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Glen S Markowitz

Publications and source records attributed to Glen S Markowitz.

At least 19 recordsLinked to original sources
PubMed2003

Identification of IgG subclasses and C-reactive protein in lupus nephritis: the relationship between the composition of immune deposits and FCgamma receptor type IIA alleles.

OBJECTIVE: To characterize the subclass composition of IgG deposited in lupus glomeruli, to examine its relationship to allelic polymorphisms of IgG receptors (Fcgamma receptors [FcgammaR]), and to determine whether C-reactive protein (CRP), a ligand for FcgammaRIIa, is present in these immune deposits. METHODS: Renal biopsy samples from 80 patients with lupus nephritis were examined by light microscopy and indirect immunofluorescence with IgG-subclass-specific monoclonal antibodies. FcgammaRIIA genotypes were determined using allele-specific polymerase chain reaction. Immunostaining for CRP was performed on lupus and nonlupus glomerulonephritis specimens. RESULTS: IgG2 and IgG3 were the predominant subclasses in immune deposits in all World Health Organization classes of nephritis. The frequency of genotypes containing the low-binding IgG2 allele, FcgammaRIIa-R131, was significantly greater than expected in patients with class III or class IV nephritis and in patients with intense IgG2 deposition. CRP, a ligand with particular affinity for FcgammaRIIa-R131, was consistently present in the renal immune deposits of lupus nephritis specimens. CONCLUSION: FcgammaRIIA genes are associated with proliferative renal disease and may contribute to disease pathogenesis. FcgammaRIIa-R131, the variant with low affinity for IgG2, has high affinity for CRP. Thus, FcgammaRIIa-R131 may contribute to impaired removal of circulating immune complexes, as well as efficiently triggering phagocyte activation and the release of inflammatory mediators within glomeruli.

Adolescent↗
PubMed2003

RAGE drives the development of glomerulosclerosis and implicates podocyte activation in the pathogenesis of diabetic nephropathy.

Diabetic nephropathy ensues from events involving earliest changes in the glomeruli and podocytes, followed by accumulation of extracellular matrix in the mesangium. Postulated mechanisms include roles for vascular endothelial growth factor (VEGF), produced by podocytes and contributing to enhanced excretion of urinary albumin and recruitment/activation of inflammatory cells, and transforming growth factor-beta (TGF-beta), elicited largely from mesangial cells and driving production of extracellular matrix. RAGE, a receptor for advanced glycation endproducts (AGEs) and S100/calgranulins, displays enhanced expression in podocytes of genetically diabetic db/db mice by age 13 weeks. RAGE-bearing podocytes express high levels of VEGF by this time, in parallel with enhanced recruitment of mononuclear phagocytes to the glomeruli; events prevented by blockade of RAGE. By age 27 weeks, soluble RAGE-treated db/db mice displayed diminished albuminuria and glomerulosclerosis, and improved renal function. Diabetic homozygous RAGE null mice failed to develop significantly increased mesangial matrix expansion or thickening of the glomerular basement membrane. We propose that activation of RAGE contributes to expression of VEGF and enhanced attraction/activation of inflammatory cells in the diabetic glomerulus, thereby setting the stage for mesangial activation and TGF-beta production; processes which converge to cause albuminuria and glomerulosclerosis.

Albuminuria↗
PubMed2003

Foamy podocytes.

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Diagnosis, Differential↗
PubMed2003

Toxic acute tubular necrosis following treatment with zoledronate (Zometa).

BACKGROUND: Renal failure and toxic acute tubular necrosis (ATN) may be seen following exposure to a variety of therapeutic agents. Zoledronate (Zometa) is a new, highly potent bisphosphonate used in the treatment of hypercalcemia of malignancy. We report the first clinical-pathologic study of nephrotoxicity associated with this agent. METHODS: A cohort of six patients (four males and two females) with a mean age of 69.2 years received bisphosphonate therapy for multiple myeloma (five patients) or Paget's disease (one patient). In all patients, zoledronate was administered at a dose of 4 mg intravenously monthly, infused over at least 15 minutes, and the duration of therapy was mean 4.7 months (range, 3 to 9 months). RESULTS: All patients developed renal failure with a rise in serum creatinine from a mean baseline level of 1.4 mg/dL to 3.4 mg/dL. Renal biopsy revealed toxic ATN, characterized by tubular cell degeneration, loss of brush border, and apoptosis. Immunohistochemical staining revealed a marked increase in cell cycle-engaged cells (Ki-67 positive) and derangement in tubular Na+,K+-ATPase expression. Importantly, although all patients had been treated with pamidronate prior to zoledronate, no biopsy exhibited the characteristic pattern of collapsing focal segmental glomerulosclerosis observed in pamidronate nephrotoxicity. Following renal biopsy, treatment with zoledronate was discontinued and all six patients had a subsequent improvement in renal function (mean final serum creatinine, 2.3 mg/dL at 1 to 4 months of follow-up). CONCLUSION: The close temporal relationship between zoledronate administration and the onset of renal failure and the partial recovery of renal function following drug withdrawal strongly implicate this important and widely used agent in the development of toxic ATN.

