Increased expression of pigment epithelium-derived factor in aged mesenchymal stem cells impairs their therapeutic efficacy for attenuating myocardial infarction injury.

AIMS: Mesenchymal stem cells (MSCs) can ameliorate myocardial infarction (MI) injury. However, older-donor MSCs seem less efficacious than those from younger donors, and the contributing underlying mechanisms remain unknown. Here, we determine how age-related expression of pigment epithelium-derived factor (PEDF) affects MSC therapeutic efficacy for MI. METHODS AND RESULTS: Reverse transcriptase-polymerized chain reaction and enzyme-linked immunosorbent assay analyses revealed dramatically increased PEDF expression in MSCs from old mice compared to young mice. Morphological and functional experiments demonstrated significantly impaired old MSC therapeutic efficacy compared with young MSCs in treatment of mice subjected to MI. Immunofluorescent staining demonstrated that administration of old MSCs compared with young MSCs resulted in an infarct region containing fewer endothelial cells, vascular smooth muscle cells, and macrophages, but more fibroblasts. Pigment epithelium-derived factor overexpression in young MSCs impaired the beneficial effects against MI injury, and induced cellular profile changes in the infarct region similar to administration of old MSCs. Knocking down PEDF expression in old MSCs improved MSC therapeutic efficacy, and induced a cellular profile similar to young MSCs administration. Studies in vitro showed that PEDF secreted by MSCs regulated the proliferation and migration of cardiac fibroblasts. CONCLUSIONS: This is the first evidence that paracrine factor PEDF plays critical role in the regulatory effects of MSCs against MI injury. Furthermore, the impaired therapeutic ability of aged MSCs is predominantly caused by increased PEDF secretion. These findings indicate PEDF as a promising novel genetic modification target for improving aged MSC therapeutic efficacy

Relationships of Adiponectin with Markers of Systemic Inflammation and Insulin Resistance in Infants Undergoing Open Cardiac Surgery

Background. Insulin resistance and systemic inflammation frequently occur in infants undergoing cardiac surgery with cardiopulmonary bypass, while adiponectin has been demonstrated to have insulin-sensitizing and anti-inflammatory properties in obesity and type 2 diabetes mellitus. In this prospective study, we aimed to investigate the association of adiponectin with insulin resistance and inflammatory mediators in infants undergoing cardiac surgery with cardiopulmonary bypass. Methods and Results. From sixty infants undergoing open cardiac surgery, blood samples were taken before anesthesia, at the initiation of cardiopulmonary bypass and at 0, 6, 12, 24, and 48 hours after the termination of cardiopulmonary bypass. Plasma interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and adiponectin levels were assessed in blood samples. Insulin resistance was measured by assessment of the insulin requirement to maintain euglycaemia and repeated measurements of an insulin glycaemic index. Insulin glycaemic index, IL-6, and TNF-α increased up to 3–8-fold 6 h after the operation. Adiponectin is negatively correlated with markers of systemic inflammation 6 h after CPB. Conclusions. Although the level of serum adiponectin decreased significantly, there was a significant inverse association of adiponectin with markers of systemic inflammation and insulin resistance in infants undergoing open cardiac surgery

Targeting NLRP3 (Nucleotide-Binding Domain, Leucine-Rich-Containing Family, Pyrin Domain-Containing-3) Inflammasome in Cardiovascular Disorders.

Inflammation is an important innate immune response to infection or tissue damage. Inflammasomes are involved in the onset and development of inflammation. The NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome is the best-characterized inflammasome. Recent evidence has indicated the importance of the NLRP3 inflammasome in the pathophysiology of cardiovascular disorders. To further understand the roles of the NLRP3 inflammasome in the cardiovascular system, we provide a comprehensive overview and discuss the remaining questions. First, a summary of NLRP3 inflammasome in the cardiovascular system is introduced. Then, the associations between NLRP3 inflammasome and cardiovascular disorders are presented. Finally, we discuss existing problems and potential directions with this issue. The information compiled here summarizes recent progress, thus potentially aiding in the understanding of the NLRP3 inflammasome in cardiovascular disorders, designing experimental and clinical research about the NLRP3 inflammasome, and promoting therapeutics for cardiovascular disorders

Impaired cardiac SIRT1 activity by carbonyl stress contributes to aging-related ischemic intolerance.

