[Origin of the mediacalcosis in kidney failure]

Evaluation of the ankle brachial index and toe brachial index for peripheral arterial disease diagnosis in patients over 70 years with lower limb ulcers

OBJECTIVE

The aim of our study was to evaluate the diagnostic performance of the ankle brachial index using pulsed Doppler, and the toe brachial index using laser Doppler, in comparison with the arterial Doppler ultrasound of the lower limbs as a reference test, in a population of non-diabetic subjects over 70 years old with lower limb ulcers and without chronic renal failure.

METHODS

We included 50 patients, 100 lower limbs from the vascular medicine department of the Paris Saint-Joseph hospital from December 2019 to May 2021.

RESULTS

We found a sensitivity of 54.5% for the ankle brachial index and a specificity of 67.6%. Regarding the toe brachial index, the sensitivity was 80.3% and the specificity 44.1%. We could explain the low sensitivity of the ankle brachial index in our population by the mediacalcosis of elderly subjects, avoidable with the measurement of the toe blood pressure index, which had a better sensitivity.

CONCLUSION

In a population of subjects over 70 years of age with a lower limb ulcer, without diabetes and without chronic renal failure, it would seem judicious to use the ankle brachial index in association with the toe brachial index for the diagnosis of peripheral arterial disease, followed by an arterial Doppler ultrasound of the lower limbs in order to evaluate the lesion profile of patients with a result of less than 0.7 of toe brachial index.

Expression profiles of podocytes exposed to high glucose reveal new insights into early diabetic glomerulopathy

Podocyte injury has been suggested to have a pivotal role in the pathogenesis of diabetic glomerulopathy. To glean insights into molecular mechanisms underlying diabetic podocyte injury, we generated temporal global gene transcript profiles of podocytes exposed to high glucose for a time interval of 1 or 2 weeks using microarrays. A number of genes were altered at both 1 and 2 weeks of glucose exposure compared with controls grown under normal glucose. These included extracellular matrix modulators, cell cycle regulators, extracellular transduction signals and membrane transport proteins. Novel genes that were altered at both 1 and 2 weeks of high-glucose exposure included neutrophil gelatinase-associated lipocalin (LCN2 or NGAL, decreased by 3.2-fold at 1 week and by 7.2-fold at 2 weeks), endothelial lipase (EL, increased by 3.6-fold at 1 week and 3.9-fold at 2 week) and UDP-glucuronosyltransferase 8 (UGT8, increased by 3.9-fold at 1 week and 5.0-fold at 2 weeks). To further validate these results, we used real-time PCR from independent podocyte cultures, immunohistochemistry in renal biopsies and immunoblotting on urine specimens from diabetic patients. A more detailed time course revealed changes in LCN2 and EL mRNA levels as early as 6 hours and in UGT8 mRNA level at 12 hours post high-glucose exposure. EL immunohistochemistry on human tissues showed markedly increased expression in glomeruli, and immunoblotting readily detected EL in a subset of urine samples from diabetic nephropathy patients. In addition to previously implicated roles of these genes in ischemic or oxidative stress, our results further support their importance in hyperglycemic podocyte stress and possibly diabetic glomerulopathy pathogenesis and diagnosis in humans.