Associations of left ventricular systolic dysfunction with the factors among Thai patients on peritoneal dialysis: a cross-sectional study.

BACKGROUND: Factors associated with left ventricular systolic dysfunction (LVSD) of peritoneal dialysis (PD) patients are limited. We aim to explore and quantify the associated factors of LVSD among PD patients. METHODS: Participants from a PD clinic treated between 2012 and 2014 at the HRH Princess Maha Chakri Sirindhorn Medical Center, Srinakharinwirot University, Nakhon Nayok, Thailand were recruited and divided into 2 groups according to their left ventricular ejection fraction (LVEF) (< 50% vs. ≥ 50%) with LVEF < 50% considered as LVSD. Correlations among the clinical, laboratory and echocardiographic variables were analyzed. The factors associated with LVSD were explored with univariate and multivariate logistic regression analyses. Beta coefficient along with odds ratio and 95% confidence interval (CI) were calculated and the P value < 0.05 was considered significant. RESULTS: Among 103 subjects stratified as LVSD (n = 18, 17.5%). The mean (SD) age was 59.3 (12.7) years, and nearly halves were males. Preexisting CAD, diabetes (DM) and current smoking were 20 (19.4%), 63 (61.2%) and 23 (22.3%) patients, respectively. The median time of dialysis vintage was 12 (3, 24) months. Factors associated with LVSD and corresponding ORs with 95% CI by multivariate analysis were prior coronary artery disease (CAD) [5.08 (1.16, 22.19)], DM [6.36 (1.29, 31.49)], smoking [10.62 (2.17, 51.99)], neutrophil to lymphocyte ratio (NLR) > 3.6 [6.77 (1.41, 32.52)], and high serum phosphate [9.39 (2.16, 40.92)] were significantly associated with LVSD. CONCLUSIONS: Prior history of CAD, DM, smoking, high NLR and serum phosphate levels were found to be associated with LVSD for our PD patients. The evidence from prospective study is needed to confirm the predictive value of these variables.

National survey: Evaluation of cardiovascular risk factors in Thai patients with type 2 diabetes and chronic kidney disease after the development of cardiovascular disease.

AIM: The aim of the present study was to evaluate the achievement in controlling the risk factors of cardiovascular diseases (CVD) in Thai patients with type 2 diabetes (T2DM) and chronic kidney disease (CKD). METHODS: The DMHT dataset from 2011 to 2012, which was the cross-sectional study of the national survey in Thai patients with T2DM was analyzed. RESULTS: There were 1254 of 15 149 diabetic patients with estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m2 that had developed CVD for more than 12 months. The prevalence of CVD was 8.3%. The mean age in years was 68.2 with a standard deviation (SD) of 8.7. Males and females were 38.7 and 61.3%, respectively. The mean duration of diabetes was 8.5 (SD 0.2) years. The mean body mass index was 25.5 (SD 4.4) kg/m2 . The percentage of patients with the target level of blood pressure control at ≤130/80 mm Hg was 47.1%. The percentage of patients who received angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) was 58.9%. The percentage of patients with the target level of LDL control at <70 mg/dL was 17.2%. The percentage of patients with the target level of HbA1C at 7% was 39.2%. There were 63 (5.0%) patients having recurrent CVD. CONCLUSIONS: Most Thai patients with T2DM and CKD with eGFR < 60 mL/min per 1.73 m2 could not achieve the therapeutic goals after the development of CVD. The national health policy should be planned to improve the quality of care to increase the number of patients who achieve the recommended goals.

Factors Related to Erythropoietin Hyporesponsiveness in Peritoneal Dialysis Patients with Anemia.

