4 Similar prevalence estimates have been reported around the globe and some reports note an increasing prevalence over time.[5-8] The identification of prognostic markers related to renal deterioration can improve our knowledge regarding the pathogenesis and the progression of chronic kidney disease (CKD), leading to fewer individuals having end stage renal disease[9] (0.2% of the US population or >500.000[4]).4 Recently asymmetric dimethylarginine (ADMA) levels were found to be elevated in patients with CKD (even in CKD stage 1)[10-14] and associated with atherosclerotic vascular complications.[15] Furthermore, plasma ADMA level also predicts
the progression of renal injury in patients with CKD.[9, 16, 17] These findings suggest that ADMA may be a biomarker of chronic kidney disease progression.
On the other hand ADMA’s isomer symmetric dimethylaginine (SDMA), which Akt inhibitor does not inhibit nitric oxide synthesis, is also elevated in patients with renal failure. SDMA has emerged as an endogenous marker of renal function as its levels are closely related to glomerular filtration rate, better selleck products than ADMA.[18] Accumulation of ADMA in patients with renal dysfunction might be related to renal parenchymal damage, resulting in reduced renal dimethylarginine-dimethylamino-hydrolase (DDAH) expression and activity rather than to reduce glomerular filtration of ADMA.[18] Endothelium is the inner most single cell lining of all blood vessels within the body. It is recognized as the principal regulator of vascular function such as vascular tone, permeability, platelet aggregation, inflammation and smooth cell proliferation.[19,
20] It has the property to react to various physical stimuli such as shear stress.[21] The vessels have the ability to dilate as a response to shear stress and this procedure is mainly regulated by nitric oxide (NO) from the endothelium.[21] The NO is produced by stereospecific oxidation of the terminal guanine nitrogen of L-arginine, through the mediation of the nitric oxide synthases (eNOs, nNOs, iNOs)[21-23] (Fig. 1). In Isotretinoin various pathological conditions, vasodilation is impaired in a large number of arteries (quite possible all of them) due to the reduced production of NO. The mechanisms that could lead to the insufficiency of the NO system are the following: (A) Mechanisms for insufficient NO production: (i) reduced availability of substrate (L-arginine) either due to reduced protein intake, or due to reduced synthesis (arginine is mainly formed in the kidney); (ii) diversion of arginine to other metabolic pathways (such as arginase, mainly, but also amidinotransferase and decarboxylase); (iii) reduced arginine supply to the NOs (antagonism during its intracellular transport through the Y+ transporter where the production of NO takes place); (iv) increased activity of endogenous inhibitors of NOs (methylaginines and mostly ADMA).