St\u00e1rnut\u00ed pat\u0159\u00ed mezi p\u0159irozen\u00e9 procesy, kter\u00e9 oded\u00e1vna fascinovaly lidstvo. M\u00edsto hled\u00e1n\u00ed z\u00e1zra\u010dn\u00fdch recept\u016f na nesmrtelnost se modern\u00ed v\u011bda sna\u017e\u00ed odhalit a popsat mechanizmy st\u00e1rnut\u00ed, a posunout tak hranice jeho pochopen\u00ed.<\/p>\n
Na d\u00e9lku \u017eivota m\u00e1 vliv velk\u00e9 mno\u017estv\u00ed faktor\u016f. Kter\u00e9 z\u00a0nich jsou kl\u00ed\u010dov\u00e9 je st\u00e1le nejasn\u00e9. P\u0159\u00edsp\u011bvkem do v\u011bdeck\u00e9 diskuze na toto t\u00e9ma se stal ned\u00e1vno publikovan\u00fd \u010dl\u00e1nek autor\u016f L\u00f3pez et al. (2023), kter\u00fd p\u0159edkl\u00e1d\u00e1 revidovan\u00fd souhrn p\u0159\u00ed\u010din st\u00e1rnut\u00ed.<\/p>\n
V\u011bdci se shoduj\u00ed, \u017ee d\u016fle\u017eit\u00fdm mechanismem st\u00e1rnut\u00ed je po\u0161kozen\u00ed DNA. P\u0159\u00ed\u010din je n\u011bkolik. M\u016f\u017ee b\u00fdt zp\u016fsobeno r\u016fzn\u00fdmi chemick\u00fdmi l\u00e1tkami, z\u00e1\u0159en\u00edm nebo kysl\u00edkov\u00fdmi radik\u00e1ly, kter\u00e9 se tvo\u0159\u00ed uvnit\u0159 organizmu. Lidsk\u00e9 t\u011blo si dok\u00e1\u017ee s\u00a0po\u0161kozenou DNA do ur\u010dit\u00e9 m\u00edry poradit a opravit ji; tato schopnost ale s\u00a0v\u011bkem kles\u00e1. Jinou p\u0159\u00ed\u010dinou je zkracov\u00e1n\u00ed telomer \u2013 konc\u016f DNA. P\u0159i ka\u017ed\u00e9 replikaci DNA, p\u0159i vzniku nov\u00fdch bun\u011bk, doch\u00e1z\u00ed ke ztr\u00e1t\u011b konc\u016f DNA. Kdy\u017e se telomery zkr\u00e1t\u00ed pod ur\u010ditou mez, bu\u0148ka p\u0159est\u00e1v\u00e1 b\u00fdt \u017eivotaschopn\u00e1 a u\u017e se d\u00e1l nem\u016f\u017ee d\u011blit. K\u00a0dal\u0161\u00edm p\u0159\u00ed\u010din\u00e1m po\u0161kozen\u00ed DNA, souvisej\u00edc\u00edm se st\u00e1rnut\u00edm, pat\u0159\u00ed zm\u011bna epigenetick\u00e9ho zna\u010den\u00ed. DNA je pokryta r\u016fzn\u00fdmi chemick\u00fdmi epigenetick\u00fdmi \u201ezna\u010dkami\u201c, kter\u00e9 se, podobn\u011b jako samotn\u00e1 genetick\u00e1 informace, d\u011bd\u00ed od rodi\u010d\u016f. Epigenetika m\u00e1 stejn\u011b jako genetika vliv na fungov\u00e1n\u00ed organizmu. Ka\u017ed\u00fdm d\u011blen\u00edm bun\u011bk v\u00a0lidsk\u00e9m t\u011ble doch\u00e1z\u00ed ke ztr\u00e1t\u011b \u010d\u00e1sti epigenetick\u00fdch zna\u010dek, a t\u00edm \u010dlov\u011bk st\u00e1rne.<\/p>\n
Dal\u0161\u00edm mechanizmem st\u00e1rnut\u00ed je po\u0161kozen\u00ed bun\u011bk. K\u00a0tomu doch\u00e1z\u00ed bu\u010f v\u00fd\u0161e popsan\u00fdm po\u0161kozen\u00edm DNA nebo po\u0161kozen\u00edm organel a strukturn\u00edch protein\u016f. Ve v\u0161ech bu\u0148k\u00e1ch se vyskytuje mal\u00e1 \u010d\u00e1st tzv. chybn\u011b poskl\u00e1dan\u00fdch protein\u016f. V\u00a0mlad\u00fdch,\u00a0zdrav\u00fdch bu\u0148k\u00e1ch jsou tyto proteiny rychle odkl\u00edzeny. Schopnost likvidace po\u0161kozen\u00fdch protein\u016f se ale s\u00a0v\u011bkem zhor\u0161uje. Jejich hromad\u011bn\u00ed v\u00a0bu\u0148k\u00e1ch je charakteristick\u00e9 pro nemoci souvisej\u00edc\u00ed se st\u00e1rnut\u00edm jako je Alzheimerova nebo Parkinsonova nemoc.<\/p>\n
