Changes in blood flow and permeability of vessels to protein preceding the development of cutaneous ulcers in the hind limb of the rabbit

Cardiovascular Autonomic Dysfunction Predicts Diabetic Foot Ulcers in Patients With Type 2 Diabetes Without Diabetic Polyneuropathy

We investigated the factors that might influence the development of diabetic foot ulcers (DFUs) in type 2 diabetes patients without diabetic polyneuropathy (DPN).From January 2000 to December 2005, a total of 595 patients who had type 2 diabetes without DPN between the ages of 25 and 75 years, and had no prior history of DFUs were consecutively enrolled in the study. A cardiovascular autonomic function test was performed to diagnose cardiovascular autonomic neuropathy (CAN) using heart rate variability parameters.The median follow-up time was 13.3 years. Among the 449 (75.4%) patients who completed the follow-up evaluation, 22 (4.9%) patients developed new ulcers, and 6 (1.3%) patients underwent the procedure for lower extremity amputations. The patients in the DFUs group had a longer duration of diabetes, higher baseline HbA1c levels, higher rates of nephropathy, and CAN. A Cox hazard regression analysis results revealed that the development of DFUs was significantly associated with the presence of CAN (normal vs definite CAN; HR, 4.45; 95% confidence interval, 1.29-15.33) after adjusting for possible confounding factors.The development of DFUs was independently associated with CAN in patients with type 2 diabetes without DPN. We suggested the importance of CAN as a predictor of DFUs even in the patients without DPN, and the need to pay attention to patients with definite CAN and type 2 diabetes.

Fibrinogen adsorption in the diabetic foot syndrome and peripheral arterial occlusive disease: first clinical experience

The elimination of fibrinogen from plasma improves plasma viscosity and whole-blood viscosity. For extracorporeal adsorption of fibrinogen, the pentapeptide gly-pro-arg-pro-lys was coupled to sepharose CL-4B3. Adsorbers containing 135 ml of coupled sepharose CL-4B were used to eliminate fibrinogen from the plasma of 7 men and 3 women (48-75 years old). Nine patients suffered from diabetes mellitus, 1 patient from peripheral arterial occlusive disease, and 5 patients were on regular hemodialysis. Treatments were scheduled on Days 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25, and 28. One hundred forty-four treatments with fibrinogen adsorption were performed. No clinical side effects due to the fibrinogen adsorption procedure were observed. In these 10 patients, fibrinogen concentration before the first treatment was 473.7 +/- 183.7 mg/dl. In the first treatment session, fibrinogen concentration was lowered to 241.4 +/- 125.8 mg/dl by treating 4,270 +/- 1,180 ml of plasma. In the following 134 treatments, the pretreatment concentration of fibrinogen was 262.6 +/- 83.4 mg/dl, and the posttreatment concentration was 120.6 +/- 37.2 mg/dl. The mean amount of plasma treated was 3,737 +/- 1,643 ml, and the mean duration of a treatment session (except first treatment) was 143.7 +/- 63.1 min. In 7 patients, a mean posttreatment fibrinogen concentration of < or = 123 mg/dl was obtained; in the other patients, concentrations of 133, 177, and 184 mg/dl were obtained. Yet, the decrease of fibrinogen concentration was also pronounced in these 3 patients: -82%, -67%, and -73%, respectively. During the treatment period of 28 days, wound healing was observed in 9 of the 10 patients. In conclusion, affinity chromatography using the pentapeptide gly-pro-arg-pro-lys is an effective, selective, and safe procedure to lower fibrinogen concentration in plasma. It could be a therapeutic option in severe blood vessel disease in which drug therapy is not sufficient and invasive procedures such as bypass or angioplasty cannot be applied. Yet, more information is needed, for example, about the fibrinogen concentration that has to be reached to get the maximal improvement of micro- and/or macrocirculation.

Autonomic denervation may be a prerequisite of diabetic neuropathic foot ulceration

Studies using visceral (cardiovascular) autonomic function testing have left doubt as to the importance of autonomic neuropathy in the development of diabetic neuropathic foot ulceration. A test for peripheral autonomic denervation has been developed (acetylcholine sweatspot test), dependent on intradermal acetylcholine causing secretion by innervated sweat glands, detected by starch/iodine discoloration. The response is photographed and quantified using a grid (normal score = 0 or 1; abnormal = 5 to 60). The sweatspot test was applied to the feet of 19 diabetic patients with a history of foot ulceration, 17 with neuropathic pain, 8 complaining of numbness, and to 15 diabetic control patients. The sweatspot test score of the foot ulcer patients (median 54) was very much greater than that of the other groups (pain group, 4, p less than 0.005; numbness group, 2, p less than 0.01; diabetic control group, 2, p less than 0.0001). All the patients with neuropathic foot ulceration had peripheral autonomic denervation. The results suggest that autonomic denervation in the feet is always present in patients with diabetic neuropathic foot ulceration. Tests of peripheral autonomic denervation such as the acetylcholine sweatspot test may be useful to identify patients at risk of neuropathic foot ulceration.

The diabetic foot: pathophysiology and treatment

The diabetic foot can be classified into the neuropathic foot, characterized by the neuropathic ulcer, the Charcot joint and neuropathic oedema associated with a good circulation, in which neuropathy predominates, and the ischaemic foot in which atherosclerosis is the dominant factor leading to a reduction in blood flow with absent pulses. In the neuropathic foot, blood flow is increased, the vessels are still and dilated as a result of medial wall calcification and there is evidence for arteriovenous shunting. The neuropathic ulcer characteristically develops on the plantar surface following inflammatory autolysis and haematoma formation under neglected callosities. Chiropody is therefore the mainstay of treatment and recurrence is prevented by redistribution of weight bearing forces by moulded insoles in special footwear. Charcot osteoarthropathy is often preceded by fracture which is a further complication of diabetic neuropathy and which precipitates the rapid bone and joint destruction of the Charcot joint. Neuropathic oedema responds to ephedrine with a reduction in peripheral flow and an increase in urinary sodium excretion. The ischaemic foot is characterized by rest pain, ulceration and gangrene. Medical management can be successful in up to 72%, the remainder needing arteriography to assess suitability for arterial reconstruction or angioplasty. In the diabetic leg, atherosclerosis is predominant in the branches of the popliteal artery making arterial reconstruction difficult. Optimum care of the diabetic foot is provided in a diabetic foot clinic where the skills of chiropodist, shoe-fitter and nurse receive full support from physician and surgeon. Many lesions of the diabetic foot are avoidable and thus patient education is the cornerstone of prevention.

Autonomic neuropathy and diabetic foot ulceration

Autonomic function was studied in three groups of insulin-dependent diabetic patients. Heart rate changes during deep breathing and on standing were significantly less in 28 patients with a recent history of foot ulceration compared with 40 patients with peripheral neuropathy but without ulceration (p less than 0.001) and 54 patients without neuropathy (p less than 0.001). Sympathetic function was assessed in 36 of these patients from peripheral arterial diastolic flow patterns obtained by Doppler ultrasound measurements and expressed as the pulsatility index (PI). Patients with a history of ulceration (n = 10) showed considerably increased diastolic flow (PI = 4.28 +/- 0.53, mean +/- S.E.M.) compared with 12 neuropathic patients with no history of ulceration (PI = 7.80 +/- 0.68, p less than 0.002) and 14 patients without neuropathy (PI = 9.55 +/- 0.89, p less than 0.002). Severely abnormal autonomic function occurs in association with neuropathic foot ulceration, but patients without ulcers have lesser degrees of autonomic neuropathy, thus a causal relationship has not been established.