Randolph A. Hennigar

Increased expression of fatty acid synthase (OA-519) in ovarian neoplasms predicts shorter survival

Certain cancers exhibit derangement of de novo fatty acid biosynthesis, manifested as overexpression and hyperactivity of the lipogenic enzyme fatty acid synthase (FAS). Correlation of elevated FAS with high tumor grade and advanced stage in primary breast, prostate, and colorectal cancers has drawn attention to the enzyme as a possible marker of poor prognosis. To find a similar utility of FAS in ovarian neoplasms, we compared FAS expression in 68 ovarian tumors with their histological features and clinical outcome. Immunohistochemical localization of FAS was observed in 48 (71%) cases in which staining was either focal (defined as positive staining in 1% to 20% of cells) or multifocal/diffuse (positive staining in >20% of cells). Most (83%) of the 48 cases were represented by endometrioid, serous, or mucinous carcinomas and malignant mixed mullerian tumors (MMMTs). In contrast, ovarian adenomas and tumors of low malignant potential (LMPs) contained little or no FAS. Association between FAS expression and histological diagnosis was statistically significant. The extent of FAS immunostaining was also predictive of prognosis. Among all patients with ovarian malignancies (including LMPs), median survival was 64.8 months, when their tumors exhibited no or focal immunostaining for FAS, as opposed to 31.2 months, when staining was multifocal/diffuse (P = .005). Similar median survival values were obtained when cases were limited to endometrioid, serous, and mucinous carcinomas. Short-term survival at 1 and 2 years was significantly higher in patients whose tumors showed no or focal expression of FAS compared with multifocal/diffuse expression. Thus, elevated FAS may serve as an independent marker for predicting poor clinical outcome in patients with ovarian cancer.

Distribution of cytokeratins and vimentin in adult renal neoplasms and normal renal tissue: potential utility of a cytokeratin antibody panel in the differential diagnosis of renal tumors.

Adult renal epithelial neoplasms (RENs) comprise several distinct clinicopathologic entities with potential prognostic and therapeutic differences. Individual cases can show overlapping morphologic features, necessitating the use of ancillary methods. The purpose of this study was to determine the diagnostic utility of cytokeratin (CK) subtype expression pattern in a wide range of adult RENs. RENs (including clear cell [conventional] renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, renal oncocytoma, collecting duct carcinoma (CDC), renal medullary carcinoma (RMC), urothelial carcinoma, metanephric adenoma (MA), tubulocystic carcinoma (TC) (also known as low-grade collecting duct carcinoma), and mucinous tubular and spindle cell carcinoma) were immunostained for CK subtypes (CK5/CK6, 7, 8, 13, 14, 17, 18, 19, 20), high molecular weight CKs 1, 5, 10, 14 (HMWCK), and vimentin (Vim). The expression pattern of normal kidney was also examined and correlated with RENs. Although there is some overlap, subtypes of RENs show distinctive CK expression profiles that may be useful in several differential diagnostic settings. Clear cell RCCs typically showed a restricted expression pattern of CK8, CK18 and Vim. Papillary RCCs typically expressed CK7, CK8, CK18, CK19, and Vim and could be distinguished from MA (CK7−). Chromophobe RCCs were typically CK7+, CK8+, CK18+, and Vim−, and could be distinguished from oncocytomas (typically CK7−). In oncocytomas, nonspecific staining of unblocked endogenous biotin is a potentially significant diagnostic pitfall. CDC, RMC, and TC demonstrated similar CK expression profiles (with the exception of HMWCK expression limited to CDC), supporting a close relationship between these entities. A panel of CK5/CK6, CK17, and Vim may be helpful in distinguishing CDC (typically CK5/CK6−, CK17−, Vim+) and urothelial carcinoma (typically CK5/CK6+, CK17+, Vim−). In conclusion, CK expression patterns may be helpful in several differential diagnostic situations when dealing with adult RENs.