Background: Anemia in peritoneal dialysis (PD) patients can be improved after treatment with erythropoietin (EPO). However, several factors previously reported can cause EPO hyporesponsiveness including nutritional deficiency, infection or inflammation, secondary hyperparathyroidism with bone marrow fibrosis, angiotensin converting enzyme inhibitor (ACEI) administration, and dialysis inadequacy. Correction of these factors may lower doses and costs of EPO for these patients. Objective: To calculate the prevalence of EPO hyporesponsiveness and the associated factors in PD patients with anemia. Material and Method: We reviewed medical records of 195 PD patients who received EPO treatment during January 2000 to June 2013.The doses of EPO were titrated maximally to 8,000 U/week to maintain a target Hematocrit (Hct) level between 33% and 36%. PD patients Hct less than 30% before and after EPO administration for 3 months were included in this study. There were 44 patients who were recruited by the criteria. They had no history of bleeding or red cell transfusions within 2 months. The EPO resistance index (ERI) was calculated as weekly EPO doses per Hct levels per kilograms body weight (kg). The EPO hyporesponsiveness was defined as the weekly EPO doses was >150 U/kg. The relationship between the ERI and continuous parameters was calculated by the student's t-test. Chi-square and Fisher's exact correlation were performed to analyze the relationship between ERI and categorical variables. The p-value <0.05 was considered statistically difference. Results: There were 13 (6.7%) patients having Hct less than 33% after the administration EPO >150 U/kg/week for 3 months. The statistically significant relationship between ERI and gender was detected. Female had higher rate of having EPO hyporesponsiveness (p = 0.02). Conclusion: The prevalence of EPO hyporesponsiveness was 6.7%. Female gender was a factor related to EPO hyporesponsiveness in our study.

A Report of Peritonitis from Aeromonas sobria in a Peritoneal Dialysis (PD) Patient with Necrotizing Fasciitis.

A 70-years of age, male patient with underlying type 2 diabetes mellitus, hypertension, dyslipidemia and ischemic heart disease had undergone continuous ambulatory peritoneal dialysis (CAPD)for 3 years without any episodes of peritonitis. He was diagnosed with necrotizing fasciitis and later developed peritonitis after receiving a laceration from an aquatic injury suffered during the flood disaster of 2011. The blood culture, necrotic tissue and the clear dialysate collected upon admission had shown Aeromonas sobria. The route of peritonitis may be from the hematogenous spread of A. sobria resulting in necrotizing fasciitis. A. sobria should be considered as the pathogen of peritonitis in PD patients who have history of wounds from contaminated water. We suggest that the PD patients who present with septicemia and did not meet the criteria for peritonitis, the initial dialysate effluent should be sent for culture. The benefit of this is to allow early recognition and treatment of peritonitis.

Echocardiographic and Clinical Characteristics Cross-Sectional Study in Association with Thai Peritoneal Dialysis Patients: Data from a Single Center Study.

BACKGROUND: The dialysis patients have a lot of changes in cardiac structure and function detected by echocardiography and they have been recognized as key outcome predictors. However, the available data regarding echocardiographic alterations in Thai Continuous Ambulatory Peritoneal Dialysis (CAPD) patients is limited. This study aimed to determine the correlation between baseline clinical and echocardiographic characteristics of Thai CAPD patients. MATERIAL AND METHOD: This study was a single center and cross-sectional observational study, which enrolled all CAPD outpatients (104 patients), treated at Srinakharinwirot Medical University between 1 September 2012 and 31 June, 2014. Their demographic and echocardiographic data were collected one time and the latest laboratory data to the patient's echocardiographic study date were analyzed. RESULTS: One hundred and four patients (50 men and 54 women) whose mean age was 59.4 ± 12.7 years and median duration of CAPD was 12 months were recruited. An extremely high prevalence of elevated left ventricular mass index (LVMI), 82.7% was found which mean LVMI was higher in male than female (166.2 ± 55.6 vs. 131 ± 47.6 g/m2). All patients had diastolic dysfunction and most ofthem had diastolic dysfunction grade I. The studyfactors of male gender, history of hypertension, high serum phosphate, low hemoglobin level, corrected QT interval, and duration of CAPD longer than 24 months can predict the variation of LVMI. Interestingly, the study found that a duration of CAPD of longer than 42 months might reduce right ventricular systolic pressure. CONCLUSION: This study revealed a higher prevalence of left ventricular hypertrophy (LVH) in Thai CAPD patients when compared with previous studies and anemia still be an important independentfactor for developing LVH. Longer period of CAPD may regress LVH and lower RVSP that should be proven by longer well-designed prospective studies.

Time-dependent incidence rates and risk factors for transferring to hemodialysis in patients on peritoneal dialysis under the Thai PD-First Policy.

