Aims:

Alterations in calcium homeostasis in the intracellular endo/sarcoplasmic reticulum (ER/SR) and mitochondria of cardiomyocytes cause cell death via the SR and mitochondrial apoptotic pathway, contributing to ventricular dysfunction. However, the role of the calcium-sensing receptor (CaR) in cardiac hypertrophy and heart failure has not been studied. This study examined the possible involvement of CaR in the SR and mitochondrial apoptotic pathway in an experimental model of heart failure.

Methods and Results:

In Wistar rats, cardiac hypertrophy and heart failure were induced by subcutaneous injection of isoproterenol (Iso). Calindol, an activator of CaR, and calhex231, an inhibitor of CaR, were administered by caudal vein injection. Cardiac remodeling and left ventricular function were then analyzed in these rats. After 2, 4, 6 and 8 weeks after the administration of Iso, the rats developed cardiac hypertrophy and failure. The cardiac expression of ER chaperones and related apoptotic proteins was significantly increased in the failing hearts. Furthermore, the expression of ER chaperones and the apoptotic rate were also increased with the administration of calindol, whereas the expression of these proteins was reduced with the treatment of calhex231. We also induced cardiac hypertrophy and failure via thoracic aorta constriction (TAC) in mice. After 2 and 4 weeks of TAC, the expression of ER chaperones and apoptotic proteins were increased in the mouse hearts. Furthermore, Iso induced ER stress and apoptosis in cultured cardiomyocytes, while pretreatment with calhex231 prevented ER stress and protected the myocytes against apoptosis. To further investigate the effect of CaR on the concentration of intracellular calcium, the calcium concentration in the SR and mitochondria was determined with Fluo-5N and x-rhod-1 and the mitochondrial membrane potential was examined with JC-1 using laser confocal microscopy. After treatment with Iso for 48 hours, activation of CaR reduced [Ca(2+)]SR, increased [Ca(2+)]m, decreased the mitochondrial membrane potential, increased the expression of ER stress chaperones and related apoptotic proteins, and induced the release of cytochrome c from the mitochondria.

Conclusions:

Our results demonstrated that CaR activation caused Ca(2+) release from the SR into the mitochondria and induced cardiomyocyte apoptosis through the SR and mitochondrial apoptotic pathway in failing hearts.

Background/Aims:

. The aim of this study was to elucidate the effects of glucose restriction (GR) on cell replicative senescence in vitro by human diploid fibroblasts IMR-90.

Methods:

IMR-90 cells were cultured under 40, 60% GR or high glucose medium and biomarkers of cell senescence were compared with cells cultured in normal glucose medium (5.5 mM glucose). The impact of different concentrations of glucose and initial passages on cell replicative senescence were assessed by cell survival days, cumulative population doublings (PD), cell proliferation rate (CPR) and SA-β-gal site-stain.

Results:

When compared with control cells, mean survival days and lifespan of IMR-90 were increased 16.7% and 11.4% by 40% GR (3.3 mM glucose). However, mean survival days and lifespan of IMR-90 were decreased 31.0% and 26.9% by HG treatment (25.0 mM glucose). The effects on survival days of IMR-90 were associated not only with different glucose concentrations but also with initial passages. The CPR of IMR-90 could be retarded by GR culture and this effect was especially associated with GR degree. It was 87% positive cells of SA-β-gal in aging stages and more slim and fibrous cells were observed in 40% GR group than NG group onset from 26 PD.

Conclusion:

Mean survival days and lifespan of human diploid fibroblasts IMR-90 were extended by glucose restriction. The higher GR levels, the earlier onset of GR, the larger benefits on extending survival days of IMR-90 could be observed. Slowing down cell proliferation by GR increased the number of cell survival days, an effect associated with GR levels. High glucose induced premature senescence of IMR-90 when started from any passages.

Background:

Mesenchymal stem cells (MSC) are promising tools for tissue-engineering and musculoskeletal regeneration. They reside within various tissues, like adipose tissue, periosteum, synovia, muscle, dermis, blood and bone marrow, latter being the most common tissue used for MSC isolation. A promising alternative source for MSC is adipose tissue due to better availability and higher yield of MSC in comparison to bone marrow. A drawback is the yet fragmentary knowledge of adipose-derived stem cell (ASC) physiology in order to make them a safe tool for in vivo application. Methods/

Results:

Here, we identified Sox9 as a highly expressed and crucial transcription factor in undifferentiated rat ASC (rASC). In comparison to rat bone marrow-derived stem cells (rBMSC), mRNA and protein levels of Sox9 were significantly higher in rASC. To study the role of Sox9 in detail, we silenced Sox9 with shRNA in rASC and examined proliferation, apoptosis and the expression of osteogenic differentiation markers. Our results clearly point to a difference in the expression profile of osteogenic marker genes between undifferentiated rASC and rBMSC in early passages. Sox9 silencing induced the expression of osteocalcin, Vegfα and Mmp13, and decreased rASC proliferation accompanied with an induction of p21 and cyclin D1 expression and delayed S-phase entry.