Reactive aldehydes can initiate protein oxidative damage which may contribute to heart senescence. Sirtuin 1 (SIRT1) is considered to be a potential interventional target for I/R injury management in the elderly. We hypothesized that aldehyde mediated carbonyl stress increases susceptibility of aged hearts to ischemia/reperfusion (I/R) injury, and elucidate the underlying mechanisms with a focus on SIRT1. Male C57BL/6 young (4-6 mo) and aged (22-24 mo) mice were subjected to myocardial I/R. Cardiac aldehyde dehydrogenase (ALDH2), SIRT1 activity and protein carbonyls were assessed. Our data revealed that aged heart exhibited increased endogenous aldehyde/carbonyl stress due to impaired ALDH2 activity concomitant with blunted SIRT1 activity (P<0.05). Exogenous toxic aldehydes (4-HNE) exposure in isolated cardiomyocyte verified that aldehyde-induced carbonyl modification on SIRT1 impaired SIRT1 activity leading to worse hypoxia/reoxygenation (H/R) injury, which could all be rescued by Alda-1 (ALDH2 activator) (all P<0.05). However, SIRT1 inhibitor blocked the protective effect of Alda-1 on H/R cardiomyocyte. Interestingly, myocardial I/R leads to higher carbonylation but lower activity of SIRT1 in aged hearts than that seen in young hearts (P<0.05). The application of Alda-1 significantly reduced the carbonylation on SIRT1 and markedly improved the tolerance to in vivo I/R injury in aged hearts, but failed to protect Sirt1(+/-) knockout mice against myocardial I/R injury. This was verified by Alda-1 treatment improved postischemic contractile function recovery in ex vivo perfused aged but not in Sirt1(+/-) hearts. Thus, aldehyde/carbonyl stress is accelerated in aging heart. These results provide a new insight that impaired cardiac SIRT1 activity by carbonyl stress plays a critical role in the increased susceptibility of aged heart to I/R injury. ALDH2 activation can restore this aging-related myocardial ischemic intolerance

Serum (A) and cardiac (B) tumor necrosis factor (TNF)-α and Serum (C) and cardiac (D) interleukin (IL)-6 production in rats subjected to CPB with different treatments (n = 8/group).

<p>Values presented are mean±SEM. G, ghrelin; GI, [D-Lys3]-GHRP-6, ghrelin inhibitor; W, wortmannin, a PI3K inhibitor. **<i>P<</i>0.01 vs. Sham, ^##<i>P<</i>0.01 vs. CPB, ^#<i>P<</i>0.05 vs. CPB, ^δ<i>P<</i>0.05 vs. CPB+G.</p

Myocardial injury in rats subjected to cardiopulmonary bypass (CPB) with different treatments (n = 8/group).

<p>Values presented are mean±SEM. A: serum cardiac troponin I (cTnI) level. B: serum lactate dehydrogenase (LDH) level. G, ghrelin; GI, [D-Lys3]-GHRP-6, ghrelin inhibitor; W, wortmannin, a PI3K inhibitor. **<i>P<</i>0.01 vs. Sham, ^##<i>P<</i>0.01 vs. CPB, ^δδ<i>P<</i>0.01 vs. CPB+G.</p

Effects of ghrelin on cardiac function in different groups after CPB (n = 8, mean±SEM).

<p>G, ghrelin; GI, [D-Lys3]-GHRP-6, ghrelin inhibitor; W, wortmannin, a PI3K inhibitor; HR, heart rate; MAP, mean arterial blood pressure; LVDP, left ventricular developed pressure; ±LVdP/dt_max, the instantaneous first derivation of left ventricle pressure.</p>*<p><i>P</i><0.05 vs. Sham,</p>#<p><i>P</i><0.05 vs. CPB,</p>δ<p><i>P</i><0.05 vs. CPB+G.</p

Phosphorylation of Akt <i>in vivo</i> (A) and <i>in vitro</i> (B) following different treatments.

<p>Values presented are mean±SEM. N = 6; G, ghrelin; GI, [D-Lys3]-GHRP-6, ghrelin inhibitor; W, wortmannin, a PI3K inhibitor. **<i>P<</i>0.01 vs. Sham, ^##<i>P<</i>0.01 vs. CPB or SCPB.</p

Myocardial apoptosis, MPO activity, reduced glutathione (GSH) and oxidized glutathione (GSSH) in rats subjected to cardiopulmonary bypass (CPB) with different treatments (n = 8/group).

<p>A, top: representative photomicrographs of in situ detection of apoptotic myocytes by terminal deoxynucleotidyl nick-end labeling (TUNEL) staining in ischemic heart tissue from rats subjected to 60 min CPB. Green fluorescence shows TUNEL-positive nuclei; blue fluorescence shows nuclei of total cardiomyocytes. Bottom: percentage of TUNEL-positive nuclei in heart tissue sections. (x20 objective) B: myocardial caspase-3 activity. C: MPO activity. D: reduced glutathione (GSH). E: oxidized glutathione (GSSH). Values presented are mean±SEM. G, ghrelin; GI, [D-Lys3]-GHRP-6, ghrelin inhibitor; W, wortmannin, a PI3K inhibitor. **<i>P</i><0.01 vs. Sham, ^##<i>P</i><0.01 vs. CPB, ^δ<i>P</i><0.05 vs. CPB+G.</p