Aged↗
PubMed2003

C1q nephropathy: a variant of focal segmental glomerulosclerosis.

BACKGROUND: C1q nephropathy is a poorly understood and controversial entity with distinctive immunopathologic features. In order to better define the clinical-pathologic spectrum, we report the largest single-center series. METHODS: Nineteen biopsies with C1q nephropathy were identified from among 8909 native kidney biopsies received from 1994 to 2002 (0.21%). Defining criteria included (1). dominant or co-dominant immunofluorescence staining for C1q, (2). mesangial electron dense deposits, and (3). no clinical or serologic evidence of systemic lupus erythematosus (SLE). RESULTS: The 19 patients were predominantly African American (73.7%), female (73.7%), young adults and children (range, 3 to 42 years; mean, 24.2 years). Presentation included nephrotic range proteinuria (78.9%), nephrotic syndrome (50%), renal insufficiency (27.8%), and hematuria (22.2%). No patient had hypocomplementemia or evidence of underlying autoimmune or infectious disease. Renal biopsy revealed focal segmental glomerulosclerosis (FSGS) in 17 (including six collapsing and two cellular) and minimal-change disease (MCD) in two. All biopsies displayed co-deposits of immunoglobulin G (IgG), with more variable IgM (84.2%), IgA (31.6%), and C3 (52.6%). Foot process effacement varied from 20% to 100% (mean, 51%). Twelve of 16 patients with available follow-up received immunosuppressive therapy. One patient had complete remission of proteinuria and six had partial remission. Four patients with FSGS pattern had progressive renal insufficiency, including two who reached end-stage renal disease (ESRD). Median time from biopsy to ESRD was 81 months. On multivariate analysis, the best correlate of renal insufficiency at biopsy and at follow-up was the degree of tubular atrophy and interstitial fibrosis (P = 0.0495 and 0.0341, respectively). CONCLUSION: C1q nephropathy falls within the clinical-pathologic spectrum of MCD/FSGS. Although further studies are needed to determine the pathomechanism of C1q deposition, we hypothesize that it may be a non-specific marker of increased mesangial trafficking in the setting of glomerular proteinuria.

Adolescent↗
PubMed2003

Fibrillary and immunotactoid glomerulonephritis: Distinct entities with different clinical and pathologic features.

BACKGROUND: Controversy surrounds the relatedness of fibrillary glomerulonephritis (FGN) and immunotactoid glomerulonephritis (IT). METHODS: To better define their clinicopathologic features and outcome, we report the largest single center series of 67 cases biopsied from 1980 to 2001, including 61 FGN and 6 IT. FGN was defined by glomerular immune deposition of Congo red-negative randomly oriented fibrils of < 30 nm (mean, 20.1 +/- 0.4 nm). IT was defined by glomerular deposition of hollow, stacked microtubules of > or = 30 nm (mean, 38.2 +/- 5.7 nm). RESULTS: FGN comprised 0.6% of total native kidney biopsies and IT was tenfold more rare (0.06%). Deposits in FGN were immunoglobulin G (IgG) dominant and polyclonal in 96%. IgG subtype analysis in 19 FGN cases showed monotypic deposits in four (two IgG1 and two IgG4) and oligotypic deposits in 15 (all combined IgG1 and IgG4). In IT, deposits were IgG dominant in 83% and monoclonal in 67% (three IgG1 kappa and one IgG1 lambda). FGN patients were a mean age of 57 years, 92% were Caucasian, and 39% were male. At biopsy, FGN patients had the following clinical characteristics (mean, range): creatinine 3.1 mg/dL (0.5 to 14), proteinuria 6.5 g/day (0.8 to 25), 60% microhematuria, and 59% hypertension. Histologic patterns of FGN were diverse, including diffuse proliferative glomerulonephritis (DPGN) (nine cases), membranoproliferative glomerulonephritis (MPGN) (27 cases), mesangial proliferative/sclerosing (MES) (13), membranous glomerulonephritis (MGN) (four), and diffuse sclerosing (DS) (eight). The more proliferative (MPGN and DPGN) and sclerosing (DS) forms presented with a higher creatinine and greater proteinuria compared to MES and MGN. Median time to end-stage renal disease (ESRD) was 24.4 months for FGN and mean time to ESRD varied by histologic subtype: DS 7 months, DPGN 20 months, MPGN 44 months, compared to MES 80 months and MGN 87 months. There was no statistically significant effect of immunosuppressive therapy (given to 36% of FGN patients). By Cox regression (hazard ratio, confidence interval, P value), independent predictors of progression to ESRD were creatinine at biopsy [2.05 (1.55 to 2.72) P < 0.001] and severity of interstitial fibrosis [2.01 (1.05 to 3.85) P = 0.034]. Although IT had similar presentation, histologic patterns, and outcome compared to FGN, it had a greater association with monoclonal gammopathy (P = 0.014), underlying lymphoproliferative disease (P = 0.020), and hypocomplementemia (P = 0.032). CONCLUSION: FGN is an idiopathic condition characterized by polyclonal immune deposits with restricted gamma isotypes. Most patients present with significant renal insufficiency and have a poor outcome despite immunosuppressive therapy, and outcome correlates with histologic subtype. By contrast, IT often contains monoclonal IgG deposits and has a significant association with underlying dysproteinemia and hypocomplementemia. Differentiation of FGN from the much more rare entity IT appears justified on immunopathologic, ultrastructural, and clinical grounds.

