The decrement in circulating endothelial progenitor cells (EPCs) in type 2 diabetes is independent of the severity of the hypoadiponectemia

MiR-31 regulates the function of diabetic endothelial progenitor cells by targeting Satb2

Endothelial malfunctions in patients with diabetes are known to result in vascular diseases, and endothelial progenitor cells (EPCs) are indispensable for the functional preservation of the vascular endothelium. MicroRNA-31 (miR-31) has been found to be able to modulate the differentiation of stem cells. However, it is still unclear how miR-31 functions in diabetic EPCs. The aim of this study was to investigate how miR-31 regulates diabetic EPC function. In the current study, miR-31 expression was compared between normal and diabetic EPCs. Satb2 was recognized as a functionally related target of miR-31 in EPCs according to computational prediction. We also explored the role of miR-31 in terms of its anti-apoptotic effects. A remarkable elevation in miR-31 expression was found in diabetic EPCs, and this elevated expression resulted in suppressed cell proliferation under high glucose. It was also found that miR-31 targets Satb2, leading to the anti-apoptotic effect and maintenance of the functions of EPCs. Furthermore, knockdown of Satb2 exhibited an inhibitory effect on proliferation and migration of EPCs in both healthy and diabetic subjects, which showed the same trend as miR-31 overexpression. Conversely, overexpression of Satb2 showed the opposite effect. Moreover, overexpression of Satb2 attenuated the miR-31-induced migration and colony-forming ability reduction and apoptosis induction of EPCs in both healthy and diabetic subjects. In diabetic EPCs, elevated glucose level was found to up-regulate miR-31 expression, which in turn enhanced the malfunction and death of EPCs. In conclusion, our results indicate that up-regulation of miR-31 may underlie endothelial dysfunction in diabetes by targeting Satb2.

Association of endothelial progenitor cells and peptic ulcer treatment in patients with type 2 diabetes mellitus

The present study aimed to investigate the association between endothelial progenitor cells (EPCs) and peptic ulcers in patients with or without type 2 diabetes mellitus (T2DM), in association with the efficiency of peptic ulcer treatment. The study recruited healthy subjects and peptic ulcer patients with or without T2DM. All the ulcer patients, including those with and without T2DM, were administered omeprazole for 8 weeks. Peptic ulcer patients with T2DM were additionally treated with glipizide and novolin. Blood samples were then obtained from the three groups following ulcer treatment. CD133⁺ cells were isolated from the blood samples using magnetic bead selection, and cultured in complete medium 199. Morphological and quantity changes in EPCs were observed by light and fluorescence microscopy. In addition, flow cytometric analysis was used to quantify the number of vascular endothelial cells. The treatment was partially effective in 7 of the 32 peptic ulcer patients without T2DM and 12 of the 32 peptic ulcer patients with T2DM. However, this treatment was ineffective in 20 of the 32 peptic ulcer patients with T2DM. Notably, 25 peptic ulcer patients without T2DM were defined as completely recovered following treatment. In addition, the number of circulating EPCs as well as their colony forming ability was significantly reduced (P<0.05) in the peptic ulcer patients with T2DM following ulcer treatment, compared with the other groups. Circulating EPC counts were significantly increased in peptic ulcer patients without T2DM, as compared with the healthy controls. With regards to colony formation, peptic ulcer patients without T2DM did not exhibit improved colony formation ability. In conclusion, the number of circulating EPCs and their colony-forming ability was significantly reduced in peptic ulcer patients with T2DM following ulcer treatment when compared with the other groups. This suggests that the poor curative effect of peptic ulcer treatment in these patients is associated with impairment of EPCs.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

Specific role of impaired glucose metabolism and diabetes mellitus in endothelial progenitor cell characteristics and function

The disease burden of diabetes mellitus (DM) and its associated cardiovascular complications represent a growing and major global health problem. Recent studies suggest that circulating exogenous endothelial progenitor cells (EPCs) play an important role in endothelial repair and neovascularization at sites of injury or ischemia. Both experimental and clinical studies have demonstrated that hyperglycemia related to DM can induce alterations to EPCs. The reduction and dysfunction of EPCs related to DM correlate with the occurrence and severity of microvascular and macrovascular complications, suggesting a close mechanistic link between EPC dysfunction and impaired vascular function/repair in DM. These alterations to EPCs, likely mediated by multiple pathophysiological mechanisms, including inflammation, oxidative stress, and alterations in Akt and the nitric oxide pathway, affect EPCs at multiple stages: differentiation and mobilization in the bone marrow, trafficking and survival in the circulation, and homing and neovascularization. Several different therapeutic approaches have consequently been proposed to reverse the reduction and dysfunction of EPCs in DM and may represent a novel therapeutic approach to prevent and treat DM-related cardiovascular complications.

