Impact of air quality on the gastrointestinal microbiome: A review.

BACKGROUND: Poor air quality is increasingly associated with several gastrointestinal diseases suggesting a possible association between air quality and the human gut microbiome. However, details on this remain largely unexplored as current available research is scarce. The aim of this comprehensive rigorous review was to summarize the existing reports on the impact of indoor or outdoor airborne pollutants on the animal and human gut microbiome and to outline the challenges and suggestions to expand this field of research. METHODS AND RESULTS: A comprehensive search of several databases (inception to August 9, 2019, humans and animals, English language only) was designed and conducted by an experienced librarian to identify studies describing the impact of air pollution on the human gut microbiome. The retrieved articles were assessed independently by two reviewers. This process yielded six original research papers on the animal GI gastrointestinal microbiome and four on the human gut microbiome. ß-diversity analyses from selected animal studies demonstrated a significantly different composition of the gut microbiota between control and exposed groups but changes in α-diversity were less uniform. No consistent findings in α or ß-diversity were reported among the human studies. Changes in microbiota at the phylum level disclosed substantial discrepancies across animal and human studies. CONCLUSIONS: A different composition of the gut microbiome, particularly in animal models, is associated with exposure to air pollution. Air pollution is associated with various taxa changes, which however do not follow a clear pattern. Future research using standardized methods are critical to replicate these initial findings and advance this emerging field.

Prognostic Value of Baseline Neutrophil-to-Lymphocyte Ratio in Metastatic Urothelial Carcinoma Patients Treated With First-line Chemotherapy: A Large Multicenter Study.

BACKGROUND: A high neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation and is associated with poor survival in localized or metastatic cancer. This study assessed the prognostic value of NLR after first-line chemotherapy (CT) in patients with metastatic urothelial carcinoma (mUC). PATIENTS AND METHODS: Two hundred eighty consecutive patients treated with first-line platinum-based CT at 4 centers in France and Turkey between 2002 and 2014 were included. The association of NLR and Memorial Sloan Kettering Cancer Center (MSKCC) scores with overall survival (OS) and progression-free survival (PFS) was determined by univariate Cox models. RESULTS: Median OS was 10.6 months (follow-up, 42.8 months). In univariate analysis, high NLR was associated with worse OS (hazard ratio [HR] for death = 1.36; 95% confidence interval [CI], 1.23-1.51; P < .0001); the result was similar after adjustment for MSKCC prognostic group (HR = 1.28; 95% CI, 1.14-1.43; P < .0001). Low NLR was associated with longer PFS (HR = 1.18; 95% CI, 1.05-1.33; P < .005). When NLR was divided in terciles, OS in the lowest tercile (NLR 0.6-2.78) was 12.4 to 16.6 (median, 13.4) months versus 5.3 to 9.9 (median, 7.3) months in the highest tercile (NLR 4.70-48.9) (P = .001). Similar trends were observed for PFS (5.6-8.9 [median, 7.6] months vs. 3.1-5.7 [median, 4.8] months) in patients with NLR values in the lowest versus highest tercile, respectively (P = .021). CONCLUSION: High pre-CT NLR was an independent prognostic factor for poor OS and PFS in mUC patients. The prognostic value of NLR, as either a continuous or categorical variable, compared favorably with MSKCC score but was easier to assess and monitor.