The hepatocyte growth factor/c-met pathway is a key determinant of the fibrotic kidney local microenvironment

The kidney local microenvironment (KLM) plays a critical role in the pathogenesis of kidney fibrosis. However, the composition and regulation of a fibrotic KLM remain unclear. Through a multidisciplinary approach, we investigated the roles of the hepatocyte growth factor/c-met signaling pathway in regulating KLM formation in various chronic kidney disease (CKD) models. We performed a retrospective analysis of single-cell RNA sequencing data and determined that tubular epithelial cells and macrophages are two major cell populations in a fibrotic kidney. We then created a mathematical model that predicted loss of c-met in tubular cells would cause greater responses to injury than loss of c-met in macrophages. By generating c-met conditional knockout mice, we validated that loss of c-met influences epithelial plasticity, myofibroblast activation, and extracellular matrix synthesis/degradation, which ultimately determined the characteristics of the fibrotic KLM. Our findings open the possibility of designing effective therapeutic strategies to retard CKD.

Detection of tumorigenesis in rat bladders with optical coherence tomography

Optical coherence tomography (OCT) is a novel technique that enables noninvasive cross-sectional imaging of biological tissues. Because of its high resolution (approximately 10 microm), superior dynamic range (140 dB in our case) and up to 2-3 mm penetration depth, OCT is potentially useful for noninvasive screening of superficial lesions. Bladder cancer arises within the transitional epithelium. Despite the ability to visualize the epithelium via cystoscopy, it is often difficult to detect early epithelial cancers and to determine their penetration to the underlying layers. To investigate the potential of OCT to enhance imaging of bladder cancers and other epithelial lesions, we applied OCT to normal and diseased bladder epithelium, and correlated the results with histological findings. OCT images of porcine bladder (a close homolog of human bladder) confirm the ability of this method to image human tissues. To determine whether OCT can track the course of bladder cancer, a standard rat model of bladder cancer in which Fisher rats are exposed to methyl-nitroso-urea (MNU), was followed both with OCT and histological studies. Our results show that the micro morphology of porcine bladder such as the urothelium, submucosa and muscles is identified by OCT and well correlated with the histological evaluations. OCT detected edema, inflammatory infiltrates, and submucosal blood congestion as well as the abnormal growth of urothelium (e.g., papillary hyperplasia and carcinomas). By contrast, surface imaging, which resembles cystoscopy, provided far less sensitivity and resolution than OCT. This is the first OCT study of any tumor documented in a systematic fashion, and the results suggest the potential of OCT for the noninvasive diagnosis of both bladder inflammatory lesions and early urothelial abnormalities, which conventional cystoscopy often misses, by imaging characterization of the increases in urothelial thickening and backscattering. However, because of the depth limitation, OCT may have limited applications in staging the invasion of higher-state urothelial cancers, especially for papillary carcinomas.

Renal and metabolic effects of caffeine in obese (fa/fa(cp)), diabetic, hypertensive ZSF1 rats

In Western society, the triad of hypertension, metabolic syndrome and obesity (which caries a high risk for renal disease) is increasing, as is the intake of caffeine. However, no information is available regarding the metabolic or renal consequences of caffeine consumption in this complex disease entity. The purpose of this study was to investigate the effects of chronic caffeine consumption on renal function and metabolic status in obese ZSF1 rats, an animal model of obesity, hypertension and the metabolic syndrome. Fifteen, 18-week-old male, obese ZSF1 rats were randomized to drink tap water (Cont, n = 8) or 0.1% solution of caffeine (Caff, n = 7) for 8 weeks. Metabolic and renal function measurements were performed at baseline and after 4 and 8 weeks of treatment. Caffeine treatment significantly (p < 0.05) reduced body weight, food, and fluid consumption and improved insulin sensitivity (fasting insulin 129.6+/-8.1 vs 97.5+/-3.6 microIU/mL; fed insulin 146.3+/-8.5 vs 110.6+/-3.4 microIU/mL; fasting glucose 138.7+/-13.4 vs 145+/-8.0 mg/dL; fed glucose 373+/-19.4 vs 283.3+/-19.6 mg/dL, Cont vs Caff, respectively). After 8 weeks of caffeine treatment, animals were less glycosuric as compared with control group. Area under glucose curves (AUC-glucose) in oral glucose tolerance test did not differ between the two groups (AUC- glucose: 592.5+/-42.7 vs 589.5+/-20.5 mg/dL x h, Cont vs Caff), whereas caffeine treatment significantly decreased AUC of insulin (AUC-insulin: 257.77+/-12.9 vs 198.0+/-5.9 microIU/mL x h, Cont vs. Caff, p<0.05). No differences were found with regard to plasma triglycerides and glycerol levels; however, caffeine significantly increased cholesterol levels after 4 and 8 weeks (2F-Anova, p<0.001). Moreover, caffeine significantly decreased creatinine clearance after 4 and 8 weeks (CrCl, Cont: 3.5+/-0.4, Caff: 2.2+/-0.2 L/kg/day, p<0.05) and increased protein/CrCl ratio (Cont: 323+/-30, Caff: 527+/-33 mg/L/day). Caffeine treatment for 8 weeks tended to increase plasma norepinephrine levels (p<0.06), but the two groups did not differ with regard to plasma renin activity, blood pressure, renal blood flow or and renal vascular resistance. The study indicates that caffeine improves insulin sensitivity but increases plasma cholesterol levels and impairs renal function in obesity with the metabolic syndrome and hypertension. Our results imply that the health consequences of chronic caffeine consumption may depend heavily on underlying pathophysiology process.

