Background—: Obesity and diabetes mellitus are independently associated with the development of heart failure. In this study, we determined the respective effects of obesity, insulin resistance, and diabetes mellitus on the intrinsic contraction and mitochondrial function of the human myocardium before the onset of cardiomyopathy. Methods and Results—: Right atrial myocardium was obtained from 141 consecutive patients presenting no sign of cardiomyopathy. We investigated ex vivo isometric contraction, mitochondrial respiration and calcium retention capacity, and respiratory chain complex activities and oxidative stress status. Diabetes mellitus was associated with a pronounced impairment of intrinsic contraction, mitochondrial dysfunction, and increased myocardial oxidative stress, regardless of weight status. In contrast, obesity was associated with less pronounced contractile dysfunction without any significant perturbation of mitochondrial function or oxidative stress status. Tested as continuous variables, glycated hemoglobin A _1C , but neither body mass index nor the insulin resistance index (homeostasis model assessment–insulin resistance), was independently associated with cardiac mitochondrial function. Furthermore, diabetes mellitus was associated with cardiac mitochondrial network fragmentation and significantly decreased expression of the mitochondrial fusion related protein MFN1. Myocardial MFN1 content was inversely proportional to hemoglobin A _1C . Conclusion—: Worsening of intrinsic myocardial contraction in the transition from obesity to diabetes mellitus is likely related to worsening of cardiac mitochondrial function because impaired mitochondrial function and dynamics and contractile dysfunction are observed in diabetic patients but not in “metabolically healthy” obese patients at early stage in insulin resistance.

Rationale: Underinflation of the tracheal cuff frequently occurs in critically ill patients and represents a risk factor for microaspiration of contaminated oropharyngeal secretions and gastric contents that plays a major role in the pathogenesis of ventilator-associated pneumonia (VAP). Objectives: To determine the impact of continuous control of tracheal cuff pressure (Pcuff) on microaspiration of gastric contents. Methods: Prospective randomized controlled trial performed in a single medical intensive care unit. A total of 122 patients expected to receive mechanical ventilation for at least 48 hours through a tracheal tube were randomized to receive continuous control of Pcuff using a pneumatic device (intervention group, n = 61) or routine care of Pcuff (control group, n = 61). Measurements and Main Results: The primary outcome was microaspiration of gastric contents as defined by the presence of pepsin at a significant level in tracheal secretions collected during the 48 hours after randomization. Secondary outcomes included incidence of VAP, tracheobronchial bacterial concentration, and tracheal ischemic lesions. The pneumatic device was efficient in controlling Pcuff. Pepsin was measured in 1,205 tracheal aspirates. Percentage of patients with abundant microaspiration (18 vs. 46%; P = 0.002; OR [95% confidence interval], 0.25 [0.11–0.59]), bacterial concentration in tracheal aspirates (mean ± SD 1.6 ± 2.4 vs. 3.1 ± 3.7 log10 cfu/ml, P = 0.014), and VAP rate (9.8 vs. 26.2%; P = 0.032; 0.30 [0.11–0.84]) were significantly lower in the intervention group compared with the control group. However, no significant difference was found in tracheal ischemia score between the two groups. Conclusions: Continuous control of Pcuff is associated with significantly decreased microaspiration of gastric contents in critically ill patients.

The glycocalyx constitutes the first line of the blood tissue interface and is thus involved in many physiological processes, deregulation of which may lead to microvascular dysfunction. Because administration of LPS is accompanied by severe microvascular dysfunction, the purpose of the study was to investigate microvascular glycocalyx function during endotoxemia. Bolus infusion of LPS (10 mg kg⁻¹) to male Sprague-Dawley rats elicited the development of hyporeactivity to vasoactive agents and microvascular derangements, including decreased capillary density and significant increases in intermittent and stopped flow capillaries in the small intestine muscularis layer compared with controls. LPS elicited plasma hyluronan release and reduction in endothelial surface thickness, indicative of glycocalyx degradation. Because endothelial glycocalyx is extremely sensitive to free radicals, oxidative stress was evaluated by oxidation of dihydrorhodamine in microvascular beds and levels of heart malondialdehyde and plasma carbonyl proteins, which were all increased in LPS-treated rats. Activated protein C (240 μg kg⁻¹ h⁻¹) enhanced systemic arterial pressure response to norepinephrine in LPS-treated rats. Activated protein C (240 μg kg⁻¹ h⁻¹) prevented capillary perfusion deficit in the septic microvasculature that were associated with reduced oxidative stress and preservation of glycocalyx. Our findings support the conclusion that LPS induces major microcirculation dysfunction accompanied by microvascular oxidative stress and glycocalyx degradation that may be limited by activated protein C treatment.