[Functional glomerular microangiopathy].

Changes in leg skin temperature during and after cigarette smoking were examined in 25 diabetics with autonomic neuropathy (au-neuropathy) (mean age 52 +/- 2 years) and 23 without (mean age 49 +/- 2 years), and 15 normal controls (mean age 49 +/- 2 years) using a Thermoviewer JTG 3300. All subjects were habitual smokers. Japanese Seven Star cigarettes (each containing 1.2 mg nicotine) were used for the test. Tender brand cigarettes (0.3 mg) were used additionally to compare the effect of nicotine content on the results. The smoking-stimulated thermographic pattern in the control group was rather flat, with a slight decrease in temperature followed by a slight increase before returning to the baseline level 15-20 min after smoking. The frequency of the typical temperature decreasing pattern, characterized by a profound decrease and gradual return to the baseline level in about 1 h, was significantly higher in the diabetic group than in the control group (33/48 vs 1/15; P less than 0.005). A comparison of the two diabetic subgroups revealed that the frequency was considerably higher in the subgroup with au-neuropathy (23/25 vs 10/23). These results suggest that au-neuropathy affects smoking-induced vasoconstriction in diabetic subjects. The maximum temperature decreases recorded were 1.5 +/- 2.0 and 2.69 +/- 0.24 degrees C in the controls and diabetics with au-neuropathy, respectively. The effect of Tender cigarettes with a low nicotine content was much weaker than that of Seven Star, which further suggests that smoking-induced vasoconstriction was also nicotine-dependent.

Diabetic Angiopathies↗

PubMed1992

Aetiology of diabetic foot ulceration: a role for the microcirculation?

Neuropathy, mechanical stress, and macrovascular disease are involved in the pathogenesis of diabetic foot ulceration. Implicit in the development of gangrene and ulceration is the recognition that these factors interact with the microcirculation, resulting in the failure of skin capillary flow to meet nutritive requirements. There is little evidence to associate structural microangiopathy with foot microcirculatory failure. Significant functional abnormalities of the microcirculation have been defined. In accord with the haemodynamic hypothesis early hyperaemia and capillary hypertension promote more sinister late functional abnormalities with increasing duration of diabetes. These late functional abnormalities include loss of autoregulation and reduced hyperaemic responses which interact with loss of neurogenic flow regulation, disturbed endothelial function, and abnormal rheology to produce the familiar clinical picture of the diabetic foot. Ischaemia secondary to multi-segment arterial disease induces additional abnormalities of microcirculatory function which are superimposed on the pre-existing diabetic microvascular structural and functional microangiopathy.

Diabetic Angiopathies↗