William A. Wilmer’s research while affiliated with The Ohio State University and other places

Relapse or worsening of nephrotic syndrome (NS) in idiopathic membranous nephropathy (IMN) is generally assumed to be due to recurrent disease. Here we document that often that may not be the case. This is a prospective study of 7 consecutive IMN patients whose renal status improved, then worsened after completing a course of immunosuppressive therapy. Each underwent detailed testing and repeat kidney biopsy. In 4 patients (group A), the biopsy showed recurrent IMN (fresh subepithelial deposits). Immunosuppressive therapy was begun. In the other 3 patients (group B), the biopsy showed that the deposits had been eradicated. However, the glomerular basement membrane (GBM) was thickened and vacuolated. Immunosuppressive therapy was withheld. Groups A and B were comparable except that group B had very high intakes of salt and protein, based on 24-hour urine testing. Reducing their high salt intake sharply lowered proteinuria to the subnephrotic range and serum creatinine stabilized. This work is the first to demonstrate that relapse/worsening of NS can occur in IMN even though the GBM deposits have been eradicated. High salt and protein intake in combination with thickened and vacuolated GBM appears to be the mechanism.

The cyclopentenone prostaglandin 15-deoxy-delta12,14-prostaglandin J2 (15dPGJ2) affects mesangial proliferation, survival and production of proinflammatory proteins. During a survey of the mesangial cell proteome after treatment with 15dPGJ2, heat shock protein 70 (HSP70) was found to be the most conspicuously up-regulated protein, suggesting that stress proteins are key mediators or modulators of the effects of 15dPGJ2. Because cyclopentenone prostaglandins are highly reactive toward intracellular thiols, the role of intracellular thiol modification in the stress response to 15dPGJ2 was examined. Human mesangial cells were treated with 15dPGJ2 and intracellular thiol status was monitored by the fluorescent thiol probe monobromobimane (MBB). Specific intracellular thiol pools were manipulated by treating the cells with buthionine sulfoximine (BSO) to deplete glutathione (GSH), or phenylarsine oxide (PAO) to modify protein vicinal dithiols. Transcription pathways were examined with reporter gene or adenoviral constructs. 15dPGJ2 decreased mesangial GSH and other intracellular thiols, but depletion of GSH specifically with BSO did not induce HSP70. Thiol-replenishing reagents, which can restore modified protein thiols, attenuated 15dPGJ2-induced HSP70 levels. Furthermore, PAO mimicked the effects of 15dPGJ2 on HSP70. 15dPGJ2 also activated the stress-responsive transcription factor Nrf2, which requires thiol modification of its cytoplasmic inhibitor protein for transcriptional activity, and induced the Nrf2-dependent stress protein heme oxygenase-1 (HO-1). 15dPGJ2 activates a stress response in human mesangial cells by covalent modification of protein thiols through its unique cyclopentenone ring structure. This stress response may be beneficial in preventing renal cell injury or death during kidney inflammation or ischemia.

It is widely accepted that proteinuria reduction is an appropriate therapeutic goal in chronic proteinuric kidney disease. Based on large randomized controlled clinical trials (RCT), ACE inhibitor (ACEI) and angiotensin receptor blocker (ARB) therapy have emerged as the most important antiproteinuric and renal protective interventions. However, there are numerous other interventions that have been shown to be antiproteinuric and, therefore, likely to be renoprotective. Unfortunately testing each of these antiproteinuric therapies in RCT is not feasible. The nephrologist has two choices: restrict antiproteinuric therapies to those shown to be effective in RCT or expand the use of antiproteinuric therapies to include those that, although unproven, are plausibly effective and prudent to use. The goal of this work is to provide the documentation needed for the nephrologist to choose between these strategies. This work describes 25 separate interventions that are either antiproteinuric or may block injurious mechanisms of proteinuria. Each intervention is assigned a level of recommendation (Level 1 is the highest; Level 3 is the lowest) according to the strength of the evidence supporting its antiproteinuric and renoprotective efficacy. Pathophysiologic mechanisms possibly involved are also discussed. The number of interventions at each level of recommendation are: Level 1, n = 7; Level 2, n = 9; Level 3, n = 9. Our experience indicates that we can achieve in most patients the majority of Level 1 and many of the Level 2 and 3 recommendations. We suggest that, until better information becomes available, a broad-based, multiple-risk factor intervention to reduce proteinuria can be justified in those with progressive nephropathies. This work is intended primarily for clinical nephrologists; therefore, each antiproteinuria intervention is described in practical detail.