Conclusions:

We suggest a pro-proliferative role for Sox9 in undifferentiated rASC which may explain the higher proliferation rate of rASC compared to rBMSC. Moreover, we propose an osteogenic differentiation delaying role of Sox9 in rASC which suggests that Sox9 expression is needed to maintain rASC in an undifferentiated, proliferative state.

Depression is a multicausal disorder and has been associated with the risk to develop cancer, dementia, diabetes, epilepsy and stroke. As a metabolic disorder depression has been associated with obesity, diabetes, insulin sensitivity, neuropeptide Y, glucose regulation, poor glycemic control, glucagone-like peptide-1, cholezystokinin, ghrelin, leptin, the endocannabinoid system, insulin-like growth factor and gastrin-releasing peptide. As a cardiovascular disease a close relationship exists between depression and blood pressure, heart rate, norepinephrine, sympathetic tone, vascular resistance, blood viscosity, plasma volume, intima thickness and atherosclerosis. Additionally blood coagulation, fibrinolysis, D-dimers, plasminogen activator inhibitor-1 protein, platelet activation, VEGF, plasma nitric oxide and its synthase are changed in depressed patients. As an endocrinological and stress disorder depression has been connected with the concentration of free T4, TSH, CRH, arginine vasopressin, corticotrophin, corticosteroid release and ACTH. Depression as an inflammatory disorder is mediated by pro-inflammatory cytokines, interleukin-1, interleukin-6, TNF-alpha, soluble interleukin-2 receptors, interferon-alpha, interleukin 8, interleukin-10, hs-CRP, acute phase proteins, haptoglobin, toll like receptor 4, interleukin-1beta, mammalian target of rapamycin pathway, substance P, cyclooxygenase-2, prostaglandin-E2, lipid peroxidation levels and acid sphingomyelinase. Nutritional factors might influence depression risk, i.e. the consumption of folate, omega-3 fatty acids, monounsaturated fatty acids, olive oil, fish, fruits, vegetables, nuts, legumes, vitamin B6 and vitamin B12. The neurodegenerative hypothesis of depression explains decreased hippocampal volumes in depressed patients and changes of neurotrophic support by BDNF, erythropoietin, GDNF, FGF-2, NT3, NGF and growth hormone. In this context, a fast neuroprotective and antidepressant effect has also been observed by ketamine, which acts via the glutamatergic system. Hence, GABA, AMPA, EAAT, NMDA- and metabotropic glutamate receptors (mGluR1 to mGluR8) have gained interest in depression recently. Alternative, causative or also easy available treatment strategies beyond serotonin and noradrenaline reuptake inhibition might be a major topic of future psychiatric care. In this review, an attempt is made to overview concepts of the disease and search for perspectives on antidepressant treatment strategies beyond approved medications.

Background:

Cannabinoid type 2 (CB2) receptor agonists can protect myocardium against ischemia/reperfusion (I/R) injury although the underlying mechanism remains unclear. Here we report the antiapoptotic effect of CB2 receptor agonist, JWH133, during myocardial ischemia/reperfusion injury and potential underlying mechanisms.

Methods:

Ischemia was performed by blocking left coronary artery of rat for 30 min. After ischemia for 30 min, the rat heart was reperfused for 120 min by loosing the ligation of blocking left coronary artery. JWH133 (20 mg/kg), a CB2 receptor selective agonist, or vehicles were injected intravenously 5 minutes before ischemia. Infarct size of myocardium was assessed by histological stain, myocardial apoptosis index (AI) was determined by TUNEL, and mitochondrial membrane potential (∆Ψm) was measured by flow cytometry. Western blots were performed to measure the cytochrome c release, cleaved caspase 3, cleaved caspase 9 and PI3K/Akt kinase phosphorylation.

Results:

JWH133 significantly reduced the infarct size and AI of myocardium suffering I/R compared to vehicle-treated group. Further mechanistic study revealed that activation of CB2 receptor by JWH133 inhibited the loss of ΔΨm, reduction of the cleaved caspases-3 and -9, release of mitochondrial cytochrome c to the cytosol, and increase of phosphorylated Akt. These JWH133-mediated effects could be totally abrogated by PI3K inhibitor wortmanin or CB2 receptor antagonist AM630.

Conclusion:

Our results demonstrate that activation of CB2 receptor by JWH133 prevent apoptosis during ischemia/reperfusion through inhibition of the intrinsic mitochondria-mediated apoptotic pathway and involvement of the PI3K/Akt signal pathway.