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Measuring Single-Cell Mitochondrial DNA Copy Number and Heteroplasmy Using Digital Droplet Polymerase Chain Reaction
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The role of mitochondrial DNA copy number in cardiometabolic disease: a bidirectional two-sample mendelian

Pei Qin1, Tianhang Qin2, Lei Liang3

  • 1Department of General Practice, The Affiliated Luohu Hospital of Shenzhen University, No. 47, Youti Road, Shenzhen, 518001, Guangdong, China.

Cardiovascular Diabetology
|January 28, 2024
PubMed

Insights

Mitochondrial DNA (mtDNA) copy number does not causally influence cardiometabolic diseases. However, dyslipidemia and coronary artery disease (CAD) may lead to reduced mtDNA copy number, suggesting its potential as a biomarker.

Area of Science:

  • Genetics
  • Cardiology
  • Metabolic Health

Background:

  • Mitochondrial DNA (mtDNA) copy number is implicated in cellular energy production.
  • Cardiometabolic diseases encompass a range of conditions including obesity, diabetes, and cardiovascular disorders.
  • The causal relationship between mtDNA copy number and cardiometabolic diseases remains unclear.

Purpose of the Study:

  • To investigate the potential causal effect of mtDNA copy number on cardiometabolic diseases using a bidirectional Mendelian randomization approach.
  • To explore the reverse causation, examining if cardiometabolic diseases influence mtDNA copy number.

Main Methods:

  • A bidirectional 2-sample Mendelian randomization study was employed.
  • Genome-wide association study (GWAS) summary statistics from UK Biobank (n=395,718) were utilized for genetic instruments.
  • Inverse variance weighting (IVW) was the primary analysis, with MR-Egger, weighted median, and MR-PRESSO as sensitivity analyses.

Main Results:

  • Genetically predicted mtDNA copy number showed no significant causal association with obesity, hypertension, dyslipidemia, type 2 diabetes (T2DM), coronary artery disease (CAD), stroke, ischemic stroke, or heart failure.
  • In reverse analyses, genetically predicted dyslipidemia was significantly associated with decreased mtDNA copy number (P=2.416e-14).
  • Suggestive evidence indicated a potential causal association between CAD and reduced mtDNA copy number (P=0.025).

Conclusions:

  • This study does not support a causal role for mtDNA copy number in the development of cardiometabolic diseases.
  • Dyslipidemia and CAD may causally lead to a reduction in mtDNA copy number.
  • mtDNA copy number may serve as a potential biomarker for dyslipidemia and CAD.
Abstract

Keywords:
BidirectionalCardiometabolic diseaseMitochondrial DNA copy numberTwo-sample mendelian randomization study

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