Adult↗
PubMed2003

Collapsing glomerulopathy.

Collapsing glomerulopathy is a morphologic variant of focal segmental glomerulosclerosis (FSGS) characterized by segmental and global collapse of the glomerular capillaries, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. The cause of this disorder is unknown, but nearly identical pathologic findings are present in idiopathic collapsing glomerulopathy and human immunodeficiency virus (HIV)-associated nephropathy, and collapsing glomerulopathy has been associated with parvovirus B19 infection and treatment with pamidronate. The pathogenesis of collapsing glomerulopathy involves visceral epithelial cell injury leading to cell cycle dysregulation and a proliferative phenotype. Clinically, collapsing glomerulopathy is characterized by black racial predominance, a high incidence of nephrotic syndrome, and rapidly progressive renal failure. Collapsing glomerulopathy also may recur after renal transplantation or present de novo, often leading to loss of the allograft. The optimal treatment for collapsing glomerulopathy is unknown. Treatments may include steroids or cyclosporine in addition to aggressive blood pressure control, angiotensin converting enzyme inhibitors and/or angiotensin II receptor blockers, and lipid lowering agents. The role of other immunosuppressive agents such as mycophenolate mofetil in the treatment of collapsing FSGS remains to be defined. Prospective clinical trials are needed to define optimal therapy of this aggressive form of FSGS.

Capillaries↗
PubMed2002

Trans-heterozygous Pkd1 and Pkd2 mutations modify expression of polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) occurs by germline mutation in PKD1 or PKD2. Evidence of homozygous inactivation of either gene in human cyst lining cells as well as in mouse knockout models strongly supports a two-hit mechanism for cyst formation. Discovery of trans-heterozygous mutations in PKD1 and PKD2 in a minority of human renal cysts has led to the proposal that such mutations also can play a role in cyst formation. In the current study, we investigated the role of trans-heterozygous mutations in mouse models of polycystic kidney disease. In Pkd1(+/-), Pkd2 (+/-) and Pkd1(+/-) : Pkd2 (+/-) mice, the renal cystic lesion was mild and variable with no adverse effect on survival at 1 year. In keeping with the two-hit mechanism of cyst formation, approximately 70% of kidney cysts in Pkd2 (+/-) mice exhibited uniform loss of polycystin-2 expression. Cystic disease in trans-heterozygous Pkd1(+/-) : Pkd2 (+/-) mice, however, was notable for severity in excess of that predicted by a simple additive effect based on cyst formation in singly heterozygous mice. The data suggest a modifier role for the 'trans' polycystin gene in cystic kidney disease, and support a contribution from threshold effects to cyst formation and growth.

Animals↗
PubMed2002

Angiotensin converting enzyme inhibition in chronic allograft nephropathy.

BACKGROUND: Although angiotensin-converting enzyme inhibition has been shown to slow progression of chronic allograft nephropathy in animal models, no studies have examined its efficacy in humans. METHODS: We retrospectively analyzed 63 patients with biopsy-proven chronic allograft nephropathy who had > or =6 months dialysis-free follow-up at our institution. A total of 32 patients treated for > or =6 consecutive months with angiotensin-converting enzyme inhibition and/or angiotensin-receptor blocker (ARB) therapy (group 1) were compared with 31 patients not on these agents (group 2). RESULTS: Except for a higher incidence of hypertension (100 vs. 78%, P=0.005) in group 1, there were no significant differences in baseline clinical characteristics at time of biopsy. With a mean follow-up time of 27 months in both groups, 6 of 32 (19%) group 1 patients vs. 12 of 31 (39%) group 2 reached the primary endpoint of > or =50% increase in serum creatinine (P=0.10). Mean time to primary endpoint was 46.6 months in group 1 vs. 32.7 months in group 2 (P=0.07). Three of 32 (9%) of group 1 patients vs. 8 of 31 (26%) of group 2 returned to dialysis during this time (P=0.11). Significantly fewer patients in group 1 reached the combined secondary endpoint of allograft failure or death (9.4 vs. 35.5%, P=0.01); in addition, group 1 had a longer mean time to this endpoint (51.2 vs. 37.6 months, P=0.03). On multivariate analysis, the only predictor of progression to primary endpoint was a high baseline serum creatinine (P=0.02). No significant differences in hyperkalemia or anemia were found between the two groups. CONCLUSIONS: Angiotensin-converting enzyme inhibition/angiotensin-receptor blocker therapy is well tolerated in renal allograft recipients with chronic allograft nephropathy. It is associated with a trend of slowing renal insufficiency as well as a significant survival benefit in the combined endpoint of allograft failure or death.

