Phase I safety, pharmacokinetic, and pharmacodynamic study of ENMD-2076, a novel angiogenic and Aurora kinase inhibitor, in patients with advanced solid tumors

PURPOSE

ENMD-2076 is a unique orally bioavailable Aurora kinase and VEGFR inhibitor. The purpose of this phase 1 study of ENMD-2076 was to determine the MTD, pharmacokinetic, and pharmacodynamic profiles and preliminary antitumor activity.

EXPERIMENTAL DESIGN

Patients with refractory advanced solid malignancies were treated with ENMD-2076 orally with continuous once daily dosing. Doses from 60 to 200 mg/m(2) were evaluated using a standard 3 (to 4) + 3 design. Pharmacokinetic parameters were studied on days 1, 28, and 30 to 35 of cycle 1. Expanded MTD cohorts included patients with ovarian cancer, colorectal cancer, and refractory solid tumors.

RESULTS

A total of 67 patients (46 F, 21M; ages 30-76) entered the study. Dose levels of 60, 80, 120, 200, and 160 mg/m(2) were evaluated. Two patients experienced grade 3 hypertension at 200 mg/m(2), and additional grade 3 neutropenia events limited tolerability at this dose. An intermediate dose of 160 mg/m(2) was determined to be the MTD. The most common drug-related adverse events included hypertension, nausea/vomiting, and fatigue. The pharmacokinetics of ENMD-2076 were characterized by a rapid absorption phase (T(max) 3-7.8 hours), a t(1/2) of 27.3 to 38.3 hours after a single dose, and dose proportional exposure. Decreased plasma sVEGFR2 was observed posttreatment. Two patients with platinum refractory/resistant ovarian cancer had RECIST partial responses.

CONCLUSIONS

ENMD-2076 was well tolerated, had a linear pharmacokinetic profile, and showed promising antitumor activity, particularly in ovarian cancer. The recommended phase 2 dose of ENMD-2076 is 160 mg/m(2) administered orally once daily with continuous dosing.

Assessment of the in vivo antitumor effects of ENMD-2076, a novel multitargeted kinase inhibitor, against primary and cell line-derived human colorectal cancer xenograft models

PURPOSE

This in vivo study was designed to investigate the efficacy of ENMD-2076, a small-molecule kinase inhibitor with activity against the Aurora kinases A and B, and several other tyrosine kinases linked to cancer, including vascular endothelial growth factor receptor 2, cKit, and fibroblast growth factor receptor 1, against murine xenograft models of human colorectal cancer (CRC).

EXPERIMENTAL DESIGN

HT-29 CRC cell line xenografts were treated with either vehicle or ENMD-2076 (100 or 200 mg/kg) orally daily for 28 days. Tumor growth inhibition, dynamic contrast-enhanced magnetic resonance imaging, and (18)FDG-positron emission tomography were conducted to assess the antiproliferative, antiangiogenic, and antimetabolic responses, respectively. Effects on proliferation were also analyzed by immunohistochemical methods. Additionally, three patient-derived xenografts from primary and metastatic sites were treated with ENMD-2076 (100 mg/kg) and assessed for tumor growth inhibition.

RESULTS

In the HT-29 xenograft model, ENMD-2076 induced initial tumor growth inhibition followed by regression. Treatment was associated with significant tumor blanching, indicating a loss of vascularity and substantial reductions in tumor vascular permeability and perfusion as measured by dynamic contrast-enhanced magnetic resonance imaging. Positron emission tomography scanning showed significant decreases in (18)FDG uptake at days 3 and 21 of treatment, which was associated with a marked reduction in proliferation as assessed by Ki-67. All three of the patient-derived xenografts tested were sensitive to treatment with ENMD 2076 as measured by tumor growth inhibition.

CONCLUSIONS

ENMD-2076 showed robust antitumor activity against cell line and patient-derived xenograft models of CRC that is detectable by functional imaging, supporting clinical investigation of this agent in CRC.

