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CD163, a scavenger receptor with anti-inflammatory function expressed exclusively on monocytes/macrophages, is dysregulated in cases of diabetes complications. This study aimed to characterize circulating CD163+ monocytes in the presence (D+Comps) or absence (D−Comps) of diabetes-related complications. RNA-sequencing and mass cytometry were conducted on CD163+ monocytes in adults with long-duration diabetes and D+Comps or D−Comps. Out of 10,868 differentially expressed genes identified between D+Comps and D−Comps, 885 were up-regulated and 190 were down-regulated with a ≥ 1.5-fold change. In D+Comps, 'regulation of centrosome cycle' genes were enriched 6.7-fold compared to the reference genome. MIR27A, MIR3648-1, and MIR23A, the most up-regulated and CD200R1, the most down-regulated gene, were detected in D+Comps from the list of 75 'genes of interest'. CD163+ monocytes in D+Comps had a low proportion of recruitment markers CCR5, CD11b, CD11c, CD31, and immune regulation markers CD39 and CD86. A gene–protein network identified down-regulated TLR4 and CD11b as 'hub-nodes'. In conclusion, this study reports novel insights into CD163+ monocyte dysregulation in diabetes-related complications. Enriched centrosome cycle genes and up-regulated miRNAs linked to apoptosis, coupled with down-regulated monocyte activation, recruitment, and immune regulation, suggest functionally distinct CD163+ monocytes in cases of diabetes complications. Further investigation is needed to confirm their role in diabetes-related tissue damage. [ABSTRACT FROM AUTHOR]

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Foot ulcers and poor wound healing are problematic for patients with diabetes. The beehive protectant Propolis can improve wound healing but whether it can improve healing in diabetic wounds has not been investigated. In this study, the effect of a single application of Propolis on epithelial closure, wound morphology, cellular infiltrate, and blood vessel density were investigated. Diabetes was induced in rats using streptozocin. After 6 weeks, diabetic and control animals were wounded and the wounds were treated with Propolis or saline as control. At days 6 and 12 animals were sacrificed and wounds were excised. Compared with controls, diabetes decreased epithelial closure and reepithelialization but had no effect on wound contraction. These delays were prevented by Propolis. At day 12, the impaired macrophage infiltration (C:1.49±0.09 vs. D:0.25±0.14), persistent neutrophil infiltration (C:0.22±0.19 vs. D:1.33±0.81), and increased myeloperoxidase activity (fourfold) in diabetic wounds were prevented by Propolis. Diabetes had no effect on wound volume, vessel number, or branch points. These novel data indicate that Propolis can accelerate wound healing in diabetes. As neutrophil infiltration is normalized, its mechanism of action may be through anti-inflammatory pathways. This result and the established safety profile of Propolis provide a rationale for studying topical application of this agent in a clinical setting. [ABSTRACT FROM AUTHOR]

