Fibroblast growth factor 21: A "rheostat" for metabolic regulation?

Fibroblast growth factor 21 is an evolutionarily conserved factor that plays multiple important roles in metabolic homeostasis. During the past two decades, extensive investigations have improved our understanding of its delicate metabolic roles and identified its pharmacological potential to mitigate metabolic disorders. However, most clinical trials have failed to obtain the desired results, which raises issues regarding its clinical value. Fibroblast growth factor 21 is dynamically regulated by nutrients derived from food intake and hepatic/adipose release, which in turn act on the central nervous system, liver, and adipose tissues to influence food preference, hepatic glucose, and adipose fatty acid output. Based on this information, we propose that fibroblast growth factor 21 should not be considered merely an anti-hyperglycemia or anti-obesity factor, but rather a means of balancing of nutrient fluctuations to maintain an appropriate energy supply. Hence, the specific functions of fibroblast growth factor 21 in glycometabolism and lipometabolism depend on specific metabolic states, indicating that its pharmacological effects require further consideration.

Endosulfan promotes cell proliferation and extracellular matrix accumulation through TGF-ß/Smad signaling pathway in HRMCs.

Endosulfan is an organochlorine pesticide, which poses a potential danger to human health and safety. It is known that dysfunction of glomerular mesangial cells causes glomerular sclerosis, associated with chronic kidney diseases. In the present study, we investigated the effects of endosulfan on cell proliferation and extracellular matrix accumulation (ECM) in human renal mesangial cells (HRMCs). Cells were treated with endosulfan, endosulfan (10 µM) plus specific inhibitor of TGF-ß signaling (LY2109761) or antioxidant (NAC). The results showed that endosulfan significantly promoted cell proliferation, accompanied with the decrease of p27 mRNA expression and the increase in the mRNA expression levels of p21 and inflammatory factors IL-6/IL-8. qRT-PCR results showed that matrix metalloproteinase-2 (MMP2) and tissue metalloproteinase-3 (TIMP3) were down-regulated whereas laminin was up-regulated when exposure to endosulfan. Western blot results showed that p-Smad2/3 was up-regulated, while Smad7 was down-regulated when exposure to endosulfan, which were reversed in the presence of LY2109761. Endosulfan significantly decreased the activity of SOD and increased the MDA level and CAT activity, which were reversed in the presence of NAC. These findings suggest that endosulfan can cause excessive proliferation and massive accumulation of ECM through TGF-ß/Smad signaling pathway, and also induced oxidative stress and inflammation in HRMCs.

The Effects of Acarbose on Non-Diabetic Overweight and Obese Patients: A Meta-Analysis.

INTRODUCTION: This systematic review aims to verify the efficacy of acarbose monotherapy in treating obese or overweight patients without diabetes. METHODS: In the study, we conducted a systematic search of the Pub-Med, EMBASE, Cochrane and Science Citation Index Expanded databases in search of clinical trials on acarbose treatment, overweight and obesity. The crucial inclusion criteria were as follows: (1) patients were diagnosed as overweight or obese (BMI ≥ 25 kg/m2); (2) randomized controlled trials (RCTs); (3) patients had undergone acarbose monotherapy or placebo control; (4) acarbose treatment had been carried out for at least 3 months. Exclusion criteria were as follows: (1) patients diagnosed with diabetes mellitus (DM); (2) patients had received a weight loss medication or surgery in the past 3 months; (3) papers not published in English; (4) repeated research results of the same experiment or repeated published documents. RESULTS: A total of 7 studies involving 132 in the acarbose group and 137 in placebo group, 269 subjects in total, were included in this meta-analysis. From the selected seven papers, we extracted the following clinical parameters: systolic blood pressure (SBP), diastolic blood pressure (DBP), body weight (BW), body mass index (BMI), triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL), high density cholesterol (HDL) and fasting plasma glucose (FPG). An important finding of our research is that TG was the only significantly reduced parameter in the acarbose group. Weight mean difference (WMD) was - 0.21 (95% CI - 0.33, - 0.09) mmol/l between acarbose (P = 0.0006) and placebo patients. Reduction of BMI was also greater for acarbose than placebo subjects, although the discrepancy was not statistically significant (P = 0.56). Moreover, no hypoglycemia occurred in either the acarbose group or placebo group. A few subjects experienced gastrointestinal reactions, but these were mild and improved over time. Acarbose has no obvious influence on other metabolic indexes. CONCLUSION: Acarbose monotherapy is beneficial in reducing TG levels in obese or overweight patients and will not result in hypoglycemia during medication. The side effects of acarbose are mild.

