Liver Macrophage Depletion Ameliorates The Effect of Mesenchymal Stem Cell Transplantation in a Murine Model of Injured Liver.

Mesenchymal stem cells (MSCs) therapy show different levels of effectiveness in the context of different types of liver damage, suggesting that the microenvironment of the injured liver is a key determinant for effective stem cell therapy. The objective was to assess the modulatory effect of hepatic stem cell niche components on the transplanted MSCs during liver injury induced by carbon tetrachloride (CCl4). Superparamagnetic iron oxide (SPIO)-labeled human MSCs were injected intravenously into mice treated with CCl4 and subjected to hepatic macrophage-depletion. Liver tissues were collected at different intervals post transplantation for subsequent histopathological, morphometric, immunohistochemical, gene expression and ultrastructural studies. The homing of the transplanted MSCs was evidenced by tracing them within the niche by iron staining and immunohistochemical studies. MSCs differentiated into hepatocyte-like cells and intimal smooth muscle cells as evidenced by their expression of human albumin and α-smooth muscle actin with a concomitant increase in the level of mouse hepatocyte growth factor. A post transplantation reduction in the liver fibro-inflammatory reaction was found and was promoted by liver macrophages depletion. Thus, it could be concluded from the present study that prior manipulation of the microenvironment is required to improve the outcome of the transplanted cells.

Prevalence of microscopic colitis in patients with chronic diarrhea in Egypt: a single-center study.

BACKGROUND/AIM: Microscopic colitis (MC) is diagnosed when a patient with chronic watery non-bloody diarrhea (CWND) has an endoscopically normal colon, but colonic biopsies show unique inflammatory changes characteristic of lymphocytic or collagenous colitis. MC is a disorder of unknown etiology. Studies comparing the prevalence of the disease in developing countries as compared to developed countries may shed more light on the possibility of a post-infectious etiology. Most data on the incidence and prevalence of MC are from developed countries where it accounts for 4-13% of cases of CWND. There are only a few reports from developing countries. Two studies from Peru and Tunis, with high prevalence of infectious gastroenteritis, revealed MC in 40% and 29.3% of cases of CWND, respectively. The aim of this study was to investigate the prevalence of MC in patients presenting with CWND in Egypt. MATERIALS AND METHODS: A total of 44 patients with CWND of unexplained etiology who had undergone full colonoscopy with no macroscopic abnormalities between January 2000 and January 2010 were assessed retrospectively. RESULTS: The histological appearance of MC was identified in 22 (50%) patients. Twelve (55%) patients were male and 10 (45%) female. Mean age was 40 years (range: 20-65 years). Twenty (91%) of MC cases had lymphocytic colitis and 2 (9%) had collagenous colitis. CONCLUSIONS: The prevalence of MC in Egyptian patients with CWND is high when compared to that in developed countries. MC mainly affects young and middle-aged patients and it is more commonly of the lymphocytic type.