Abstract C75: A novel multi-targeted Aurora A and VEGFR2 kinase inhibitor, ENMD-2076, demonstrates synergistic antiproliferative and proapoptotic effects in combination with chemotherapy and trastuzumab in breast cancer cell lines

Introduction: ENMD-2076 is an orally bioavailable small molecule kinase inhibitor with antiproliferative activity via Aurora A kinase inhibition, and antiangiogenic activity via VEGFR2 inhibition. ENMD-2076 is being studied in a phase I clinical trial in advanced solid tumors and has demonstrated a tolerable side-effect profile. Due to the involvement of both Aurora A and angiogenic signaling pathways in breast cancer, we explored the combination of ENMD-2076 and chemotherapy or anti-HER2 therapy against a panel of breast cancer cell lines.

Methods: Breast cancer cell lines were exposed to varying submicromolar concentrations of ENMD-2076 alone and in combination with carboplatin, docetaxel, or trastuzumab (HER2-overexpressing cell lines only). Proliferation was assessed using an SRB assay and analyzed using the Calcusyn program, whereby synergy was defined as a Combination Index of less than 1. FISH was performed to assess Aurora A gene amplification, VEGF concentrations were measured by ELISA, and apoptosis was analyzed using a caspase 3/7 assay.

Results: The combination of ENMD-2076 and carboplatin resulted in synergistic inhibition of proliferation in both HER2 + (BT-474, SKBr3, ZR-75-30) and in triple negative (MDA 231, MDA 468) breast cancer cell lines. Likewise, ENMD-2076 and trastuzumab resulted in robust synergistic growth inhibition in HER2 + breast cancer cell lines. Synergy was not observed with the ENMD-2076 and docetaxel combination. FISH analysis demonstrated that tumor cells were sensitive to ENMD-2076 regardless of levels of Aurora A amplification. An increase in apoptosis that was maximal at 72 hours was observed with single agent ENMD-2076 and the combinations with carboplatin or trastuzumab. Similarly, VEGF concentrations were decreased in response to treatment with ENMD-2076 alone or in combination with the other agents.

Discussion: These in vitro results demonstrate that ENMD-2076 acts synergistically with carboplatin to inhibit proliferation of triple negative breast cancer cell lines, and with both carboplatin and trastuzumab towards HER2+ breast cancer cell lines. This activity is associated with induction of cell death and reduction of VEGF secretion. These data are being confirmed in vivo using both trastuzumab-sensitive and trastuzumab-resistant xenograft models.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C75.

BRCA in breast cancer: from risk assessment to therapeutic prediction

BRCA1/2 mutations are the most commonly identified germ line gene mutations in patients with hereditary breast cancer. These proteins have many critical cellular functions, including repair of DNA double-strand breaks. The role of defective BRCA1/2 as a predictor of response to DNA-damaging agents has been studied extensively in preclinical models, but prospective clinical validation is lacking. Poly [ADP-ribose] polymerase (PARP) inhibitors illustrate the concept of synthetic lethality in cells with defective BRCA1/2 and numerous PARP inhibitors are being evaluated in patients with BRCA1/2-associated tumors. BRCA1/2 mutation or functional loss will likely serve as a useful predictive biomarker of response to treatment with PARP inhibitors.

Early-stage BRCA2-linked breast cancer diagnosed in the first trimester of pregnancy associated with a hypercoagulable state

This patient was found to have a BRCA2 gene mutation. She underwent lumpectomy and axillary lymph node dissection without any evidence of lymph node metastasis. Systemic chemotherapy with doxorubicin and cyclophosphamide for four cycles was administered beginning in the second trimester. She was treated with prophylactic LMWH until delivery and then for 6 weeks postpartum. She delivered a healthy baby boy and, after a period of breast-feeding, underwent bilateral mastectomy with immediate reconstruction. She remains well and is expecting her second child. Prophylactic oophorectomy is planned after completion of this pregnancy.

