Effect of Probiotic Supplementation on Endothelial Function II

Recently, a direct link between intestinal microbiota, dietary phosphatidylcholine, and
promotion of cardiovascular disease has been elegantly demonstrated. In this study, broad
spectrum antibiotics were employed to disrupt the intestinal microbiota, and metabolomic
analysis identified 3 metabolites of phosphatidylcholine, including TMAO, linked to
atherosclerosis. However, the impact of intestinal dysbiosis on the heart and its
susceptibility to injury from ischemia/reperfusion has not been known until now.

Novel work has demonstrated a mechanistic link between changes in the intestinal microbiota
and severity of myocardial infarction. Treatment of Dahl S rats with the commercially
available probiotic bacterium Lactobacillus plantarum 299v, and a non-absorbed antibiotic
vancomycin to alter abundance of multiple microbiota reduced circulating leptin levels,
reduced myocardial infarct size, and improved recovery of post-ischemic mechanical function.
Pretreatment with leptin abolished cardioprotection by the probiotic and the antibiotic.

These findings also show the reach of the intestinal microbiota extends far beyond local
effects to remote organ systems such as the heart and provide support for the metabolomic
studies to be conducted in Specific Aim 2. The prior discovery of a relationship between
intestinal microbiota, their metabolites and myocardial infarction provides opportunities for
novel therapeutic approaches (probiotics, non-absorbable antibiotics and/or microbial
metabolites) for the treatment and prevention of cardiovascular disease.

Prior studies indicate an important role of leptin in signaling between the intestinal
microbiota and the heart. Supplementation of the diet with active cultures of Lactobacillus
plantarum 299v leads to significant reductions in fibrinogen and LDL-cholesterol, and leptin
concentrations in smokers. These clinical studies demonstrate that a probiotic is capable of
decreasing risk factors for cardiovascular disease. Note that neither leptin nor TMAO levels,
per se, are recognized cardiovascular risk factor. This is currently an area with enormous
potential for gaining new mechanistic insight and may lead to a therapeutic product or
clinical use.

Impaired endothelial function is recognized as an early and modulating process in the
pathogenesis of atherosclerotic cardiovascular disease. Endothelial function is easily
measurable by non-invasive means and endothelial dysfunction measured non-invasively
independently predicts future cardiovascular risk in patients both with and without
clinically apparent cardiovascular disease. Conduit vessel endothelial function in humans is
commonly quantified by measurement of flow-mediated dilation (FMD) in the brachial artery,
which represents the endothelium-dependent relaxation of a conduit artery - typically the
brachial artery - due to an increased blood flow. FMD correlates with impaired
endothelium-dependent relaxation in the coronary arteries and is a commonly recognized
"barometer" of cardiovascular risk. Taken together, these data suggest brachial FMD is an
ideal surrogate marker of cardiovascular risk to monitor the effects of Lactobacillus
plantarum 299v as proposed in this work.

Inclusion Criteria:

- Age between 40-75 years old

- History of known coronary artery disease (by either history of myocardial infarction,
angiogram demonstrative >=50% stenosis in at least 1 major epicardial coronary artery,
or a previous stress test that showed evidence of ischemia that has not been revealed
to be a false positive test by angiography)

Exclusion Criteria:

- Unstable angina or myocardial infarction by history, ECG, and/or enzymatic criteria
within 1 month of enrollment.

- LV dysfunction as defined by an LV ejection fraction documented as < 45% within 1 year
of enrollment by an echocardiogram, MRI, or nuclear imaging.

- Uncontrolled hypertension with a blood pressure greater than 170/100 mmHg at the
screening visit.

- Known history of chronic renal insufficiency, liver dysfunction, or cancer besides
non-melanoma skin carcinomas or localized prostate cancer requiring systemic treatment
within five years of enrollment.

- Known history of cognitive impairment or inability to follow study procedures

- Patient with an implanted defibrillator or permanent pacemaker on which the potential
participant is known to rely upon for greater than 50% of ventricular depolarizations.

- Patients who received probiotics, prebiotics, and antibiotics in the last 12 weeks.

- Patients with dosing changes of vasoactive medications and HMG-CoA reductase
inhibitors in the 6 weeks prior to enrollment.

- Pregnancy