Intracavernous administration of bone marrow mononuclear cells: a new method of treating erectile dysfunction?

While PDE5 inhibitors have revolutionized treatment of ED, approximately 30% of patients are non-responsive. A significant cause of this is vascular and smooth muscle dysfunction, as well as nerve atrophy. Autologous administration of bone marrow mononuclear cells (BMMC) has been performed in over 2000 cardiac patients without adverse effects, for stimulation of angiogenesis/regeneration. Despite its ease of access, and dependence on effective vasculature for function, comparatively little has been perform in terms of BMMC therapy for ED. Here we outline the rationale for use of autologous BMMC in patients with ED, as well as provide early safety data on the first use of this procedure clinically.

Low clonogenic potential of circulating angiogenic cells is associated with lower density of capillaries in skeletal muscle in patients with impaired glucose tolerance

BACKGROUND

Reduced density of capillaries in skeletal muscle can limit insulin, glucose, and oxygen supply to the muscle, thereby contributing to worsening metabolism in older adults. The lower skeletal muscle capillarization in impaired glucose tolerance (IGT) may partially be due to circulating angiogenic cell dysfunction. Circulating angiogenic cells maintain the vasculature and promote angiogenesis, but circulating angiogenic cell number and function may be reduced in IGT. The goal of this study was to determine whether the clonogenic potential of circulating angiogenic cells is lower in IGT compared with normal-glucose-tolerant (NGT) controls and is associated with skeletal muscle capillarization.

METHODS

Glucose tolerance, endothelial cell colony-forming unit (CFU-EC) number, and vastus lateralis capillary density were measured in sedentary, older (62 ± 1 years, mean ± SEM) men and women with NGT (n = 16) and IGT (n = 12).

RESULTS

Adults with IGT had 43% lower CFU-EC number (11.4 ± 2.3 versus 20.1 ± 2.0 colonies, p < 0.01) and 12% lower capillary density (291 ± 11 versus 330 ± 9 capillaries/mm², p < 0.01) compared with those with NGT. In regression analyses, CFU-EC number inversely correlated with 120-min postprandial glucose in all subjects (r = -0.47, p < 0.05), and capillary density was directly associated with CFU-EC number (r = 0.53, p < 0.05).

CONCLUSIONS

We conclude that the clonogenic potential of circulating angiogenic cells is lower in sedentary older adults with IGT and is associated with lower skeletal muscle capillarization. Low circulating angiogenic cell clonogenic potential in IGT suggests a state of impaired angiogenesis occurring prior to overt type 2 diabetes that may mediate early microvascular changes in the development and progression of IGT to type 2 diabetes.

Attenuation of hind-limb ischemia in mice with endothelial-like cells derived from different sources of human stem cells

Functional endothelial-like cells (EC) have been successfully derived from different cell sources and potentially used for treatment of cardiovascular diseases; however, their relative therapeutic efficacy remains unclear. We differentiated functional EC from human bone marrow mononuclear cells (BM-EC), human embryonic stem cells (hESC-EC) and human induced pluripotent stem cells (hiPSC-EC), and compared their in-vitro tube formation, migration and cytokine expression profiles, and in-vivo capacity to attenuate hind-limb ischemia in mice. Successful differentiation of BM-EC was only achieved in 1/6 patient with severe coronary artery disease. Nevertheless, BM-EC, hESC-EC and hiPSC-EC exhibited typical cobblestone morphology, had the ability of uptaking DiI-labeled acetylated low-density-lipoprotein, and binding of Ulex europaeus lectin. In-vitro functional assay demonstrated that hiPSC-EC and hESC-EC had similar capacity for tube formation and migration as human umbilical cord endothelial cells (HUVEC) and BM-EC (P>0.05). While increased expression of major angiogenic factors including epidermal growth factor, hepatocyte growth factor, vascular endothelial growth factor, placental growth factor and stromal derived factor-1 were observed in all EC cultures during hypoxia compared with normoxia (P<0.05), the magnitudes of cytokine up-regulation upon hypoxic were more dramatic in hiPSC-EC and hESC-EC (P<0.05). Compared with medium, transplanting BM-EC (n = 6), HUVEC (n = 6), hESC-EC (n = 8) or hiPSC-EC (n = 8) significantly attenuated severe hind-limb ischemia in mice via enhancement of neovascularization. In conclusion, functional EC can be generated from hECS and hiPSC with similar therapeutic efficacy for attenuation of severe hind-limb ischemia. Differentiation of functional BM-EC was more difficult to achieve in patients with cardiovascular diseases, and hESC-EC or iPSC-EC are readily available as "off-the-shelf" format for the treatment of tissue ischemia.