Peritoneal dialysis (PD) peritonitis is usually caused by infection and less commonly by a sterile inflammatory reaction. The authors report the case of a kidney-pancreas transplant recipient who was receiving PD after kidney transplant rejection 5 years after transplantation. The patient had a viable pancreas transplant. He had abdominal pain associated with cloudy PD effluent. The PD leukocyte count was elevated with a predominance of monocytic leukocytes. Blood, urine, and PD effluent cultures were negative. An ultrasound scan of the transplanted kidney and a computerized tomography (CT) scan of the abdomen and pelvis did not identify the cause of the peritonitis. Foley catheter decompression of the bladder resulted in improvement of the abdominal pain and PD effluent leukocytosis. Twenty-five days later, the patient again experienced abdominal pain and cloudy PD effluent. Cultures of blood and PD effluent were again negative. CT scanning and cystoscopy of the transplanted pancreas identified a leak at the pancreaticoduodenocystotomy anastamosis. Urinary bladder decompression was followed by surgical exploration that identified an erosion of the distal transplanted duodenum, necessitating enteric diversion of the transplanted pancreas's exocrine secretions. The patient underwent conversion to hemodialysis, and the pancreas transplant continued to function well. He has subsequently received a living related kidney transplant. This is the first reported case of noninfectious PD peritonitis caused by pancreaticoduodenocystotomy leak in a patient with a functional pancreas transplant.

Transforming growth factor-beta1 (TGF-beta1) mediates the development of glomerulosclerosis by stimulating mesangial cell production of extracellular matrix (ECM) proteins. TGF-beta1 and several ECM genes are regulated by promoter O-tetradecanoylphorbol 13-acetate-responsive elements (TREs) that are transactivated by the activator protein-1 (AP-1) transcription factor complex. AP-1-TRE interactions are regulated by redox changes. Recently, peroxisome proliferator-activated receptors (PPARs) were shown to negatively regulate several transcription factor families. In these studies, we postulated that PPAR-alpha could antagonize TGF-beta1 expression by cultured human mesangial cells (HMC). A TGF-beta1 luciferase expression plasmid was transduced into HMC via recombinant deficient adenoviral vectors. The TGF-beta1 promoter activity increased twofold (209%) following 18-h treatments with H(2)O(2) (1,000 micro M). Using RT-PCR, we demonstrated that HMC possess PPAR-alpha RNA, and PPAR-alpha protein was identified by immunohistochemistry. Pretreatment of cells with the PPAR-alpha ligands WY14643 (100-500 micro M) or clofibrate (100-500 micro M) dose-dependently inhibited oxidant-mediated induction of TGF-beta1. This inhibition occurred without affecting the H(2)O(2)-mediated activation of the mitogen-activated protein kinase (MAPK) pathways extracellular regulated kinase, p38 MAPK, or Jun N-terminal kinase, which are responsible for the regulation of AP-1 phosphorylation. These studies are the first to identify PPAR-alpha expression by HMC. The results of these studies suggest that TGF-beta1 expression mediated by oxidant stress may be suppressible by PPAR-alpha activation.

Calciphylaxis is a small vessel vasculopathy involving mural calcification with intimal proliferation, fibrosis, and thrombosis. This syndrome occurs predominantly in individuals with renal failure and results in ischemia and necrosis of skin, subcutaneous fat, visceral organs, and skeletal muscle. The syndrome causes significant morbidity in the form of infection, organ failure, and pain. Mortality rates are high. In individuals with renal failure, risk factors for the development of calciphylaxis include female sex, Caucasian race, obesity, and diabetes mellitus. Many cases occur within the first year of dialysis treatment. Several recent reports demonstrate that prolonged hyperphosphatemia and/or elevated calcium x phosphorus products are associated with the syndrome. Protein malnutrition increases the likelihood of calciphylaxis, as does warfarin use and hypercoagulable states, such as protein C and/or protein S deficiency. Recent advances in diagnostic tools and therapeutic strategies have helped in the management of patients with calciphylaxis.

Background: Proliferation of intrinsic glomerular cells is a common response to renal injury. Acutely, proliferation may be beneficial, but sustained glomerular hypercellularity after injury is associated with progressive renal failure. To identify endogenous factors that may be responsible for regulating glomerular cell number, the effects of J-series cyclopentenone prostaglandins (PGs) on human glomerular mesangial cell proliferation and death were examined. Methods: Human mesangial cells were grown in the presence or absence of PGJ2 or its metabolite 15-Deoxy-Delta12,14-PGJ2 (15dPGJ2). The number of viable cells was measured by the reduction of the tetrazolium MTS to a colored formazan product. Apoptosis was assessed by caspase-3 activation and DNA fragmentation. Results: PGJ2 at concentrations up to 10 micromol/L caused mesangial proliferation. 15dPGJ2 also caused mesangial proliferation at low concentrations (< or =2.5 micromol/L), but induced mesangial cell death at higher concentrations (>5 micromol/L). Cell death occurred in part through apoptosis, measured as an increase in caspase-3 activity and DNA fragmentation in 15dPGJ2-treated cells. Cell death was associated with a decline in baseline phosphorylation of the survival factor Akt and increased Akt degradation, whereas 15dPGJ2-induced mesangial proliferation was blocked by inhibition of the PI 3-kinase/Akt pathway. 15dPGJ2 is a potent PPARgamma agonist. Like 15dPGJ2, treatment of mesangial cells with thiazolidinedione-type PPARgamma ligands (10 to 20 micromol/L) caused significant cell death, but at lower concentrations also caused a small degree of proliferation. Conclusions: J-series prostaglandins thus may be involved in the initiation of glomerular hypercellularity through Akt-dependent proliferation, and restoration of normal glomerular architecture through PPARgamma-mediated apoptosis. Manipulation of these prostaglandins may be relevant to the treatment of progressive glomerular disease.

