ProNGF,a cytokine induced after myocardial infarction in humans,targets pericytes to promote microvascular damage and activation

Treatment of acute cardiac ischemia focuses on reestablishment of blood flow in coronary arteries. However, impaired microvascular perfusion damages peri-infarct tissue, despite arterial patency. Identification of cytokines that induce microvascular dysfunction would provide new targets to limit microvascular damage. Pro–nerve growth factor (NGF), the precursor of NGF, is a well characterized cytokine in the brain induced by injury. ProNGF activates p75 neurotrophin receptor (p75^NTR) and sortilin receptors to mediate proapoptotic responses. We describe induction of proNGF by cardiomyocytes, and p75^NTR in human arterioles after fatal myocardial infarction, but not with unrelated pathologies. After mouse cardiac ischemia-reperfusion (I-R) injury, rapid up-regulation of proNGF by cardiomyocytes and p75^NTR by microvascular pericytes is observed. To identify proNGF actions, we generated a mouse expressing a mutant Ngf allele with impaired processing of proNGF to mature NGF. The proNGF-expressing mouse exhibits cardiac microvascular endothelial activation, a decrease in pericyte process length, and increased vascular permeability, leading to lethal cardiomyopathy in adulthood. Deletion of p75^NTR in proNGF-expressing mice rescues the phenotype, confirming the importance of p75^NTR-expressing pericytes in the development of microvascular injury. Furthermore, deficiency in p75^NTR limits infarct size after I-R. These studies identify novel, nonneuronal actions for proNGF and suggest that proNGF represents a new target to limit microvascular dysfunction.The primary therapeutic goal after acute myocardial infarction (MI) is to limit the duration of ischemia and to establish reperfusion using angioplasty or thrombolysis. However, even with improved arterial flow, a significant proportion of patients experience microvascular damage that leads to decreased microvascular perfusion and chronically impaired heart function (Eltzschig and Collard, 2004; Bekkers et al., 2010). At this time, the proinflammatory cytokines induced by ischemia that mediate microvascular dysfunction or apoptosis after cardiac ischemia remain largely unknown.We considered whether nerve growth factor (NGF), and specifically its uncleaved precursor proNGF, could act as a potential proapoptotic and proinflammatory cytokine in the ischemic heart. NGF is initially synthesized as proNGF, which is normally cleaved intracellularly to release mature NGF (Heymach and Shooter, 1995). Mature NGF binds to the TrkA receptor tyrosine kinase to mediate survival and differentiative effects in neurons (Reichardt, 2006). Under pathological conditions, proNGF is secreted and acts as a distinct ligand to promote neuronal apoptosis by binding to the p75 neurotrophin receptor (p75^NTR), a member of the tumor necrosis factor receptor family, and the transmembrane receptor sortilin (Lee et al., 2001; Nykjaer et al., 2004). This receptor complex activates stress and apoptotic signaling molecules, such as JNK (c-Jun N-terminal kinase) and caspase-3 (Nykjaer et al., 2005; Jansen et al., 2007; Volosin et al., 2008; Hempstead, 2009).ProNGF and p75^NTR are present at low to undetectable levels in normal, uninjured adult tissues (Fanburg-Smith and Miettinen, 2001; Harrington et al., 2004; Lommatzsch et al., 2005; Hempstead, 2009). However, they are rapidly induced after acute neuronal injury and mediate cell death or degeneration after seizures or axotomy (Harrington et al., 2004; Volosin et al., 2008). In addition, proNGF is up-regulated in neurodegenerative diseases and aging (Pedraza et al., 2005; Jansen et al., 2007). However, ngf mRNA is expressed in many organs, and secreted mature NGF promotes sympathetic innervation during development and regulates sympathetic tone in the adult (Donovan et al., 1995; Glebova and Ginty, 2005; Habecker et al., 2008). In the adult heart, mature NGF is secreted tonically by cardiac myocytes to modulate synaptic transmission by sympathetic neurons (Luther and Birren, 2006). Additionally, within hours of cardiac ischemia-reperfusion (I-R) injury in rodents, ngf mRNA is induced (Hiltunen et al., 2001), and immunoreactivity to the mature NGF domain increases in human hearts after acute MI (Meloni et al., 2010). These studies, however, do not distinguish whether mature NGF or proNGF is induced after cardiac ischemia. P75^NTR expression is also induced in the vasculature after acute injury to the aorta (Donovan et al., 1995), and p75^NTR activation promotes vascular smooth muscle and endothelial cell death in vitro (Wang et al., 2000; Kim et al., 2004). Genetic deletion of p75^NTR in mice (p75^−/−) results in reduced apoptosis of vascular smooth muscle cells after vascular injury, suggesting that locally produced neurotrophins regulate this response (Kraemer, 2002).The induction of ngf mRNA by cardiomyocytes and of p75^NTR by vascular cells after injury suggests a potential paracrine role for NGF or proNGF in modulating vascular integrity. Microvascular endothelial survival depends on reciprocal interactions with neighboring pericytes during development, and pericytes maintain microvascular structure and function in the adult animal (Gaengel et al., 2009). Disruption of endothelial cell–pericyte communication during development leads to vascular hemorrhage and embryonic death, as is readily observed in platelet-derived growth factor B (Pdgfb)– or platelet-derived growth factor receptor β (Pdgfrb)–deficient mice, where pericyte recruitment to specific vascular beds is impaired (Lindahl et al., 1997; Hellström et al., 1999; Bjarnegård et al., 2004). In adult mice, TGF-β and bone morphogenetic proteins play critical roles in maintaining pericyte survival and promoting microvascular integrity (El-Bizri et al., 2008; Walshe et al., 2009). These observations suggest that disruption of endothelial cell–pericyte interactions during cardiac microvascular maturation may lead to cardiac dysfunction later in life.In this study, we examined the expression of proNGF and its receptors, p75^NTR and sortilin-related VPS10 domain containing receptor 2 (SorCS2), a sortilin family member (Willnow et al., 2008), in the infarcted myocardium after cardiac ischemia in human autopsy material and in an established mouse model of I-R injury. We observed the induction of proNGF by cardiac myocytes and arterioles, and of p75^NTR and SorCS2 by mural cells of arterioles in the peri-infarct region of individuals who died after a recent MI. Comparable induction patterns were observed in mouse tissue after I-R injury. To investigate the consequences of proNGF expression on the cardiac vasculature, we generated and analyzed a knockin mouse that expresses one allele of cleavage-resistant proNGF (proNgf-hemagglutinin [HA]/⁺). We found that proNGF overexpression targets p75^NTR- and SorCS2-immunoreactive pericytes in the perinatal period, leading to a reduction of pericyte processes, microvascular endothelial activation, and increased vascular permeability in young adulthood, culminating in a dilated cardiomyopathy and premature lethality. This phenotype is rescued in mice that are deficient in p75^NTR. Furthermore, deficiency in p75^NTR limits the infarct size expansion after myocardial I-R injury, when compared with infarct size in wild-type mice. These observations identify proNGF and p75^NTR as potential therapeutic targets to limit microvascular dysfunction in the ischemic heart.     