N-3 polyunsaturated Fatty acids prevent diabetic retinopathy by inhibition of retinal vascular damage and enhanced endothelial progenitor cell reparative function

Objective

The vasodegenerative phase of diabetic retinopathy is characterized by not only retinal vascular degeneration but also inadequate vascular repair due to compromised bone marrow derived endothelial progenitor cells (EPCs). We propose that n-3 polyunsaturated fatty acid (PUFA) deficiency in diabetes results in activation of the central enzyme of sphingolipid metabolism, acid sphingomyelinase (ASM) and that ASM represents a molecular metabolic link connecting the initial damage in the retina and the dysfunction of EPCs.

Research Design and Methods

Type 2 diabetic rats on control or docosahexaenoic acid (DHA)-rich diet were studied. The number of acellular capillaries in the retinas was assessed by trypsin digest. mRNA levels of interleukin (IL)-1β, IL-6, intracellular adhesion molecule (ICAM)-1 in the retinas from diabetic animals were compared to controls and ASM protein was assessed by western analysis. EPCs were isolated from blood and bone marrow and their numbers and ability to form colonies in vitro, ASM activity and lipid profiles were determined.

Results

DHA-rich diet prevented diabetes-induced increase in the number of retinal acellular capillaries and significantly enhanced the life span of type 2 diabetic animals. DHA-rich diet blocked upregulation of ASM and other inflammatory markers in diabetic retina and prevented the increase in ASM activity in EPCs, normalized the numbers of circulating EPCs and improved EPC colony formation.

Conclusions

In a type 2 diabetes animal model, DHA-rich diet fully prevented retinal vascular pathology through inhibition of ASM in both retina and EPCs, leading to a concomitant suppression of retinal inflammation and correction of EPC number and function.

Reversal of endothelial progenitor cell dysfunction in patients with type 2 diabetes using a conditioned medium of human embryonic stem cell-derived endothelial cells

BACKGROUND

The potential clinical application of bone marrow or peripheral blood-derived progenitor cells for cardiovascular regeneration in patients with diabetes mellitus (DM) is limited by their functional impairment. We sought to determine the mechanisms of impaired therapeutic efficacy of peripheral blood-derived progenitor cells in type 2 DM patients and evaluated the use of cell-free conditioned medium obtained from human embryonic stem cell-derived endothelial-like cells (ESC-ECs) to reverse their functional impairment.

METHODS

The angiogenic potential of late outgrowth endothelial cells (OECs) and cytokine profile of the conditional medium of proangiogenic cells (PACs) derived from peripheral blood-mononuclear cells of healthy control and DM patients and ESC-ECs was compared by in vitro tube formation assay and a multiplex bead-based immunoassay kit, respectively. The in vivo angiogenic potential of ESC-ECs derived conditioned medium in rescuing the functional impairment of PB-PACs in DM patients was investigated using a hindlimb ischemia model.

RESULTS

Human ESC-ECs had similar functional and phenotypic characteristics as OECs in healthy controls. Cytokine profiling showed that vascular endothelial growth factor, stromal cell-derived factor 1 and placental growth factor were down-regulated in PACs from DM patients. Tube formation assay that revealed functional impairment of OECs from DM patients could be rescued by ESC-ECs conditioned medium. Administration of ESC-ECs conditioned medium restored the therapeutic efficacy of PB-PACs from DM patients in a mouse model of hindlimb ischemia.

CONCLUSIONS

Our results showed that peripheral blood-derived progenitor cells from DM patients have impaired function because of defective secretion of angiogenic cytokines, which could be restored by supplementation of ESC-ECs conditioned medium.

Long term effects of the implantation of autologous bone marrow mononuclear cells for type 2 diabetes mellitus

Previous studies have shown that several types of stem cells can differentiate into insulin-secreting islet beta-cells and that these cells can reduce blood glucose in some trials, but there has been no report of a long-term follow-up. We assessed the long-term effects of the use of autologous bone marrow mononuclear cells in the treatment of type 2 diabetes mellitus (T2DM). Based on the willingness to receive implantation of bone marrow mononuclear cells, One hundred and eighteen patients with T2DM were divided into two groups; the patients in group I were treated with autologous bone marrow mononuclear cells and patients in group II were treated with insulin intensification therapy. Mononuclear cells from bone marrow were injected back into the patient's pancreas via a catheter. Patients were followed-up after the operation at monthly intervals for the first 3 months and thereafter every 3 months for the next 33 months, the occurrence of any side effects and the results of laboratory examinations were evaluated. There were no reported acute or chronic side effects in group I and both the HbA1c and C-peptide in group I patients were significantly better than either pretherapy values or group II patients during the follow-up period. These data suggested that the implantation of autologous bone marrow mononuclear cells for the treatment of T2DM is safe and effective. This therapy can partially restore the function of islet beta-cells and maintain blood glucose homeostasis in a longer time.