Iranian Journal of Kidney Diseases
Year:2009 | Volume:3 | Issue:1|Papers Count:12

Section of Nephrology, Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA During the past decades, our knowledge of renal phosphate handling has advanced dramatically. This advance is primarily due to the discovery of sodium-phosphate transport channels and their regulation in health and disease. The discovery of phosphatonins, initially in patients with tumor-induced osteomalacia, has not only allowed us to develop a better understanding of several rare diseases including vitamin D-resistant rickets, but also it has expanded our knowledge of the dynamic interaction between the bone and the kidney critical to bone mineralization. In this review, the author focuses on these new developments and their importance to our understanding of phosphate homeostasis in health and disease.

The kidney is both a cause and victim of hypertension. High blood pressure is a key pathogenetic factor that contributes to deterioration of kidney function. Presence of kidney disease is a common and underappreciated preexisting medical cause of resistant hypertension.1 Therefore, treatment of hypertension has become the most important intervention in the management of all forms of chronic kidney disease (CKD). For this reason, the forthcoming World Kidney Day (WKD) on March 12th, 2009 will emphasize the role of hypertension for kidney disease.

A 20-year-old man presented with elevated serum creatinine level 3 months after kidney transplantation. Cytomegalovirus (CMV) pp65 antigen was detected by indirect immunofluorescent method. Figure A shows contaminated cells in phosphorous green (× 400). Kidney needle biopsy was performed and tubulointerstitial nephritis with CMV cytopathic effects was observed on pathologic examination.

Introduction: Microalbuminuria is a marker of vascular endothelial damage. In addition, it is reported that high serum levels of C-reactive protein (CRP) is a novel cardiovascular risk factor that impairs endothelial function. The aim of this study was to evaluate the relationship between microalbuminuria and elevated serum level of high-sensitivity CRP (HS-CRP) in type 2 diabetic patients.Materials and Methods: We measured serum levels of HS-CRP in 87 patients with type 2 diabetes mellitus. They were divided into a microalbuminuric group (n=45) and those with a 24-hour urine albumin less than 30mg/d (n=42). The relationship of serum HS-CRP level with albuminuria and other characteristics of the patients were assessed.Results: Patients with microalbuminuria were significantly older and affected by diabetes mellitus longer than those without microalbuminuria. Also, their mean HS-CRP was significantly higher (4.98±1.45mg/L versus 2.82±2.10mg/L; P<.001). The Pearson correlation test showed a significant correlation between HS-CRP level and urine albumin level (r=0.43; P<.001). The specificity and sensitivity of HS-CRP for detection of microalbuminuria in were 78.5% and 68.8%, respectively, and the positive and negative predictive values were 77.5% and 70.2%, respectively.Conclusions: In type 2 diabetic patients, microalbuminuria is accompanied by elevated HS-CRP, suggesting activation of inflammatory pathways in progression of renal and cardiovascular atherosclerotic disease. As an easier and cheaper test for assessment of diabetic nephropathy, we recommend further studies on HS-CRP in diabetic patients.

Introduction. Risk factors of renal involvement in Henoch-Schonlein nephritis (HSN) have been extensively studied, but their relations with the severity of glomerular lesions at the disease onset are much less known.Materials and Methods. Data were collected retrospectively on 45 patients (age range, 2 to 15 years) with HSN to identify the initial clinical and laboratory features that most accurately correlate with histological findings. Nephritic syndrome was defined as hypertension, proteinuria, hematuria, and a creatinine clearance of 60mL/min/1.73m2 or less. Kidney biopsy findings were graded according to the International Study of Kidney Disease in Children classification for HSN.Results. Purpura was present in all the 45 children, arthritis in 73.3%, abdominal symptoms with or without bleeding in 68.6%, and a high serum IgA level in 24.4%. Hematuria was present in 88.6% of the patients, hematuria and proteinuria (not in nephritic range) in 66.7%, nephrotic syndrome in 17.8%, acute nephritic syndrome in 8.9%, and nephritic-nephrotic syndrome in 13.3%. Grades II (33.3%) and III (22.2%) lesions were the most common pathologic findings on kidney biopsy followed by grades IV (17.8%), V (15.6%), and I (11.1%) lesions. Univariate analysis demonstrated that nephrotic syndrome, acute nephritic syndrome and a creatinine clearance less than 30mL/min/1.73m2 were all associated with a significantly increased risk of developing grades IV and/or V lesions. multivariate analysis showed nephritic-nephrotic syndrome as significant independent predictors of severity of glomerular disease at onset.Conclusions. The severity of renal symptoms at onset determines the intensity of glomerular lesions.

