Phenotype-Associated Renal and Systemic Patterns During Short-Term Reduced-Tidal-Volume Mechanical Ventilation in Obese and Endotoxemic Rats: An Exploratory Study.

Background: Mechanical ventilation (MV) may be associated with extrapulmonary responses shaped by the host inflammatory-metabolic background. Methods: This exploratory study characterized renal changes during 1 h of reduced-tidal-volume mechanical ventilation in male Wistar rats with diet-induced obesity or lipopolysaccharide (LPS)-induced endotoxemia, together with concurrent respiratory, acid-base, metabolic, and hemodynamic alterations. Arterial blood gas, biochemical, hemodynamic, and urinary variables were assessed at the pre-MV and post-MV time points. Renal protein expression was evaluated only at the post-MV time point. Results: The arterial partial pressure of carbon dioxide (PaCO2) decreased significantly in both groups. In the Obese group, metabolic acid-base abnormalities persisted and were accompanied by increases in serum urea and the urinary protein-to-creatinine ratio. In the LPS group, lactate increased, bicarbonate decreased, and mean arterial pressure and serum creatinine increased. At the post-MV time point, renal interleukin-6 expression was lower in the LPS group than in the Obese group, whereas renal tumor necrosis factor-alpha expression was higher in the LPS group than in the Obese group. Conclusions: These results support interpreting the physiological and renal changes observed in association with the integrated experimental protocol, including mechanical ventilation, in relation to the host's underlying pathophysiology and inflammatory-metabolic context.