Nephrotic syndrome in chronic lymphocytic leukemia: a paraneoplastic syndrome?

The association of malignancy and various glomerulopathies is a well recognized phenomenon. We report a case of nephrotic syndrome secondary to minimal-change disease in a patient with chronic lymphocytic leukemia (CLL) and review the literature on nephrotic syndrome in this disorder. Since the relative distribution of etiologies differ from what might be expected for primary nephrotic syndrome in a similar aged population, we propose that nephrotic syndrome is a potential paraneoplastic phenomenon associated with CLL. We hypothesize a possible etiologic role of different cell surface markers of the lymphocyte to explain the diverse renal histologic manifestations.

Pathology residents' use of a Web-based tutorial to improve Gleason grading of prostate carcinoma on needle biopsies

Little is known about pathology residents' ability to Gleason grade or their ability to learn surgical pathology using Internet-based technology. A free Web-based program (available at www.pathology. jhu.edu/prostate) was developed that consisted of 20 pretutorial images for grading, 24 tutorial images, and the same 20 posttutorial images for Gleason grading. The grading images were selected from cases that had a consensus Gleason grade from 10 uropathology experts. In 2.5 months, 255 residents visited the website, and 151 (59%) completed it. Of those who completed the website, their year in training was known in 85 (56%): 1st year, 25.8%; 2nd year, 20%; 3rd year, 22.3%; 4th year, 14.1%; 5th year, 15.3%; and 6th year, 2.4%. Eighty percent learned Gleason grading in residency versus being self-taught, and 66% were male. In a multivariate analysis, higher pretutorial scores were associated with both their year in training (P = .001) and their hospital size (P = .003). Improvements in grading posttutorial were not related to the residents' year in training. Overall, the website significantly improved grading in 11 of 20 images and had no effect in 9 of 20 images. Improvements were noted in 1 of 1 Gleason score 4; 2 of 7 Gleason score 5 to 6; 2 of 6 Gleason score 7; and 6 of 6 Gleason score above 7 tumors. In summary, a Web-based tutorial improved Gleason grading accuracy by pathology residents to an equal extent regardless of their year in training. It is more difficult to teach residents to grade Gleason scores 5 to 7 tumors, and additional training should be concentrated in this area.

Focal segmental glomerulosclerosis associated with nephrotic syndrome in cholesterol atheroembolism: clinicopathological correlations

To better characterize the heavy proteinuria occasionally described in cholesterol atheroembolic renal disease (CAE), we reviewed the clinical features and histological findings of 24 patients found at renal biopsy to have CAE. Twelve (50%) had a typical clinical presentation soon after an invasive vascular procedure. Eight (33%) underwent biopsies to evaluate proteinuria and four (17%) with insidiously developing renal failure to exclude rapidly progressive glomerulonephritis. All had usual and similar risk factors for CAE; 71% were male, 96% had peripheral vascular disease, 79% had recently undergone an invasive vascular procedure, 74% were hypercholesterolemic, and all were hypertensive. Proteinuria was higher and serum creatinine lower in the proteinuria group. In the nine (38%) nephrotic patients, serum creatinine measurements were lower (2.7 +/- 1.2 v 5.6 +/- 2.4 mg/dL), duration of renal disease to biopsy longer, and time from biopsy to dialysis greater (23.5 +/- 14.8 v 0.03 +/- 0.098 mo, P < 0.05 for all). Focal segmental glomerulosclerosis (FSGS) was observed in 15 (63%) of the biopsy specimens. Although FSGS itself did not occur more commonly in nephrotic patients, these patients did have a higher fraction of segmentally sclerosed glomeruli (0.158 +/- 0.097 v 0.026 +/- 0.050, P < 0.01). A variant of FSGS, the cellular lesion with epithelial cell prominence and capillary loop collapse, was observed in 7 of 9 (78%) patients with nephrotic-range proteinuria, but in only 3 of 12 (25%) patients with lesser degrees of protein excretion (P < 0.05). The cellular lesion was accompanied by higher mean proteinuria, 7.6 +/- 4.3 versus 2.1 +/- 2.4 g/24 hr (P < 0.01). In a larger group of patients with a similar age range as the CAE group who were identified by search of a computerized biopsy database, membranous nephropathy was the only other form of idiopathic glomerulonephritis that occurred with CAE. One of 82 (1.2%) patients with membranous nephropathy also had CAE, compared with 20 of 102 (19.6%) with FSGS (P < 0.0002, chi2). Thus, the finding of FSGS with CAE was not coincidence. Mean follow-up was 20 +/- 26 months (range, 0 to 103 months). Six patients (25%) were followed-up at least 3 years after renal biopsy. These findings indicate that extended survival in CAE is not rare and that heavy proteinuria occurs as part of a chronic disorder with distinctive histological features. Cholesterol atheroembolism with FSGS should be considered in the differential diagnosis of nephrotic syndrome in elderly patients with advanced atherosclerosis.

