The potential influence of diabetic history on peripheral blood flow in superficial skin ☆ Gladys Lai-Ying Cheing a, ⁎, Jiahui Sun a,b , Rachel Lai-Chu Kwan a , Yongping Zheng c a Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China b Physiotherapy Department, Kowloon Hospital, Hong Kong SAR, China c Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China abstract article info Article history: Accepted 13 June 2013 Available online 22 July 2013 Vascular complication occurrence increases with the duration of diabetes. The present study compared the peripheral blood flow in superficial skin among subjects with a short or long history of diabetes as compared to a healthy control group. Thirty-two subjects with type 2 diabetes were recruited and stratified into a group of those with a short history of diabetes (i.e., shorter than or equal to ten years) and a group of those with a long history of diabetes (i.e., over ten years). Thirty-eight healthy age-matched volunteers were recruited as the control. The blood flow velocity of the superficial small veins in the skin over the base of the 1st metatarsal bone was measured by ultrasound biomicroscopy. The blood flow (flux) of the cutaneous microcirculation over the base of the 1st metatarsal bone (Flux1) and over the distal 1st phalanges bone (Flux2) was measured by Laser Doppler Flowmetry. One-way analysis of variance was used to analyze the differences between the three groups. No significant between-group difference was found in any outcome (all P N 0.05). However, the group with a long history of diabetes tended to have a more reduced blood flow than did the healthy control group. A difference was found between the diabetes group and the healthy control in any outcomes. A trend of hemodynamic changes in the three groups was observed, but the difference did not reach significance. Ten years seems to be the time when angiopathy becomes noticeable among people with diabetes. © 2013 Elsevier Inc. All rights reserved. Introduction The rapid increase in the incidence of diabetes mellitus is a world- wide health problem (Amos et al., 1997). Diabetes mellitus (DM) can lead to macro- and micro-angiopathic changes in the vascular system (Boutayeb and Boutayeb, 2005). Over time, various diabetes-associated structural abnormalities can be detected in the microvasculature, includ- ing thickening of the capillary basement membrane and diminished cap- illary size (Chao and Cheing, 2009). Microcirculation is the only place where the transport and exchange of nutritive substances and metabolic wastes between the blood and tissue fluid take place. In microcirculation, the changes in blood flow play an important role in the pathogenesis of diabetic-associated tissue damage. Dysfunctions of the vascular system include hemodynamic abnormality, hypoperfusion, and neuronal ische- mia, which could be the main causes leading to neuropathic pain, senso- ry loss, and foot ulcer in people with diabetes (The Expert Committee on The Diagnosis and Classification of Diabetes Mellitus, 2002). Previous study demonstrated that the occurrence of vascular complications did increase with the duration of diabetes (Shestakova et al., 2008). In clinical settings, people who have had a long history of diabetes are prone to developing angiopathy in both the macrovascular and mi- crovascular systems. However, no studies have identified the timeline for the progression of diabetes-associated angiopathy. Previous studies reported that people with a long history of diabetes tend to develop ar- teriosclerosis and microvascular sclerosis in the vascular system (Tooke, 1995, 1996a, 1996b; Winer and Sowers, 2004). Following such vascular damage, abnormal hemodynamic changes could take place in microcir- culation. Human skin is a good model for studying diabetic-associated microangiopathy. Tooke suggested that the pathophysiological changes of the cutaneous microcirculation in people with DM are likely to result in similar changes in other microvascular beds, such as the kidneys and retinas (Tooke, 1996b). Normal skin is comprised of two major layers: the epidermis (the most superficial layer) and the dermis. There is no vascular structure in the epidermis layer. In contrast, the dermis layer consists of two mi- crovascular nets, namely the papillary capillaries and the subpapillary vascular bed. The microvasculature in different types of skin differs sub- stantially in blood flow, with its dominant mechanisms of regulation (Vinik et al., 2001). The apical (glabrous) skin is present in the palmer surface of the hand, the plantar surface of the foot, and the face. Within Microvascular Research 90 (2013) 112–116 Abbreviations: A-V, arteriovenous; ANOVA, analysis of variance; DM, diabetes mellitus; LDF, Laser Doppler Flowmetry; UBM, ultrasound biomicroscopy. ☆ Part of this study was presented in a poster format under the title “High frequency ultrasound: A potential tool to examine peripheral blood flow velocity in people with diabetes” at the Diabetic Foot Global Conference, Los Angeles, USA, 19–21 March 2009. ⁎ Corresponding author. Fax: +852 23308656. E-mail address: rsgladys@polyu.edu.hk (G.L.-Y. Cheing). 0026-2862/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.mvr.2013.06.006 Contents lists available at ScienceDirect Microvascular Research journal homepage: www.elsevier.com/locate/ymvre