BACKGROUND: Haemodialysis (HD) transfer (HDT) is the major challenge of peritoneal dialysis (PD). This study aimed to analyse the time-dependent incidence rates and risk factors for permanent HDT in patients under Thailand's PD First policy. METHODS: The records of 20,545 patients from January 2008 to June 2018 were studied. The time on therapy (TOT) was divided into 0-3, 3-12, 12-24, 24-36, 36-48 and more than 48 months. The time-dependent incidence rates and causes of PD dropout were investigated. The risk factors for HDT were analysed by multivariable Poisson regression model and presented as incidence rate ratios (IRRs) and 95% confidence intervals (CIs). RESULTS: The main cause of PD dropout was death (45.7%) with 17.4% of the patients transferred to HD. The median (25th to 75th interquartile range) dialysis vintage was 1.4 (0.5-2.7) years. The incidence rates of HDT increased with TOT. Patients with universal coverage were transferred to HD less frequently than those with other health schemes. Patients who were illiterate or only had primary school education had a higher risk of being transferred to HD after 48 months of TOT (IRR 1.41 (95% CI 1.07-1.89)). Peritonitis within the first year of PD was the risk for HDT during 13-48 months of PD. The reasons for HDT changed with TOT. Mechanical complications followed by peritonitis were the main causes of HDT during the first 3 months, and after that peritonitis was the main reason. CONCLUSIONS: The incidence of HDT increased with TOT. The risks for HDT changed over time on PD.

COVID-19 incidence and outcomes among patients with kidney replacement therapy.

BACKGROUND: We aimed to investigate the incidence, fatality, and associated factors in patients with hemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KT) hospitalized for coronavirus disease 2019 (COVID-19) infection and reimbursed from the National Health Security Office (NHSO). METHODS: The retrospective cohort analysis was conducted from an electronic-claimed database, and COVID-19 vaccination status was evaluated in patients with HD, PD, and KT from January 2020 to December 2021. There were 85,305 patients reimbursed for HD, PD, and KT by the NHSO. The rates of COVID-19 infection, COVID-19 vaccination, comorbidities, fatalities, and the cost of treatment were evaluated. RESULTS: COVID-19 infection was observed in 1,799 of 36,982 HD cases (4.9%), 1,531 of 45,453 PD cases (3.4%), and 95 of 2,870 KT cases (3.3%). Patients receiving COVID-19 vaccinations were most common in the KT group, followed by those with HD and PD (76.93% vs. 70.65% vs. 51.34%, respectively). KT patients had a lower fatality rate compared to those with PD and HD (8.42% vs. 18.41% vs. 21.40%, respectively). Advanced age, diabetes, cardiovascular diseases, and COVID-19 vaccination status were associated with fatality. The adjusted odds ratios of fatality after receiving one or two doses of vaccines were 0.7 (95% confidence interval [CI], 0.6-0.9) and 0.3 (95% CI, 0.2-0.4), respectively. The cost of treatment was highest in patients with HD, followed by PD and KT. CONCLUSION: The incidence of COVID-19 infection was higher in patients with HD than in those with PD or KT. COVID-19 vaccination following the national health policy should be encouraged for these patients to prevent fatality.

The technique and outcome of peritoneal dialysis catheter revision.

OBJECTIVE: Tenchkhoff catheter malposition is a significant cause of technical failure in patients with peritoneal dialysis (PD). Many surgical revised techniques have been reported including wire manipulation and laparoscopy. The objective of the present study was to report the outcome of surgical revised technique for catheter malposition in patients with PD. MATERIAL AND METHOD: The data of one hundred and twenty three patients with peritoneal dialysis at the HRH Princess Maha Chakri Sirindhorn Medical Center were reviewed. The Tenchkhoff catheters were revised in ten patients who had delayed outflow drainage and failed with nonsurgical treatment. The outcome of catheter placement and revision were reported. RESULTS: The longest catheter survival time in the authors' patient was 71 months. The Tenchkhoff catheters were revised successfully in ten patients. The positions of exit sites were not changed. The immediate postoperative complication was not found. The second revision of Tenchkhoff catheter was performed in three patients. Five patients died from other causes not related to the catheter malposition, one patient was referred to another hospital, and four patients had still undergone CAPD. CONCLUSION: The authors catheter-revised technique is safe, simple, straightforward and no special instrument needed therefore it is suitable to be practiced in Thailand.

Pulmonary hemorrhage with acute renal injury in a patient with IgA nephropathy.

