Cutaneous microangiopathy in patients with type 2 diabetes: Impaired vascular endothelial growth factor expression and its correlation with neuropathy, retinopathy and nephropathy

Associations of age-adjusted coefficient of variation of R-R intervals with autonomic and peripheral nerve function in non-elderly persons with diabetes

AIMS/INTRODUCTION

Early diagnosis of diabetes-associated cardiac autonomic neuropathy using the coefficient of variation of R-R intervals (CVRR) may improve outcomes for individuals with diabetes. The present study examined the associations of decreased CVRR at rest and during deep breathing (DB) with other autonomic nerve function parameters.

MATERIALS AND METHODS

The electronic records of 141 inpatients with diabetes (22-65 years) admitted to our hospital between March 2015 and March 2019 were analyzed retrospectively. After assessment by exclusion criteria, 51 inpatients were included. All inpatients were assessed for peripheral and autonomic nerve function, clinical characteristics, and physical abilities.

RESULTS

Inpatients with decreased CVRR at rest (n = 9 (17.6%)) and during DB (n = 12 (23.5%)) had a longer duration of known diabetes, a higher prevalence of diabetic retinopathy, lower body mass index (BMI), skeletal mass index (SMI), and knee extension strength, and a higher proportion of impaired standing balance. Decreased CVRR at rest was associated with a greater fall in diastolic BP from supine to standing, higher resting HR, longer QTc, longer time of voiding, and sensory symptoms.

CONCLUSIONS

Decreased CVRR at rest and during deep breathing was associated with lower BMI, SMI, and knee strength and a higher proportion of impaired standing balance among non-elderly inpatients with diabetes. Decreased CVRR at rest appeared more strongly associated with a greater orthostatic BP decline, higher resting heart rate, longer QTc, lower urinary tract dysfunction, and sensory symptoms than a decreased CVRR during deep breathing.

Peripheral sensory neuropathy is associated with circulating angiopoietins in type 2 diabetes patients in Ghana

Objective

Peripheral sensory neuropathy (PSN) is a common complication of type 2 diabetes (T2DM) that can lead to frequent ulcerations, lower extremities, and reduced quality of life. Imbalance in the circulating levels of angiogenic growth factors, notably, angiopoietin (Ang)-1, Ang-2 and vascular endothelial growth factor (VEGF) may be among the underlying mechanisms of PSN in T2DM patients. We studied the association between PSN and angiogenic growth factors, Ang-1, Ang-2 and VEGF in T2DM patients in Ghana.

Methods

In a case-control study design, PSN was evaluated in 160 patients with T2DM and 108 nondiabetic controls using vibration perception threshold (VPT) and diabetic neurological examination (DNE). The definition of PSN was abnormal VPT (≥25 mV) or the presence of neuropathic symptoms on examination (DNE score > 3). In addition, fasting venous blood samples were collected to measure circulating levels of Ang-1, Ang-2 and VEGF.

Results

Compared to non-diabetic controls, patients with T2DM had a higher prevalence of PSN using abnormal VPT (20.6 % vs 2.8 %, p < 0.001) or neuropathic symptoms (35.6 % vs 3.7 %, p < 0.001). Compared to nondiabetic controls, patients with T2DM had increased levels of Ang-2 [597 (274 - 1005) vs 838 (473 - 1241) ng/ml, p = 0.018] and VEGF [48.4 (17.4 - 110.1) vs 72.2 (28 - 201.8), p = 0.025] and decreased Ang-1 levels [41.1 (30 - 57.3) vs 36.1 (24.7 - 42.1) ng/ml, p = 0.01]. In regression analyses, an increase in Ang-1 levels was associated with decreased odds, while an increase in Ang-2 levels was associated with increased odds, of abnormal VPT and neuropathic symptoms in T2DM patients.

Conclusion

In our study population, PSN was associated with reduced plasma levels of Ang-1 and increased plasma levels of Ang-2 in patients with T2DM. Therefore, an imbalance of angiopoietins may be associated with PSN in T2DM.

Cutaneous changes in diabetic patients: Primed for aberrant healing?

Cutaneous manifestations affect most patients with diabetes mellitus, clinically presenting with numerous dermatologic diseases from xerosis to diabetic foot ulcers (DFUs). Skin conditions not only impose a significantly impaired quality of life on individuals with diabetes but also predispose patients to further complications. Knowledge of cutaneous biology and the wound healing process under diabetic conditions is largely limited to animal models, and studies focusing on biology of the human condition of DFUs remain limited. In this review, we discuss the critical molecular, cellular, and structural changes to the skin in the hyperglycaemic and insulin-resistant environment of diabetes with a focus specifically on human-derived data. Elucidating the breadth of the cutaneous manifestations coupled with effective diabetes management is important for improving patient quality of life and averting future complications including wound healing disorders.

