Endothelial Progenitor Cells Biology in Diabetes Mellitus and Peripheral Arterial Disease and their Therapeutic Potential.

Endothelial progenitors are a population of cells with the inherent capacity to differentiate into mature endothelial cells and proangiogenic paracrine action. These characteristics have led to extensive studies being performed and tested in the treatment of tissue ischemia. The natural course of diabetes mellitus (DM) results in multiple areas of vascular damage. Thus endothelial progenitor cells'(EPCs) beneficial potential is particularly desirable in diabetic patients. In this review, we summarize contemporary knowledge of EPC biology in DM. It has been shown that EPC functions are considerably impaired by DM. The presence of peripheral arterial disease (PAD) seems to further exacerbate the deficiencies of EPCs. However, studies examining EPC counts in PAD and DM observed disparate results, which can be due to a lack of consensus on precise EPC immunotype used in the different studies. Nevertheless, the results of EPC-based autologous cell therapy (ACT) are promising. In addition, EPCs have been shown to bean independent predictor of cardiovascular risk and diabetic foot ulcer healing.

Difference in Serum Endostatin Levels in Diabetic Patients with Critical Limb Ischemia Treated by Autologous Cell Therapy or Percutaneous Transluminal Angioplasty.

The aim of this study was to compare the serum levels of the anti-angiogenic factor endostatin (S-endostatin) as a potential marker of vasculogenesis after autologous cell therapy (ACT) versus percutaneous transluminal angioplasty (PTA) in diabetic patients with critical limb ischemia (CLI). A total of 25 diabetic patients with CLI treated in our foot clinic during the period 2008-2014 with ACT generating potential vasculogenesis were consecutively included in the study; 14 diabetic patients with CLI who underwent PTA during the same period were included in a control group in which no vasculogenesis had occurred. S-endostatin was measured before revascularization and at 1, 3, and 6 months after the procedure. The effect of ACT and PTA on tissue ischemia was confirmed by transcutaneous oxygen pressure (TcPO2) measurement at the same intervals. While S-endostatin levels increased significantly at 1 and 3 months after ACT (both P < 0.001), no significant change of S-endostatin after PTA was observed. Elevation of S-endostatin levels significantly correlated with an increase in TcPO2 at 1 month after ACT ( r = 0.557; P < 0.001). Our study showed that endostatin might be a potential marker of vasculogenesis because of its significant increase after ACT in diabetic patients with CLI in contrast to those undergoing PTA. This increase may be a sign of a protective feedback mechanism of this anti-angiogenic factor.

[Diabetic foot syndrome: importance of calf muscles MR spectroscopy in the assessment of limb ischemia and effect of revascularization]. / Syndrom diabetické nohy: význam MR spektroskopie lýtkových svalu pro hodnocení koncetinové ischemie a efektu revaskularizace.

AIM: The standard method for assessment of effect of revascularization in patients with diabetic foot (DF) and critical limb ischemia (CLI) is transcutaneous oxygen pressure (TcPO2). Phosphorus magnetic resonance spectroscopy (31P MRS) enables to evaluate oxidative muscle metabolism that could be impaired in patients with diabetes and its complications. The aim of our study was to compare MRS of calf muscle between patients with DF and CLI and healthy controls and to evaluate the contribution of MRS in the assessment of the effect of revascularization. METHODS: Thirty-four diabetic patients with DF and CLI treated either by autologous cell therapy (ACT; 15 patients) or percutaneous transluminal angioplasty (PTA; 12 patients) in our foot clinic during 2013-2016 and 19 healthy controls were included into the study. TcPO2 measurement was used as a standard method of non-invasive evaluation of limb ischemia. MRS examinations were performed using the whole-body 3T MR system 1 day before and 3 months after the procedure. Subjects were examined in a supine position with the coil fixed under the m. gastrocnemius. MRS parameters were obtained at rest and during the exercise period. Rest MRS parameters of oxidative muscle metabolism such as phosphocreatine (PCr), inorganic phosphate (Pi), phosphodiesters (PDE), adenosine triphosphate (ATP), dynamic MRS parameters such as recovery constant PCr (τPCr) and mitochondrial capacity (Qmax), and pH were compared between patients and healthy controls, and also before and 3 months after revascularization. RESULTS: Patients with CLI had significantly lower PCr/Pi (p < 0.001), significantly higher Pi and pH (both p < 0.01), significantly lower Qmax and prolonged τPCr (both p < 0.001) in comparison with healthy controls. We observed a significant improvement in TcPO2 at 3 months after revascularization (from 26.4 ± 11.7 to 39.7 ± 17.7 mm Hg, p < 0.005). However, the rest MRS parameters did not change significantly after revascularization. In individual cases we observed improvement of dynamic MRS parameters. There was no correlation between MRS parameters and TcPO2 values. CONCLUSION: Results of our study show impaired oxidative metabolism of calf muscles in patients with CLI in comparison with healthy controls. We observed an improvement in dynamic MRS parameters in individual cases; this finding should be verified in a large number of patients during longer follow-up.Key words: autologous cell therapy - critical limb ischemia - diabetic foot - MR spectroscopy.