IgM as a novel predictor of disease progression in secondary focal segmental glomerulosclerosis.

AIM: To determine the role of immunoglobulin M (IgM) deposits in clinical manifestations, disease outcome, and treatment response of idiopathic and secondary focal segmental glomerulosclerosis (FSGS). METHODS: Kidney biopsy specimens of 171 patients diagnosed with FSGS (primary and secondary) and 50 control patients were retrospectively included in the study. For each patient, clinical and outcome data were obtained and compared to morphological parameters, including immunofluorescence analysis of mesangial IgM and complement 3 (C3) deposits analyzed on kidney biopsy samples. RESULTS: There were significant positive correlations between IgM and C3 deposition in secondary FSGS (P<0.001) and between IgM and mesangial deposits detected by electron microscopy in secondary FSGS (P=0.015), which indicated that higher IgM deposition correlated with higher C3 deposition and mesangial deposits only in secondary FSGS. Patients with secondary FSGS and the deposition of IgM showed inferior renal outcomes at earlier time points in comparison with patients with negative IgM expression (P=0.022). CONCLUSIONS: We detected a positive correlation between IgM and C3 in secondary FSGS. The association between IgM deposition and worse renal outcome in secondary FSGS indicates that IgM may play a role in the progression of this disease.

IL-33 exacerbates acute kidney injury.

Inflammation contributes to the pathogenesis of acute kidney injury (AKI). IL-33 is a proinflammatory cytokine, but its role in AKI is unknown. Here we observed increased protein expression of full-length IL-33 in the kidney following induction of AKI with cisplatin. To determine whether IL-33 promotes injury, we administered soluble ST2 (sST2), a fusion protein that neutralizes IL-33 activity by acting as a decoy receptor. Compared with cisplatin-induced AKI in untreated mice, mice treated with sST2 had fewer CD4 T cells infiltrate the kidney, lower serum creatinine, and reduced acute tubular necrosis (ATN) and apoptosis. In contrast, administration of recombinant IL-33 (rIL-33) exacerbated cisplatin-induced AKI, measured by an increase in CD4 T cell infiltration, serum creatinine, ATN, and apoptosis; this did not occur in CD4-deficient mice, suggesting that CD4 T cells mediate the injurious effect of IL-33. Wildtype mice that received cisplatin and rIL-33 also had higher levels of the proinflammatory chemokine CXCL1, which CD T cells produce, in the kidney compared with CD4-deficient mice. Mice deficient in the CXCL1 receptor also had lower serum creatinine, ATN, and apoptosis than wildtype mice following cisplatin-induced AKI. Taken together, IL-33 promotes AKI through CD4 T cell-mediated production of CXCL1. These data suggest that inhibiting IL-33 or CXCL1 may have therapeutic potential in AKI.

The value of urinary decoy cells finding in patients with kidney transplantation.

Childhood infection with polyomaviruses leads to a life-long latent infection of renal and urinary tract epithelia. Replication in the reno-urinary epithelium is associated with viral cytopathic changes such as nuclear inclusions and decoy cells. During the 2005-2009 period, cytological urine analysis was performed in 154 samples (94 male and 60 female) from patients with kidney transplantation (n = 19), simultaneous pancreas-kidney transplantation (SPKT) (n = 9) and simultaneous kidney and liver transplantation (n = 2). Urine samples were analyzed monthly following transplantation according to the protocol. The period from transplantation to the first occurrence of decoy cells in the urine and the period of decoy cell persistence in the urine were assessed. The presence of decoy cells (< 10 and > 10 decoy cells) and red blood cells (< 20 E, 20-100 E and > 100 E) per cytospin smear was semiquantitatively determined, along with analysis of inflammatory cells (neutrophilic granulocytes) and fungi. In patients with decoy cells detected, their sensitivity, specificity, and negative and positive predictive value for BK virus nephropathy were calculated. Correlation of the study parameters was estimated by use of Kruskal-Wallis test (Statistica 7.1, StatSoft Inc., Tulsa, USA). Decoy cells were found in 30 patients (20 male and 10 female), age median 40 (range 16-69) years, at a mean of day 115 (range day 5-747) post transplantation, whereas their presence was recorded for a mean of 141 (range 77-771) days. Immunohistochemical staining of kidney biopsy sample for polyomavirus (SV40 large T-antigen) yielded positive reaction in 2/30 (7%) patients. Erythrocyturia was present in 29/30 patients with decoy cells. The number of decoy cells per cytospin smear generally ranged less than 10 in 25/30 patients, whereas more than 10 decoy cells per cytospin smear were only recorded in 5/30 patients. Immunohistochemistry produced positive finding for BK virus in one patient with SPKT and simultaneous kidney and liver transplantation each, which was statistically significantly more common as compared with patients with kidney transplantation alone (p = 0.0244). Immunohistochemical positivity for BK virus was more significant in cases with more than 10 decoy cells detected in cytospin smear (p = 0.013). In BK nephropathy, the finding of urinary decoy cells showed a 100% sensitivity, 84% specificity, 100% negative predictive value and 6% positive predictive value. BK virus nephropathy remains a significant post transplantation complication.

Prognostic Significance of Lacunarity in Preoperative Biopsy of Colorectal Cancer.

