Youzhao Jiang

Comparison of bone marrow mesenchymal stem cells with bone marrow-derived mononuclear cells for treatment of diabetic critical limb ischemia and foot ulcer: A double-blind, randomized, controlled trial

AIMS To identify better cells for the treatment of diabetic critical limb ischemia (CLI) and foot ulcer in a pilot trial. METHODS Under ordinary treatment, the limbs of 41 type 2 diabetic patients with bilateral CLI and foot ulcer were injected intramuscularly with bone marrow mesenchymal stem cells (BMMSCs), bone marrow-derived mononuclear cells (BMMNCs), or normal saline (NS). RESULTS The ulcer healing rate of the BMMSC group was significantly higher than that of BMMNCs at 6 weeks after injection (P=0.022), and reached 100% 4 weeks earlier than BMMNC group. After 24 weeks of follow-up, the improvements in limb perfusion induced by the BMMSCs transplantation were more significant than those by BMMNCs in terms of painless walking time (P=0.040), ankle-brachial index (ABI) (P=0.017), transcutaneous oxygen pressure (TcO(2)) (P=0.001), and magnetic resonance angiography (MRA) analysis (P=0.018). There was no significant difference between the groups in terms of pain relief and amputation and there was no serious adverse events related to both cell injections. CONCLUSIONS BMMSCs therapy may be better tolerated and more effective than BMMNCs for increasing lower limb perfusion and promoting foot ulcer healing in diabetic patients with CLI.

Peroxisome Proliferator–Activated Receptor-γ Coactivator-1α (PGC-1α) Enhances Engraftment and Angiogenesis of Mesenchymal Stem Cells in Diabetic Hindlimb Ischemia

To examine whether the peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α), a key regulator linking angiogenesis and metabolism, could enhance the engraftment and angiogenesis of mesenchymal stem cells (MSCs) in diabetic hindlimb ischemia, we engineered the overexpression of PGC-1α within MSCs using an adenoviral vector encoding green fluorescent protein and PGC-1α, and then tested the survivability and angiogenesis of MSCs in vitro and in vivo. Under the condition of hypoxia concomitant with serum deprivation, the overexpression of PGC-1α in MSCs resulted in a higher expression level of hypoxia-inducible factor-1α (Hif-1α), a greater ratio of B-cell lymphoma leukemia-2 (Bcl-2)/Bcl-2–associated X protein (Bax), and a lower level of caspase 3 compared with the controls, followed by an increased survival rate and an elevated expression level of several proangiogenic factors. In vivo, the MSCs modified with PGC-1α could significantly increase the blood perfusion and capillary density of ischemic hindlimb of the diabetic rats, which was correlated to an improved survivability of MSCs and an increased level of several proangiogenic factors secreted by MSCs. We identified for the first time that PGC-1α could enhance the engraftment and angiogenesis of MSCs in diabetic hindlimb ischemia.

Identification of novel HLA-A 0201-restricted cytotoxic T lymphocyte epitopes from Zinc Transporter 8.

Numerous evidences demonstrated that type 1 diabetes (T1D) is due to a loss of immune tolerance to islet antigens, and CD8(+) T cells play an important role in the development of T1D. Zinc Transporter 8 (ZnT8) has emerged in recent years as a target of disease-associated autoreactive T cells in human T1D. However, ZnT8-associated CTL specific-peptides have not been identified. In this study, we predicted and identified HLA-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes derived from ZnT8, and utilized it to immunize HLA-A2.1/Kb transgenic (Tg) mice. The results demonstrated that peptides of ZnT8 containing residues 107-115, 115-123 and 145-153 could elicit specific CTLs in vitro, and induce diabetes in mice. The results suggest that these specific peptides are novel HLA-A*0201-restricted CTL epitopes, and could have therapeutic potential in preventing of T1D disease.

Serum retinol-binding protein 4 levels are elevated but do not contribute to insulin resistance in newly diagnosed Chinese hypertensive patients.

