Acute renal failure clinical relevance

There are bilateral and unilateral models of ischemic ARF. The bilateral model is used more often because it is more similar to the pathophysiology of the syndrome of acute renal failure in humans and the most likely to yield clinically relevant information. Moreover, uninephrectomy immediately before renal artery occlusion may offer protection from this insult [21, 22]. 

Studies of the pathophysiology of acute renal failure has classically considered both tubular and vascular mechanisms [227,228]. In vitro techniques isolating either the vascular or tubular components have been developed. For example, the use of isolated proximal tubules in suspension or in culture allows the study of tubular mechanisms of injury in the absence of vascular factors [229] [230]. There are both in vitro and in vivo models to study vascular injury in the kidney. In vitro models include the study of vascular smooth muscle cells or endothelial cells in culture. In this section, the in vivo methods to evaluate the renal micro-circulation will be discussed. This is of relevance as many nephrotoxins exert their deleterious effects through pharmacologic actions on the resistance vasculature with parenchymal injury occurring as a consequence of ischemia. In clinical practice nephrotoxins may cause prerenal azotemia as a result of increased renal vascular resistance. Nephrotoxins that cause acute renal failure on a vascular basis include prostaglandin inhibitors e.g. aspirin, non-steroidal anti-... 

A number of reports in the mid to late 1980 s described patients who developed rhabdomyolysis while using cocaine [118-120]. Some of these patients experienced acute renal failure [121-125]. While the exact incidence of acute renal failure secondary to cocaine rhabdomyolysis is unknown, in one reported series it occurred in only three of 211 admissions for cocaine related complications [114]. On the other hand, in another series of nearly 40 patients the incidence of cocaine related acute rhabdomyolysis increased over the period of enrollment from 2 patients in 1985 to 22 patients in 1987 [126]. Several reports of patients with cocaine-induced rhabdomyolysis have clearly defined both the clinical syndrome and the risk factors for the development of acute renal failure and an adverse outcome [123, 126, 127]. Most patients have been previously healthy young males (mean age 30-35 years old and 80-85% male). The cocaine has been smoked, used intravenously, snorted, or taken orally implying that route of administration was not relevant [122,123,126, 127]. In contrast to narcotic related rhabdomyolysis, a history of prolonged coma or stupor is absent. On presentation, the majority of patients are combative and... 

There are four possible relevant clinical presentations for acute CsA nephrotoxicity asymptomatic increases in serum creatinine without overt renal dysfunction, acute renal failure, delayed graft function after renal transplantation and recurrent or ie novo hemolytic uremic syndrome (Table 2). 

Assessing sodium concentration is of clinical relevance as low urine sodium concentration may indicate dehydration, while a relatively high urine sodium concentration suggests acute renal failure. Lvova and coworkers (2009) proposed an E-tongue composed of chemical sensors to detect urinary system dysfunctions and creatinine levels. The electrochemical system was composed of miniaturized metallic sensors and ISEs with PVC solvent polymeric membranes. The device enabled the correct classification of urine samples from healthy volunteers, according to creatinine levels and to predict the creatinine content of urine. 

Recent experimental studies in rats with acute glycerol-induced renal failure and with chronic renal failure showed a decreased expression of intestinal, renal and brain P-glycoprotein [39-41]. Other authors could not confirm this finding [42]. The clinical relevance of these experimental observations remains unclear. 

The role of the sympathetic nervous system in renal injury, end-stage renal disease, and renovascular hypertension are discussed through a literature review accompanying sympathetic nerve mechanisms in hypertension and obesity. Relevant studies of sympathetic nerve activity and 32-adrenoceptor polymorphism might contribute to the onset and maintenance of renal injury in healthy subjects and in patients with chronic heart failure and cardiovascular events in ESRD patients. A better understanding of the relationships of sympathetic nerve activity with renal injury might help clinical implications (treatment) for renal injury in hypertensive patients and hypertension in patients with ESRD. Recently, the role of denervation of renal sympathetic nerve in refractory hypertension has been examined and showed its efficacy in humans. The outcome from the study have not been established, but a number of animal studies show theoretical benefits for those patients in the acute phase. Further studies are needed to clarify the relationships between the sympathetic nerve activity and renal injury. 

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