High glucose (HG) environments activate several protein kinase pathways in mesangial cells, including the mitogen-activated protein kinase (MAPK) pathway, ERK. The p38 MAPK pathway is activated by events that occur in the setting of diabetes, such as protein kinase C (PKC) up-regulation and cellular stresses (osmotic stress and redox changes). Substrates of activated p38 MAPK include transcription factors that are involved in the microvascular complications of diabetes. This current study investigated the mechanisms of HG-mediated activation of p38 MAPK in cultured human mesangial cells (HMCs) and the effects of p38 MAPK activation on the transcription factor activator protein-1 (AP-1). HMCs were cultured in 5 mmol/L D-glucose [normal glucose (NG)] or 30 mmol/L D-glucose (HG) for seven days. Cells were also treated with HG for brief periods of time (0.5 to 4 hours) to assess the acute effects of HG on p38 MAPK. Using Western blotting of HMC lysates, changes in the tyrosine and threonine phosphorylation of p38 MAPK were measured. The kinase activity of immunoprecipitated p38 MAPK was determined by an in vitro assay that measured the phosphorylation and activation of MAPKAP kinase-2, an intermediary signaling protein downstream of p38 MAPK. To investigate the role of osmotic stress in HG activation of p38 MAPK, cells were acutely treated with mannitol (25 to 250 mOsm/L x 5 to 60 min) or were grown seven days in media supplemented with mannitol at concentrations iso-osmotic to HG media. To investigate the role of PKC in HG-mediated p38 MAPK activation, HMCs were treated with the PKC inhibitors GF 109203X, Ro 32-0432, or rottlerin during the last several hours of HG treatment. HG conditioned cells were also treated with the antioxidants L-N-acetylcysteine (L-NAC) or diphenyliodonium (DPI) prior to harvest. To determine a functional significance of HG-mediated p38 MAPK activation, the DNA binding of the transcription factor complex AP-1 was measured by electrophoretic mobility shift assay. The p38 MAPK pathway was not activated by the acute addition of HG to the HMCs. However, activation of p38 MAPK in HMCs grown seven days in HG was demonstrated by increased tyrosine and threonine phosphorylation of p38 MAPK proteins and increased kinase activity of immunoprecipitated p38 MAPK. As assessed by a kinase assay, p38 MAPK activity in cells grown in HG for seven days exceeded that of NG cells by more than 250%. This difference was not due to differences in the amount of p38 MAPK protein between the treatment groups. Acute osmotic activation of p38 MAPK occurred at extremely high mannitol concentrations (250 mOsm/L) that exceeded the osmotic stress of acute HG. Furthermore, in cells grown for seven days in mannitol at concentrations similar to HG, p38 MAPK activity was similar to control values. Phorbol ester (PMA) treatment stimulated a twofold increase in p38 MAPK activity. The addition of GFX or Ro 32-0432 to HG cells, at concentrations that inhibited PMA activation of p38 MAPK, did not inhibit the glucose-mediated p38 MAPK activation. Rottlerin, a PKC delta inhibitor, also failed to reverse the HG-mediated p38 MAPK activation. Treatment of HG cells with L-NAC or DPI inhibited the HG-mediated p38 MAPK phosphorylation. As we have previously shown, DNA binding of the transcription factor complex AP-1 was increased in HG cells. This binding was reversed by treatment of the HG cells with the p38 MAPK inhibitor SB 203580. Chronic exposure of HMC to HG concentrations activates the p38 MAPK pathway. This activation appears to be independent of changes in the amount of total p38 MAPK produced by the cells, independent of chronic osmotic stress and independent of PKC activation. The reversal of p38 MAPK by L-NAC and DPI suggests the glucose-mediated p38 MAPK activation may occur via reactive oxygen species. The activity of AP-1, a transcription factor complex that regulates several genes involved in diabetic nephropathy, is reversed when the p38 MAPK pathway is inhibited. These findings suggest the p38 MAPK pathway may be an important pathway involved in diabetic complications.