The effects of metformin on simple obesity: a meta-analysis.

OBJECTIVE: To evaluate the efficacy of metformin versus a placebo in the treatment of patients with simple obesity without obesity related diseases. METHODS: A search was done on Pub-Med, EMBASE, Cochrane, and Science Citation Index Expanded databases. The main inclusion criteria included the following:(1) randomized controlled trials. (2) patients diagnosed as being overweight or obese. (3) patients were randomly assigned to receive metformin or control. Exclusion criteria included the following: patients diagnosed with an obesity related disease, such as diabetes mellitus (DM) or polycystic ovary syndrome (PCOS). RESULTS: Compared with the placebo, weighted mean difference (WMD) was 2.33 (95% CI 0.31, 4.35) kg higher with metformin (p = 0.02). Compared with the placebo, WMD was 0.57 (95% CI 0.35, 0.79) kg/m² higher with metformin(p < 0.00001). There was no significant difference in the reduction of waist circumference between the metformin group and the control group (p = 0.05). The fasting blood glucose levels were significantly lower in the metformin group than in the control group (p < 0.00001). However, no hypoglycemia was noted in the metformin group or the control group. CONCLUSION: Metformin is effective in reducing body weight of simple obesity patients, and metformin does not induce hypoglycemia as a side effect.

The relationship between inflammatory factors, oxidative stress and DIO-1 concentration in patients with chronic renal failure accompanied with or without euthyroid sick syndrome.

Objective To investigate the relationship between inflammatory factors, oxidative stress and type 1 deiodinase (DIO-1) concentration in patients with chronic renal failure (CRF) with or without euthyroid sick syndrome (ESS). Methods This study recruited patients with CRF and divided them into two groups: group 1 had low free triiodothyronine (FT3) levels; and group 2 had normal FT3 levels. Group 3 consisted of healthy volunteers. Serum levels of interleukin (IL)-6, IL-1ß, tumour necrosis factor (TNF)-α, 8-isoprostane and DIO-1 were measured using enzyme-linked immunosorbent assays. Multiple regression analysis was used to analyse correlations between parameters. Results Sixty patients were enrolled into each group and the groups were comparable in terms of vital signs, white blood cell count, free thyroxine and thyroid stimulating hormone concentrations. The serum DIO-1 concentration was significantly higher in group 2 than in groups 1 and 3. Multivariate regression analysis revealed that the DIO-1 concentration was inversely correlated with the TNF-α concentration. Conclusions Patients with CRF without ESS showed higher concentrations of DIO-1 than patients with ESS. The DIO-1 concentration was inversely correlated with the TNF-α concentration, which might indicate that the inflammatory response was milder in the patients with CRF without ESS than in those with ESS.

Downregulation of miR-129-2 by promoter hypermethylation regulates breast cancer cell proliferation and apoptosis.

Aberrant expression of the miR-129 family has been found in several types of cancer, yet its expression and potential biologic role in breast cancer remain largely unknown. In the present study, we found that miR-129-2 was consistently downregulated in the breast cancer specimens and cell lines. Overexpression of miR-129-2-3p markedly suppressed breast cancer cell proliferation and induced its apoptosis. In addition, a luciferase reporter assay revealed that miR-129-2-3p suppressed BCL2L2 expression. Furthermore, BCL2L2 was able to reverse miR-129-2-3p-mediated cell apoptosis, indicating that BCL2L2 plays a crucial role in mediating the tumor-suppressive role of miR-129-2-3p. Moreover, bisulfite DNA sequencing PCR (BSP) analysis identified that promoter hypermethylation was responsible for the downregulation of miR-129-2 in breast cancer. Collectively, our findings indicate that miR-129-2 is downregulated in breast cancer cells by promoter hypermethylation. Moreover, downregulation of miR-129-2 results in BCL2L2 overexpression and disease progression in breast cancer patients.

