Targeting Procalcitonin Protects Vascular Barrier Integrity.

Rationale: Capillary leakage frequently occurs during sepsis and after major surgery and is associated with microvascular dysfunction and adverse outcome. Procalcitonin is a well-established biomarker in inflammation without known impact on vascular integrity. Objectives: We determined how procalcitonin induces endothelial hyperpermeability and how targeting procalcitonin protects vascular barrier integrity. Methods: In a prospective observational clinical study, procalcitonin levels were assessed in 50 patients who underwent cardiac surgery and correlated to postoperative fluid and vasopressor requirements along with sublingual microvascular functionality. Effects of the procalcitonin signaling pathway on endothelial barrier and adherens junctional integrity were characterized in vitro and verified in mice. Inhibition of procalcitonin activation by dipeptidyl-peptidase 4 (DPP4) was evaluated in murine polymicrobial sepsis and clinically verified in cardiac surgery patients chronically taking the DPP4 inhibitor sitagliptin. Measurements and Main Results: Elevated postoperative procalcitonin levels identified patients with 2-fold increased fluid requirements (P < 0.01), 1.8-fold higher vasopressor demand (P < 0.05), and compromised microcirculation (reduction to 63.5 ± 2.8% of perfused vessels, P < 0.05). Procalcitonin induced 1.4-fold endothelial and 2.3-fold pulmonary capillary permeability (both Ps < 0.001) by destabilizing VE-cadherin. Procalcitonin effects were dependent on activation by DPP4, and targeting the procalcitonin receptor or DPP4 during sepsis-induced hyperprocalcitonemia reduced capillary leakage by 54 ± 10.1% and 60.4 ± 6.9% (both Ps < 0.01), respectively. Sitagliptin before cardiac surgery was associated with augmented microcirculation (74.1 ± 1.7% vs. 68.6 ± 1.9% perfused vessels in non-sitagliptin-medicated patients, P < 0.05) and with 2.3-fold decreased fluid (P < 0.05) and 1.8-fold reduced vasopressor demand postoperatively (P < 0.05). Conclusions: Targeting procalcitonin's action on the endothelium is a feasible means to preserve vascular integrity during systemic inflammation associated with hyperprocalcitonemia.

Development of heart failure with preserved ejection fraction in type 2 diabetic mice is ameliorated by preserving vascular function.

AIMS: Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial dysfunction and is frequent in people with type 2 diabetes mellitus. In diabetic patients, increased levels of the eicosanoid 12-hydroxyeicosatetraenoic acid (12-HETE) are linked to vascular dysfunction. Here, we aimed to identify the importance of 12-HETE in type 2 diabetic patients exhibiting diastolic dysfunction, and mice exhibiting HFpEF and whether targeting 12-HETE is a means to ameliorate HFpEF progression by improving vascular function in diabetes. MATERIAL AND METHODS: Subjects with diagnosed type 2 diabetes mellitus and reported diastolic dysfunction or healthy controls were recruited and 12(S)-HETE levels determined by ELISA. 12(S)-HETE levels were determined in type 2 diabetic, leptin receptor deficient mice (LepRdb/db) and HFpEF verified by echocardiography. Mitochondrial function, endothelial function and capillary density were assessed using Seahorse technique, pressure myography and immunohistochemistry in LepRdb/db or non-diabetic littermate controls. 12/15Lo generation was inhibited using ML351 and 12(S)-HETE action by using the V1-cal peptide. KEY FINDINGS: Endothelium-dependent vasodilation and mitochondrial functional capacity both improved in response to either application of ML351 or the V1-cal peptide. Correlating to improved vascular function, mice treated with either pharmacological agent exhibited improved diastolic filling and left ventricular relaxation that correlated with increased myocardial capillary density. SIGNIFICANCE: Our results suggest that 12-HETE may serve as a biomarker indicating endothelial dysfunction and the resulting cardiovascular consequences such as HFpEF in type 2 diabetic patients. Antagonizing 12-HETE is a potent means to causally control HFpEF development and progression in type 2 diabetes by preserving vascular function.