Tewfik Nawar

Chronic Renal Failure Secondary to 2,8-Dihydroxyadenine Deposition: The First Report of Recurrence in a Kidney Transplant

We report a case of adenine phosphoribosyltransferase deficiency in which the initial presentation was chronic renal failure. Diagnosis was made after infrared microscopy analysis of microcrystalline deposits on a kidney allograft biopsy specimen. This type of presentation is rarely seen, the most frequent manifestation of this disease being urolithiasis. This is the first report of recurrence of the microcrystalline nephritis in a kidney transplant with subsequent loss of allograft function.

Large arteries and the kidney

In subjects with chronic renal disease, high systolic blood pressure (SBP) is the most modifiable cardiovascular (CV) risk factor that enables prevention of the progression of chronic kidney disease renal failure and the occurrence of CV events. Although large-artery stiffness and wave reflections are the principal hemodynamic determinants of SBP, their precise role in the progression of chronic renal disease has been poorly investigated. However, in subjects with mild to severe renal insufficiency, increased arterial stiffness and reduced creatinine clearance are closely related, independently of age; mean arterial pressure level; and presence of other traditional risk factors, including atherosclerotic plaques. Through inflammatory mechanisms, as well as through the development of arterial calcifications (including microscopic) and sodium-related alterations in extracellular matrix composition, arterial stiffness is associated with significant SBP and increased pulse pressure (PP). In the presence of renal dysfunction, frequently observed in elderly hypertensive or diabetic subjects, or even in some living donors, the resulting increase in PP may be transmitted toward and across glomeruli, even when peripheral blood pressure values are maintained. This alteration alone may initiate glomerulosclerosis and/or tubulointerstitial damage, eventually leading to CV events. In subjects with end-stage renal disease and high CV risk, pharmacological modulation of the renin-angiotensin system has been shown to prevent independently such complications.

Effect of angiotensin converting enzyme inhibition on thirst and salt-appetite

Normally, eating and drinking provide the body with a surplus of water and electrolytes. Water and sodium balance therefore are normally achieved by renal regulation. Stimulation of water and salt intake are back-up mechanisms [1].

Angiotensin converting enzyme inhibition in the microcirculation

Microcirculation networks represent highly specialized segments of the general circulation in terms of structure and function. Definition of these segments is critical to establish the volume of blood contained, the endothelial surface exposed to the neighbouring fluid compartments, including the interstitial and cellular compartments, the lumen diameter and wall thickness of each segment. In fact, these structural characteristics determine a large part of the physiological functions of the vasculature, from hydrostatic pressure development to fluid and nutrient exchanges in peripheral organs.