Low circulating maternal adiponectin in patients with pyelonephritis: adiponectin at the crossroads of pregnancy and infection

Abstract

Objective: An emerging theme in modern biology is that adipose tissue can respond to metabolic stress, and to inflammatory stimuli, by regulating the secretion of a complex network of soluble mediators, termed adipokines. Adiponectin, the most prevalent circulating adipokine in human, has profound insulin-sensitizing and anti-inflammatory properties. Indeed, the notion that adiponectin plays an important role in the interactions between the metabolic and the immune systems has been strongly suggested. Thus, the aim of this study was to determine if pyelonephritis during pregnancy is associated with changes in maternal serum adiponectin concentrations.

Study design: This cross-sectional study included women in the following groups: 1) normal pregnant women (n=200); and 2) pregnant women with pyelonephritis (n=50). Maternal plasma adiponectin concentrations were determined by ELISA. Non-parametric statistics were used for analyses.

Results: 1) The median maternal plasma adiponectin concentration was lower in patients with pyelonephritis than in those with a normal pregnancy (P<0.001); 2) among pregnant women with a normal weight, patients with pyelonephritis had a lower median plasma adiponectin concentration than those with a normal pregnancy (P<0.001); 3) similarly, among overweight/obese patients, those with pyelonephritis had a lower median plasma adiponectin concentration than those with a normal pregnancy (P<0.001); and 4) the presence of pyelonephritis was independently associated with maternal plasma adiponectin concentrations after adjustment for maternal age, smoking, gestational age at sampling, and pregestational body mass index (BMI).

Conclusion: 1) The findings that acute pyelonephritis in pregnancy is characterized by low maternal plasma concentrations of adiponectin in both lean and overweight/obese patients are novel and concur with the antiinflammatory properties of adiponectin; and 2) the results of this study support the notion that adiponectin may play a role in the intricate interface between inflammation and metabolism during pregnancy.

Figure 1. Comparison of the median maternal plasma adiponectin concentration between women with normal pregnancies and patients with pyelonephritis

The median maternal plasma adiponectin concentration was lower in patients with pyelonephritis than in those with a normal pregnancy (7,223 ng/mL, IQR 5,852-8,962 vs. 10,430 ng/mL, IQR 9,262-12,112; p<0.001).

Figure 2. Comparison of the median maternal plasma adiponectin concentration in normal weight pregnant women with normal pregnancy and patients with pyelonephritis

Among pregnant women with a normal weight, those with pyelonephritis had a lower median plasma adiponectin concentration than women with a normal pregnancy (7,467 ng/mL, IQR 6,649-9,213 vs. 10,610 ng/mL, IQR 9,351-12,255; p<0.001).

Figure 3. Comparison of the median maternal plasma adiponectin concentration in overweight/obese pregnant women with normal pregnancy and patients with pyelonephritis

Among overweight/obese pregnant women, those with pyelonephritis had a lower median plasma adiponectin concentration than women with a normal pregnancy (5,164 ng/mL, IQR 4,805-7,997 vs. 9,981 ng/mL, IQR 8,801-11,850; p<0.001).