The quantity and quality of preoperative material in colorectal cancer is often limiting factor in determination of risk factors and therapy planning. The most important negative prognostic factors are intravascular and perineural invasion, as well as tumor budding. Usually, the only parameter available in preoperative biopsy is tumor budding. However, the growing body of evidence suggests that cancer differentiation based on the poorly differentiated clusters has better prognostic value. The limiting factor in applying of these new parameters is reproducible, simple, cheap and fast method of their determination. In this paper we investigated the prognostic value of lacunarity, determined in preoperative biopsy. Lacunarity is a measure of spatial heterogeneity (inhomogeneity) in an image. It quantifies how objects fill the space, and enables analysis of gaps distribution, homogeneity of gaps, and presence of structures. It was shown that lacunarity and the total number of buds could be combined in a model which clearly divides colorectal cancer patients in low, medium and high risk subgroups. The paper also points out that the quantitative numerical methods are superior to semiquantitative methods, and that individual methods should be combined using algorithms to obtain a more accurate prediction. Because the study described is designed as a pilot study, verification is needed on a larger sample of patients from independent researchers.

Perfusion storage reduces apoptosis in a porcine kidney model of donation after cardiac death.

BACKGROUND: Donation after cardiac death (DCD) kidneys suffer a high incidence of delayed graft function attributable to warm ischemia and cold ischemia (CI). Neither the mechanism of injury nor type of cell death has been described. Clinical studies suggest that perfusion storage (PS) of DCD kidneys may reduce injury although the mechanism of protection is unknown. In a porcine model of DCD, we hypothesized that DCD kidneys have increased caspase-1 due to warm ischemia (WI) and increased caspase-3 and apoptosis due to CI. METHODS: Male Yorkshire pigs subjected to cardiac death were perfused with cold University of Wisconsin solution. The perfused kidneys were removed and stored in cold University of Wisconsin solution for 24 hr. Kidney biopsies were obtained before cardiac death and at 0 and 24 hr of CI. RESULTS: There was an increase in caspase-1 activity due to WI before cold preservation. CI was associated with a massive increase in apoptosis, caspase-3/7 activity, and caspase-3 protein expression. Next, we hypothesized that PS would protect against apoptosis. We compared DCD kidneys subjected to static versus PS for 24 hr. PS significantly reduced proximal tubular apoptosis and was associated with increased B-cell lymphoma-extra large, and hypoxia-inducible transcription factor-1α. CONCLUSIONS: These findings suggest that in DCD kidneys, WI preferentially activates caspase-1, whereas CI activates caspase-3 and causes apoptosis. PS may protect DCD kidneys through activation of antiapoptotic pathways involving B-cell lymphoma-extra large and hypoxia-inducible transcription factor-1α.

Renal protection from prolonged cold ischemia and warm reperfusion in hibernating squirrels.

BACKGROUND: We have previously shown that cold ischemia (CI) results in massive increases in caspase-3 activity, tubular apoptosis, and brush border injury (BBI) in mouse kidneys. During hibernation, the 13-lined ground squirrel (GS) cycles through repeated CI during torpor, followed by warm ischemia/reperfusion (WI) during interbout arousal (IBA). We sought to determine whether CI and WI during hibernation caused caspase-3 activation, tubular apoptosis, acute tubular necrosis, or BBI, and reduced renal function. We also determined whether protection was dependent on the stage of hibernation. METHODS: Radiotelemeters were implanted in 1-year-old GS, and core body temperature was remotely monitored. GS kidneys at various stages of hibernation were subjected to ex vivo CI. RESULTS: Tubular apoptosis was not detected and caspase-3-like activity was not different between hibernating and summer kidneys. Despite prolonged CI followed by WI and reperfusion, acute tubular necrosis and apoptosis did not occur in hibernating kidneys. BBI was absent in torpid kidneys but significantly increased in IBA kidneys and associated with an increase in caspase-3-like activity, suggesting that IBA kidneys are more susceptible to injury than summer or torpid kidneys. Renal function and urine concentrating ability diminished during torpor but returned during IBA. CONCLUSIONS: Despite BBI, IBA kidneys clear serum creatinine and concentrate urine. Kidneys from both summer and hibernating animals tolerated ex vivo CI, confirming that protection from apoptotic and necrotic cell death is independent of the stage of hibernation. An understanding of how renal protection occurs during hibernation may help in understanding the pathophysiology of delayed graft function.

Apoptosis and autophagy in cold preservation ischemia.

BACKGROUND: Prolonged cold ischemia (CI) is a risk factor for the development of delayed graft function that predicts reduced 5-year kidney transplant survival. CI results in caspase-3 activation, tubular injury, and apoptosis. Autophagy, a highly conserved pathway that permits recycling of nutrients within the cell during stress, is linked to apoptosis. We hypothesized that CI during kidney preservation would induce autophagy. We sought to determine apoptosis and autophagic flux in CI. METHODS: Autophagic flux and apoptosis were examined in kidneys of wild-type and green fluorescent protein (GFP)-microtubule-associated protein1 light chain 3 (LC3) transgenic mice that were subjected to 48 hr of CI. Autophagic flux was determined by performing experiments with and without bafilomycin A1. RESULTS: CI alone significantly increased the number of apoptotic cells/hpf, caspase-3/7 activity, and protein expression of autophagy markers LC3 II and autophagy-related protein 5. To determine the effect of inhibiting autophagic flux on apoptosis, kidneys of wild-type and GFP-LC3 transgenic mice were subjected to 48 hr of CI in the presence of lysosomal inhibitor bafilomycin A1. The combination of CI and bafilomycin A1 suppressed autophagic flux and significantly reduced the number of apoptotic cells/hpf, caspase-3/7 activity, LC3 II (both by immunoblot and in GFP-LC3 transgenic mice), and autophagy-related protein 5 protein expression. CONCLUSION: In summary, we have shown that autophagy and autophagic flux are reduced in cold ischemic kidneys treated with bafilomycin A1. Reduced autophagy and autophagic flux were associated with a significant reduction in apoptotic cell death, which may provide a therapeutic rationale for including bafilomycin A1 in University of Wisconsin solution during organ preservation.