A Prospective, Open-Label Trial of Sirolimus in the Treatment of Focal Segmental Glomerulosclerosis

Calcineurin inhibitors are effective therapy for steroid-resistant focal segmental glomerulosclerosis (FSGS) but are associated with significant morbidity and nephrotoxicity. Sirolimus is a novel immunosuppressive agent that is structurally related to tacrolimus but demonstrates no long-term nephrotoxicity. For determination of the efficacy of sirolimus in reducing proteinuria, a prospective, open-label trial was conducted of 21 patients with idiopathic, steroid-resistant FSGS. A complete response was defined as <300 mg protein/24 h after 6 mo, whereas a partial response was defined as a 50% reduction in baseline proteinuria. After 6 mo of therapy, sirolimus induced complete remission in four (19%) of 21 patients and partial remissions in eight (38%). Among sirolimus-responsive patients, 6 mo of therapy decreased proteinuria from a mean of 8.8 +/- 1.7 to 2.1 +/- 0.5 g/24 h (P = 0.0003). In responsive patients, GFR was maintained (45 +/- 6 versus 47 +/- 7 ml/min per 1.73 m2 at 6 mo) throughout the study, whereas nonresponders tended to decrease (31 +/- 4 versus 28 +/- 5 ml/min per 1.73 m2). Using dextran sieving analysis, complete or partial response was associated with an increase in the glomerular ultrafiltration coefficient (K(f), 7 +/- 1. versus 8 +/- 0.9 units at 6 mo; P < 0.05). Glomerular permselectivity and K(f) tended to decrease in nonresponders (8.2 +/- 1.9 versus 6.2 +/- 1.3 units at 6 mo; P = 0.07). Patients with complete remission had a higher GFR (45 +/- 6 versus 31 +/- 4 ml/min per 1.73 m2) at the end of 6 mo compared with nonresponders. In patients with steroid-resistant FSGS, sirolimus reduced proteinuria and glomerular pore size and increased K(f) in patients with steroid-resistant FSGS.

Idiopathic IgA Nephropathy: Pathogenesis, Histopathology, and Therapeutic Options

IgA nephropathy is one of the most common causes of glomerulonephritis in the world. Proliferative and crescentic forms of IgA are found in up to 30% of cases and are associated with nephrotic-range proteinuria, accelerated hypertension, and accelerated decline toward ESRD. Despite its prevalence and clinical importance, there is no unifying nomenclature or consensus for the treatment of specific histologic subgroups. As a consequence, the development of clinically effective treatment regimens for IgA nephropathy have lagged behind other, less common forms of glomerulonephritis. Herein is reviewed the pathogenesis and histologic subtypes of IgA nephropathy and how conventional and immunosuppressive therapies have an impact on renal survival and recurrence rates. The use of known clinical risk factors for disease progression in conjunction with specific histologic features can be a guide to both induction and consolidation therapies for individual patients with IgA nephropathy.

Fatal West Nile Virus Encephalitis in a Renal Transplant Recipient

West Nile virus (WNV), a mosquito-transmitted single-stranded RNA flavivirus, causes human disease of variable severity. We report clinical and pathologic findings of fatal encephalitis from the transmission of WNV from an organ donor to a kidney transplant recipient. The patient developed a febrile illness 18 days after transplantation, which progressed to encephalitis. Postmortem examination demonstrated extensive viral encephalopathic changes. Immunohistochemical studies highlighted WNV antigens within neurons, especially in the cerebellum and brainstem. Flavivirus virions were detected ultrastructurally within the cerebellum, and WNV was isolated from the brain and the brainstem. Thus, this case demonstrates the first death in the first solid organ transplant-associated transmission of WNV. Immunosuppression of the transplant recipient might have been responsible for the fulminant viral effects. The pathologic diagnosis helped guide subsequent epidemiologic and laboratory studies.

Characterization of fatty acid synthase in cell lines derived from experimental mammary tumors.