Introduction: Oxidative stress due to overproduction of reactive oxygen species and impairment in antioxidant defense mechanisms have been suggested as possible factors contributing to the pathogenesis of atherosclerosis in patients with end-stage renal disease. We compared glutathione levels, glutathione peroxidase and glutathione reductase activities, and total antioxidant capacity between patients on hemodialysis and peritoneal dialysis and healthy individuals.Materials and Methods: Thirty patients receiving regular hemodialysis and 12 on continuous ambulatory peritoneal dialysis were recruited as well as 25 healthy volunteers. Diabetes mellitus, recent febrile or infectious episodes, and hospitalization during the past month were the exclusion criteria. Erythrocyte glutathione level, plasma activities of glutathione peroxidase and glutathione reductase, total antioxidant capacity were determined and compared between the three studied groups.Results: Glutathione levels and glutathione peroxidase activity were markedly lower in the patient groups than in the controls. Conversely, higher activity of glutathione reductase and total antioxidant capacity were noted in the patients than in the controls. There were no significant differences between antioxidant markers of the patients on hemodialysis and peritoneal dialysis. Strong positive correlation were observed between total antioxidant capacity and uric acid in the patients (r=0.59, P=.045 and r=0.63, P=.03, respectively).Conclusions: Although total antioxidant capacity of plasma is increased in patient on dialysis, depletion of glutathione as a key antioxidant component and disturbances in its related enzymes show oxidative stress. This condition may increase the risk of developing cardiovascular disease in patients with end-stage renal disease.

Introduction: Mannose-binding lectin (MBL) constitutes defense against infections when adaptive immune response is compromised. Elevation in serum MBL levels has been shown in patients with kidney failure. We compared serum MBL levels before and after kidney transplant and evaluated association of MBL deficiency with infectious complications in kidney transplant recipients.Materials and Methods: This study was performed in 71 kidney transplant recipients and 48 healthy controls. In 36 recipients (group 1), serum MBL levels were tested before and on days 7 and 14 after transplantation. They were followed up for 6 months. In 35 recipients (group 2), serum MBL was measured during their posttransplant follow-up visits. In both groups, frequencies of clinically significant infections and acute rejection were compared between those with low MBL (<500ng/mL) and normal/highResults: Serum MBL levels (1744 ± 905ng/mL) were not higher in group 1 before transplantation than in controls. One and 2 weeks after transplantation, MBL levels decreased to 1699±1030ngmL and 1562±1020ng/mL, respectively. Five patients who had low serum MBL levels experienced more frequent episodes of infections (P=.008) and CMV disease (P<.001). Ten patients in group 2 with low MBL levels had more frequent episodes of CMV disease (P=.01).Conclusions: These findings suggest a potential role for MBL in defense against developing posttransplant CMV disease and that low serum MBL levels in kidney transplant recipients be considered an indicator of the need for CMV prophylaxis.

Introduction: Living unrelated kidney donation has a high rate in Iran, where a unique organ procurement model is running. We evaluated feelings and attitude of these donors after kidney donation. Materials and Methods: A questionnaire was sent to 25 kidney transplantation centers in Iran. It was designed to assess kidney allograft donors in terms of their reason for donation, their feeling after donation, and their attitude on keeping in touch with the recipients. Of 721 donors recorded in the national registry during the study period, we collected data of 600 living donors and their answers to the questionnaire. Results: Of 600 donors, 495 (82.5%) were men and 568 (94.8%) were unrelated to the recipients. Motivation for donation was stated to be purely financial by 224 respondents (37.3%) and purely altruistic by 11 (1.9%). Their feelings before discharge were complete satisfaction in 519 (86.5%), relative satisfaction in 69 (11.5%), regret in 9 (1.5%), and indifference in 3 (0.5%). Willingness to get informed of the transplant outcome and make connection with the recipient following transplantation was chosen by 457 (76.2%) and 400 (66.7%) donors, respectively. Conclusions: We found that satisfaction of donors shortly after donation, on the one hand, and no reportedly serious complications in long-term follow-up of donors, on the other hand, may give the impression that the Iranian model may solve the problem of increasing demand for kidney allograft. Nevertheless, every country should build its own standards for living unrelated kidney donation consistent with its capacities and resources.

