Effect of diabetes on the cutaneous microcirculation of the feet in patients with intermittent claudication

The study of microcirculation and tissue metabolism as early diagnostic criteria for the risk of diabetic foot development

Aim. To assess the state of the microvasculature, tissue metabolism and its reserve capabilities for the purpose of early intervention for the prevention of diabetic foot syndrome. Materials and methods. Thirty patients were examined. The patients were divided into three groups depending on the hypoglycemic therapy (metformin, empagliflozin, dapagliflozin). The comparison group consisted of 12 volunteers who did not have carbohydrate metabolism disorders. Results. It was found: the HbA1c indicator significantly decreased in all three groups; significant dynamics in the state of the microvasculature was not observed in any of the three groups; in all groups, there was an improvement in tissue metabolism, however, in this case, no significant dynamics were observed in any of the 3 groups, which indicates the need for provocative tests. Conclusion. For this purpose, the authors recommend the method of combined use of laser Doppler flowmetry and laser fluorescence spectroscopy. This technique allows diagnosing the state of the microvasculature and tissue metabolism and its reserve capabilities, using thermal and cold tests.

Possibility of Injecting Adipose-Derived Stromal Vascular Fraction Cells to Accelerate Microcirculation in Ischemic Diabetic Feet: A Pilot Study

Background and Objectives

Beneficial effects of human adipose-derived stromal vascular fraction (SVF) cell injection on microcirculation have been recently reported in in vitro and in vivo studies. However, no clinical studies have reported its effect in diabetic patients who commonly experience compromised tissue perfusion, regardless of the status of intravascular blood flow. The present piloting study was designed to clinically examine the possibility of SVF cell injection to accelerate microcirculation, particularly in ischemic diabetic feet.

Methods

Ten diabetic feet were included to receive subcutaneous injection of SVF cells around wounds. Transcutaneous partial oxygen pressure (TcPO₂) and cutaneous microvascular blood flow were measured before and every four weeks after cell injection until the 12^th week visit.

Results

TcPO₂ values increased from 31.3±7.4 before injection to 46.4±8.2 mmHg at 12 weeks after SVF injection (1.5-fold, p<0.05). Cutaneous microvascular blood flow levels increased from 34.0±21.1 before injection to 76.1±32.5 perfusion unit at 12 weeks after SVF injection (2.2-fold, p<0.05). There were no adverse events related to SVF cell injection.

Conclusions

Results of this study demonstrate that adipose-derived SVF cell injection have the possibility to provide beneficial effects on microcirculation in ischemic diabetic feet.

Laser Doppler: A Tool for Measuring Pancreatic Islet Microvascular Vasomotion In Vivo

As a functional status of microcirculation, microvascular vasomotion is important for the delivery of oxygen and nutrients and the removal of carbon dioxide and waste products. The impairment of microvascular vasomotion might be a crucial step in the development of microcirculation-related diseases. In addition, the highly vascularized pancreatic islet is adapted to support endocrine function. In this respect, it seems possible to infer that the functional status of pancreatic islet microvascular vasomotion might affect pancreatic islet function. Analyzing the pathological changes of the functional status of pancreatic islet microvascular vasomotion may be a feasible strategy to determine contributions that pancreatic islet microcirculation makes to related diseases, such as diabetes mellitus, pancreatitis, etc. Therefore, this protocol describes using a laser Doppler blood flow monitor to determine the functional status of pancreatic islet microvascular vasomotion, and to establish parameters (including average blood perfusion, amplitude, frequency, and relative velocity of pancreatic islet microvascular vasomotion) for evaluation of the microcirculatory functional status. In a streptozotocin-induced diabetic mouse model, we observed an impaired functional status of pancreatic islet microvascular vasomotion. In conclusion, this approach for assessing pancreatic islet microvascular vasomotion in vivo may reveal mechanisms relating to pancreatic islet diseases.