Increased renal expression of monocyte chemoattractant protein-1 and osteopontin in ADPKD in rats

BACKGROUND

Human autosomal-dominant polycystic kidney disease (ADPKD) is variable in the rate of deterioration of renal function, with end-stage renal disease (ESRD) occurring in only approximately 50% of affected individuals. Evidence suggests that interstitial inflammation may be important in the development of ESRD in ADPKD. Han:SPRD rats manifest ADPKD that resembles the human disease. Homozygous cystic (Cy/Cy) rats develop rapidly progressive PKD and die near age 3 weeks. Heterozygous (Cy/+) females develop slowly progressive PKD without evidence of renal dysfunction until the second year of life, whereas heterozygous (Cy/+) males develop more aggressive PKD with renal failure beginning by 8 to 12 weeks of age.

METHODS

To examine the relationship between proinflammatory chemoattractants and the development of interstitial inflammation and ultimately renal failure in ADPKD, we evaluated monocyte chemoattractant protein-1 (MCP-1) and osteopontin mRNAs and proteins in kidneys from Han:SRPD rats.

RESULTS

MCP-1 and osteopontin mRNAs, expressed at low levels in kidneys from normal (+/+) animals at all ages, were markedly elevated in kidneys from 3-week-old Cy/Cy animals. In kidneys from heterozygous (Cy/+) adults of either gender, MCP-1 and osteopontin mRNAs were more abundant than normal; MCP-1 mRNA was more abundant in Cy/+ males than in females. Thus, chemoattractant mRNA expression correlated with the development of renal failure in Cy/Cy and Cy/+ rats. Osteopontin mRNA, localized by in situ hybridization, was moderately expressed in the renal medulla of normal animals; however, this mRNA was expressed at very high levels in the cystic epithelia of Cy/+ and Cy/Cy animals. MCP-1 and osteopontin proteins, localized by immunohistochemistry, were weakly detected in +/+ kidneys but were densely expressed in Cy/Cy and in adult Cy/+ kidneys, primarily over cystic epithelium. Increased expression of chemoattractants was associated with the accumulation of ED-1 positive cells (macrophages) in the interstitium of cystic kidneys.

CONCLUSIONS

We suggest that proinflammatory chemoattractants have a role in the development of interstitial inflammation and renal failure in ADPKD.

Chemokine expression in the obstructed kidney

Chemokines are chemotactic cytokines that are important mediators of leukocyte extravasation and chemotaxis. Herein, we provide evidence that after 1 day of unilateral ureteral obstruction (UUO), the mouse obstructed kidney (OBK) expresses MCP-1 (monocyte chemoattractant protein-1), RANTES (Regulated on activation normal T-cell expressed and secreted) and IP-10 (interferon-gamma-induced protein-10). In addition, by day 7, MIP-2 (macrophage inflammatory protein-2) expression is elevated in the obstructed kidneys compared to the contralateral control kidneys (CLK). After 7 days of obstruction, RANTES was the most abundant of the four chemokines detected in the OBK. In situ hybridization results indicate that several cellular compartments contribute to the expression of RANTES in the OBK. However, clearly cortical tubules within the OBK contribute substantially to the elevated expression of RANTES. These data support the contention that the cortical tubular epithelium plays a pivotal role in the inflammation associated with experimental hydronephrosis.

Angiotensinogen and AT(1) antisense inhibition of osteopontin translation in rat proximal tubular cells

