Infection and smoking are associated with decreased plasma concentration of the anti-Aging protein, -klotho

Objective: The objective of this study was to determine whether maternal plasma concentrations of soluble -klotho are different between women with microbial invasion of the intra-Amniotic cavity (MIAC) and those without MIAC among preterm labor and intact membranes (PTL) or preterm prelabor rupture of membranes (pPROM). Methods : A cross-sectional study was conducted to include women in the following groups: i) PTL with MIAC (n 14); ii) PTL without MIAC (n 79); iii) pPROM with MIAC (n 30); and iv) pPROM without MIAC (n 33). MIAC was defined as a positive amniotic fluid culture for microorganisms (aerobic/anaerobic bacteria or genital mycoplasmas). Amniotic fluid samples were obtained within 48 h of maternal blood collection. Plasma concentration of soluble -klotho was determined by ELISA. Results : i) The median plasma concentration (pg/mL) of soluble -klotho was significantly lower in patients with MIAC than in those without MIAC (787.0 vs. 1117.8; P 0.001). ii) Among patients with PTL, those with MIAC had a lower median plasma concentration (pg/mL) of soluble -klotho than those without MIAC (787.0 vs. 1138.9; P 0.007). iii) Among patients with pPROM, those with MIAC had a lower median plasma concentration (pg/mL) of soluble -klotho than those without MIAC (766.4 vs. 1001.6; P 0.045). iv) There was no significant difference in the median plasma concentration of soluble -klotho between PPROM without MIAC and PTL without MIAC (1001.6 pg/mL vs. 1138.9 pg/mL, respectively; P 0.5). v) After adjustment for potential confounders (maternal age, tobacco use, gestational age at venipuncture), soluble -klotho remained significantly associated with MIAC (P 0.02); and vi) Among patients without MIAC, smoking was significantly associated with a lower median plasma concentration soluble -klotho than in non-smokers (794.2 pg/mL vs. 1382.0 pg/mL, respectively; P 0.001); however, this difference was not observed in patients with MIAC. Conclusions : Intra-Amniotic infection occurring at preterm gestations (regardless of membrane status) was associated with a decrease in maternal plasma concentrations of soluble -klotho. Moreover, among patients without infection, the plasma concentration of -klotho was lower in smokers.