BackgroundInsulin resistance (IR) is closely correlated with cardiovascular disease (CVD). Retinol-binding protein 4 (RBP4) is a novel adipokine that modulates the action of insulin in various diseases. This study addressed the relationship between RBP4 and IR in newly diagnosed essential hypertension.MethodsSerum RBP4, anthropometric and metabolic parameters were determined in 267 newly diagnosed essential hypertensive patients not taking antihypertensive medications. The patients along with 64 control (NC) normotensive and lean subjects paired by age and sex were divided into two groups depending on body mass index (BMI), hypertension with obesity (HPO) and hypertension without obesity (HP).ResultsA striking difference was observed in RBP4 levels between the HP and NC groups. Significantly higher levels were noted in the HP group compared with the NC group; slightly, but not significantly, lower levels were observed in the HPO group compared with the HP group. After adjusting for BMI, WC and WHR, a modestly linear relationship was observed between RBP4 levels and SBP (r = 0.377; p = 0.00), DBP (r = 0.288; p = 0.00) and HOMA-β(r = 0.121; p = 0.028). Multiple stepwise regression analysis showed that SBP, WHR and drinking were independently related with serum RBP4 levels.ConclusionsThe results of this study indicated that RBP4 levels were increased in naive hypertensive patients; however, no differences were observed in obese or non-obese hypertensive subjects. Our data suggest for the first time that RBP4 levels are significantly increased but do not contribute to the development of IR in newly diagnosed hypertensive Chinese patients.

PGC-1α prevents apoptosis in adipose-derived stem cells by reducing reactive oxygen species production in a diabetic microenvironment

AIMS To examine whether overexpression of peroxisome proliferator activated receptor-gamma coactivator-1 alpha (PGC-1α) can prevent apoptosis in adipose-derived stem cells (ASCs) by reducing reactive oxygen species (ROS) production and enhancing mitochondrial function in a diabetic environment. METHODS After the isolation, expansion and characterisation of rat ASCs, we overexpressed PGC-1α in ASCs using an adenoviral vector encoding green fluorescent protein (GFP) or PGC-1α and tested the apoptotic effect under conditions of high glucose, hypoxia and serum deprivation. The production of intracellular ROS and mitochondrial ROS was evaluated using dihydroethidium and CM-H2XRos fluorescent probes. RESULTS Under conditions of high glucose, hypoxia and serum deprivation, the overexpression of PGC-1α in ASCs decreased apoptosis and led to an increased survival rate. The ASCs modified with PGC-1α produced lower intracellular and mitochondrial ROS. The mitochondrial morphology and structure in the PGC-1α-ASC group remained relatively complete compared with the control group. CONCLUSIONS These results reveal a crucial protective role for PGC-1α in the treatment of diabetes mellitus and its complications using stem cells therapy.

Down-regulation of zinc transporter 8 in the pancreas of db/db mice is rescued by Exendin-4 administration

Recent human genetic studies have revealed that common variants of the zinc transporter 8 (ZnT-8) gene are strongly associated with type 2 diabetes mellitus (T2DM). ZnT-8 has been suggested as a potential candidate in the regulation of insulin secretion in pancreatic β-cells. In this study, we aimed to explore the expression of ZnT-8 in the development of T2DM. The expression of ZnT-8 was investigated in the pancreas and adipose tissue of homozygous db/db mice compared to heterozygous sibling db/+ mice (n=6-8). Furthermore, the effect of Exendin-4 (an analogue of glucagon-like peptide-1) on ZnT-8 expression was examined in the db/db mice. Exendin-4 or vehicle (control) was administered (i.p., 1 nmol/kg) to diabetic 8-week-old db/db mice daily for 14 days (n=8). The results revealed that ZnT-8 protein levels in the pancreas of db/db mice were reduced, accompanied by a decrease in ZnT-8 mRNA. ZnT-8 mRNA and protein levels were also significantly reduced in the epididymal and visceral fat of the db/db mice. Treatment with Exendin-4 up-regulated ZnT-8 gene expression in the pancreas of the db/db mice, but did not affect its expression in adipose tissue. These findings suggest that ZnT-8 synthesis in the pancreas and adipose tissue is down-regulated in db/db mice. Reduced ZnT-8 production in the pancreas may advance defects in insulin secretion in diabetes. These may be reversed, at least partially, by the administration of Exendin-4.

Decreased A20 mRNA and protein expression in peripheral blood mononuclear cells in patients with type 2 diabetes and latent autoimmune diabetes in adults

AIMS A20 is a negative regulator of nuclear factor kappa B activation and the central gatekeeper in inflammation and immunity. While its role in type 1 diabetes has been widely studied, its expression level in immune cells from type 2 diabetes (T2D) and latent autoimmune diabetes in adult (LADA) patients remains unclear. This study aimed to clarify whether the expression of A20 is altered in patients with T2D or LADA. METHODS Quantitative real-time polymerase chain reaction and western blotting were utilized to determine the expression of A20 mRNA and protein respectively in peripheral blood mononuclear cells (PBMCs) from patients with T2D (n=36) or LADA (n=17) and sex- and age-matched healthy controls (n=34). RESULTS The mRNA and protein expression of A20 in PBMCs from T2D and LADA patients was significantly decreased compared with healthy controls (P<0.05). Furthermore, A20 mRNA and protein expression was significantly lower in newly diagnosed T2D patients (≤1 year since diagnosis) than in patients with a long T2D duration (>1 year since diagnosis) (P<0.05). CONCLUSIONS Our results suggest that decreased expression of A20 in PBMCs may be involved in the pathogenesis of diabetes, and targeting A20 may offer a potential therapeutic tool in the treatment of diabetes.