Antisense oligonucleotide inhibition of angiotensinogen and ANG II type 1 receptor (AT(1)) mRNA translation in rat proximal tubules (PT) was examined to provide direct evidence for a role of the renin-angiotensin system (RAS) in upregulated osteopontin expression observed following mechanical cell stretch. Male Sprague-Dawley rats underwent unilateral ureteral obstruction (UUO) under Brevital anesthesia. In situ hybridization and Western blot analysis demonstrated angiotensinogen mRNA and angiotensin converting enzyme (ACE) protein localized to PTs and upregulated in obstructed kidneys, respectively, confirming an increased expression of renal RAS in vivo. In vitro studies were performed to provide mechanistic insight into ANG II-dependent osteopontin expression following mechanical cell stretch, which putatively mimics the increased PT luminal pressure post-UUO. A cationic transfection method was used to introduce either angiotensinogen or AT(1) antisense oligonucleotide into cultured rat PT cells prior to 1 h of cyclic mechanical cell stretch. Northern blot analysis revealed that PT cells subjected to cyclic mechanical stretch with/without prior transfection with a sense oligonucleotide exhibited increased osteopontin mRNA expression compared with unstretched cells. Blockade of either angiotensinogen or AT(1) mRNA translation by antisense oligonucleotide inhibition prior to cell stretch was found to significantly decrease osteopontin mRNA levels 2.4-fold (P<0.004) and 1.6-fold (P<0.001), respectively, compared with values observed in control unstretched cells. This study provides evidence that stretch-induced upregulation of osteopontin mRNA expression is mediated, in part, via production of ANG II. These results lend insight into upregulation of osteopontin via a local PT RAS leading to macrophage infiltration in the tubulointerstitium in experimental hydronephrosis.

Variation in the PPARalpha gene is associated with altered function in vitro and plasma lipid concentrations in Type II diabetic subjects

AIMS/HYPOTHESIS

Peroxisome proliferator activated receptor alpha (PPARalpha) regulates genes involved in lipid metabolism, haemostasis and inflammation, in response to fatty acids and fibrates, making it a candidate gene for risk of dyslipidaemia, atherosclerosis and coronary artery disease. Plasma non-esterified fatty acids are increased in subjects with Type II (non-insulin-dependent) diabetes mellitus, suggesting that PPARalpha could link Type II diabetes and dyslipidaemia, and affect response to fibrates. This has been investigated in association studies in healthy and diabetic subjects and in vitro studies.

METHODS

The human PPARalpha gene was isolated and screened for variation by single strand conformation polymorphism analysis. Genotypes were determined for 129 Type II diabetic subjects and 2508 healthy men. The association with plasma lipid concentrations was examined. The function of the V162 variant was examined in co-transfection assays.

RESULTS

We identified two polymorphisms, one in intron 3 and a missense mutation, leucine 162 to valine, in the DNA binding domain. In Type II diabetic patients, V162 allele carriers had higher total cholesterol, HDL cholesterol and apoAI whereas intron 3 rare allele carriers had higher apoAI concentrations. By contrast, no effect was observed in healthy rare allele carriers. In vitro, the V162 variant showed greater transactivation of a reporter gene construct.

CONCLUSION/INTERPRETATION

Naturally occurring variation alters PPARalpha function, influencing plasma lipid concentrations in Type II diabetic patients but not healthy people. This demonstrates that PPARalpha is a link between diabetes and dyslipidaemia, and so could influence the risk of coronary artery disease, the greatest cause of morbidity and mortality in Type II diabetes.

Alpha macroglobulins and the low-density-lipoprotein-related protein/alpha-2-macroglobulin receptor in experimental renal fibrosis

