Heart Failure Associated with Depleted Intestinal Microbiota

The gut has a worse blood supply in instances of heart failure; the intestinal wall is thicker and more permeable, whereby bacteria and bacterial components may find their way into the blood.

In the gut of patients with heart failure, important groups of bacteria are found less frequently and the gut flora is not as diverse as in healthy individuals. In spite of current medical treatment approaches, mortality of chronic heart failure (HF) remains high and novel treatment modalities are thus urgently needed.

A team of scientists led by those at University Medical Centre Schleswig-Holstein (Kiel, Germany) analyzed the intestinal microbiome of 20 patients with heart failure with reduced ejection fraction due to ischemic or dilated cardiomyopathy and was investigated by applying high-throughput sequencing of the bacterial 16S rRNA gene. Microbial profiles were compared to those of matched controls in which heart failure was ruled out by clinical assessment and N-terminal pro b-type natriuretic peptide (NT-proBNP) serum levels.

The investigators extracted DNA using the QIAcube and the QIAamp DNA stool kit and Variable regions v1-v2 of the 16S rRNA gene were amplified using primers. Polymerase chain reaction (PCR) products were normalized and pooled based on Qubit dsDNA BR Assay Kit measurements and sequenced on an Illumina MiSeq.

The scientists found that HF cases showed a nominally significantly lower diversity index compared to controls, and testing for genera abundance showed a tendency towards a decreased alpha diversity of HF patients. Beta-diversity measures (inter-individual diversity) revealed a highly significant separation of HF cases and controls. Assessing the individual abundance of core measurable microbiota (CMM), a significant decrease of Coriobacteriaceae, Erysipelotrichaceae and Ruminococcaceae was observed on the family level. In line with that, Blautia, Collinsella, and unknown genera that belong to the families Erysipelotrichaceae and Ruminococcaceae showed a significant decrease in HF cases compared to controls on the genus level.

The authors concluded that heart failure patients showed a significantly decreased diversity of the intestinal microbiome as well as a downregulation of key intestinal bacterial groups. The data point to an altered intestinal microbiome as a potential player in the pathogenesis and progression of heart failure. The study was first published on April 21, 2017, in the journal ESC Heart Failure.

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University Medical Centre Schleswig-Holstein