Long-Term Impact of Diabetes Mellitus on Initially Conservatively Managed Patients With Severe Aortic Stenosis

Immunohistochemical Detection of Bacteria in the Resected Valves was Associated with Stromal Immune Checkpoint Protein Expression that may Contribute to Calcific Aortic Stenosis

Aortic stenosis (AS) is a disease characterized by narrowing of the aortic valve (AV) orifice. The purpose of this study was to clarify the significance of bacterial detection and clinicopathological factors, including valve-infiltrating immune cells and disease severity, in relation to AS. After obtaining the written informed consent form from 50 patients with AS, we performed immunohistochemical analysis of lipopolysaccharide (LPS) for gram-negative bacteria and lipoteichoic acid (LTA) for gram-positive bacteria on surgically resected-AVs. Moreover, we evaluated the relationships among the presence of bacteria, immune checkpoint protein PD-L1 expression, and immune cell infiltrations such as CD8-positive T lymphocytes, CD163-positive macrophages, and FOXP3-positive regulatory T cell (Treg) in resected-aortic valves. LPS detection in the resected-aortic valve tissues was significantly associated with stromal PD-L1 expression, valve calcification, and LTA existence in resected samples. We showed that the presence of LPS was significantly related to high PD-L1 expression only in calcified-AVs, not in non-calcified-AVs. Moreover, the high expression of PD-L1 in AS samples without LPS was significantly associated with positive infiltration of CD163-positive macrophages and FOXP3-positive Tregs. Immunohistochemical bacterial detection in resected-aortic valves was associated with PD-L1 accumulation and valve calcification. PD-L1 significantly accumulated only in calcified valves with LPS existence.

Diabetes mellitus is associated with an increased incidence of aortic valve stenosis

BACKGROUND

The prognosis of patients with diabetes mellitus (DM) is particularly determined by vascular comorbidities. A recent theory implies that DM could also promote aortic valve stenosis (AS). The present study investigates this association in a large collective of outpatients.

METHODS

This retrospective cohort study compared the incidence of AS in patients with an initial diagnosis of type 2 DM and a matched non-DM cohort in 809 general and diabetologist practices in Germany between January 2005 and December 2018. Cox regression models were performed to study the association between type 2 DM and AS incidence.

RESULTS

A total of 78,805 patients with type 2 DM and 78,805 patients without diabetes were analysed. Diabetes patients were more frequently diagnosed with obesity (52% vs 21%). Four percent of patients with and three percent of without diabetes were diagnosed with AS (p < 0.001). Diabetes was significantly associated with an increased incidence of AS (HR: 1.36, p < 0.001). This association was higher in men (HR: 1.41) versus women (HR: 1.30). The strongest association was observed in young patients (18-50 years, HR: 2.35, p < 0.001).

CONCLUSION

In our study, diabetes patients had a higher incidence of aortic stenosis during their disease course.