In this study, we evaluated the location of non-specific proteinase inhibitors and their receptor in experimental glomerular and interstitial fibrosis. The alpha macroglobulins alpha-2-macroglobulin (alpha2M) and alpha-1-inhibitor 3 (alpha1I3) are proteinase inhibitors, including metalloproteinases and serine proteases. Using immunohistochemistry, we detected alpha1I3 in the glomerular mesangium in control rats. In acute and chronic fibrosis, the alpha1I3 protein expression was dramatically increased throughout the glomerulus and at sites of increased extracellular matrix deposition in the interstitium. The presence of alpha1I3 in normal and nephrotic kidneys was confirmed by Western blotting. Under chemically reducing conditions, we found that, in contrast to native alpha1I3, kidney-derived alpha1I3 has reacted upon by proteinases, thereby revealing a functional role for this macroglobulin under normal and pathological conditions. Double staining revealed that high amounts of glomerular alpha1I3 were present in sclerotic lesions. alpha2M was absent in glomeruli and interstitium from control rats, but present in small amounts in glomerular mesangial areas of acute nephrotic rats. alpha2M was also present in significant amounts in glomeruli from rats with chronic fibrosis. The receptor mediating the uptake of proteinase inhibitor-proteinase complexes, the low-density-lipoprotein-related protein/alpha-2-macroglobulin receptor, was found in the glomerular mesangium and tubulo-interstitium from control rats. Significant increments in receptor expression were found in glomeruli and interstitium of rats with chronic fibrosis, with a preferential localization in fibrotic areas. Interstitial staining for low-density-lipoprotein-related protein/alpha-2-macroglobulin receptor was attributed to fibroblasts, since double staining ruled out dendritic cells and macrophages. In conclusion, these studies demonstrate the intrarenal presence of plasma-derived proteinase inhibitors together with their receptors. These findings may point to a novel mechanism for renal fibrosis wherein matrix-degrading proteinases are inhibited, resulting in renal fibrosis.

Mechanisms of interstitial fibrosis in obstructive nephropathy

Numerous pathological processes are involved in the renal tubulointerstitial fibrogenic reaction that occurs after ureteral ligation. Central to these maladaptive events is a florid interstitial monocytic infiltration of the tubulointerstitium, which is preceded by a proximal tubular up-regulation of macrophage chemoattractants. Once within the peritubular and periglomerular space, these macrophages are capable of releasing a potent armamentarium of peptide growth factors. TGF-beta has been singled out as a pivotal growth factor mediating fibrogenesis owing to its multifaceted effects on fibroblasts, tubular cells, matrix metalloproteinases, and TIMPs. A growing body of experimental studies using the rat hydronephrosis model is now demonstrating that angiotensin II may, in addition to its well-known hemodynamic effect, also be pro-inflammatory and pro-fibrogenic.

The role of macrophages and reactive oxygen species in experimental hydronephrosis

A common feature to a number of immune and non-immune renal diseases of diverse etiology is the infiltration of the glomerular and tubulointerstitial compartments by infiltrating macrophages. This review will focus on experimental data supporting the role of the infiltrating renal macrophage as a mediator of interstitial fibrosis during the course of obstructive nephropathy as it pertains to the unilateral ureteral obstruction model in the rat. The mechanical disturbance resulting from complete ureteral obstruction causes tubular injury/dysfunction resulting in a florid pro-inflammatory and fibrogenic response. The central pathobiological theme drawn from data in this model is that macrophage-derived pro-inflammatory mediators, including fibrogenic cytokines and reactive oxygen species, represent pivotal links between the pro-inflammatory state of ureteral obstruction and the late development of interstitial fibrosis. We propose that increased intrarenal oxidant stress, owing to an overproduction of reactive oxygen species and dysregulated tubular antioxidant enzymes, can induce overexpression of fibrogenic cytokines and chemoattractants, as well as increased transcription and synthesis of extracellular matrix proteins, leading to tubular loss and fibrogenesis.

Regulation of proximal tubular osteopontin in experimental hydronephrosis in the rat

BACKGROUND

Osteopontin is a tubular-derived glycoprotein with macrophage chemoattractant properties. Our previous observations demonstrate that osteopontin is involved in the accumulation of macrophages within the renal cortex of rats following unilateral ureteral obstruction (UUO).

METHODS

The present study performed Northern and Western blot analyses of isolated proximal tubular cells exposed to exogenous angiotensin II, and cultured rat proximal tubular cells subjected to one hour of cyclic mechanical stretch, which provided insight into mechanisms involving the proximal tubular renin-angiotensin system in the increased expression of cortical osteopontin following hydronephrosis.