The lipogenic enzyme fatty acid synthase (FAS) is elevated in various human primary cancers and certain human cancer cell lines. FAS overexpression in human neoplasia has clinical relevance because of its association with tumor aggression and potential chemotherapeutic intervention. Here, we surveyed FAS in cell lines established from normal murine mammary epithelium (NMuMG) and from mammary tumors induced by either rodent polyoma (Py) virus or murine mammary tumor virus (MMTV). Western blotting revealed greater content of FAS in Py-transformed A1-1 and T1 than NMuMG or MMTV-transformed Mm5MT, RIIIMT and MMT060562. These data suggest that signaling events mediated by Py transformation may increase cellular amounts of FAS. Although FAS content was elevated to similar levels in A1-1 and T1, specific activities were significantly different as enzyme activity in T1 was 3-fold higher than A1-1. Likewise, FAS activity in NMuMG was about 0.5-fold higher than the MMTV-transformed lines, even though enzyme content was similar. Immunoprecipitation studies employing anti-phosphoamino acid antibodies followed by immunoblot analysis with anti-FAS antisera (and vice versa) were used to characterize the constitutive phosphorylation state of the enzyme. Phosphoserine and phosphothreonine residues were detected in the more active FAS from T1 and NMuMG, but not in the less active FAS from Mm5MT or A1-1. Discovery of phosphorylated FAS suggests that the enzyme may have more immediate control over lipogenesis than previously thought. High-dose (10-4 M) dexamethasone induced FAS content and activity in NMuMG and MMTV-transformed lines but not Py-transformed cells. Lower concentrations (10-8, 10-6 M) of dexamethasone also activated FAS but without concomitant elevation of its protein content, which was consistent with a phosphorylated form of FAS. Finally, cell lines were treated with the FAS inhibitor cerulenin: almost all breast cancer lines were growth inhibited at significantly lower amounts of drug than normal cell lineages, suggesting that FAS plays a greater role in viability of tumor cells than normal cells. Pretreatment with palmitate (a primary end-product of FAS) prior to cerulenin rescued A1-1 cells only slightly from growth inhibition, whereas pretreatment with oleate (a monounsaturated fatty acid synthesized from palmitate) synergized cerulenins cytotoxic effects.

Prevalence of clinical rejection after surveillance biopsies in pediatric renal transplants: Does early subclinical rejection predispose to subsequent rejection episodes?

Abstract:  We analyzed rates of both SCR and CR in children receiving SB at three months post‐transplant to determine if SCR predisposed patients to acute CR. Acute rejection was defined according to Banff criteria to include borderline classification or higher. All cases of SCR and CR were treated with anti‐rejection protocols. Between October 2004 and July 2008, 89 SB were performed at three months post‐transplant. Twenty‐six cases of SCR were detected (29%). Sixteen patients experienced 22 episodes of biopsy‐proven CR occurring after SB, including seven episodes following SCR and 15 after normal SB. The onset of CR varied from one to 27 months after SB and occurred at similar intervals for cases with SCR and normal SB. The percentage of patients remaining free of CR at 30 months post‐transplant was similar in patients with SCR and normal SB. Renal function and graft survival at 30 months also were no different between patients with SCR and those with normal SB. Early‐SCR, when treated with rejection protocols, is not a prognostic indicator for subsequent CR episodes.

Vascular mesangial channels in human nodular diabetic glomerulopathy

The presence of vascular mesangial channels has been reported in idiopathic nodular glomerulosclerosis and diabetic glomerulopathy. However, only limited information on the morphology and immunohistochemical phenotype of these channels is available. This study aims to describe the light and electron microscopic features of these channels and delineate their immunohistochemical phenotype. Thirty-eight cases of human nodular diabetic glomerulopathy with mesangial channels identified by light microscopy were prospectively selected (2010-2012). The cases were stained with CD31/periodic acid-Schiff combined stain. Selected cases were immunostained for CD34, podoplanin, ERG, and Ki-67. Frequent, small and peripheral vascular mesangial channels were seen in all cases, whereas larger and more centrally located vascular channels were also observed. Communication between peripheral capillary loops and peripheral vascular mesangial channels was seen as was communication between peripheral and central vascular mesangial channels. The vascular mesangial channel lining cells showed a typical endothelial phenotype with strong expression of CD31, CD34, and ERG by immunohistochemistry. The lymphatic channel marker podoplanin was negative in all channels, and the proliferation marker Ki-67 showed no evidence of increased proliferation. By electron microscopy, mesangial channels show angulated, irregular borders with lining cells compatible with endothelium and surrounded by mesangial matrix. No basement membranes were identified surrounding the mesangial channels. These findings support the existence of vascular mesangial channels in nodular diabetic glomerulopathy and suggest neovascularization and altered blood flow within these glomeruli.

Nephrotic Syndrome Post–Kidney Transplant

A 55-year-old woman with ESRD attributed to hypertension presented with nephrotic syndrome 9 months post–kidney transplant. She was on dialysis for 6 years before pediatric dual kidney transplant from a previously healthy 5-year-old black boy weighing 23.5 kg. Kidney sizes were 6.5 and 7.5 cm and