IgA nephropathy (IgAN) is a form of glomerular diseases which is usually aggravated by infection in respiratory or gastrointestinal systems. The clinical manifestations in IgAN can be asymptomatic microscopic hematuria, gross hematuria, nephritic syndrome, nephrotic syndrome or acute renal injury from crescentic glomerulonephritis. Acute interstitial nephritis (AIN) has been previously described as an unusual cause of acute renal injury in IgAN. Hemoptysis from diffuse pulmonary hemorrhage is a rare manifestation in IgAN. We reported a patient who presented with fever hemoptysis from diffuse pulmonary hemorrhage, and acute renal injury. Renal biopsy revealed IgAN concomitant with AIN which was the cause of renal dysfunction. We conclude that pulmonary hemorrhage and acute interstitial nephritis can be found in IgAN. The etiology of pulmonary hemorrhage and acute interstitial nephritis might be from infection. Renal biopsy is a mandatory investigation to make the correct diagnosis.

Identification of platelet-derived growth factor D in human chronic allograft nephropathy.

Chronic allograft nephropathy (CAN), a descriptive term denoting chronic scarring injury of the renal parenchyma and vasculature in allograft kidneys arising from various etiologies including chronic rejection, is the most common cause of late allograft failure, but mediators of this progressive injury largely remain unknown. We hypothesized that platelet-derived growth factor D (PDGF-D) and its specific receptor PDGF-Rbeta may be an important mediator in the pathogenesis of CAN and, hence, sought to identify its expression in this setting. Allograft nephrectomies demonstrating CAN, obtained from patients with irreversible transplant kidney failure (n = 15), were compared with renal tissues without prominent histopathological abnormalities (n = 18) and a series of renal allograft biopsies demonstrating acute vascular rejection (AVR) (n = 12). Antibodies to PDGF-D and PDGF-Rbeta were used for immunohistochemistry. Double and triple immunohistochemistry was used to identify cell types expressing PDGF-D. PDGF-D was widely expressed in most neointimas in arteries exhibiting the chronic arteriopathy of CAN and only weakly expressed in a small proportion of sclerotic arteries in the other 2 groups. Double and triple immunolabeling demonstrated that the neointimal cells expressing PDGF-D were alpha-smooth muscle actin-expressing cells, but not infiltrating macrophages or endothelial cells. PDGF-Rbeta expression evaluated in serial sections was localized to the same sites where neointimal PDGF-D was expressed. PDGF-Rbeta was expressed in interstitial cells more abundantly in the CAN group compared with the normal and AVR groups, without demonstrable colocalization of PDGF-D. PDGF-D is present in the neointima of the arteriopathy of CAN, where it can engage PDGF-Rbeta to promote mesenchymal cell migration, proliferation, and neointima formation. PDGF-D may engage the PDGF-Rbeta to promote interstitial injury in chronic allograft injury, but its sources within the interstitium were unidentified.

Survival Analysis and Associated Factors in Thai Patients on Peritoneal Dialysis Under the PD-First Policy.

BACKGROUND: The peritoneal dialysis First (PD-First) policy means that PD is the first modality of dialysis chosen for patients with end-stage renal disease (ESRD), as put forth by the Universal Health Coverage (UHC) scheme. It was initiated in Thailand in 2008. Our aim is to analyze patient survival, technique survival, and associated factors. METHODS: Data of PD patients from January 2008 to November 2016 were studied. We calculated patient and technique survival rates (censored for death and kidney transplantation). Factors associated with survival were analyzed by the Cox proportional hazard model. Patient and technique survival rates between 2008 - 2012 and 2013 - 2016 were compared. RESULTS: Our study included 11,477 patients. The mean (standard deviation [SD]) age at initiation of PD was 54.0 (14.4) years. The level of education in 85.2% of cases was illiterate or primary school. A total of 60.9% of patients developed ESRD secondary to diabetes. The 1- to 5-year patient survival rates were 82.6, 71.8, 64.0, 58.5, and 54.0%, respectively. The first-year technique survival rate was 94.8%. The patient and technique survival rates during 2013 - 2016 were better than those seen during 2008 - 2012. Factors associated with lower patient survival rates were: female gender, increased age at start of PD, coverage with civil servant medical benefit scheme, low educational levels, and a history of diabetes. CONCLUSION: Most patients had diabetes and low educational levels as seen in the outcomes in the previous literature. These factors impacted the survival of patients under the PD-First policy.

The impact of the quality of care and other factors on progression of chronic kidney disease in Thai patients with Type 2 Diabetes Mellitus: A nationwide cohort study.