Biomarkers in diabetic neuropathy

CONTEXT

The prevalence of diabetic neuropathy is drastically increasing in the world. To halt the progression of diabetic neuropathy, there is an unmet need to have potential biomarkers for the diagnosis and new drug discovery.

OBJECTIVE

To study various biomarkers involved in the pathogenesis of diabetic neuropathy.

METHODS

The literature was searched with the help of various scientific databases and resources like PubMed, ProQuest, Scopus, and Google scholar from the year 1976 to 2020.

RESULTS

Biomarkers of diabetic neuropathy are categorised as inflammatory biomarkers such as MCP-1, VEGF, TRPV1, NF-κB; oxidative biomarkers such as adiponectin, NFE2L2; enzyme biomarkers like NADPH, ceruloplasmin, HO-1, DPP-4, PARP α; miscellaneous biomarkers such as SIRT1, caveolin 1, MALAT1, and microRNA. All biomarkers have a significant role in the pathogenesis of diabetic neuropathy.

CONCLUSION

These biomarkers have a potential role in the progression of diabetic neuropathy and can be considered as potential targets for new drug discovery.

Intralesional Infiltrations of Cell-Free Filtrates Derived from Human Diabetic Tissues Delay the Healing Process and Recreate Diabetes Histopathological Changes in Healthy Rats

Lower limb ulcers in type-2 diabetic patients are a frequent complication that tributes to amputation and reduces survival. We hypothesized that diabetic healing impairment and other histopathologic hallmarks are mediated by a T2DM-induced tissue priming/metabolic memory that can be transferred from humans to healthy recipient animals and consequently reproduce diabetic donor’s phenotypes. We examined the effect of human T2DM tissue homogenates injected into non-diabetic rat excisional wounds. Fresh granulation tissue, popliteal artery, and peroneal nerve of patients with T2DM were obtained following amputation. Post-mammoplasty granulation and post-traumatic amputation-tissue of normal subjects acted as controls. The homogenates were intralesionally injected for 6–7 days into rats’ excisional thickness wounds. Infiltration with the different homogenates caused impaired wound closure, inflammation, nerve degeneration, and arterial thickening (all P &lt; 0.01 vs relevant control) resembling histopathology of diabetic donor tissues. Control materials caused marginal inflammation only. Infiltration with glycated bovine albumin provoked inflammation and wound healing delay but did not induce arterial thickening. The reproduction of human diabetic traits in healthy recipient animals through a tissue homogenate support the notion on the existence of tissue metabolic memory-associated and transmissible factors, involved in the pathogenesis of diabetic complications. These may have futuristic clinical implications for medical interventions.

Differential involvement of myelinated and unmyelinated nerve fibers in painful diabetic polyneuropathy

BACKGROUND

We aimed at evaluating the differential involvement of large myelinated Aβ-, small myelinated Aδ-, and unmyelinated C-fibers in patients with diabetic polyneuropathy and how they contribute to neuropathic pain.

METHODS

We collected clinical and diagnostic test variables in 133 consecutive patients with diabetic polyneuropathy. All patients underwent Aβ-fiber mediated nerve conduction study, Aδ-fiber mediated laser-evoked potentials and skin biopsy mainly assessing unmyelinated C-fibers.

RESULTS

Pure large-fiber and small-fiber polyneuropathy were relatively uncommon; conversely mixed-fiber polyneuropathy was the most common type of diabetic polyneuropathy (74%). The frequency of neuropathic pain was similar in the three different polyneuropathies. Ongoing burning pain and dynamic mechanical allodynia were similarly associated with specific small-fiber related variables.

CONCLUSIONS

Diabetic polyneuropathy mainly manifests as a mixed-fiber polyneuropathy, simultaneously involving Aβ-, Aδ-, and C-fibers. In most patients, neuropathic pain is distinctly associated with small-fiber damage. The evidence that the frequency of neuropathic pain does not differ across pure large-, pure small-, and mixed-fiber polyneuropathy, raises the possibility that in patients with pure large-fiber polyneuropathy nociceptive nerve terminal involvement might be undetected by standard diagnostic techniques.