Meta-analysis of coronary artery bypass graft surgery combined with stem cell transplantation in the treatment of ischemic heart diseases.

OBJECTIVE: The use of bone marrow cells (BMCs) to regenerate the myocardium and vessels is a new treatment for ischemic heart diseases (IHD) that has been receiving attention. In this study, a meta-analysis was used to analyze the efficacy of combining coronary artery bypass graft (CABG) surgery with BMC transplantation in the treatment of IHD. METHODS AND RESULTS: MEDLINE, EMBASE, Cochrane, CNKI, WAN-FANG, and WEI-PU databases were searched. The main inclusion criteria were as follows: (a) studies that analyzed patients diagnosed with chronic IHD. (b) Studies that had randomized-controlled trials. (c) Studies that included research comparing the efficacy of CABG and CABG combined with bone BMC transplantation in the treatment of IHD. (d) Studies with specific enumeration data at the end of the follow-up with a follow-up time of at least 3 months. Nine randomized trials were included. There were 158 patients in the group that received the treatment of CABG surgery as well as stem cell transplantation, referred to as the 'cell transplantation group.' A total of 147 patients were in the group that only received the treatment of CABG surgery, referred to as the 'CABG group'. Our data show that not only did stem cell transplantation significantly improve left ventricular ejection fraction (odds ratio=11.7, 95% confidence interval: 4.04-19.36; P=0.003) but it also significantly reduced the left ventricular end-diastolic volume and left ventricular end-systolic volume (P<0.001). CONCLUSION: BMC transplantation is associated with a significant improvement in left ventricular ejection fraction and the attenuation of left ventricular remodeling.

Increased expression of CXCR4 and integrin alphaM in hypoxia-preconditioned cells contributes to improved cell retention and angiogenic potency.

Cell-based angiogenesis is a promising method for the treatment of ischemic diseases, but the poor retention of implanted cells in targeted tissues is a major drawback. We tested whether hypoxic preconditioning increased retention and angiogenic potency of implanted cells in ischemic tissue. Hypoxic preconditioning of mouse peripheral blood mononuclear cells (PBMNCs) was done with 24 h of culture under 2% O(2). Normoxia-cultured PBMNCs were used as a control. Hypoxic preconditioning increased the adhesion capacity of the PBMNCs. Moreover, the expression of integrin alphaM and CXCR4 was significantly higher in the hypoxia-preconditioned PBMNCs than in the normoxia-cultured PBMNCs. Interestingly, the expression of intercellular adhesion molecule-1 (ICAM-1), a ligand of integrin alphaM, and stromal cell-derived factor-1 (SDF-1), a chemokine for CXCR4, were remarkably increased in the ischemic hindlimbs. The retention of the hypoxia-preconditioned PBMNCs was significantly higher than that of the normoxia-cultured PBMNCs, 3 days after their intramuscular implantation into ischemic hindlimbs. We also noted better blood flow in the ischemic hindlimbs implanted with the hypoxia-preconditioned PBMNCs than in those implanted with the normoxia-cultured PBMNCs, 14 days after treatment. Furthermore, antibody neutralization of integrin alphaM and CXCR4 abolished completely the increased cell retention and angiogenic potency of the hypoxia-preconditioned PBMNCs after implantation into the ischemic hindlimbs. These results indicate that hypoxic preconditioning of implanted cells is a feasible method of enhancing therapeutic angiogenesis by increasing their retention.

Antioxidant therapy attenuates diabetes-related impairment of bone marrow stem cells.

