Monocyte phenotype as a predictive marker for wound healing in diabetes-related foot ulcers.

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.

Maternal vs paternal diabetes: The parental history is different in younger onset versus older onset type 2 diabetes.

BACKGROUND: A number of previous studies exploring family history of type 2 diabetes have reported a predominance of maternal diabetes. These studies have not explicitly compared parental history of diabetes across the spectrum of disease onset from youth to later adulthood. METHODS: Family history data from 11,467 patients with type 2 diabetes were extracted from the RPA Diabetes Centre database. Parental histories of diabetes were compared across a range of age of diagnosis strata (15-<30, 30-<40, 40-<50, 50-<60 and 60-<70 years). For the young-onset group (diagnosed between 15 and 30 years of age), associations between parental history of diabetes and the presence of cardio-metabolic risk factors and diabetic complications were also explored. RESULTS: For the total cohort and within each age of diagnosis strata, more individuals reported maternal history than paternal history of diabetes. The young-onset group demonstrated the highest prevalence of any parental history of diabetes (60.7%), the highest combined maternal and paternal history (15.8%) and the smallest differential between maternal (25.1%) and paternal (19.7%) history of diabetes. Within the young-onset group, no significant association between parental history and cardio-metabolic risk factors or diabetic complications were identified after a median of 15.0 years of diabetes exposure. CONCLUSION: Overall, our results demonstrate a consistent maternal excess of diabetes which could be consistent with an underlying epigenetic effect. However, the differential between maternal and paternal history is significantly lower in the young-onset group. Earlier emergence of type 2 diabetes may therefore reflect a different interaction and impact of genetic and environmental factors.

Cardiac Effects of Sulfonylurea-Related Hypoglycemia.

OBJECTIVE: To determine the effect of sulfonylurea-related hypoglycemia on cardiac repolarization and ectopy in the setting of well-controlled type 2 diabetes. RESEARCH DESIGN AND METHODS: Thirty subjects with sulfonylurea-treated type 2 diabetes underwent 48 h of concurrent continuous glucose monitoring and ambulatory electrocardiography. Ventricular repolarization (QTc) and QT dynamicity were analyzed during periods of hypoglycemia (<3.5 mmol/L for >20 min) and compared with periods of euglycemia and hyperglycemia combined. Cardiac ectopy rates during hypoglycemia were compared with ectopy rates when blood glucose was 4-10 mmol/L. RESULTS: Mean HbA1c was 6.9% (52 mmol/mol). Hypoglycemia was detected in 9 of 30 subjects (30%); episodes were typically nocturnal (67%) and asymptomatic (73%). Hypoglycemia-associated QTc prolongation was seen in five of nine subjects with a large variation in individual response. Higher QT dynamicity, a poor prognostic factor in cardiac disease, was seen in subjects who experienced hypoglycemia compared with subjects who did not (0.193 vs. 0.159 for the nocturnal period; P = 0.01). This finding persisted after the hypoglycemic event. The rates of ventricular and supraventricular ectopy demonstrated a nonsignificant trend toward an increase during hypoglycemia (median rate ratio 1.58 and 1.33, respectively). Similar, nonsignificant results were observed in a separate insulin-treated cohort. CONCLUSIONS: Hypoglycemia, often unrecognized, is a frequent finding in well-controlled sulfonylurea-treated type 2 diabetes. It is associated with the novel finding of increased QT dynamicity and QTc prolongation in some individuals. Our findings suggest sulfonylurea-related hypoglycemia can have detrimental cardiovascular sequelae. Similar effects are also seen in the setting of insulin therapy.

Hypoglycaemia and QT interval prolongation: Detection by simultaneous Holter and continuous glucose monitoring.

This study using simultaneous Holter and continuous glucose monitoring demonstrates that prolongation of QT interval can occur with hypoglycaemia in an ambulatory setting in people with type 1 and type 2 diabetes treated with insulin. This highlights the potential proarrhythmic harms associated with hypoglycaemia.

The effects of diabetes and aminoguanidine treatment on endothelial function in a primate model of type 1 diabetes.

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.

Detection and characterisation of microcirculatory abnormalities in the skin of diabetic patients with microvascular complications.

The aim of this study was to characterise microvascular blood flow in the skin and to compare it with biomarkers of endothelial dysfunction and tissue inflammation in patients with type 2 diabetes with (n=20) or without (n=20) microvascular complications and 20 control subjects. Microvascular function was measured by laser Doppler velocimetry in combination with iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP). Blood was collected for measurement of biomarkers including plasminogen activator inhibitor-1 (PAI-1), soluble intercellular adhesion molecule (sICAM), soluble vascular cell adhesion molecule (sVCAM) and high-sensitivity C-reactive protein (hsCRP). Both ACh and SNP responses fall progressively with the development of diabetes and microvascular complications. For the total cohort, there was a significant overall correlation between ACh and SNP response (r=0.7, p<0.0001), and this relationship was particularly strong in those with microvascular complications. There was a trend towards higher hsCRP levels across the three groups, but no difference in other biomarkers. Abnormalities of microvascular blood flow are evident in diabetes and become more marked with the development of microvascular complications. This relationship was similar to that shown by the marker of inflammation (hsCRP), but stronger than that pertaining to biomarkers of endothelial function. As both ACh and SNP responses are attenuated, the disturbance is not characteristic of endothelial dysfunction alone.