Diabetic neuropathy is based on the impairment of nerve blood flow and the metabolic disorder. Although the vasodilating agents and anticoagulants improve nerve function and symptoms in diabetic neuropathy, more effective treatments are needed. Because endothelial progenitor cells (EPCs) have been identified in adult human peripheral blood, many studies have shown that transplantation of EPCs improves circulation to ischemic tissues. In this study, we have demonstrated that therapeutic neovascularization using human umbilical cord blood–derived EPCs reversed diabetic neuropathy. EPCs were isolated and expanded on day 7 of culture from cord blood mononuclear cells. Unilateral intramuscular injection of EPCs into hindlimb skeletal muscles significantly ameliorated impaired sciatic motor nerve conduction velocity and sciatic nerve blood flow in the EPC-injected side of streptozotocin-induced diabetic nude rats compared with the saline-injected side of diabetic nude rats. Histological study revealed an increased number of microvessels in hindlimb skeletal muscles in the EPC-injected side of diabetic rats. These findings suggest that transplantation of EPCs from cord blood may be a useful treatment for diabetic neuropathy.

Development of cardiovascular disease (CVD), including coronary artery disease, arrhythmia, and ischemic stroke, depends on environmental and genetic factors. To investigate the epigenetic basis of myocardial infarction (MI), we performed an epigenome-wide association study for this condition in elderly Japanese subjects. A total of 192 case subjects with MI and 192 control subjects were recruited from hospital attendees and the general population, respectively. Genome-wide DNA methylation (DNAm) profiles for DNA isolated from whole blood were obtained by analysis with an Infinium HumanMethylation450 BeadChip. The relation of DNAm sites found to be significantly associated with MI to nearby single nucleotide polymorphisms (SNPs) previously shown to be associated with CVD was assessed in the control group. Three DNAm sites (cg06642177, cg07786668, cg17218495) showed genome-wide significant associations with MI (p = 4.33 × 10−8, 3.96 × 10−10, and 3.77 × 10−8, respectively). Two of these sites (cg07786668, cg17218495) still showed such associations after adjustment for classical risk factors of MI (p = 1.04 × 10−7 and 6.60 × 10−8, respectively). The DNAm sites cg07786668 and cg17218495 are located in ZFHX3 (zinc finger homeobox 3) and SMARCA4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4) genes, respectively. SNPs in ZFHX3 or SMARCA4 that were previously found to be associated with CVD were not significantly associated with these DNAm sites in our control subjects. We identified two DNAm sites—cg07786668 in ZFHX3 and cg17218495 in SMARCA4— that are independently and significantly associated with MI. Our results suggest that the development of MI might be influenced by changes in DNAm at these sites via a pathway that differs from that affected by CVD-associated SNPs in these genes. The Kita-Nagoya Genomic Epidemiology (KING) study, which was the source of control samples in the present study, was registered in ClinicalTrials.gov (NCT00262691) on 6 December 2005.

Aims/Introduction: Dental pulp stem cells (DPSCs) are thought to be an attractive candidate for cell therapy. We recently reported that the transplantation of DPSCs increased nerve conduction velocity and nerve blood flow in diabetic rats. In the present study, we investigated the immunomodulatory effects of DPSC transplantation on diabetic peripheral nerves.Materials and Methods: DPSCs were isolated from the dental pulp of Sprague–Dawley rats and expanded in culture. Eight weeks after the streptozotocin injection, DPSCs were transplanted into the unilateral hindlimb skeletal muscles. Four weeks after DPSC transplantation, neurophysiological measurements, inflammatory gene expressions and the number of CD68‐positive cells in sciatic nerves were assessed. To confirm the immunomodulatory effects of DPSCs, the effects of DPSC‐conditioned media on lipopolysaccharide‐stimulated murine macrophage RAW264.7 cells were investigated.Results: Diabetic rats showed significant delays in sciatic nerve conduction velocities and decreased sciatic nerve blood flow, all of which were ameliorated by DPSC transplantation. The number of CD68‐positive monocytes/macrophages and the gene expressions of M1 macrophage‐expressed cytokines, tumor necrosis factor‐α and interleukin‐1β, were increased in the sciatic nerves of the diabetic rats. DPSC transplantation significantly decreased monocytes/macrophages and tumor necrosis factor‐α messenger ribonucleic acid expression, and increased the gene expression of the M2 macrophage marker, CD206, in the sciatic nerves of the diabetic rats. The in vitro study showed that DPSC‐conditioned media significantly increased the gene expressions of interleukin‐10 and CD206 in lipopolysaccharide‐stimulated RAW264.7 cells.Conclusions: These results suggest that DPSC transplantation promoted macrophages polarization towards anti‐inflammatory M2 phenotypes, which might be one of the therapeutic mechanisms for diabetic polyneuropathy.

Relief from painful diabetic neuropathy is an important clinical issue. We have previously shown that the transplantation of cultured endothelial progenitor cells or mesenchymal stem cells ameliorated diabetic neuropathy in rats. In this study, we investigated whether transplantation of freshly isolated bone marrow-derived mononuclear cells (BM-MNCs) alleviates neuropathic pain in the early stage of streptozotocin-induced diabetic rats. Two weeks after STZ injection, BM-MNCs or vehicle saline were injected into the unilateral hind limb muscles. Mechanical hyperalgesia and cold allodynia in SD rats were measured as the number of foot withdrawals to von Frey hair stimulation and acetone application, respectively. Two weeks after the BM-MNC transplantation, sciatic motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), sciatic nerve blood flow (SNBF), mRNA expressions and histology were assessed. The BM-MNC transplantation significantly ameliorated mechanical hyperalgesia and cold allodynia in the BM-MNC-injected side. Furthermore, the slowed MNCV/SNCV and decreased SNBF in diabetic rats were improved in the BM-MNC-injected side. BM-MNC transplantation improved the decreased mRNA expression of NT-3 and number of microvessels in the hind limb muscles. There was no distinct effect of BM-MNC transplantation on the intraepidermal nerve fiber density. These results suggest that autologous transplantation of BM-MNCs could be a novel strategy for the treatment of painful diabetic neuropathy.

A relationship between periodontal disease and atherosclerosis has been suggested by epidemiological studies. Ligature-induced experimental periodontitis is an adequate model for clinical periodontitis, which starts from plaque accumulation, followed by inflammation in the periodontal tissue. Here we have demonstrated using a ligature-induced periodontitis model that periodontitis activates monocytes/macrophages, which subsequently circulate in the blood and adhere to vascular endothelial cells without altering the serum TNF-α concentration. Adherent monocytes/macrophages induced NF-κB activation and VCAM-1 expression in the endothelium and increased the expression of the TNF-α signaling cascade in the aorta. Peripheral blood-derived mononuclear cells from rats with experimental periodontitis showed enhanced adhesion and increased NF-κB/VCAM-1 in cultured vascular endothelial cells. Our results suggest that periodontitis triggers the initial pathogenesis of atherosclerosis, inflammation of the vasculature, through activating monocytes/macrophages.