Real-life adaptations in walking patterns in patients with established peripheral arterial disease assessed using a global positioning system in the community: a cohort study

OBJECTIVE

Lower extremity peripheral arterial disease (PAD) is a chronic condition most commonly presenting with intermittent claudication (IC). Intermittent claudication limits walking ability and may negatively affect health-related quality of life. Treadmill assessment of maximal walking distance (MWD) is the gold standard to assess PAD symptom severity. Despite being a well-established and reproducible tool, it may be inappropriate (due to frailty or fear) for some patients and only describes maximal abilities for a single walk test. Global positioning systems (GPS) have been proposed as reliable and reproducible tool to measure total, mean and maximal walking distances in patients with PAD, in the community setting. Using GPS, our study attempted to explore what happens to the walking ability of patients with IC following no intervention under 'real-life' conditions.

DESIGN AND METHODS

Using the GlobalSat DG100 GPS, forty-three patients (69 ± 9 years; nine female; no invasive interventions or rehabilitation) undertook two 60-min walking assessments, 6 months apart. Assessments took place in community spaces that had even terrain, no tall trees or buildings and were free from motorized vehicles. Global positioning systems-measured maximum walking distance was the main study outcome measure.

RESULTS

Over the 6-month period, patients demonstrated significantly shorter GPS-measured, mean (552 m versus 334 m; P = 0·02) and maximum (714 m versus 545 m; P = 0·04) walking distances, stopping also more frequently (nine versus five times; P = 0·03).

CONCLUSIONS

Given the reported symptom progression, we advocate early intervention (e.g. exercise interventions) combined with frequent patient monitoring in attempts to maintain or improve walking ability.

Nonlinear dynamics of skin blood flow response to mechanical and thermal stresses in the plantar foot of diabetics with peripheral neuropathy

BACKGROUND

Diabetic foot ulcers (DFU) are a major complication in diabetics. Impaired microvascular reactivity is a major contributor to the development of DFU and has been traditionally quantified by time-domain or frequency-domain measures of skin blood flow (SBF). These measures, however, are unable to characterize the changes of nonlinear dynamics of SBF associated with diabetes and peripheral neuropathy.

OBJECTIVE

The objective of this study was to investigate altered nonlinear dynamics of skin blood flow in the plantar foot of diabetics with peripheral neuropathy.

METHODS

18 type 2 diabetics with peripheral neuropathy and 8 healthy controls were recruited. SBF at the first metatarsal head in response to a loading pressure of 300 mmHg and a local heating was measured using laser Doppler flowmetry. A sample entropy approach was used to quantify the degree of regularity of SBF.

RESULTS

Our results showed that the regularity degree of SBF in the diabetic foot underwent only small changes during post-occlusive reactive hyperemia and thermally induced biphasic response compared to non-diabetics. SBF of the diabetic foot has higher degree of irregularity during reactive hyperemia because of attenuated myogenic activity, and demonstrated higher regularity during the biphasic response largely due to significantly enhanced cardiac activities.

CONCLUSIONS

This study suggests that the regularity degree of SBF at the first metatarsal head could be used to assess impaired microvascular reactivity and thus may be used to assess the risk for DFU in diabetics with peripheralneuropathy.

Assessing the evidence: Exploring the effects of exercise on diabetic microcirculation

Diabetes mellitus (DM) is associated with cardiovascular complications. Impairment of glycemic control induces noxious glycations, an increase in oxydative stress and dearangement of various metabolic pathways. DM leads to dysfunction of micro- and macrovessels, connected to metabolic, endothelial and autonomic nervous system. Thus, assessing vascular reactivity might be one of the clinical tools to evaluate the impact of harmful effects of DM and potential benefit of treatment; skin and skeletal muscle microcirculation have usually been tested. Physical exercise improves vascular dysfunction through various mechanisms, and is regarded as an additional effective treatment strategy of DM as it positively impacts glycemic control, improves insulin sensitivity and glucose uptake in the target tissues, thus affecting glucose and lipid metabolism, and increases the endothelium dependent vasodilation. Yet, not all patients respond in the same way so titrating the exercise type individualy would be desirable. Resistance training has, apart from aerobic one, been shown to positively correlate to glycemic control, and improve vascular reactivity. It has been prescribed in various forms or in combination with aerobic training. This review would assess the impact of different modes of exercise, the mechanisms involved, and its potential positive and negative effects on treating patients with Type I and Type II DM, focusing on the recent literature.