RESULTS

In situ hybridization, using a 35S-labeled antisense riboprobe, showed osteopontin mRNA transcription localized to the cortical tubules of the obstructed kidney. Freshly isolated proximal tubules incubated with angiotensin II (10-5 M) for one hour had increased osteopontin mRNA and protein expression by Northern and Western blot analyses, respectively. Pre-treatment of proximal tubules with losartan (10-5 M) for one hour prior to the addition of exogenous angiotensin II (10-5 M) decreased osteopontin mRNA and protein expression. Rat proximal tubule cells subjected to cyclic mechanical stretch for one hour exhibited a 2.1-fold increment in osteopontin mRNA levels, which was normalized following pre-treatment with losartan.

CONCLUSIONS

This study provides evidence that angiotensin II, produced by the proximal tubule in the obstructed kidney as a result of mechanical injury, possibly mechanical stretch, may stimulate angiotensin II type I receptor activation, leading to up-regulated osteopontin expression and secretion by the proximal tubule, thereby facilitating macrophage recruitment into the renal interstitium.

Cardiovascular outcomes in type 2 diabetes. A double-blind placebo-controlled study of bezafibrate: the St. Mary's, Ealing, Northwick Park Diabetes Cardiovascular Disease Prevention (SENDCAP) Study

OBJECTIVE

To determine whether serum lipid intervention, in addition to conventional diabetes treatment, could alter cardiovascular outcomes in type 2 diabetes.

RESEARCH DESIGN AND METHODS

There were 164 type 2 diabetic subjects (117 men, 47 women) without a history of clinical cardiovascular disease randomized to receive either bezafibrate or placebo daily on a double-blind basis in addition to routine diabetes treatment and followed prospectively for a minimum of 3 years. Serial biochemical and noninvasive vascular assessments, carotid and femoral artery B-mode ultrasound measurements, and those pertaining to coronary heart disease (CHD)--clinical history, the World Health Organization (WHO) cardiovascular questionnaire, and resting and exercise electrocardiogram (ECG)--were recorded.

RESULTS

Bezafibrate treatment was associated with significantly greater reductions over 3 years in median serum triglyceride (-32 vs. 4%, P = 0.001), total cholesterol (-7 vs. -0.3%, P = 0.004), and total-to-HDL cholesterol ratio (-12 vs. -0.0%, P = 0.001), and an increase in HDL cholesterol (6 vs. -2%, P = 0.02) as compared with placebo. There was a trend toward a greater reduction of fibrinogen (-18 vs. -6%, P = 0.08) at 3 years. No significant differences between the two groups were found in the progress of ultrasonically measured arterial disease. In those treated with bezafibrate, there was a significant reduction (P = 0.01, log-rank test) in the combined incidence of Minnesota-coded probable ischemic change on the resting ECG and of documented myocardial infarction.

CONCLUSIONS

Improving dyslipidemia in type 2 diabetic subjects had no effect on the progress of ultrasonically measured arterial disease, although the lower rate of "definite CHD events" in the treated group suggests that this might result in a reduction in the incidence of coronary heart disease.

Ureteral obstruction as a complication of renal transplantation: a review

Ureteral obstruction in a renal allograft, due to a variety of etiologies, is both a challenging diagnostic and therapeutic disorder. Since ureteral obstruction in a renal transplant recipient usually presents as azotemia, it must also be distinguished from acute rejection. Although ultrasound is non-invasive and readily available, the most definitive diagnostic tool is percutaneous nephrostomy tube placement with antegrade nephrostogram. A variety of therapeutic approaches are available to treat ureteral obstruction in a renal allograft. These procedures can be open (e.g., repeat ureteroneocystotomy) or utilize an endourological approach (e.g., transluminal ureteral dilatation). From an experimental standpoint, recent data in rodent models of experimental hydronephrosis demonstrate similar pathobiologic events in both the obstructed kidney and an allograft undergoing the chronic rejection process. To this end, investigation needs to be conducted to assess whether partial, unrecognized ureteral obstruction in an allograft hastens the development of chronic rejection. This would further underscore the importance of ureteral obstruction as a cause for not only acute azotemia in an allograft, but also chronic deterioration in renal transplant function.

Hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP) complicating adult Still's disease: remission induced with intravenous immunoglobulin G

Coexistence of hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP) and adult Still's disease is extremely rare. We describe the case history of a 22-year-old young man who presented with evidence of a thrombotic microangiopathy complicated by dialysis-dependent renal failure, encephalopathy, and an ischemic retinopathy. The most important and novel feature of this case was the dramatic and sustained clinical remission of the TMA induced by intravenous immunoglobulin (IVIg) after failure of plasmapheresis and glucocorticoids to do so.

Antioxidant expression in experimental hydronephrosis: role of mechanical stretch and growth factors

We assessed whether levels of renal reactive oxygen species (ROS) and antioxidant enzymes are perturbed in rats following unilateral ureteral obstruction (UUO). The mechanism of catalase perturbation was investigated using proximal tubule suspensions following stimulation with transforming growth factor (TGF)-beta and interleukin (IL)-1 and in a proximal tubular cell line (OKC) subjected to cyclic mechanical stretch, which mimics the early hydrodynamic derangement after UUO. Levels of catalase and copperzinc superoxide dismutase (Cu,Zn-SOD) mRNA from 96-h UUO rats showed a 5.5-fold (P < 0.001) and 5.0-fold (P < 0.001) decrease, respectively, compared with the contralateral unobstructed kidney (CUK). Levels of superoxide anion and hydrogen peroxide showed a significant 1.8-fold (P < 0.0001) and 14.0-fold (P < 0.0001) increase, respectively, in 96-h UUO kidney slice cultures. In situ hybridization and immunohistochemistry showed Cu,Zn-SOD and catalase mRNA and protein transcription expressed in proximal tubules of UUO and CUK specimens. Catalase mRNA levels were markedly downregulated following a 1-h exposure of isolated proximal tubules to TGF-beta (0.1-10 ng) and IL-1 (1-5 ng), in comparison to control proximal tubular suspensions. OKC subjected to cyclic mechanical stretch for 1-24 h had marked decrements in catalase mRNA levels, compared with unstretched cells at the same time point. These results indicate that a primary downregulation of proximal tubular Cu,Zn-SOD and catalase expression develops in the proximal tubules of UUO with consequent increments in cortical oxidant levels. These findings suggest that either an early mechanical disturbance produced by UUO or local tubular generation of cytokines can reduce tubular catalase expression. The downregulation of catalase mRNA expression, together with increased oxidant stress in the rat renal cortex post-UUO, may amplify the proinflammatory state of experimental hydronephrosis culminating in tubulointerstitial injury and fibrosis.

Increased expression of decorin in experimental hydronephrosis

Transforming growth factor (TGF)-beta1 is a potential mediator of tubulointerstitial (TI) fibrosis in the rat unilateral ureteral obstruction (UUO) model. Decorin is a protein composed of a core protein and a chondroitin sulfate side chain and is capable of inactivating TGF-beta. Since TGF-beta strongly induces the synthesis of decorin in experimental glomerulonephritis, it was our intent to investigate whether altered decorin expression is operant in the rat UUO model. Renal cortical decorin mRNA levels initially became elevated (2.5-fold) in obstructed kidney (OBK) versus contralateral unobstructed kidney (CUK) 24 hours post-UUO and remained greater in the OBK specimens at 48 (2.3-fold), 96 (2.2-fold), and 168 (1.9-fold) hours post-ureteral ligation. Whole-body X-irradiation 11 days prior to UUO significantly reduced decorin mRNA at 24 and 96 hours post-UUO. On immunolabeling, decorin was only evident in the adventitia of blood vessels in CUK specimens at any time point after UUO. In contrast, OBK specimens initially demonstrated periglomerular and peritubular interstitial localization of decorin at 96 hours post-ureteral ligation, which became even more intense and diffuse in the tubulointerstitium at 168 hours post-UUO. On Western analysis, there were highly significant increases in decorin protein expression in the OBK versus the CUK specimens at 96 and 168 hours post-UUO. Levels of active TGF-beta1 in the renal cortex of OBK were 1.9- and 3.6-fold higher than CUK at 48 and 96 hours post-UUO. In summary, we demonstrated that post-UUO, decorin mRNA and protein expression is up-regulated in the renal cortex of OBK, but not CUK, specimens in a temporal parallel with active TGF-beta1 levels and macrophage infiltration. We postulate that the development of TI fibrosis in this model may be related to only a physiologic induction of decorin by TGF-beta, and that pharmacologic levels may be required to retard or prevent scarring via TGF-beta inhibition.

