Myofibroblasts are a main cell-type of collagen-producing cells during tissue fibrosis, but their origins remains controversial. While bone marrow-derived myofibroblasts in renal fibrosis has been reported, the cell origin and mechanisms regulating their transition into myofibroblasts remain undefined. In the present study, cell lineage tracing studies by adoptive transfer of GFP+ or dye-labelled macrophages identified that monocyte/macrophages from bone marrow can give rise to myofibroblasts via the process of macrophage-myofibroblast transition (MMT) in a mouse model of unilateral ureteric obstruction. The MMT cells were a major source of collagen-producing fibroblasts in the fibrosing kidney, accounting for more than 60% of α-SMA+ myofibroblasts. The MMT process occurred predominantly within M2-type macrophages and was regulated by TGF-β/Smad3 signalling as deletion of Smad3 in the bone marrow compartment of GFP+ chimeric mice prevented the M2 macrophage transition into the MMT cells and progressive renal fibrosis. In vitro studies in Smad3 null bone marrow macrophages also showed that Smad3 was required for TGF-β1-induced MMT and collagen production. In conclusion, we have demonstrated that bone marrow-derived fibroblasts originate from the monocyte/macrophage population via a process of MMT. This process contributes to progressive renal tissue fibrosis and is regulated by TGF-β/Smad3 signalling.

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BackgroundIt is important to find a comorbidity measure with better performance for use with administrative data. The new method proposed by Elixhauser et al. has never been validated and compared to the widely used Charlson method in the Asia region. The objective of this study was to compare the performance of three comorbidity measures using information from different data periods in predicting short- and long-term mortality among patients with acute myocardial infarction (AMI) and chronic obstructive pulmonary disease (COPD).MethodsWe conducted a retrospective cohort study using National Health Insurance claims data (2001-2002) in Taiwan. We constructed the Elixhauser, the Charlson/Deyo, and the Charlson/Romano methods based on the International Classification of Disease, 9th Revision, Clinical Modification codes in the claims data. Two data periods, including the index hospitalization as well as the index and prior 1-year hospitalizations, were used in the analysis. The performances were compared using the c-statistics derived from multiple logistic regression models that included age, gender, race, and whether the patient received surgery or not. The outcomes of interest were in-hospital and 1-year mortality.ResultsThe performance was in the same rank order among both populations regardless of the outcome and data period: Elixhauser > Charlson/Romano > Charlson/Deyo. In predicting in-hospital mortality, the Elixhauser models using information from the index hospitalization performed best, even better than the Charlson/Deyo or Charlson/Romano models using information from the index and prior hospitalizations. Nevertheless, in predicting 1-year mortality, the Elixhauser models using information from the index and 1-year prior hospitalizations performed better than using information from the index hospitalization only.ConclusionsThis is so far the first study to validate the Elixhauser method and compare it to other methods in the Asia region, and is the first to report its differences in data periods between short- and long-term outcomes. The comorbidity measurement developed by Elixhauser et al. has relatively good predictive validity, and researchers should consider its use in claims-based studies.

This study provides the first phenotypic and morphological evidence that glomerular epithelial-myofibroblast transdifferentiation participates in the formation and evolution of glomerular crescents.

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine that also counter-regulates glucocorticoid action. We investigated whether immunoneutralization of MIF could reverse established experimental crescentic glomerulonephritis and if this treatment could modulate endogenous glucocorticoid levels. Accelerated anti-GBM glomerulonephritis was induced in six littermate pairs of rats. Once crescentic disease was established on day 7, one animal in each pair was given a daily injection of neutralizing anti-MIF antibody (Ab) or irrelevant isotype control Ab for 14 days and then killed on day 21. In addition, a group of 6 animals was killed on day 7 of disease without any treatment. Animals receiving the control Ab exhibited a rapidly progressive glomerulonephritis with severe renal injury (proteinuria), loss of renal function (creatinine clearance), anemia, and marked histologic damage (including glomerular crescent formation), compared with animals killed on day 7 without treatment. In contrast, anti-MIF Ab treatment partially reversed the disease by restoring normal renal function and reducing histological damage compared with untreated animals killed on day 7 (p < 0.05). Interestingly, anti-MIF Ab treatment also prevented severe anemia (p < 0.05). Reversal of disease was associated with a significant reduction in leukocyte infiltration and activation and renal interleukin-1 (IL-1) production. Importantly, anti-MIF Ab treatment caused a significant increase in endogenous serum corticosterone levels, which correlated with the reversal of disease parameters. In conclusion, this study has demonstrated that blocking MIF activity can partially reverse established crescentic glomerulonephritis and suggests that MIF operates by both enhancing the cellular immune response and suppressing the endogenous anti-inflammatory glucocorticoid response.

This study has shown that local proliferation is an important mechanism in both macrophage and myofibroblast accumulation during the development of renal injury in the rat remnant kidney. In addition, local macrophage proliferation is postulated as a mechanism for amplifying kidney damage in nonimmune renal injury.

The digestion of Fued tissue sections is a critical step in the optimization of any in situ hybridization protocol. We describe a novel application of microwave oven heating to optimize mRNA detection in paraformaldehyde-fued tissues by in situ hybridization using digoxigenin-labeled probes.This technique replaces protease digestion of fmed tissue sections with 10 min of microwave pretreatment, followed by either conventional hybridization or hybridization involving microwave incubation. This new technique has several advantages over the standard protease treatment-based methods presently in use. (a) Microwave oven heating is a simple, rapid, and highly reproducible technique.(b) Microwave pretreatment significantly increased the hybridization signal and reduced the background compared to conventional protease digestion. Consequently, the hybridization time required to obtain optimal mRNA detection was reduced to 30 min. (c) Ten minutes of microwave pretreatment produced

Objective To investigate the prevalence of nodular goiter and thyroid dysfunction in uremic patients undergoing hemodialysis (HD) and peritoneal dialysis. Design Cross-sectional study. Setting Single dialysis unit and outpatient clinic. Patients The study included 221 patients [143 HD and 78 continuous ambulatory peritoneal dialysis (CAPD) patients] along with 135 consecutively selected outpatients as controls. Main Outcome Measures Ultrasonography was used to detect patients’ thyroid function and nodular goiter. Results Nodular goiter was detected in 54.8% of the uremic patients and in 21.5% of the controls. Uremic patients had higher prevalence of thyroid dysfunction, which included reduced serum concentration of total T3, total T4, and free T4, and increased serum level of TSH. Hypothyroidism was also observed more frequently in uremic patients than in the control group (5.4% vs 0.7%, p < 0.05). Nodular goiter was more frequently found in females than in males (63.5% vs 48%, p < 0.05). Moreover, the prevalence of nodular goiter increased with age (p < 0.02) in uremic patients. Hemodialysis patients had a higher frequency of reduced total T3 level (46.9% vs 29.5%, p < 0.02). However, CAPD patients had lower T4 levels (6.23 ± 1.82μg/dL vs 7.15± 1.99μg/dL, p < 0.05). Conclusion Because of the high incidence of hypothyroidism and nodular goiter in uremic patients, screening of thyroid function and goiter detection with ultrasound should be considered in evaluation of end-stage renal disease patients.