OBJECTIVE: The present study investigates the impact of quality of care (QoC) and other factors on chronic kidney disease (CKD) stage progression among Type 2 Diabetes Mellitus (T2DM) patients. METHODS: This study employed a retrospective cohort from a nationwide Diabetes and Hypertension study involving 595 Thai hospitals. T2DM patients who were observed at least 2 times in the 3 years follow-up (between 2011-2013) were included in our study. Ordinal logistic mixed effect regression modeling was used to investigate the association between the QoC and other factors with CKD stage progression. RESULTS: After adjusting for covariates, we found that the achievement of the HbA1c clinical targets (≤7%) was the only QoC indicator protective against the CKD stage progression (adjusted OR = 0.76; 95%CI = 0.59-0.98; p<0.05). In terms of other covariates, age, occupation, type of health insurance, region of residence, HDL-C, triglyceride, hypertension and insulin sensitizer were also strongly associated with CKD stage progression. CONCLUSIONS: This cohort study demonstrates the achievement of the HbA1c clinical target (≤7%) is the only QoC indicator protective against progression of CKD stage. Neither of the other clinical targets (BP and LDL-C) nor any process of care targets could be shown to be associated with CKD stage progression. Therefore, close monitoring of blood sugar control is important to slow CKD progression, but long-term prospective cohorts are needed to gain better insights into the impact of QoC indicators on CKD progression.

Safety and immunogenicity of a 2009 influenza A (H1N1) vaccine in hemodialysis patients.

A worldwide vaccination campaign against the 2009 pandemic influenza A (H1N1) virus was launched among high-risk subjects, including hemodialysis patients. The long-term immunogenicity of an influenza vaccine has not been investigated in hemodialysis patients. This study aimed to (1) assess the long-term immunogenicity of a monovalent non-adjuvanted influenza A (H1N1) vaccine in hemodialysis patients and (2) determine the safety of this vaccine. We conducted a prospective cohort study of 44 hemodialysis patients and 149 healthy controls in 2010. All of the participants received a single dose of the monovalent non-adjuvanted 2009 influenza A (H1N1) vaccine. The level of antibodies was measured at baseline and at 4 and 24 weeks post-vaccination using a hemagglutination inhibition assay. The outcomes were the percentages of participants who achieved seroconversion and seroprotection (titer ≥ 1:40) 4 and 24 weeks after vaccination. At 4 weeks post-vaccination, seroconversion was observed in 17 (38.6%) of the hemodialysis patients and 94 (63.1%) of the controls (P=0.056), and protective titers were obtained in 22 (50%) of the hemodialysis patients and 100 (67.1%) of the controls (P=0.426). At 24 weeks post-vaccination, immunogenicity decreased in both the hemodialysis patients and the controls, but there were no significant differences between the hemodialysis patients and the controls in the seroconversion rate (27.3% versus 36.9%, P=0.526) or the seroprotection rate (38.6% versus 48.3%, P=0.996). No differences in adverse events were observed between the hemodialysis patients and the controls. In summary, the 2009 influenza A (H1N1) vaccine elicits a similar immune response in both hemodialysis patients and healthy controls, but immunity declines 24 weeks after vaccination in both groups. Hemodialysis patients should at least be vaccinated annually against the influenza virus.

Connective tissue growth factor gene expression and decline in renal function in lupus nephritis.

In lupus nephritis (LN), kidney inflammation may be followed by fibrosis and progressive decline in function. Transforming growth factor (TGF)-ß is a notable mediator of fibrosis, but it has other beneficial roles, thus indicating a need for alternate therapeutic targets for inhibition of fibrosis. Connective tissue growth factor (CTGF) acts as a downstream mediator of TGF-ß in promoting fibrosis, without mediating the immunosuppressive effects of TGF-ß. Animal studies show that CTGF may have important roles in renal fibrosis, but data are limited in human subjects. The present study tested the hypothesis that renal CTGF mRNA expression is related to TGF-ß1 and collagen I expression and is predictive of renal function deterioration in patients with LN (n=39). Gene expression was measured using multiplex real-time quantitative RT-PCR and renal function was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) glomerular filtration rate (GFR) equation. Decline in GFR was assessed by regression of GFR at biopsy to 1 year following biopsy. CTGF mRNA expression was significantly correlated with TGF-ß1 and collagen I. GFR at biopsy was 89.2±39.2 ml/ min. Renal CTGF mRNA expression correlated inversely with baseline GFR. Renal CTGF mRNA was significantly higher in patients with moderate to severe CKD compared to those in the milder CKD group (low GFR 4.92±4.34 vs. high GFR 1.52±1.94, p<0.005). CTGF mRNA was also higher in patients with subsequent decline in GFR [GFR decline (5.19±4.46) vs. no GFR decline (1.79±1.97); P<0.01]. In conclusion, renal expression of CTGF was positively related to TGF-ß1 and collagen I in patients with LN. Furthermore, high CTGF mRNA expression was associated with poor GFR at baseline and subsequent deterioration of kidney function. CTGF expression in the kidney may serve as an early marker for renal disease progression and could be evaluated as a target for therapeutic intervention to prevent renal failure in LN.