BACKGROUND: Bone marrow cells from humans and animals with diabetes exhibit decreased angiogenic potency, thought to be related to oxidative stress, so the present study investigated if antioxidant therapy would attenuate the diabetes-related impairment. METHODS AND RESULTS: Diabetic mice were given antioxidant therapy, as a daily subcutaneous injection of superoxide dismutase-mimic (10 mg kg(-1) day(-1)). Diabetic and healthy mice given a vehicle treatment were used as the control. After 4 weeks of treatment, bone marrow mononuclear cells (BM-MNCs) were collected for analysis and the endothelial progenitor cells in BM-MNCs were evaluated by flow cytometry. The intracellular reactive oxygen species (ROS) levels in BM-MNCs were measured using 6-carboxy-2'7'-dichlorodihydrofluorescein diacetate. Endothelial differentiation from the BM-MNCs was estimated by immunostaining with VE-cadherin 7 days after culture. BM-MNCs from the control diabetic mice had fewer Flk-1/CD34 double-positive progenitor cells and higher intracellular ROS levels, with lower potency of endothelial differentiation than BM-MNCs from the healthy mice. Antioxidant therapy decreased the intracellular ROS level in BM-MNCs from that in the diabetic mice significantly (P<0.05), but increased significantly the percentage of endothelial progenitor cells (P<0.05) and their potency of differentiation into endothelial cells (P<0.05). CONCLUSIONS: Antioxidant therapy attenuated the diabetes-related impairment of BM-MNCs by reducing oxidative stress.

Transient increase of cytokines in the acute ischemic tissue is beneficial to cell-based therapeutic angiogenesis.

BACKGROUND: Implantation of bone marrow cells (BMCs) is a treatment of ischemic disease. It is well known that many inflammatory cytokines are released in ischemic tissue, especially in the acute phase, so in the present study it was investigated if the transient increase of cytokines in the acute ischemic tissue influences cell-based therapeutic angiogenesis. METHODS AND RESULTS: Ischemic limb models were created in C57BL/6 mice as 24 h (acute) or 2 weeks (chronic) after ischemia. BMCs were cultured with total tissue protein, which was extracted from the acute and chronic ischemic muscles. The survival, adhesion, and migration of BMCs were significantly better after culture with 1 mg/ml total tissue protein extracted from the acute ischemic limbs than from the chronic ischemic limbs (p<0.001). For the in-vivo study, 8 x 10(6) BMCs, collected from green fluorescent protein (GFP) transgenic mice, were implanted into the acute or chronic ischemic limbs of the mice. The survival of implanted cells and blood flow were significantly better when BMCs were implanted into the acute ischemic limbs than into the chronic ischemic limbs (p<0.001). CONCLUSIONS: A transient increase of cytokines in the acute ischemic tissue is beneficial for cell-based therapeutic angiogenesis.

Myocardial repair achieved by the intramyocardial implantation of adult cardiomyocytes in combination with bone marrow cells.

Various cytokines produced by bone marrow cells can protect adult cardiomyocytes against apoptosis. Thus, we investigated the feasibility of implanting adult cardiomyocytes in combination with bone marrow cells for myocardial repair. Ventricular cardiomyocytes were isolated from adult rats and cocultured with bone marrow cells. Using a rat model of doxorubicin-induced cardiomyopathy, we injected 6 x 10(5) adult cardiomyocytes, 3 x 10(7) bone marrow cells, or both into damaged hearts, for myocardial repair. Coculture of the cardiomyocytes with the bone marrow cells enhanced the expression of integrin-beta1D and focal adhesion kinase in cardiomyocytes, resulting in increased survival and decreased apoptosis of the cardiomyocytes after 7 days of culture. Compared with the baseline levels, cardiac function was preserved by the implantation of bone marrow cells alone and by the implantation of cardiomyocytes in combination with bone marrow cells, but it was decreased significantly 28 days after the implantation of cardiomyocytes alone. Furthermore, apoptosis of the host cardiomyocytes was decreased significantly after the implantation of bone marrow cells alone, or in combination with cardiomyocytes, compared with that after the implantation of cardiomyocytes alone (p < 0.01). Interestingly, the implantation of adult cardiomyocytes in combination with bone marrow cells resulted in a dramatic increase in the survival of donor cardiomyocytes, and induced the myogenic differentiation of donor bone marrow stem cells. Our findings indicate that cardiomyocytes and bone marrow cells can assist and compliment each other; thus, the implantation of adult cardiomyocytes in combination with bone marrow cells shows promise as a feasible new strategy for myocardial repair.

