Elevated asymmetric dimethylarginine is associated with oxidant stress aggravation in patients with early stage autosomal dominant polycystic kidney disease.

BACKGROUND/AIMS: In experimental models of polycystic kidney disease impaired bioavailability of nitric oxide (NO) and elevated mRNA expression of oxidative stress markers at the kidney level was noted. However, clinical studies investigating the potential role of endothelial dysfunction and oxidative stress in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD) are limited. We evaluated asymmetric dimethylarginine (ADMA) as marker of NO synthase inhibitor as well as 15-F2t-Isoprostane and oxidized-low density lipoprotein (oxidized-LDL) as measures of oxidative stress in patients with early stages ADPKD. METHODS: We recruited 26 ADPKD patients (Group A) with modestly impaired renal function (eGFR 45-70 ml/min/1.73 m(2)), 26 age- and sex-matched ADPKD patients (Group B) with relatively preserved renal function (eGFR)>70 ml/min/1.73 m(2)), and 26 age- and sex-matched controls (Group C). Determination of circulating levels of ADMA, 15-F2t-Isoprostane, oxidized-LDL and routine biochemistry was performed. RESULTS: Group A and B had significantly higher ADMA levels as compared to controls (1.68 ± 0.7 vs 0.51 ± 0.2 µmol/l, P<0.001 and 1.26 ± 0.7 vs 0.51 ± 0.2 µmol/l, P<0.001, respectively). 15-F2t-IsoP and oxidized-LDL levels were also significantly higher in Group B relative to controls (788.8 ± 185.0 vs 383.1 ± 86.0 pgr/ml, P<0.001 and 11.4 ± 6.6 vs 6.4 ± 2.6 EU/ml, P<0.05 respectively) and were further elevated in Group A. In correlation analysis, ADMA levels exhibited strong associations with levels of 15-F2t-Isoprostane (r=0.811, P<0.001) and oxidized-LDL (r=0.788, P<0.001), whereas an inverse correlation was evident between ADMA and eGFR (r=-0.460, P<0.001). CONCLUSION: This study shows elevation in circulating levels of ADMA along with aggravation of oxidative stress from the early stages of ADPKD. © 2014 S. Karger AG, Basel.

Role of asymmetrical dimethylarginine in the progression of renal disease.

Asymmetric dimethylarginine (ADMA) is a naturally occurring amino acid found in tissues and cells that circulates in plasma and is excreted in urine. It inhibits nitric oxide synthases (NOs) and produces considerable cardiovascular biological effects. Several studies have suggested that plasma concentrations of ADMA provide a marker of risk for endothelial dysfunction and cardiovascular disease. In animal and in population studies ADMA has been associated with progression of CKD. Several mechanisms may be involved in this association, such as compromise of the integrity of the glomerular filtration barrier and development of renal fibrosis. This review summarizes the existing literature on the biology and physiology of ADMA focusing on its role in the progression of renal disease.

Right atrium myxoma coexisting with antiphospholipid syndrome: a case report.

In this case report we describe a rare case of right atrium myxoma that coexisted with antiphospholipid syndrome in a young woman. We describe the unusual findings and diagnostic challenges combined with a review of the literature.

New aspects on the pathogenesis of renal disorders related to monoclonal gammopathies.

BACKGROUND: Multiple myeloma and other related monoclonal gammopathies are frequently encountered conditions associated with renal damage, especially in elderly population. They are arising from clonal proliferation of plasma cells in bone marrow producing various quantities of abnormal monoclonal immunoglobulins, or their components/fragments. SUMMARY: These abnormal proteins differ from normal immunoglobulins in the amino acid sequence and in the three-dimensional structure of the molecule, which may determine their toxicity. Kidney seems to be a target organ as a major catabolic site. The pathology of renal disease is highly heterogeneous involving a variety of different mechanisms, which are divided into immunoglobulin dependent and immunoglobulin independent mechanisms. The Ig-dependent mechanisms may involve the four components of the kidney parenchyma, and the primary structure of these proteins determine the pattern of renal disease. KEY MESSAGE: This review summarizes the existing literature in the pathobiology of multiple myeloma, and the pathological properties of the M-proteins, focusing on the mechanisms of the renal manifestations related to these abnormal proteins, especially glomerular injury. Also it supports the opinion that monoclonal gammopathy of undetermined significance (MGUS) should not be used in cases where there is proven renal impairment due to these proteins, even if it is mild and does not meet the current criteria.

Scleroderma renal crisis accompanied by new-onset pulmonary arterial hypertension: an acute systemic endothelial injury? Case report and literature.

Systemic Sclerosis (SSc) is a multisystem connective tissue disease characterized by fibrosis of the skin and internal organs and extensive vasculopathy. We report a case of a 41 year-old white woman with a 10 year-history of limited scleroderma, who developed the rare combination of Scleroderma Renal Crisis (SRC) and Systemic Sclerosis related Pulmonary Arterial Hypertension (SScPAH) in the same time. Although the patient received the proposed antihypertensive treatment, the renal function did not recover, and she initiated on renal replacement therapy. SRC and SScPAH are two aspects of SSc vasculopathy characterized by endothelial dysfunction mediated by endothelin-1 and other vasoactive hormones. Further new studies with therapies directed towards the underlying mechanisms of SRC (i.e. endothelin-receptor antagonists), which are proven helpful in SScPAH, should take place to establish new therapeutic options and improve prognosis of these patients, for which our therapeutic armamentarium is currently poor.