Mitochondrial DNA and survival after sepsis

Mitochondrial DNA and survival after sepsis: a prospective study.

Baudouin SV, Saunders D, Tiangyou W, Elson JL, Poynter J, Pyle A, Keers S, Turnbull DM, Howell N, Chinnery PF.
University Department of Surgical & Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.

BACKGROUND: Human genome evolution has been shaped by infectious disease. Although most genetic studies have focused on the immune system, recovery after sepsis is directly related to physiological reserve that is critically dependent on mitochondrial function. We investigated whether haplogroup H, the most common type of mitochondrial DNA (mtDNA) in Europe, contributes to the subtle genetic variation in survival after sepsis. METHODS: In a prospective study, we included 150 individuals who were sequentially admitted to the intensive care unit in a hospital in Newcastle upon Tyne, UK. After clinical data were obtained, patients underwent mtDNA haplotyping by analysis with PCR and restriction fragment length polymorphism. As endpoints, we used death during the 6-month period or survival at 6 months. FINDINGS: Follow-up was complete for all study participants, although the haplotype of two patients could not be reliably determined. On admission to the intensive care unit, the frequency of mtDNA haplogroup H in study patients did not differ between study patients admitted with severe sepsis and 542 age-matched controls from the northeast of England. MtDNA haplogroup H was a strong independent predictor of outcome during severe sepsis, conferring a 2.12-fold (95% CI 1.02-4.43) increased chance of survival at 180 days compared with individuals without the haplogroup H. INTERPRETATION: Although haplogroup H is the most recent addition to the group of European mtDNA, paradoxically it is also the most common. Increased survival after sepsis provides one explanation for this observation. MtDNA haplotyping offers a new means of risk stratification of patients with severe infections, which suggests new avenues for therapeutic intervention.#

Yet again, mitochondrial DNA seems to have an affect on some aspect of health. Haplogroup H carriers being twice as likely to survive severe sepsis. There is a Chinese study along the same lines..

Mitochondrial DNA haplogroup R predicts survival advantage in severe sepsis in the Han population.

Yang Y, Shou Z, Zhang P, He Q, Xiao H, Xu Y, Li C, Chen J.
Kidney Disease Center, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.

PURPOSE: To determine whether the main mitochondrial DNA (mtDNA) haplogroups of the Han people have an impact on long-term clinical outcome. METHODS: We prospectively studied 181 individuals who were sequentially admitted to the intensive care unit. Demographic and clinical data were recorded along with clinical outcome over 180 days. Follow-up was completed for all study participants. We then determined the mtDNA haplogroups of the patients and 570 healthy, age-matched Han people from Zhejiang province, Southeast China, by analyzing sequences of hypervariable mtDNA segments and testing diagnostic polymorphisms in the mtDNA coding region with DNA probes. RESULT: The frequency of the main subhaplogroups of the Han population in the study cohort did not differ significantly from the control group. mtDNA haplogroup R, one of the three main mtDNA haplogroups of the Han people, was a strong independent predictor for the outcome of severe sepsis, conferring a 4.68-fold (95% CI 1.903-10.844, P = 0.001) increased chance of survival at 180 days compared with those without the haplogroup R. CONCLUSION: In the Han population, mtDNA haplogroup R was a strong independent predictor for the outcome of severe sepsis, conferring an increased chance of long-term survival compared with individuals without the R haplogroup.

Sepsis; AKA blood poisoning or ‘going septic’. Very nasty, with a mortality rate of 20% and up. Something you’d really want a resistance to.

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