Abnormalities of endothelial function have been demonstrated in diabetes and are thought to play a role in the pathogenesis of diabetic complications. The aims of this study were to determine whether aminoguanidine, an inhibitor of glycation, can prevent endothelial and microcirculation abnormalities in a primate model of type 1 diabetes. Male baboons (Papio hamadryas) were assigned to one of the four groups: control, diabetes, control treated with aminoguanidine or diabetes treated with aminoguanidine. Diabetes was induced by streptozocin (60 mg/kg) and treated with once daily injection of insulin. Aminoguanidine was given subcutaneously (10 mg/kg), once a day. Diabetic animals had a mean duration of diabetes of 8.9±3.4 years and HbA1c of 8.9±1.1%. Microvascular function was measured by laser Doppler velocimetry, with examination of endothelium-dependent increase in skin blood flow (SkBF) following iontophoresis of acetylcholine (ACh) and endothelium-independent increase in SkBF in response to the nitric oxide (NO) donor sodium nitroprusside (SNP). Multiple regression analysis identified diabetes (P=0.049) and aminioguanidine treatment (P=0.026) as significant determinants of ACh response. The diabetic baboons treated with aminoguanidine had less Ach-mediated SkBF response compared with controls (1.39±0.32 vs. 2.26±0.61, F=3.3, P=0.04), but there was no difference between groups in SkBF response to SNP. We conclude that endothelial dysfunction can be demonstrated in this primate model of type 1 diabetes at a stage when overt diabetic complications are not present. This occurred in the absence of insulin resistance or significant hypercholesterolemia. Administration of aminoguanidine from the onset of diabetes was not able to prevent this abnormality and in fact aggravated the endothelial response. Effects of aminoguanidine on NO synthase may contribute to this phenomenon. Am. J. Primatol. 70:796–802, 2008. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Unlabelled: Diabetic renal disease is characterized by accumulation of extracellular matrix, glomerulosclerosis, and tubulointerstitial fibrosis. Connective tissue growth factor (CTGF) is implicated in these changes, as it contributes to new matrix synthesis and is increased in the diabetic kidney. CTGF also inhibits mesangial matrix degradation through up-regulation of the tissue inhibitor of matrix metalloproteinase 1 (TIMP-1). In a non-human primate model of diabetes, we determined whether the level of renal CTGF protein before development of albuminuria correlated with renal matrix and TIMP-1 changes and whether renal CTGF predicts progression to albuminuria.Methods: In a group of diabetic (n=9) and control (n=6) baboons after a 5-year duration of diabetes, renal tissue CTGF and TIMP-1 were detected by immunohistochemistry and compared with glomerular basement membrane (GBM) thickness and mesangial volume measurements from electron photomicrographs of renal biopsies. Urinary albumin levels were measured at 5 and 10 years of diabetes.Results: GBM thickness, CTGF protein, and TIMP-1 protein were increased after 5 years of diabetes (each P<.05). Tubular fibronectin scores correlated with tubular CTGF scores (r=0.72, P=.002). In diabetic animals, GBM thickness correlated with tubular and total CTGF levels (P=.002 and P=.04, respectively), whereas mesangial cell and total matrix volume correlated with glomerular TIMP-1 (P=.02 and P=.01, respectively). Tubular CTGF scores (P=.008) and GBM thickness (P=.03) at 5 years in diabetes each predicted the degree of albuminuria at 10 years.Conclusions: These results suggest that early increases in renal CTGF protein contribute to incipient diabetic nephropathy and that renal CTGF may have utility as an early marker for progression to dysfunction in the diabetic kidney. [ABSTRACT FROM AUTHOR]

The prevalence of diabetes is increasing worldwide and has been forecasted to double in the next 20 years. The major increase in morbidity and mortality of diabetes is due to the development of both macro- and microvascular complications, including failure of the wound-healing process. Foot ulcers occur in 15% of all patients with diabetes and precede 84% of all lower-leg amputations. The essential components of diabetic foot ulcer treatment are to reduce foot bearing pressure (in neuropathic ulcers) and to increase blood supply (in the case of vascular ulcers). Antibacterial therapy is also important. Despite optimized treatment, for reasons not completely understood, some ulcers fail to heal. Previous research studies have shown clearly that failure of healing eventually leads to deep-seated infection and amputation. Therefore, impaired wound healing is the pivotal event responsible for most of the morbidity (and mortality) of diabetic foot disease. Improving wound healing in diabetes requires a multidisciplinary approach in terms of clinical management as well as an increased effort aimed at better understanding the pathogenesis of poor wound healing in diabetes. Consequently, a detailed understanding of the wound-healing process in diabetes and how it can be improved is of great importance. However, efforts to develop new therapies are hampered by a lack of knowledge of the molecular mechanisms responsible for the pathologies, as well as a lack of suitable models for the study of chronic wounds. Therefore, this review will address both clinical and biochemical aspects of wound healing in diabetes. [ABSTRACT FROM AUTHOR]

Aims: Delayed healing of diabetes-related foot ulcers (DRFUs) is associated with increased macrophage and matrix metalloproteinases (MMPs) at the wound site. Whether circulating monocyte phenotype and/or MMPs are altered in association with wound healing outcome is unknown, and was investigated in this study.Methods: Blood was obtained from 21 participants with DRFU, at initial visit (V1), week-4 (V2), and week-8 (V3) for measurement of monocyte number (CD14+), phenotype (CD16, CD163) and chemokine receptors (CCRs) by flow cytometry, and circulating MMPs and TIMP-1 by ELISA.Results: Six wounds healed during the study. At V1, non-classical CD16++ monocytes and MMP-3 were higher in healed vs unhealed (both p < 0.05). At V3, the increased %CD16++ persisted and %CCR2+ was decreased in healed, but no other monocyte markers nor MMP/TIMP differed between groups. Increased wound closure rate (WCR) at V3 correlated with increased %CD16++ monocytes and decreased MMP-2 at V1 or V1 + V2. Receiver operating characteristic (ROC) curves yielded an area-under-the-curve of %CD16++ at V1 of 0.78 to predict ulcer healing at V3.Conclusions: These results indicate that circulating monocyte phenotype and MMPs alter as DRFUs heal. The relationship of %CD16++ monocytes with WCR and ROC curve suggest a predictive role of %CD16++ monocytes for ulcer healing. [ABSTRACT FROM AUTHOR]