Dermal microvessel density and maturity is closely associated with atherogenic dyslipidemia and accumulation of advanced glycation end products in adult patients with type 1 diabetes.

In patients with diabetes, functional changes in microcirculation and subclinical vascular pathology precede clinical manifestation of microangiopathic complications. The objective of this study was to evaluate the association between established vascular risk factors and density, maturity, and reactivity of dermal blood vessels in adults with type 1 diabetes (DM1). We included 148 DM1 patients (87 men) with a median (IQR) age of 40.5 (30.5-49) years and a median diabetes duration of 21 (17-29.5) years. The control group consisted of 13 healthy volunteers (6 men) with a median (IQR) age of 36 (31-43). Accumulation of advanced glycation end products (AGEs) was assessed using the AGE-Reader device. In the immunohistochemical (IHC) analyses, anti-CD133, anti-CD34, anti-CD31, and anti-vWF autoantibodies were used. Microvessel density (MVD) in the skin was calculated using the "hot spots technique". Microvascular function was examined by single-point laser-Doppler flowmetry (LDF). Median MVD, calculated for both papillary and reticular dermis, for CD31 antigen expression was 38 (19-56) per 1 mm2. The median CD34+ blood vessel density was 121 (100-155) per 1 mm2, CD133+ was 79 (63-92) per 1 mm2, and vWF+ was 50 (40-69) per 1 mm2. The average CD34/CD31 index was 2.78, the vWF/CD31 ratio was 1.32 and the CD133/CD31 ratio was 1.75. The CD34/CD31 index was positively associated with serum triglyceride concentration (Beta: 0.26, p = 0.012) and negatively associated with serum HDL cholesterol concentration (Beta: -0.22, p = 0.027), both independently from age, sex, diabetes duration, BMI, HbA1c value, presence of hypertension, and eGFR. We found a negative correlation between MVD assessed by CD31 and skin AF (r = -0.21, p = 0.016). In LDF, the area under the blood flow/time curve (AUC) correlated positively with CD31+ MVD (r = 0.21, p = 0.011) and negatively with CD34+ MVD (r = -0.20, p = 0.017). The MVD did not differ between participants with diabetes and healthy controls, and it did not differ according to the presence of retinopathy among the participants with diabetes. Atherogenic dyslipidemia is associated with increased formation of new blood vessels, characterized by high expression of CD34 and low reactivity in LDF. Conversely, chronic hyperglycemia and excessive formation of AGEs may result in decreased vascularity.

An increased skin microvessel density is associated with neurovascular complications in type 1 diabetes mellitus.

The aim of this study was to assess the blood vessel density and maturity in the skin of adults with type 1 diabetes in relation to the presence of late neurovascular complications. We included 148 patients (87 men) with a median (interquartile range) age of 41 (31-49) and median diabetes duration of 21 (17-30) years. Microvessel (CD133, CD34, CD31 and von Willebrand factor) markers were evaluated by indirect immunohistochemistry assay in material from a skin biopsy. Diabetic retinopathy was diagnosed using direct ophthalmoscopy, and diabetic kidney disease was estimated in people with increased albuminuria and a 10-year duration of diabetes or evidence of diabetic retinopathy . Diabetic peripheral neuropathy diagnosis was based on Toronto definition, cardiac autonomic neuropathy on validated ProSciCard III program. Microvessel density, assessed by CD34 and CD133, was significantly higher in patients with cardiac autonomic neuropathy [160 (125-175) vs 121 (100-154)/1 mm2, p = 0.001 and 92 (83-104) vs 79 (63-92)/1 mm2, p = 0.007, respectively] and CD34 in patients with diabetic peripheral neuropathy [135 (106-168) vs 121 (95-145)/1 mm2, p = 0.018], as compared with subjects without complications. In multivariate logistic regression, density of CD34 and CD133 positive vessels was associated with presence of cardiac autonomic neuropathy [odds ratio 1.016 (95% confidence interval: 1.002-1.029), p = 0.019 and odds ratio 1.037 (95% confidence interval: 1.008-1.067), p = 0.011, respectively]. It was independent from age, sex, diabetes duration, smoking status, body mass index and HbA1c value. Density of CD34 positive vessels was also associated with diabetic peripheral neuropathy, independently from sex and diabetes duration [odds ratio 1.009 (95% confidence interval: 1.001-1.020), p = 0.037]. Skin microvessel density is increased in adults with clinical evidence of neurovascular complications of type 1 diabetes. This is associated with predominance of the vessels of low maturity.

