• Yongyue Wei, Paula Tejera, Zhaoxi Wang, Ruyang Zhang, Feng Chen, Li Su, Xihong Lin, Ednan K Bajwa, B Taylor Thompson, and David C Christiani.
• 1 Department of Environmental Health and.
• Am. J. Respir. Crit. Care Med. 2017 May 15; 195 (10): 1353-1361.

RationalePlatelets are believed to contribute to acute respiratory distress syndrome (ARDS) pathogenesis through inflammatory coagulation pathways. We recently reported that leucine-rich repeat-containing 16A (LRRC16A) modulates baseline platelet counts to mediate ARDS risk.ObjectivesTo examine the role of LRRC16A in ARDS survival and its mediating effect through platelets.MethodsA total of 414 cases with ARDS from intensive care units (ICUs) were recruited who had exome-wide genotyping data, detailed platelet counts, and follow-up data during ICU hospitalization. Association of LRRC16A single-nucleotide polymorphisms (SNPs) and ARDS prognosis, and the mediating effect of SNPs through platelet counts were analyzed. LRRC16A mRNA expression levels for 39 cases with ARDS were also evaluated.Measurements And Main ResultsMissense SNP rs9358856G>A within LRRC16A was associated with favorable survival within 28 days (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.38-0.87; P = 0.0084) and 60 days (P = 0.0021) after ICU admission. Patients with ARDS who carried the variant genotype versus the wild-type genotype showed an attenuated platelet count decline (∆PLT) within 28 days (difference of ∆PLT, -27.8; P = 0.025) after ICU admission. Patients with ∆PLT were associated with favorable ARDS outcomes. Mediation analysis indicated that the SNP prognostic effect was mediated through ∆PLT within 28 days (28-day survival: HRIndirect, 0.937; 95% CI, 0.918-0.957; P = 0.0009, 11.53% effects mediated; 60-day survival: HRIndirect, 0.919; 95% CI, 0.901-0.936; P = 0.0001, 14.35% effects mediated). Functional exploration suggested that this SNP reduced LRRC16A expression at ICU admission, which was associated with a lesser ∆PLT during ICU hospitalization.ConclusionsLRRC16A appears to mediate ∆PLT after ICU admission to affect the prognosis in patients with ARDS.

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