The proteolytic activity in inflammatory bowel disease: insight from gut microbiota.

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disease caused by the destruction of the intestinal mucosal epithelium that affects a growing number of people worldwide. Although the etiology of IBD is complex and still elucidated, the role of dysbiosis and dysregulated proteolysis is well recognized. Various studies observed altered composition and diversity of gut microbiota, as well as increased proteolytic activity (PA) in serum, plasma, colonic mucosa, and fecal supernatant of IBD compared to healthy individuals. The imbalance of intestinal microecology and intestinal protein hydrolysis were gradually considered to be closely related to IBD. Notably, the pivotal role of intestinal microbiota in maintaining proteolytic balance received increasing attention. In summary, we have speculated a mesmerizing story, regarding the hidden role of PA and microbiota-derived PA hidden in IBD. Most importantly, we provided the diagnosis and therapeutic targets for IBD as well as the formulation of new treatment strategies for other digestive diseases and protease-related diseases.

Development of a non-infectious rat model of acute exacerbation of idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with severe pulmonary fibrosis. The main cause of IPF-associated death is acute exacerbation of IPF (AE-IPF). This study aims to develop a rat model of AE-IPF by two intratracheal perfusions with bleomycin (BLM). METHODS: Ninety male Sprague Dawley (SD) rats were randomized into three groups: an AE-IPF model group (BLM + BLM group), an IPF model group (BLM group), and a normal control group. Rats in the BLM + BLM group underwent a second perfusion with BLM on day 28 after the first perfusion with BLM. Rats in the other two groups received saline as the second perfusion. Six rats in each group were sacrificed on day 31, day 35, and day 42 after the first perfusion, respectively. Additional 18 rats in each group were observed for survival. RESULTS: Rats in the BLM + BLM group had significantly worse pulmonary alveolar inflammation and fibrosis than rats in the BLM group. Rats in the BLM + BLM group also developed large amounts of hyaline membrane, showed high levels of albumin (ALB) and various inflammatory factors in the bronchoalveolar lavage fluid (BALF), and had markedly increased lung water content. Furthermore, rat survival was reduced in the BLM + BLM group. The pathophysiological characteristics of rats in the BLM + BLM group resemble those of patients with AE-IPF. CONCLUSIONS: A second perfusion with BLM appears to induce acute exacerbation of pulmonary fibrosis and may be used to model AE-IPF in rats.

Serum Krebs von den Lungen-6 level as a diagnostic biomarker for interstitial lung disease in Chinese patients.

OBJECTIVES: The purpose of this study was to determine the diagnostic and prognostic values of serum KL-6 levels in Chinese patients with interstitial lung disease (ILDs). METHODS: A total of 1084 subjects including 373 cases of ILDs, 584 cases of non-ILD pulmonary diseases, and 127 healthy individuals were recruited from three clinical centers in China between January 2011 and December 2013. A total of 106 patients undergoing treatments for ILDs in Shanghai Pulmonary Hospital between January 2011 and December 2013 were enrolled. Baseline and posttreatment serum KL-6 levels were determined. RESULTS: Serum KL-6 levels in patients with ILDs were significantly higher than those in patients with non-ILD pulmonary diseases or in healthy individuals (1492.09 ± 2230.08 U/mL vs 258.67 ± 268.73 U/mL or 178.73 ± 71.17 U/mL, all P < 0.05). At the cut-off value of 500 U/mL, the sensitivity and specificity of serum KL-6 as a diagnostic marker for ILDs was 77.75% and 94.51%, respectively. The Kappa value was 0.743 (P < 0.001). The area below the receiver operating characteristic curve was 0.922 with a 95% Confidence interval of 0.904-0.941 (P < 0.001). The posttreatment serum KL-6 levels significantly reduced in patients with improved ILDs, whereas markedly increased in patients with exacerbated ILDs (All P < 0.05). CONCLUSIONS: Serum KL-6 levels might be a promising diagnostic biomarker for ILDs in Chinese patients. The prognostic value of serum KL-6 levels for ILDs remains to be verified by large-scaled studies.

Establishment of the mouse model of acute exacerbation of idiopathic pulmonary fibrosis.

PURPOSE: To explore and establish an animal model of AE-IPF. METHODS: An animal model of idiopathic pulmonary fibrosis (IPF) was established using bleomycin (BLM). Then, BLM was administered a second time on day 21 to induce AE-IPF (which mimics human AE-IPF). Evaluation of the success of animal model was based on the survival of mice, as well as assessment of pathological changes in lung tissue. Preliminary investigation into the immunological mechanism of AE-IPF was also explored via the detection and identification of the inflammatory cells in mouse bronchoalveolar lavage fluid (BALF) and the concentrations of six cytokines (IL-4, IL-6, IL-10, IL-17A, MIG, and TGF-ß1) in BALF supernatants, which were closely associated with IPF and AE-IPF. The intervention role of IL-17A antibody to AE was explored. RESULTS: By week 4 after the second BLM administration, the mortality in the AE-IPF group was significantly greater (45%, 9/20) than that in stable-IPF group (0/18) (P = .0017). The average body weight in AE-IPF group was significantly lower than that in stable group (P < .0001). In AE-IPF group, inflammation and fibrosis were severer by histopathology analysis. In BALF, IL-17A, MIG (CXCL-9), IL-6, and TGF-ß1 levels in AE group were significantly higher. The percentages of neutrophils and Th17 cells in BALF were significantly higher in AE group (P < .01; P = .0281). IL-17A antibody could attenuated the lung inflammation induced by twice BLM challenges. CONCLUSION: A mouse model of AE-IPF can be established using two administrations of BLM; Th17 cells may play a key role during the pathological process of AE-IPF.

Blood glucose fluctuations in hemodialysis patients with end stage diabetic nephropathy.

OBJECTIVE: To characterize blood glucose fluctuation during hemodialysis in patients with end stage diabetic nephropathy (ESDN) by a continuous glucose monitoring system (CGMS), and aim to improve blood glucose control in this patient population. METHODS: Forty-six patients with or without type 2 diabetes mellitus (T2DM), receiving hemodialysis, were recruited in this study. Thirty-six patients had end stage diabetic nephropathy (ESDN group), the other ten patients had end stage renal disease without diabetes (ESRD group). A continuous glucose monitoring system (CGMS) was employed to monitor glycemic fluctuation for 72 hours. Blood samples were collected and analyzed. RESULTS: Mean, standard deviation (SD), maximum, and mean amplitude glycemic excursion (MAGE) of blood glucose and the ratio of blood glucose readings that was greater than 13.9 mmol/L of ESDN group, were significantly greater than those of ESRD group (p<0.01 for all) during 72 hours of observation. The mean blood glucose was significantly lower, while SD and MAGE were significantly higher in ESDN group on hemodialysis day than on days off hemodialysis (p<0.05), while these were not been observed in ESRD group. Though mean, SD, and MAGE of blood glucose during hemodialysis were significantly lower than those of peri-hemodialysis in both groups (p<0.01 or p<0.05, respectively), they were significantly higher in ESDN group than that in ESRD group (p<0.05). The mean blood glucose value calculated from HbA1c did not reflect the actual mean blood glucose measured by CGM in both groups, and gave an inaccurate impression of a significantly lower mean glucose. CONCLUSIONS: ESDN patients had larger glycemic fluctuations as compared with ESRD patients. Hemodialysis caused reduction in mean, SD, and MAGE, which in turn caused bigger glycemic fluctuations on hemodialysis day. The HbA1c in ESDN patients gave an inaccurate value, which did not truly reflect blood glucose status for a prolonged period.