Obstructive nephropathy as a result of retroperitoneal fibrosis: a review of its pathogenesis and associations

Retroperitoneal fibrosis is a rare disease, typically with an insidious clinical course. It is thought that this disease process is perhaps an exaggerated reaction to an inciting inflammatory event. In this study, a case of retroperitoneal fibrosis is reported, in which the patient presented with typical symptoms of retroperitoneal fibrosis, along with some atypical vasculitic symptomatology. Retroperitoneal fibrosis is a disease process with an unknown etiology, which has been observed to be associated with a number of different possible inciting factors. Two factors that have been documented in the literature as being associated with retroperitoneal fibrosis include the use of beta-blocking agents, and connective tissue disease processes such as systemic lupus erythematosus. The patient discussed was using beta-blocker medication and also had signs and symptoms suggestive of a lupus syndrome. There are no reported cases of the combined association of beta-blocker usage, lupus, and retroperitoneal fibrosis.

Endotheliopathy: a continuum of hemolytic uremic syndrome due to mitomycin therapy

Hemolytic uremic syndrome (HUS) is a rare, often fatal complication of mitomycin C therapy. It is generally accepted that HUS is, in part, caused by endothelial cell dysfunction. Endothelial cells modulate blood flow, blood pressure, and myointimal proliferation. Endothelial cells synthesize and release products that modulate vascular tone and regulate vascular smooth muscle cell growth. We describe a patient who developed HUS secondary to mitomycin C, resulting in end-stage renal disease and necessitating chronic hemodialysis. Over several months, the patient subsequently developed multisystem organ failure involving the heart, liver, and intestine that was associated with angiographically documented small, distal vessel occlusive disease and ultrasonographically identified coronary artery intimal hyperplasia. We propose that a diffuse ongoing endothelial cell dysfunction (ie, endotheliopathy) is the putative mechanism for this patient's clinical course. To our knowledge, this continuum of HUS presenting as a multisystem, progressive disorder has not been previously reported.

Oxidized LDL stimulates the expression of TGF-beta and fibronectin in human glomerular epithelial cells

Abnormal lipid accumulation in glomeruli is a recognized early event in the development of glomerulosclerosis. The presence of LDL and scavenger receptors has recently been demonstrated in glomerular cells, including the visceral epithelial cells. To explore the possible molecular mechanisms of lipid-induced glomerular injury, the present investigation was conducted to examine the effects of oxidized LDL (ox-LDL) on the expression of transforming growth factor (TGF)-beta and fibronectin by cultured human glomerular epithelial cells (GEC). Cultured GEC were exposed to human ox-LDL (0 to 100 micrograms/ml) for various time points. Ox-LDL induced a dose- and time-dependent increase in the expression of TGF-beta mRNA. Actinomycin D, a transcriptional inhibitor, but not cycloheximide, a protein synthesis inhibitor, inhibited the response. GEC exposed to ox-LDL also demonstrated elevated levels of fibronectin mRNA. In addition, treatment of GEC with ox-LDL resulted in increased TGF-beta and fibronectin protein expression as detected by immunocytochemistry. Addition of anti-TGF-beta antibody significantly inhibited the increase in fibronectin message level induced by ox-LDL. These data suggest that ox-LDL stimulates matrix protein fibronectin in GEC by a mechanism involving expression of TGF-beta. Thus, accumulation of lipids in human glomerular epithelial cells may contribute to the pathogenesis of glomerulosclerosis through TGF-beta mediated mechanism(s).