Hypoglycemia and the predisposition to cardiovascular disease: Is the pro-inflammatory-pro-coagulant diathesis a plausible explanation?

Oral Porphyromonas gingivalis infection affects intestinal microbiota and promotes atherosclerosis

AIM

The link between periodontitis and intestinal dysbiosis, two factors that contribute to atherosclerosis, has not been clearly defined. We investigated the integrative effects of oral infection with Porphyromonas gingivalis (PG), the major pathogen for periodontitis, on intestinal microbiota and atherosclerosis.

MATERIALS AND METHODS

ApoE-/- mice were fed a normal chow diet (NC), a Western diet (WD) or a WD with oral PG infection (PG). The PG infection was investigated by placing a total of 109 CFUs of live PG into the oral cavity of each mouse using a feeding needle five times a week for 3 weeks. Atherosclerotic lesions of the aortae were measured, and blood lipoproteins and the expression of molecules related to lipid metabolism in the liver were analysed. We also performed 16S RNA sequencing and a microbiome analysis using faeces.

RESULTS

En face bloc preparation of the aortae showed that the PG group had a 1.7-fold increase in atherosclerotic lesions compared with the WD group (p < .01). Serum analyses showed that oral PG infection induced a significant decrease in high-density lipoprotein (HDL) and triglyceride. Western blots of hepatic tissue lysates revealed that PG infection reduced the expression of scavenger receptor class B type 1 (SR-B1) in the liver by 50%. Faecal microbiota analysis revealed that species richness estimates (Chao1, ACE) decreased immediately after PG infection. PG infection also induced a significant decrease in Shannon diversity and an increase in Simpson's indices in the WD-fed mice. PG infection significantly increased the phyla Actinobacteria and Deferribacteres, along with the species Mucispirillum schaedleri and Lactobacillus gasseri, in the mice. The functional study showed that PG infection increased the expression of proteins that function in carbohydrate and glucose metabolism, including phosphotransferase system (PTS) proteins and the GntR family transcriptional regulator.

CONCLUSIONS

Oral PG infection promotes atherosclerosis and induces significant metabolic changes, including reduced serum HDL and reduced hepatic SR-B1 and ABCA1 expression, as well as changes in intestinal microbiota. Our study suggests that intestinal dysbiosis accompanies periodontitis and could play a role in atherosclerosis.

Atherosclerosis Risk Factors in Patients with Reactive Hypoglycemia

PURPOSE

Glucose metabolism disorders are an established risk factor for atherosclerosis. Although reactive hypoglycemia (RH) can be classified as one of these disorders, its role as a potential atherosclerosis risk factor remains unclear. The aim of the study was to assess whether patients with RH have a higher risk of atherosclerosis.

PATIENTS AND METHODS

We recruited 178 patients (N=178) with suspected RH who were hospitalized after 2014 and underwent a prolonged 5-hour oral glucose tolerance test. The study cohort was divided into 2 groups depending on the results of the oral glucose tolerance test: Group 1 - subjects without RH (n=44), Group 2 -subjects with RH (n=134).

RESULTS

The analyzed groups differed significantly in terms of the following risk factors for atherosclerosis: high-density lipoprotein (HDL) cholesterol levels (54.3±18.8 mg/dL vs 63±18.5 mg/dL, p=0.003) and atherogenic indices (Castelli I: 3.7±1.2 vs 3.1±1.3, p=0.004; Castelli II: 2.1±0.9 vs 1.7±0.9, p=0.007; the atherogenic index of plasma: 0.34±0.33 vs 0.18±0.3, p=0.006; and the atherogenic coefficient: 2.7±1.2 vs 2.1±1.3, p=0.004). Univariate logistic regression showed that RH should not be considered to be a predictor of an increased atherogenic index of plasma (odds ratio [OR]=0.3 [95% confidence interval [CI] [0.16-0.7], p=0.002). Multivariate logistic regression revealed triglyceride levels (OR 1.14 [1.07-1.2], p=0.001) and body weight (OR 1.07 [1.03-1.12], p=0.002) to be independent risk factors for atherosclerosis.

CONCLUSION

Atherosclerosis risk factors are no more prevalent in patients with RH. RH does not increase the risk of an abnormal atherogenic index of plasma.

Hypoglycemia, Cardiovascular Outcomes, and Death: The LEADER Experience

OBJECTIVE

In the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) cardiovascular (CV) outcomes trial (NCT01179048), liraglutide significantly reduced the risk of CV events (by 13%) and hypoglycemia versus placebo. This post hoc analysis examines the associations between hypoglycemia and CV outcomes and death.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes and high risk for CV disease (n = 9,340) were randomized 1:1 to liraglutide or placebo, both in addition to standard treatment, and followed for 3.5-5 years. The primary end point was time to first major adverse cardiovascular event (MACE) (1,302 first events recorded), and secondary end points included incidence of hypoglycemia. We used Cox regression to analyze time to first MACE, CV death, non-CV death, or all-cause death with hypoglycemia as a factor or time-dependent covariate.

RESULTS

A total of 267 patients experienced severe hypoglycemia (liraglutide n = 114, placebo n = 153; rate ratio 0.69; 95% CI 0.51, 0.93). These patients had longer diabetes duration, higher incidence of heart failure and kidney disease, and used insulin more frequently at baseline than those without severe hypoglycemia. In combined analysis (liraglutide and placebo), patients with severe hypoglycemia were more likely to experience MACE, CV death, and all-cause death, with higher risk shortly after hypoglycemia. The impact of liraglutide on risk of MACE was similar in patients with and without severe hypoglycemia (P-interaction = 0.90).

CONCLUSIONS

Patients experiencing severe hypoglycemia were at greater risk of CV events and death, particularly shortly after the hypoglycemic episode. While causality remains unclear, reducing hypoglycemia remains an important goal in diabetes management.

The Association of Severe Hypoglycemia With Incident Cardiovascular Events and Mortality in Adults With Type 2 Diabetes

OBJECTIVE

There is suggestive evidence linking hypoglycemia with cardiovascular disease, but few data have been collected in a community-based setting. Information is lacking on individual cardiovascular outcomes and cause-specific mortality.

RESEARCH DESIGN AND METHODS

We conducted a prospective cohort analysis of 1,209 participants with diagnosed diabetes from the Atherosclerosis Risk in Communities (ARIC) study (analytic baseline, 1996-1998). Severe hypoglycemic episodes were identified using first position ICD-9 codes from hospitalizations, emergency department visits, and ambulance calls through 2013. Cardiovascular events and deaths were captured through 2013. We used adjusted Cox regression models with hypoglycemia as a time-varying exposure.

RESULTS

There were 195 participants with at least one severe hypoglycemic episode during a median fellow-up of 15.3 years. After severe hypoglycemia, the 3-year cumulative incidence of coronary heart disease was 10.8% and of mortality was 28.3%. After adjustment, severe hypoglycemia was associated with coronary heart disease (hazard ratio [HR] 2.02, 95% CI 1.27-3.20), all-cause mortality (HR 1.73, 95% CI 1.38-2.17), cardiovascular mortality (HR 1.64, 95% CI 1.15-2.34), and cancer mortality (HR 2.49, 95% CI 1.46-4.24). Hypoglycemia was not associated with stroke, heart failure, atrial fibrillation, or noncardiovascular and noncancer death. Results were robust within subgroups defined by age, sex, race, diabetes duration, and baseline cardiovascular risk.

CONCLUSIONS

Severe hypoglycemia is clearly indicative of declining health and is a potent marker of high absolute risk of cardiovascular events and mortality.