Medial arterial calcification and diabetic neuropathy.

Abstract

showed no response to naloxone. Three months later he was admitted in respiratory failure refractory to all treatment. Necropsy showed chronic bronchitis, bullous emphysema, and right ventricular hypertrophy. The intercostal muscles were thin and fibrous, and histology of these and the diaphragm and psoas showed changes of chronic denervation. Histology of the spinal cord was not obtained. DiscussionNaloxone reverses the apnoeic response to hypoxia in neonatal rabbits2 but, even in large doses, has no effect on respiration in hypoxic man.' Respiratory failure in this patient was thought to be caused by a combination of chronic airflow obstruction and weakness of the respiratory muscles (possibly due to chronic spinal muscular atrophy).4 Intravenous naloxone produced an increase in minute ventilation and general agitation when he was acutely ill. The increase in oxygen saturation was greater than expected for the increase in ventilation, suggesting improved ventilation-perfusion matching, but the response occurred only in the acute illness.These findings suggest that there may be overproduction of, or increased sensitivity to, endorphins in acute respiratory failure. Naloxone is beneficial in shock,5 the postulated mechanism being that endorphins inhibit the interaction of catecholamines with their receptors. Such an action might account for the changes in ventilation-perfusion balance in our patient. Medial arterial calcification and diabetic neuropathy M E EDMONDS, N MORRISON, J W LAWS, P J WATKINS Abstract X-ray examinations of the feet, knees, and hands were performed on 20 diabetics with severe neuropathy and 20 diabetics with no evidence of neuropathy but with a similar mean age and duration of diabetes. All were under 53 years old with no clinical evidence of peripheral vascular disease. Medial arterial calcification was much more common and extensive in the patients with neuropathy, occurring in the feet in 15 and in the hands in eight compared with in four (p <0 001) and none (p <0 001) of the controls respectively. Although there was some correlation between calcification and both proteinuria (p <0 05) and proliferative retinopathy (p <0 02), the association between calcification and neuropathy (p <0 001) was much stronger.Neuropathy, with sympathetic denervation of the smooth muscle of the tunica media, may be important in the aetiology of medial arterial calcification.

The Risk for Medial Arterial Calcification in CKD

“…In addition, most studies did not consider the duration of diabetes, which appears to correlate strongly with MAC (18)(19)(20). MAC is particularly common in patients with diabetes and severe neuropathy (20,28), again consistent with duration. However, duration and the presence of other diabetic complications also correlate with diabetic nephropathy; this finding also suggests that CKD could contribute to the risk for MAC in diabetes.…”

Vascular calcification and osteolysis in diabetic neuropathy?is RANK-L the missing link?

“…Jeffcoate 1 1 Foot Ulcer Trials Unit, Department of Diabetes and Endocrinology, City Hospital, Nottingham, UK although both might be related to changes in blood flow caused by sympathetic denervation. Peripheral vascular resistance is reduced in peripheral neuropathy, leading to increased peripheral flow with a widened pulse pressure in patients without significant macrovascular disease.…”

“…The link between these findings has hitherto been obscure, Association of neuropathy with vascular calcification and osteopenia Vascular calcification. The association between peripheral neuropathy and calcification of VSMCs is well recognised [1,2,3,4,5], although the causative nature of the link cannot be established in cross-sectional studies. Moreover, the demonstration of sympathetic denervation is dependent on preservation of vascular reactivity, and this is impaired when vessels are calcified.…”

Toe–brachial index is associated more strongly with albuminuria or glomerular filtration rate than ankle–brachial index in patients with type 2 diabetes

“…7 However, application of this index to diabetic patients is considered questionable because of medial arterial calcification, which falsely elevates the ABI value. 8,9 Therefore, toe-brachial index (TBI) is advocated for diabetic patients because medial arterial calcification is less frequent in the toe than in the ankle.…”