Inverse association between fruit, legume, and cereal fiber and the risk of metabolic syndrome: Tehran Lipid and Glucose Study

Aims

To evaluate the association between total dietary fiber and its types and sources with the risk of MetS.

Methods

This population-based cross-sectional study was conducted on a representative sample of 2 457 adults (1 327 male and 1 130 female), aged 19-84 years. Dietary intake was assessed using a validated semiquantitative food-frequency questionnaire. Anthropometrics, blood pressure, and fasting blood glucose and lipids were measured according to standard protocols. The MetS was defined according to definition by Adult Treatment Panel III.

Results

Multivariate-adjusted odds ratio of MetS between highest and lowest quartiles was 0.53 (95% CI: 0.39-0.74; P for trend <0.05) for total dietary fiber, 0.60 (0.43-0.84; P for trend <0.05) for soluble fiber, and 0.51 (0.35-0.72; P for trend <0.05) for insoluble fiber. Among sources of dietary fiber, fruit fiber (OR: 0.51; 95% CI: 0.37-0.72), cereal fiber (0.74; 0.57-0.97), and legume fiber (0.73; 0.53-0.99) were inversely associated with the risk of MetS, after adjustment for confounding factors. Intake of vegetable fiber and nut fiber were unrelated to the risk of MetS.

Conclusions

Total dietary fiber, soluble- and insoluble fiber, fruit fiber, cereal fiber and legume fiber were associated with a protective effect for the presence of MetS among this Tehranian population.     

Effects of apomorphine and β-carbolines on firing rate of neurons in the ventral pallidum in the rats

The ventral pallidum (VP) is a critical element of the mesocorticolimbic system that is inter-connected with motor and limbic structures and may be considered as an interface between motivational and effector neural signals. Dopamine is important in behavioral output of the VP, and dysfunctioning its dopamine quantity leads to various neuropsychiatric disorders. Understanding neural substrate underlying this phenomenon has become an important affair in recent years. In this study, neuronal activities were recorded from the VP in presence or absence of the mixed dopamine D1/D2 receptor agonist, apomorphine, and/or β-carbolines, using an extracellular single-unit recording technique. We reported that subcutaneous administration of apomorphine (0.5 mg/kg) decreased neural activity in the VP. In addition, neither harmine (7.8 mg/kg; i.p.) nor harmane (4 mg/kg; i.p.) and norharmane (2.5 mg/kg; i.p.) had any effect on neural firing in the VP. Finally, pretreatment with β-carbolines prevented the apomorphine-induced inhibition on VP firing rate. Thus, according to the results of aforementioned study and our results in the present study, we can conclude that presumably most responses in the VP are D2 dopamine dependent. Although the β-carbolines were unable to alter neural activity in the VP, interestingly, pretreatment with β-carbolines protect decreasing in firing rate of neurons in the VP followed by apomorphine administration. This protective effect could be explained by interaction between β-carbolines and dopaminergic mechanisms.     