Renal thrombotic microangiopathy after hematopoietic cell transplant: role of GVHD in pathogenesis.

BACKGROUND AND OBJECTIVES: Thrombotic microangiopathy (TMA) is a known complication of hematopoietic cell transplantation (HCT). The etiology and diagnosis of TMA in this patient population is often difficult because thrombocytopenia, microangiopathic hemolytic anemia, and kidney injury occur frequently in HCT recipients, and are the result of a variety of insults. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: The authors reviewed renal pathology and clinical data from HCT patients to determine the prevalence of TMA and to identify correlative factors for developing TMA in the kidney. Kidney tissue was evaluated from 314 consecutive autopsies on patients who died after their first HCT (received between 1992 and 1999). Renal pathology was classified into three groups: (1) no renal thrombus (65%), (2) TMA (20%), and (3) isolated thrombosis (15%). Logistic regression models estimated the associations between each histologic category and clinical parameters: donor and recipient gender, patient age, human leukocyte antigen (HLA) matching of the donor and recipient, total body irradiation (TBI), acute graft versus host disease (GVHD), acute kidney injury, medications, and viral infections. RESULTS: In a multivariate analysis, TMA correlated with acute GVHD grades II to IV, followed by female recipient/male donor, TBI > 1200 cGy, and adenovirus infection. Grades II to IV acute GVHD and female gender were associated with isolated renal thrombus. CONCLUSIONS: TMA in HCT recipients is associated with acute GVHD grades II to IV, recipient/donor mismatch, TBI > 1200 cGy, and adenovirus infection.

Platelet-derived growth factor-D expression in developing and mature human kidneys.

BACKGROUND: Platelet-derived growth factor (PDGF) is a family of growth regulatory molecules composed of sulfide-bonded dimeric structures. Two well-studied PDGF peptides (PDGF-A and PDGF-B) have been shown to mediate a wide range of biological effects. PDGF-D is a newly recognized member of the PDGF family. Initial studies of the PDGF-D gene found its expression in cells of the vascular wall, suggesting that it could participate in vascular development and pathology. However, its localization in human kidney tissues has never been studied. METHODS: PDGF-D expression in fetal (N = 30) and adult (N = 25) human kidney tissues was examined by immunohistochemistry using an affinity-purified antibody raised to human PDGF-D. Antibody absorption with the immunizing peptide was employed to confirm the specificity of this antibody. PDGF-D protein and gene expression in human kidneys also were demonstrated by Western blotting and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In the developing kidney, PDGF-D was first expressed by epithelial cells of comma- and S-shaped structures of the developing nephron, and most consistently in the visceral epithelial cells in the later stages of glomerular differentiation. In addition, PDGF-D could be found in mesenchymal, presumptively fibroblast cells in the interstitium of developing renal pelvis and in fetal smooth muscle cells in arterial vessels. In the adult normal kidney, PDGF-D was expressed by the visceral epithelial cells. There was persistent expression in arterial smooth muscle cells as well as in some neointimal smooth muscle cells of arteriosclerotic vessels, and expression in smooth muscle cells of vasa rectae in the medulla. PDGF-D could be identified at the basolateral membrane of some injured tubules in areas of chronic tubulointerstitial injury routinely encountered in aging kidneys. Western blotting of homogenates of adult kidneys demonstrated monospecific bands at 50 kD corresponding to previously established size parameter for this protein. RT-PCR of human kidney RNA resulted in a 918 basepair band, the sequence of which corresponded to human PDGF-D (Genbank number AF336376). CONCLUSIONS: To our knowledge, these are the first studies to localize PDGF-D in human kidneys and suggest that PDGF-D may have a role in kidney development. PDGF-D was shown to bind to PDGF beta receptor, which localizes to mesangial cells, parietal epithelial cells, and interstitial fibroblasts, suggesting potential paracrine interactions between those cells and the visceral epithelium.