Changes in intestinal microflora in rats with acute respiratory distress syndrome

AIM:To implement high-throughput 16S rDNA sequencing to study microbial diversity in the fecal matter of rats with acute lung injury/acute respiratory distress syndrome(ALI/ARDS).METHODS:Intratracheal instillation of lipopolysaccharide was used to induce ALI,and the pathological changes in the lungs and intestines were observed.D-lactate levels and diamine oxidase(DAO)activities were determined by enzymatic spectrophotometry.The fragments encompassing V4 16S rDNA hypervariable regions were PCR amplified from fecal samples,and the PCR products of V4 were sequenced by Illumina MiSeq.RESULTS:Increased D-lactate levels and DAO activities were observed in the model group(P<0.01).Sequencing results revealed the presence of 3780 and4142 species in the control and model groups,respectively.The percentage of shared species was 18.8419%.Compared with the control group,the model group had a higher diversity index and a lower number of species of Fusobacteria(at the phylum level),Helicobacter and Roseburia(at the genus level)(P<0.01).Differences in species diversity,structure,distribution and composition were found between the control group and early ARDS group.CONCLUSION:The detection of specific bacteria allows early detection and diagnosis of ALI/ARDS.

Early Changes in Circulatory T Helper Type 1, 2, and 17 Cells of Patients with Out-of-Hospital Cardiac Arrest after Successful Cardiopulmonary Resuscitation

Background： Immune disorder is an important feature of patients with out-of-hospital cardiac arrest （OHCA） after the return of spontaneous circulation （ROSC）. We investigated the expression of circulatory T helper type （Th）1, Th2, and Th 17 cells to explore the early immune alteration in OHCA patients after ROSC. Methods： During July-September 2016 and March-September 2017, 65 consecutive OHCA patients with ROSC 〉 12 h and 30 healthy individuals were enrolled in this study. Clinical and 28-day survival data were collected. Peripheral blood samples were analyzed to evaluate the expression of Th1/Th2/Th 17 cells by flow cytometry from OHCA patients after ROSC on days l and 3 and from healthy individuals. Results： Compared with healthy individuals, T lymphocyte counts and Thl cell counts decreased on days 1 and 3 after ROSC （1464 [1198, 2152] vs. 779 [481, 1140] vs. 581 [324, 1118/μl,χ^2= 30.342, P 〈 0.001; 154 [90, 246] vs. 39 [19, 78] vs. 24 [12, 53]μl, χ^2 = 42.880, P〈 0.001）, and Th2 and Th17 cell counts decreased on day 3 （17.0 [10.8, 24.0] vs. 9.0 [3.0, 15.5]μl, Z= -3.228, P= 0.001; 4.7 [2.7, 9.1] vs. 2.7 [1.0, 6.5]μl, Z = -2.294, P = 0.022）. No change in CD4＋/CD3＋ lymphocyte ratio was seen on day 1 or day 3 （57.9 [49.4, 63.0] vs. 55.4 [46.5, 66.5] vs. 55.4 [50.2, 67.0]%, χ^2 = 0.171, P = 0.918）. Th1/CD4＋ lymphocyte ratio decreased on days 1 and 3 （19.0 [14.0, 24.9] vs. 9.3 [4.6, 13.9] vs. 9.5 [4.9, 13.6]%, χ^2= 25.754, P 〈 0.001）, and Th2/CD4＋ lymphocyte ratio increased on day 1 and decreased on day 3 （1.9 [1.2, 2.5] vs. 2.5 [1.6, 4.0] vs. 1.9 [1.6, 3.81%,χ^2= 6.913, P = 0.032）. Thl/Th2 cell ratio also decreased on both clays （9.4 [7.3, 13.5] vs. 3.1 [1.9, 5.6] vs. 4.2 [2.8, 5.9], χ^2 = 44.262, P 〈 0.001 ）. Despite an upward trend in the median of Th 17/CD4＋ lymphocyte ratio in OHCA patients, there was no significant difference compared with healthy individuals （0.9 [0.4, 1.2] vs. 0.7 [0.4, 1.2] vs. 0.6 [0.3, 1.01%, χ^2= 2.620, P = 0.270）. The dynamic expression of Th1/Th2/Th 17 cells on days 1 and 3 were simultaneously analyzed in 28/53 OHCA patients who survived 〉3 days; patients were divided into survivors （n = 10） and nonsurvivors （n = 18） based on 28-day survival. No significant differences in Th1/Th2/Th 17 cell counts, ratios in CD4＋ lymphocytes, and Th1/Th2 cell ratio were seen between survivors and nonsurvivors on both days （all P 〉 0.05）. There was no difference over time in both survivors and nonsurvivors （all P 〉 0.05）. Conclusion： Downregulated T lymphocyte counts, including Th1/Th2/Th17 subsets and Th1/Th2 cell ratio imbalance, occur in the early period after ROSC, that may be involved in immune dysfunction in OHCA patients.