Laparoscopic management of müllerian duct cysts in infants

Purpose

The aim of the study was to demonstrate the feasibility of laparoscopic excision of pelvic müllerian duct cysts (MDCs) in infants.

Patients and Methods

Three-month-old female and 13-month-old male infants presented with frequent episodes of urinary retention and were found to have large retrovesical cystic pelvic masses. Preoperative workup including abdominopelvic ultrasonography and computed tomographic scan showed bilateral hydroureteronephrosis in the baby girl and a single left anatomical kidney with hydroureteronephrosis in the baby boy, caused by the pressure effect of the mass. The pelvic mass in both infants was excised via transperitoneal laparoscopy via a retrovesical approach.

Results

The operative times were 140 minutes in case 1 and 160 minutes in case 2. Excellent laparoscopic visualization and magnification allowed meticulous dissection of the mass from the pelvic organs in both cases. In the female infant, a 5 × 5-cm collection located retrovesically was found 3 weeks after the operation. It contained serosanguinous fluid that was percutaneously aspirated under ultrasound guidance. Histopathologic examination showed the pelvic mass to be an MDC in both patients. Postoperative abdominopelvic sonography at 3 months showed no recurrence of the mass and resolution of hydroureteronephrosis. In the male infant, a urodynamic study 3 months after the operation showed normal bladder dynamics. No voiding difficulty was noted in regular follow-up visits at the time of this writing (7 months postoperatively).

Conclusion

Laparoscopic excision of pelvic MDCs in infants is technically feasible. It is a demanding and rarely reported procedure that offers excellent surgical exposure. Longer follow-up is necessary to see if this procedure will offer less morbidity than the open techniques.     

Identification of disease-causing variants in the EXOSC gene family underlying autosomal recessive intellectual disability in Iranian families

Neurodevelopmental delay and intellectual disability (ID) can arise from numerous genetic defects. To date, variants in the EXOSC gene family have been associated with such disorders. Using next-generation sequencing (NGS), known and novel variants in this gene family causing autosomal recessive ID (ARID) have been identified in five Iranian families. By collecting clinical information on these families and comparing their phenotypes with previously reported patients, we further describe the clinical variability of ARID resulting from alterations in the EXOSC gene family, and emphasize the role of RNA processing dysregulation in ARID.     

Integrated STEM curriculum: improving educational outcomes for Head Start children

In this study, the researchers aimed to design, plan and implement a Science, Technology, Engineering and Math (STEM) model to support Pre-K children’s skills and knowledge in STEM as well as to improve Pre-K teachers’ attitudes and professional skills to plan and integrate STEM concepts in their daily classroom activities. Four classrooms from a Head Start programme in an Eastern North Carolina County participated in the study. A quasi-experimental, pre–post-intervention design was adopted to implement the steps of the project. Data were collected through multiple, convergent methods in which the research team utilized both quantitative and qualitative measures to document the participants’ progress and gains. The research outcomes proved that children attending preschool can attain higher levels of understanding in STEM when they are specifically supported through well-planned, stimulating and developmentally appropriate activities.     

Trichophyton mentagrophytes and T interdigitale genotypes are associated with particular geographic areas and clinical manifestations

The fungi Trichophyton mentagrophytes and T interdigitale account for significant amount of dermatophytosis cases worldwide. These two dermatophytes form a species complex and have a number of ribosomal internal transcribed spacer (ITS) region genotypes, allowing simultaneous species identification and strain typing. Our aim was to describe the geographic distribution of T mentagrophytes/T interdigitale ITS region genotypes and find an association between the genotypes and clinical presentations of respective infections. We performed rDNA ITS region sequencing in 397 Iranian T mentagrophytes/T interdigitale isolates and analysed all available in GenBank entries with sequences of this kind. For the study, 515 clinical annotations were available. Statistical analysis was performed by chi‐squared test and Spearman rank correlation analysis. A total of 971 sequences belonged to genotypes with at least 10 geographic annotations and were classified on the basis of exclusive occurrence in a particular region or high relative contribution to a regional sample. We discerned Asian and Oceanian (“ KU496915 ” Type V, “ KT192500 ” Type VIII, “ KU315316 ”), European (“ FM986750 ” Type III, “ MF926358 ” Type III*, “ KT285210 ” Type VI) and cosmopolitan (“ FM986691 ” Type I, “ JX122216 ” Type II, “ KP132819 ” Type II* and “ AF170453 ” Type XXIV) genotypes. There was statistically significant difference in the ITS genotype distribution between different affected body sites. Trichophyton mentagrophytes “ KT192500 ” Type VIII correlated with tinea cruris, T mentagrophytes “ KU496915 ” Type V correlated with tinea corporis, T interdigitale “ JX122216 ” Type II correlated with tinea pedis and onychomycosis. Trichophyton mentagrophytes and T interdigitale genotypes can be associated with distinct geographic locations and particular clinical presentations.