TGF-beta induces the differentiation of bone marrow stem cells into immature cardiomyocytes.

Transforming growth factor-beta(1) (TGF-beta(1)) was found to induce the myogenic differentiation of bone marrow stem cells (BMSC). We investigated the morphological and electrophysiological properties of differentiated cells, and the mechanisms related to TGF-beta(1)-induced myogenic differentiation. We found that TGF-beta increased the expression of the cardiac transcription factors, GATA-4 and NKx-2.5, in BMSC after 1-3 days of cultivation. TGF-beta also induced the expressions of cardiac myosin, troponins, and ANP after 3-14 days of cultivation. However, the Ca(2+) transient was relatively weak, the connexin-43 expression was irregular, and spontaneous beating was not detected within 28 days observation. TGF-beta stimulation up-regulated most of the TGF-beta BMP signaling pathway genes, including TGFBI, ACVR2B, and phosphorylated Smad-2 and Smad-3, within 24h. TGF-beta induced the differentiation of BMSC into immature cardiomyocytes by activating the TGF-beta BMP signaling pathway.

Hypoxic preconditioning increases survival and angiogenic potency of peripheral blood mononuclear cells via oxidative stress resistance.

Cell-based angiogenesis is a promising treatment for ischemic diseases; however, the survival of implanted cells is impaired by oxidative stress in the ischemic microenvironment. We tested the hypothesis that hypoxic preconditioning of implanted cells enhances their resistance against oxidative stress, increasing cell survival and angiogenic potency after implantation into ischemic tissue. Mouse peripheral blood mononuclear cells (PBMNCs) were collected and subjected to hypoxic preconditioning by culture for 24 h in 2% O(2) at 33 degrees C. Hypoxic preconditioning of PBMNCs increased the expression of various genes related to antioxidant and survival signals remarkably. Compared with cells cultured under normoxia, the hypoxia-preconditioned PBMNCs showed significantly lower reactive oxygen species (ROS) accumulation and higher cell survival under oxidative stress induced by LY-83583 (a superoxide generator). Three days after intramuscular implantation into the ischemic hindlimbs of mice, survival of the hypoxia-preconditioned PBMNCs was high, whereas that of the normoxia-cultured PBMNCs was relatively low. Furthermore, 28 days after treatment microvessel density and blood flow in the ischemic hindlimbs were significantly better in the mice implanted with hypoxia-preconditioned PBMNCs than in those implanted with normoxia-cultured PBMNCs. Hypoxic preconditioning increased the survival and angiogenic potency of PBMNCs, through oxidative stress resistance mechanisms.

Short-term pretreatment with low-dose hydrogen peroxide enhances the efficacy of bone marrow cells for therapeutic angiogenesis.