Adult↗
PubMed2002

Idiopathic nodular glomerulosclerosis is a distinct clinicopathologic entity linked to hypertension and smoking.

Idiopathic nodular glomerulosclerosis (ING) is an enigmatic condition that resembles nodular diabetic glomerulosclerosis but occurs in nondiabetic patients. We reviewed clinicopathologic features, immunohistochemical profiles, and outcomes in 23 patients with ING diagnosed from among 5,073 native renal biopsy samples (0.45%) at Columbia University from January 1996 to March 2001. This cohort, in which diabetes mellitus was excluded, consisted predominantly of older (mean age, 68.2 years) white (73.9%) men (78.3%). Clinical findings at presentation included renal insufficiency in 82.6% (mean serum creatinine = 2.4 mg/dL), proteinuria (> 3 g/d in 69.6%; mean 24-hour urine protein = 4.7 g/d), and-less frequently-full nephrotic syndrome (21.7%). There was a high prevalence of hypertension (95.7%; mean = 15.1 +/- 3.4 years), smoking (91.3%; mean = 52.9 +/- 6.9 pack-years), hypercholesterolemia (90%), and extrarenal vascular disease (43.5%). All 23 patients had prominent diffuse and nodular mesangial sclerosis, glomerular basement membrane thickening, arteriosclerosis, and arteriolosclerosis. Immunohistochemical staining for CD34, a marker of endothelial cells, showed an increased number of vascular channels within ING glomeruli compared with normal controls. Follow-up data were available for 17 patients, 6 of whom reached end-stage renal disease (ESRD) (35.3%). By Kaplan-Meier estimates, the median time after biopsy to ESRD was 26 months. Predictors of progression to ESRD included continuation of smoking (P =.0165), lack of angiotensin II blockade (P =.0007), degree of tubular atrophy and interstitial fibrosis (P =.0517), and degree of arteriosclerosis (P =.0096). In conclusion, ING is a progressive vasculopathic lesion linked to hypertension and cigarette smoking.

Aged↗
PubMed2001

Collapsing focal segmental glomerulosclerosis following treatment with high-dose pamidronate.

Collapsing focal segmental glomerulosclerosis (FSGS) is a distinct clinicopathologic entity seen most commonly in young African American patients who present with renal insufficiency and nephrotic syndrome. The only epidemiologic factor previously linked to collapsing FSGS is HIV infection. Here clinicopathologic findings are reported for a distinctive population of seven patients, who were older, Caucasian, and HIV negative and developed collapsing FSGS during active treatment of malignancy (multiple myeloma in six patients and metastatic breast carcinoma in one). Although oncologic treatment regimens included vincristine for four patients, doxorubicin for five patients, cisplatin for two patients, and total-body irradiation for one patient, the only agent common to all patients was pamidronate (Aredia). All patients had normal renal function before the administration of pamidronate. Patients began therapy with pamidronate at or below the recommended dose of 90 mg, intravenously, monthly, which was increased to 180 mg monthly in two patients and 360 mg monthly in three patients. Patients received pamidronate for 15 to 48 mo before presentation with renal insufficiency (mean serum creatinine, 3.6 mg/dl) and full nephrotic syndrome (mean 24-h urinary protein excretion, 12.4 g/d). Pamidronate, which is a member of the class of bisphosphonates, is widely used in the treatment of hypercalcemia of malignancy and osteolytic metastases. At the recommended dose of 90 mg, intravenously, monthly, renal toxicity is infrequent; however, higher doses have produced nephrotoxicity in animal models. The temporal association between pamidronate therapy and the development of renal insufficiency, the use of escalating doses that exceed recommended levels, and the distinctive pattern of glomerular and tubular injury strongly suggest a mechanism of drug-associated podocyte and tubular toxicity. These data provide the first association of collapsing FSGS with toxicity to a therapeutic agent.

Aged↗