Introduction: The impact of socioeconomic status on the chance of being a candidate of kidney transplantation and its effect on graft survival has been documented. Our aim was to investigate the association of socioeconomic status with kidney allograft recipients’ health-related quality of life and level of anxiety and depression.Materials and Methods: Two hundred and forty-two kidney transplant recipients were categorized according to their monthly family income into low-income, moderate-income, and high-income groups. These groups were compared in terms of health-related quality of life (short form-36) and level of anxiety and depression symptoms (hospital anxiety depression scale).Results: There was a trend of higher HRQOL scores in association with a higher income, which was significant for the total HRQOL score and its subdomains of physical function and role limitation due to physical and emotional problems. A slight increase in anxiety symptom scores was also seen in kidney recipients with lower incomes; however, the depression symptom scores were not significantly different between the income groups. Logistic regression analysis showed that the impact of income on the total HRQL and anxiety symptoms scores remained significant after controlling the effect of age, sex, and time interval from transplantation.Conclusions: A significant proportion of our kidney allograft recipients had a low income and had a poorer health-related quality of life and a greater load of anxiety according to their perception of their status, compared to those with higher incomes. Special consideration to kidney transplant recipients with a lower income may improve their wellbeing.

Conventional Jaffe method of serum creatinine measurement is influenced by several drugs and components of blood as well as the expertise of laboratory staffs. We obtained blood samples of 22 healthy volunteers and sent them to 23 laboratories in Rasht, Iran, in which the conventional Jaffe method would be used for serum creatinine measurement. Also, we tested the samples in 1 reference laboratory with the calibrated Jaffe method. Glomerular filtration rates were calculated using the abbreviated equation of the Modification of Diet in Renal Disease study. Eight of 23 laboratories (34.7%) reported significantly different mean serum creatinine levels from the mean values yielded in the reference laboratory. Seven of 23 laboratories (30.4%) had significantly different estimated glomerular filtration rates in comparison to those calculated in the reference laboratory. Different results for creatinine lead to wrong interpretation of patients’ kidney function and rectifications of this divergence are of utmost importance.

Diffuse bilateral infiltration of the kidneys by lymphoma is probably the rarest cause of renal insufficiency. Moreover, acute renal failure as the initial manifestation of the lymphoma is reported only in a few cases. A 44-year-old man complaining of bilateral flank pain and weakness for 2 months was admitted with acute renal failure. Ultraonography revealed hyperechoic bilaterally enlarged kidneys and an enlarged spleen. Fat pad aspiration was negative for amyloidosis and serum protein electrophoresis was normal. Needle biopsy of the kidney and pathologic examination showed diffuse infiltration of the interstitium with lymphocytes and atypical cells. Bone marrow aspiration and biopsy were negative for malignant cells. Open kidney biopsy was performed and infiltrated cells positive for CD20 and negative for CD3 markers were observed based upon which diagnosis of diffuse large B-cell type non-Hodgkin lymphoma was made.

Benign multilocular cyst is a rare benign multicystic renal tumor. It usually involves the kidneys unilaterally. There is no generally accepted theory concerning its pathogenesis. The usual clinical presentation is an asymptomatic abdominal mass in children and nonspecific symptoms such as abdominal pain, hematuria, and urinary tract infection in adults. This report presents a case of benign multilocular cyst in an 18-months-old boy admitted with abdominal distension and a palpable mass in his right loin. The patient underwent right total nephrectomy, and histological findings were compatible with benign multilocular cyst.