Transcutaneous oxygen pressure (TcPO2): A novel diagnostic tool for peripheral neuropathy in type 2 diabetes patients

AIMS The assessment of transcutaneous oxygen pressure (TcPO2) may serve as a non-invasive and lower-cost alternative to nerve conduction studies (NCSs) for the diagnosis of diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether the measurement of TcPO2 is useful for evaluating DPN. METHODS We performed a cross-sectional study of 381 consecutive hospitalized diabetic patients classified by clinical examination and NCS as having DPN. Anthropometric and metabolic parameters were assessed. The TcPO2 examination was performed in both supine and sitting positions. RESULTS Three hundred and one patients had DPN. The TcPO2 in both the supine and sitting positions was highest in the Non-DPN group and lower in the confirmed DPN group than the other three groups (p<0.001). The Non-DPN group had the lowest sitting-supine position difference in TcPO2 among the groups (p<0.001). The risk factors strongly associated with DPN included sitting-supine position difference in TcPO2 (OR=4.971, p<0.001), diabetic retinopathy (DR) (odds ratio [OR]=3.794, p=0.002), and HbA1c (OR=1.534, p=0.033). The area under the curve (AUC) of the sitting-supine position difference in TcPO2 was 0.722 and revealed an optimal cut-off point for the identification of DPN (19.5 mmHg) that had a sensitivity of 0.611 and a specificity of 0.738 based on AUC analysis. CONCLUSIONS This large study of diabetic patients confirms that the sitting-supine position difference in TcPO2 is higher in DPN patients than control subjects, indicating that TcPO2 examination is a promising valuable diagnostic tool for DPN.

Atgl deficiency induces podocyte apoptosis and leads to glomerular filtration barrier damage

Abnormal lipid metabolism, renal lipid accumulation and lipotoxicity are associated with the pathological features of glomerulopathy. However, the mechanisms by which lipid accumulation leads to the development or progression of this disease have not been fully elucidated. In this work, we have identified a role for the rate‐limiting enzyme in lipolysis, adipose triglyceride lipase (ATGL; also called patatin‐like phospholipase domain‐containing protein 2), in renal lipid metabolism and kidney disease. ATGL‐deficient (Atgl(−/−)) mice displayed albuminuria, accompanied by ectopic deposition of fat in the kidney. Magnetic resonance imaging demonstrated that the contrast agent gadopentetic acid was retained in kidney tissue, suggesting defects in the glomerular filtration barrier. Furthermore, transmission electron microscopy revealed lipid deposits in the podocyte, along with foot process fusion and morphological changes suggestive of apoptosis. Indeed, shRNA‐mediated depletion of ATGL promoted podocyte apoptosis, accompanied by increased levels of intracellular reactive oxygen species (ROS) and F‐actin fibre redistribution. These effects could be partially reversed by treatment with the antioxidant N‐acetylcysteine. These data suggest that ATGL deficiency induces renal lipid accumulation, proteinuria and glomerular filtration barrier dysfunction and implicate increased intracellular ROS levels in inducing podocyte F‐actin rearrangement, foot process fusion and apoptosis that underlie these pathological features.

SFRP5 is a target gene transcriptionally regulated by PPARγ in 3T3-L1 adipocytes

Secreted frizzled-related protein 5 (SFRP5) is a newly identified adipokine. SFRP5 expression increases during the differentiation and maturation of adipocytes, but the factors regulating SFRP5 expression during this process remain unclear. This study showed that peroxisome proliferator-activated receptor γ (PPARγ) adenovirus transfection could enhance the SFRP5 expression of 3T3-L1 adipocytes. Three potential binding sites of PPARγ in the SFRP5 promoter domain were found by bioinformatics analysis. Luciferase reporter gene assay demonstrated that PPARγ regulated the activity of the SFRP5 promoter through cis-acting elements at -2,284--1,500bp. Further experiments verified that PPARγ could specifically bind to the SFRP5 promoter at -2,284--2,263bp using chromatin immunoprecipitation and electrophoretic mobility shift assay. These results suggest that SFRP5 be a target gene of PPARγ, and its expression may be under the transcriptional regulation of PPARγ.