Tacrolimus-related posttransplant lymphoproliferative disorder presenting as autoimmune hemolytic anemia

Tacrolimus (formerly known as FK506) is a macrolide immunosuppressant that has been used to prevent rejection of solid organ allografts. Acute hemolytic anemia is one of the side effects associated with tacrolimus therapy, and two mechanisms have been described to account for acute hemolytic anemia in patients receiving tacrolimus: drug-induced hemolysis and alloimmune hemolysis resulting from donor lymphocytes derived from the allograft (passenger lymphocyte syndrome). We report a case of a liver transplant recipient who developed fatal autoimmune hemolytic anemia while under treatment with tacrolimus for allograft rejection, and in whom postmortem examination revealed a clinically unsuspected posttransplant lymphoproliferative disorder. This case implicates autoimmune hemolytic anemia as a novel mechanism of acute hemolysis in patients treated with tacrolimus and further suggests that acute hemolytic anemia in this group of patients may herald an occult lymphoproliferative disorder.

Pathological features of hereditary prostate cancer

The aim of this study was to characterize the pathological features of hereditary prostate cancer, a recently recognized variant of prostate cancer with an autosomal dominant inheritance of a rare highly penetrant gene associated with early onset of disease. We compared the histology at radical prostatectomy of clinical stage T2 prostate cancer, including its relationship to prostatic intraepithelial neoplasia, in men with a family history of prostate cancer to those without a family history of prostate cancer. Three cohorts (hereditary, familial and sporadic) were identified based on pedigree analysis. A hereditary subgroup (28 patients) met 1 of the following 3 criteria: 1) cluster of greater than 3 affected relatives within the nuclear family, 2) occurrence of prostate cancer in each of 3 generations in either the proband paternal or maternal lineage, or 3) a cluster of 2 relatives affected at an early age of less than 55 years. This subgroup was compared to an age-matched subgroup with family history of prostate cancer (26 patients) yet the aforementioned conditions for inclusion within the hereditary subgroup were not met and to a sporadic subgroup without a family history of prostate cancer (27 patients). All parameters were statistically similar among the groups except that hereditary and familial group multifocal tumors were of lower grade (p = 0.0001), sporadic cases had a greater proportion of small multifocal cancers associated with prostatic intraepithelial neoplasia (p = 0.02) and the familial group had a weaker correlation between total tumor volume and grade. In conclusion, our analysis failed to demonstrate substantial pathological differences among hereditary, familial and sporadic forms of prostate cancer. Rather, our data are remarkable for the wide range of all parameters studied in each group. Even the sporadic cases had features, such as increased numbers of precursor lesions and tumor multifocality, which in other organs are commonly associated with either hereditary cancer or cancer arising in a field effect due to diffuse exposure to a carcinogen.

Relationship between perineural tumor invasion on needle biopsy and radical prostatectomy capsular penetration in clinical stage B adenocarcinoma of the prostate

We studied 302 needle biopsies for perineural invasion for sensitivity and specificity in predicting capsular penetration in subsequent radical prostatectomies. Perineural invasion was seen in 20% of needle biopsies, with a sensitivity of 27% and a specificity of 96% in predicting capsular penetration. By including tumor with a Gleason sum of 7 or greater or perineural invasion on needle biopsy as being predictive, sensitivity increased to 36% with a specificity of 94%. By restricting perineural invasion to cases with more than one nerve involved or a nerve involvement of a diameter 0.1 mm or greater, specificity increased to 97% and 99%, respectively, with sensitivity falling to 15% and 9%, respectively. Measuring perineural invasion on needle biopsy helps to identify capsular penetration and may help in planning nerve-sparing radical prostatectomy in the decision of whether to sacrifice part or all of the neurovascular bundle on the side of the biopsy.