Evaluation of sudomotor function in adult patients with long­lasting type 1 diabetes.

INTRODUCTION The function of the sweat glands appears to be impaired in patients with diabetic complications. OBJECTIVES The aim of the study was to evaluate sudomotor function in adult patients with type 1 diabetes (DM1) and healthy controls and its relationship with metabolic control and diabetic complications. PATIENTS AND METHODS The study group included 404 patients with DM1 (194 women), aged 41 years (interquartile range [IQR], 32-51 years) and with disease duration of 23 years (IQR, 18-31 years). The control group included 84 healthy volunteers. Electrochemical skin conductance (ESC) in the feet and hands was measured in both groups. RESULTS Patients with DM1 had lower ESC than controls (feet: 80 µS [IQR, 65-85 µS] vs 83 µS [IQR, 78.5-87 µS], P <0.001; hands: 63 µS (IQR, 51-75 µS) vs 69 µS (IQR, 61.5-78.5 µS), P <0.001). In the study group, there was a negative correlation between ESC and patients' age, duration of diabetes, waist­to­hip ratio, skin autofluorescence, vibration perception threshold, as well as hemoglobin A1c and triglyceride levels, and a positive correlation with estimated glomerular filtration rate. Microvascular complications were diagnosed in 73.3% of the patients. Patients with retinopathy, diabetic kidney disease, peripheral neuropathy, and cardiac autonomic neuropathy had lower ESC in the feet and hands compared with those without complications. In multivariate logistic regression models, ESC was associated with the presence of any microvascular complications independently of potential confounders. CONCLUSIONS Diabetic microangiopathy, and in particular neuropathy, is related with reduced sudomotor function in DM1. A longer duration of diabetes, worse metabolic control, and reduced renal function are associated with greater sudomotor dysfunction.

Association between small fiber neuropathy and higher skin accumulation of advanced glycation end products in patients with type 1 diabetes.

INTRODUCTION Advanced glycation end products (AGEs) play a crucial role in the pathogenesis of diabetic peripheral neuropathy (DPN). OBJECTIVES The aim of the study was to assess the skin accumulation of AGEs in patients with long­lasting type 1 diabetes in relation to the presence of DPN. PATIENTS AND METHODS We evaluated 178 patients with type 1 diabetes (99 men; age, 43 years [interquartile range [IQR], 34-54 years]; disease duration, 25 years [IQR, 18-31 years]). DPN was diagnosed if 2 or more of the following 5 abnormalities were present: symptoms of neuropathy, lack of ankle reflexes, and impaired sensation of touch, temperature, and/or vibration. PGP 9.5­immunoreactive nerve fibers were counted to assess intraepidermal nerve fiber density (IENFD) in skin biopsy. The accumulation of AGEs in the skin was assessed on the basis of skin autofluorescence (AF).  RESULTS Patients with DPN (45%), compared with those without neuropathy, had higher skin AF (2.6 AU [IQR, 2.3-3.1 AU] vs 2.1 AU [IQR, 1.8-2.5 AU]; P <0.001) and lower IENFD (10 fibers/mm [IQR, 7-14 fibers/mm] vs 12 fibers/mm [IQR, 8-16 fibers/mm]; P = 0.005). We found a positive correlation between skin AF and patients' age (Rs = 0.44; P <0.001), diabetes duration (Rs = 0.32; P <0.001), and a negative correlation between skin AF and the estimated glomerular filtration rate (Rs = -0.26, P <0.001) and IENFD (Rs = -0.22; P = 0.004). In a multiple linear regression analysis, skin AF was independently associated with age (ß = 0.45; P <0.001), glycated hemoglobin level (ß = 0.19; P = 0.007), and IENFD (ß = - 0.14; P = 0.04) (R2 = 0.27; P <0.001). In multivariate logistic regression, the presence of DPN was independently associated with skin AF (odds ratio, 4.16; 95% confidence interval, 1.88-9.20; P <0.001). CONCLUSIONS The presence of DPN, and particularly small fiber neuropathy, is associated with a higher accumulation of AGEs in the skin of patients with type 1 diabetes.