Therapeutic angiogenesis can be induced by the implantation of bone marrow cells (BMCs). Hydrogen peroxide (H(2)O(2)) has been shown to increase VEGF expression and to be involved in angiogenesis. We tested the hypothesis that pretreatment with H(2)O(2) enhances the efficacy of BMCs for neovascularization. H(2)O(2) pretreatment was done by incubating mouse BMCs in 5 microM H(2)O(2) for 30 min, followed by washing twice with PBS. The H(2)O(2)-pretreated and untreated BMCs were then studied in vitro and in vivo. RT-PCR analysis showed that expression of VEGF and Flk-1 mRNA was significantly higher in H(2)O(2)-pretreated BMCs than in untreated BMCs after 12 and 24 h of culture (P<0.01). Pretreatment with H(2)O(2) also effectively enhanced the VEGF production and endothelial differentiation from BMCs after 1 and 7 days of culture (P<0.05). To estimate the angiogenic potency in vivo, H(2)O(2)-pretreated or untreated BMCs were intramuscularly implanted into the ischemic hindlimbs of mice. After 14 days of treatment, many of the H(2)O(2)-pretreated BMCs were viable, showed endothelial differentiation, and were incorporated in microvessels. Conversely, the survival and incorporation of the untreated BMCs were relatively poor. Microvessel density and blood flow in the ischemic hindlimbs were significantly greater in the mice implanted with H(2)O(2)-pretreated BMCs than in those implanted with untreated BMCs (P<0.05). These results show that the short-term pretreatment of BMCs with low-dose H(2)O(2) is a novel, simple, and feasible method of enhancing their angiogenic potency.

In vitro assessment of the effect of interleukin-1beta on angiogenic potential of bone marrow cells.

BACKGROUND: Therapeutic angiogenesis for ischemic diseases has been successfully induced by the implantation of autologous bone marrow cells (BMCs). It is understood that interleukin (IL)-1beta increases remarkably in ischemic tissue and has particular effects on angiogenesis. Thus, it is important to clarify how IL-1beta would effect BMCs survival and angiogenic potential. METHODS AND RESULTS: The effect of IL-1beta on BMCs survival, adhesion, and endothelial differentiation, as well as the production of angiogenic growth factors, was investigated using an in vitro assessment approach. BMCs were harvested from Zucker obese rats and cultured at a density of 3x10(6) cells/ml with 5 ng/ml IL-1 beta (IL-1beta group) or without IL-1 beta (control group). Survival and adhesion of BMCs were significantly increased in the IL-1beta group than in the control group after 1, 3, and 7 days of culture (p<0.01). The release of vascular endothelial growth factor in supernatant was also significantly higher in the IL-1beta group than in the control group after 3 and 7 days of culture (p<0.01). Furthermore, the number of differentiated endothelial cells derived from BMCs was significantly higher in the IL-1beta group than in the control group after 7 days of culture (p<0.01). CONCLUSIONS: These results suggest that IL-1beta has a positive effect on the angiogenic potential of BMCs in vitro.

Impaired potency of bone marrow mononuclear cells for inducing therapeutic angiogenesis in obese diabetic rats.

Using Zucker fatty rats, a strain characterized by diabetes and hyperlipidemia, we investigated the diabetes- and hyperlipidemia-related impairment of bone marrow mononuclear cells (BMCs) for inducing therapeutic angiogenesis. BMCs from Zucker fatty and normal Zucker lean rats were collected and cultured. Although the characterization and cell survival of BMCs did not differ, the VEGF production, endothelial differentiation, and endothelial cell colony-forming potential of BMCs from Zucker fatty rats were significantly lower than those of BMCs from lean rats. By using an ischemic hindlimb model, we found that the native recovery of induced limb ischemia in the Zucker fatty rats was also significantly worse than that in the lean rats. Furthermore, the expression of 5-hydroxytryptamine (5-HT(2A)) receptors was obviously higher in the Zucker fatty rats than that in the lean rats and was enhanced after limb ischemia. Although the therapeutic potency was lower than with the implantation of BMCs from normal lean rats, the implantation of BMCs from fatty rats could also induce angiogenesis and increase blood flow significantly in the ischemic hindlimbs of Zucker fatty rats. Furthermore, the blood flow in the ischemic hindlimbs was increased by the administration of sarpogrelate, a selective 5-HT(2A)-receptor antagonist. Our results clearly show diabetes- and hyperlipidemia-related dysfunction and impaired potency for inducing angiogenesis of BMCs. However, the implantation of autologous BMCs into ischemic limbs of diabetic and hyperlipidemic rats has induced therapeutic angiogenesis effectively, and blood flow would be enhanced by the administration of a 5-HT(2A)-receptor antagonist.