Performance of tacrolimus in hospitalized patients with steroid-refractory acute severe ulcerative colitis

BACKGROUND Acute severe ulcerative colitis unresponsive to systemic steroid treatment is a lifethreatening medical condition requiring hospitalization and often colectomy.Despite the increasing choice of medical therapy options for ulcerative colitis, the condition remains a great challenge in the field of inflammatory bowel diseases(IBD). The performance of the calcineurin inhibitor tacrolimus in this clinical setting is insufficiently elucidated.AIM To evaluate the short and long-term outcomes of tacrolimus therapy in adult inpatients with steroid-refractory acute severe ulcerative colitis.METHODS We conducted a retrospective monocentric study enrolling 22 patients at a tertiary care center for the treatment of IBD. All patients who were admitted to one of the wards of the Department of Gastroenterology and Hepatology of the Heidelberg University Hospital with acute severe ulcerative colitis between 2007 and 2018, and who received oral or intravenous tacrolimus for steroid-refractory disease were included. Baseline characteristics and data on the disease courses were retrieved from entirely computerized patient charts. The primary study endpoint was clinical response to tacrolimus therapy, resulting in discharge from the hospital. Secondary study endpoints were colectomy rate and time to colectomy, achievement of clinical remission under tacrolimus therapy, and the occurrence of side effects.RESULTSIn the majority of the 22 included patients(68.2%), tacrolimus therapy was initiated intravenously and subsequently converted to oral administration. The treatment duration was 128 ± 28.5 d(mean ± SEM), and the patients were followed up for 705 ± 110 d after treatment initiation. Among all patients, 86.4%were discharged from the hospital under continued oral tacrolimus therapy. In36.4% of the patients, the administration of tacrolimus resulted in clinical remission at some point during the treatment. Thirty-two percent of the patients underwent colectomy between 5 and 194 d after the initiation of tacrolimus treatment(mean: 97.4 ± 20.8 d). Colectomy-free survival rates at 1, 3, 6 and 12 mo after the initiation of tacrolimus therapy were 90.9%, 86.4%, 77.3% and 68.2%,respectively. The safety profile of tacrolimus was overall favorable. Only two patients discontinued the treatment due to side effects.CONCLUSION The short-term outcome of tacrolimus in steroid-refractory acute severe ulcerative colitis was beneficial, and side effects were rare. In all, tacrolimus therapy appears to be a viable option for short-term treatment of steroidrefractory acute severe ulcerative colitis besides ciclosporin and anti-tumor necrosis factor α treatment.

Variation of terrestrial ecosystem recorded by stable carbon isotopes of fossils in northern China during the Quaternary

Stable carbon isotopes of C3 and C4 plants have completely distinct δ13C values respectively. Carbonate in tooth enamel of herbivorous mammals is significantly and regularly enriched in 13C compared to source carbon. As a result, we can reconstruct distributions of C3 and C4 plants in geological history based on carbon isotopes of mammalian tooth enamel. Carbon isotopes of 70 mammalian tooth enamel samples from 11 Quaternary localities in northern China are analyzed. This analysis indicates that C3 plants were dominant in the terrestrial ecosystem of northern China during the Quaternary, which is completely different from Pakistan with relatively close latitudes where C4 plants were absolutely dominant. The great difference was caused by the uplift of the Tibetan Plateau. A simulation implied that a marked temperature decrease would happen in the north side of the Tibetan Plateau, but a temperature increase in the south side. The warming condition caused the transition from C3 to C4 plants in Pakistan