD encThe development of mass spectrometry (MS) technology such as high performance liquid or gas-chromatography MS (HPLC-MS/GC-MS) separation techniques and ionization methods such as electrospray ionization MS (ESI-MS), and matrix assisted laser desorption/ionization MS (MALDI-MS) have enabled the detailed analysis of chemically complex lipids from biological tissues, which contain heterogeneous pools of lipid species . These MLipids are a class of amphipathic molecules that are characterized as being insoluble in water . They coHigh density lipoprotein (HDL) and LDL cholesterol are standard measurements for patients at risk for the development of myocardial infarctions and CVD in the clinic . TroponiThe heart is composed of numerous cell and tissue types. Cardiomyocytes account for the largest percentage (30–40%) of cells within the heart, which occupy ~70–85% of heart volume ,33. StudCardiac muscle contains high numbers of mitochondria in order to produce sufficient amounts of ATP to supply the heart with abundant energy needed for the mechanical action of pumping blood throughout the body. CL is abundant in the heart and is a major phospholipid of the inner mitochondrial membrane . It is a2) molecules, which can be utilized by the electron transport chain for the production of ATP [FA and glucose are the major fuel sources of the heart ,40. Specn of ATP .In CVD including MI and pathological cardiac hypertrophy, cardiac metabolism changes from a state of primarily relying on FA and glucose through oxidative phosphorylation to utilizing anaerobic energy production such as glycolysis ,45,46. GOne of the first MS studies performed in cardiac tissue was reported in 1968 by Funasaki and Gilbertson who isolated and identified cholesteryl alkyl ethers from bovine cardiac muscle . AdvanceMI is the loss of blood flow that leads to myocardial damage . As descA study using a rat MI model reported increases in lysoPC (16:0), lysoPC (18:0), lysoPC (18:2), lysoPC (18:1), lysoPC (20:4), and lysoPE (18:0) in heart tissue by MALDI-MS imaging technology similar to that of the cell and animal studies discussed previously . However−/−) deficient mice to study its effect on ischemic heart failure [−/− mice showed altered lipidomic and metabolomic profiles and exhibited delayed heart failure progression and improved survival. However, additional studies are needed to decipher important protein, enzyme, and lipid targets that contribute to lipidome alterations during CVD progression and how these alterations can be prevented.Novel studies are now using transgenic and knockout (KO) animal models to decipher pathways, which contribute metabolic signalling in CVD. In a follow-up study, researchers used lipoxygenase  is a transcriptional co-activator, which has a role in regulating mitochondrial biogenesis genes and is thought to have a role in the development of obesity and diabetes ,67. McCoUsing cardiac specific diacylglycerol O-acyltransferase 1 (DGAT1) transgenic mice as a model of cardiac steatosis, LC-MS analysis of myocardial tissue revealed no changes in ceramides . In contMore comprehensive models are now being developed where diets are coupled with models of CVD and aging. A recent study investigated the effect of high-unsaturated fatty acid diet (HUFA) on rats subjected to supra-valvar aortic stenosis (SVAS). The study reported decreases in unsaturated (oleic and linoleic) free fatty acids as well as diacylglycerol and triacylglycerol molecules in SVAS heart tissue. However, the HUFA diet did not restore these lipids to normal levels . In one Diabetic cardiomyopathy is characterized by structural and functional changes that occur in the myocardium as a result of diabetes mellitus . SpecifiUsing leptin receptor deficient mice as a model of diabetic cardiomyopathy increases in TGs and DGs as determined by MS analysis, which were observed in cardiac tissue. There were increases in C14:1, C16:1, C16:0, C18:1, and C20:4 free fatty acid molecular subspecies in the leptin receptor deficient mice compared to controls . SimilarCardiac hypertrophy is characterized by ventricular wall thickening, which can be accompanied by both reduced systolic and diastolic function . Patholon = 10) and exhibited decreases in tetra-linoleic CL [Dilated cardiomyopathy is characterized by an enlarged ventricle, ventricular wall thinning, reduced ejection fraction, and decreased cardiac output . In contoleic CL . Similaroleic CL . This sholeic CL . These eoleic CL . Anotheroleic CL .Doxorubicin (DOX) is an anthracycline chemotherapeutic used in treating pediatric leukemias and lymphomas, but its utility is limited since high dosages of DOX put patients at risk for developing a dilated cardiomyopathy ,92. In aCVD encompasses a wide range of cardiac diseases that have different underlying causes. Cardiac lipid profiles in these models share many similarities. Specifically, most models  show increases in ceramide, sphingomyelin, and lyso-phospholipids in cardiac tissue, which suggests these may be molecular markers of disease progression. Increases in ceramides have also been linked to increases in apoptosis in a variety of models including neonatal rat cardiomyocytes ,95,96. FWhere the lipidomic studies differ is in changes to phospholipid fatty acyl composition. Specifically, phospholipid fatty acid molecules are shown to be increased and decreased in different models of CVD. This could be an indication of different alterations to FA metabolism, which may be present in different models . Other differences include changes in glycerolipids. For example, obesity and diabetic models frequently cite increases in TG and DG lipid species. Specifically, DG lipid accumulation has been linked to impaired insulin-stimulated glucose oxidation in the heart  and incoExtensive efforts have gone into examining how cardiac lipid profiles are altered in different models of CVD. The next area of lipidomic research reviewed focuses on understanding how current therapeutics used in treating cardiovascular and lipid disorders affect cardiac lipids. Non-pharmacological interventions such as diet and lifestyle changes are often the front line to prevent CVD in patients who are at risk . A recenThere is a modest amount of literature that focuses on how common drugs  used to treat cardiovascular and lipid disorders affect the cardiac tissue lipidome. Statins prevent cholesterol synthesis by inhibiting 3-hydroxy-3-methyl-glutaryl--CoA reductase and, in turn, reduce circulating levels of LDL. There are several studies that examine serum lipidomics in patients treated with statins ,104,105.Other commonly used therapeutics in treating CVD such as atherosclerosis are fibric acid derivatives. Drugs such as gemfibrozil, fenofibrate, and clofibrate lower TG and LDL levels by increasing lipoprotein lipase activity and inhibiting synthesis of very low-density lipoprotein by activating peroxisome proliferator activated receptor α (PPARα),106. TheResveratrol is a polyphenolic molecule derived from plants shown to improve myocardial lipid oxidation and cardiac function in rats . We haveAnother novel therapeutic that is gaining attention in treating CVD is elamipretide . Elamipretide is a cell permeable tetrapeptide, which is targeted to the mitochondria by binding directly to CL and reducing ROS formation while increasing mitochondrial function . It has Lipidomic analysis by MS technology is an expanding field of research. Lipids play an important role in cardiac structure, function, and disease progression. Utilizing this sensitive technique to determine changes that occur in cardiac lipid profiles in models of CVD  is important in understanding the pathology behind each disease. Furthermore, performing lipidomic studies in experimental models of CVD holds the promise of increasing our understanding of how novel therapeutics affect the heart. New challenges facing the ever-growing field of lipidomics will include data standardization to generate comparable and reproducible results. Future cardiac lipidomic studies should also focus on sorted cell populations from cardiac tissue to address heterogenous cell populations found in cardiac tissue during CVD. Ultimately, the intention of utilizing MS approaches will be to integrate lipidomics data with other -omics technology to get a better understanding of how the cardiovascular system is affected in its entirety in disease models.