Ageing‐associated large‐scale deletions of mitochondrial DNA in human hair follicles

Abstract

Hair follicles plucked from the bi-temporal region of the scalp of 433 Chinese subjects of different ages were used for the examination of ageing-associated mutations of human mitochondrial DNA (mtDNA). By use of PCR techniques, we detected the 4,977 bp and 7,436 bp deletions ofmtDNA in hair follicles from aged individuals. The frequencies of occurrence of both mtDNA deletions were found to increase with age of the subject. Moreover, we employed a semi-quantitative PCR method to determine the proportion of the 4,977 bp deleted mtDNA (dmtDNA) in hair follicles. The results showed that the average proportion of the 4,977 bp dmtDNA in hair follicles were 0.05%+0.01%, 0.00%, 0.55%+0.05%, 0.52%_+0.24%, 0.65%+0.17%, 1.33%_+0.25%, and 1.89%+0.81% for the subjects in the age groups of 21-30, 31-40, 41-50, 51-60, 61-70, 71-80, and 81-99, respectively. Furthermore, we screened all the subjects harboring the 4,977 bp and/or 7,436 bp deletions for tandem duplications in the D-loop region ofmtDNA by PCR with back-to-back primers. The results showed that none of the previously reported tandem duplications were present in all the hair follicles examined. This indicates that tandem duplications do not predispose to large-scale

Towards a “free radical theory of graying”: melanocyte apoptosis in the aging human hair follicle is an indicator of oxidative stress induced tissue damage

“…Accordingly, premature graying was named as a risk factor and indicator in age-and increased oxidative stressrelated diseases such as coronary heart disease (59) or osteoporosis (60,61). Moreover, the common deletion was determined in hair follicles to monitor aging (62) and end-stage renal disease (63). However, these later studies failed to determine hair follicle pigmentation status in the follicles used for their study.…”

The Effects of Aging and Smoking on the Deletions of Mitochondrial DNA in Turkish Population

“…17,27 Ça lış ma mız da saç ör nek le ri, bi rey ler den in vaziv ol ma yan yön tem le ko lay lık la top la na bil di ğin -den ve tok sik mad de ler le kro nik ma ru zi yet so nu cun da or ta ya çı ka cak ge no tok sik ha sar lar için iyi bir gös ter ge ola rak ka bul edi le bi le ce ğin den dola yı ör nek ola rak se çil miş tir. 22 MtDNA de les yon ları nın be lir len me si ve or ga niz ma ya ve re bi le ce ği hasar lar ile iliş ki si nin araş tı rıl ma sın da, de les yon bi riki mi nin az ol du ğu ka ra ci ğer ve kan gi bi ye ni len me hı zı faz la olan hüc re ler ye ri ne, de les yon la rın bi rikim gös ter di ği saç, be yin ve is ke let ka sı gi bi çok az ye ni le nen ve ya hiç ye ni len me yen do ku lar kul lanıl mak ta dır. Bi rey le rin saç fo li kül ör nek le rin de mtDNA de les yon la rı ve yaş lan ma ara sın da ki ko relas yon be lir le nir ken, ay nı bi rey ler den alı nan kan ör nek le rin de bu de les yon la ra rast lan ma mış tır.…”

“…Ay rı ca bu deles yon la rın yük sek oran lar da ol ma sı, si ga ra kul la nı mı na bağ lı kan ser le rin de gös ter ge si ola rak dü şü nül mek te dir. [21][22][23] Si ga ra du ma nı, po li sik lik aroma tik hid ro kar bon lar ve nit ro za min ler gi bi bir çok mu ta jen ler le ve ser best ra di kal ler de da hil ol mak üze re di ğer bi le şik ler le ko lay lık la re ak si yo na gi rebi len 3800'den faz la bi le şik ta şı yan komp leks bir ka rı şım dır. 24 Si ga ra du ma nın da ki kat ran, ki non-semi ki non-hid ro ki non (Q/Q -/QH2) komp lek si ta şı -mak ta dır 25 ve bu komp leks, mo le kü ler ok si je ni sü pe rok si de, hid ro jen pe rok si di de hid rok si ra di kali ne çe vir mek te dir.…”

Alterations of plasma antioxidants and mitochondrial DNA mutation in hair follicles of smokers

“…In addition, the relative proportion of mtDNA with the 4,977 bp deletion in somatic tissues increases exponentially during the aging process [Lee et al, 1994;Kao et al, 1997]. A high incidence of the 4,977 bp deleted mtDNA (dmtDNA) in hair follicles is not only associated with aging, but is also correlated with oxidative stress elicited by cigarette smok-ing and uremia Liu et al, 2001].…”