Proces st\u00e1rnut\u00ed bun\u011bk v\u00fdznamn\u011b ovliv\u0148uje stav mitochondri\u00ed, d\u016fle\u017eit\u00fdch organel produkuj\u00edc\u00edch energii pro fungov\u00e1n\u00ed bun\u011bk. P\u0159i tvorb\u011b energie v mitochondri\u00edch vznikaj\u00ed toxick\u00e9 vedlej\u0161\u00ed produkty. Nejnebezpe\u010dn\u011bj\u0161\u00ed jsou voln\u00e9 kysl\u00edkov\u00e9 radik\u00e1ly. Ty po\u0161kozuj\u00ed samotn\u00e9 mitochondrie, ostatn\u00ed bun\u011b\u010dn\u00e9 organely a tak\u00e9 DNA. Sou\u010dasn\u011b s hromad\u011bn\u00edm toxin\u016f a po\u0161kozen\u00fdch organel ve\u00a0st\u00e1rnouc\u00edch bu\u0148k\u00e1ch z\u00e1rove\u0148 kles\u00e1 schopnost likvidace tohoto odpadu makrof\u00e1gy, \u010d\u00edm\u017e se hromad\u011bn\u00ed \u0161kodlivin akceleruje.<\/p>\n
Kdy\u017e se v\u00a0bu\u0148ce hromad\u00ed po\u0161kozen\u00e9 proteiny, aktivuje se proces senescence. Bu\u0148ka se p\u0159est\u00e1v\u00e1 d\u011blit, aby toto po\u0161kozen\u00ed d\u00e1le nep\u0159en\u00e1\u0161ela. Vznik\u00e1 tedy m\u00e9n\u011b nov\u00fdch bun\u011bk, co\u017e v\u00a0d\u016fsledku vede ke st\u00e1rnut\u00ed organizmu. Pokud nedojde k\u00a0senescenci po\u0161kozen\u00fdch bun\u011bk a ty se nad\u00e1le d\u011bl\u00ed, vznikne rakovina. Proto je senescence d\u016fle\u017eit\u00fd mechanizmus. I kdy\u017e vede ke\u00a0st\u00e1rnut\u00ed, slou\u017e\u00ed t\u011blu jako ochrana p\u0159ed rakovinn\u00fdmi procesy.<\/p>\n
Dal\u0161\u00edm mechanismem st\u00e1rnut\u00ed jsou zm\u011bny na \u00farovni\u00a0bun\u011b\u010dn\u00e9 v\u00fd\u017eivy, kdy s\u00a0v\u011bkem kles\u00e1 schopnost bun\u011bk p\u0159\u00edj\u00edmat a zpracov\u00e1vat \u017eiviny. To vede u star\u0161\u00edch lid\u00ed k\u00a0p\u0159ej\u00edd\u00e1n\u00ed nebo naopak k v\u00fdrazn\u011b sn\u00ed\u017een\u00e9 chuti k\u00a0j\u00eddlu. V\u011bdci nyn\u00ed p\u0159ipou\u0161t\u011bj\u00ed, \u017ee kalorick\u00e1 restrikce v\u00a0ml\u00e1d\u00ed m\u016f\u017ee b\u00fdt jedn\u00edm z\u00a0\u017eivot prodlu\u017euj\u00edc\u00edch faktor\u016f.<\/p>\n
P\u0159\u00ed\u010dinn\u00fdm faktorem st\u00e1rnut\u00ed je tak\u00e9 z\u00e1n\u011bt. S\u00a0v\u011bkem se v\u00a0krvi zvy\u0161uje mno\u017estv\u00ed z\u00e1n\u011btliv\u00fdch molekul. Chronick\u00fd z\u00e1n\u011bt je p\u0159\u00edznakem mnoha onemocn\u011bn\u00ed vyskytuj\u00edc\u00edch se ve vy\u0161\u0161\u00edm v\u011bku, jako je artr\u00f3za, ateroskler\u00f3za nebo onemocn\u011bni meziobratlov\u00fdch plot\u00e9nek.<\/p>\n
Nov\u011b zkoumanou p\u0159\u00ed\u010dinou st\u00e1rnut\u00ed jsou zm\u011bny ve st\u0159evn\u00edm\u00a0mikrobiomu. S\u00a0v\u011bkem se sni\u017euje diverzita mikrobioty a zvy\u0161uje se mno\u017estv\u00ed patogenn\u00edch bakteri\u00ed na \u00fakor zdrav\u00ed prosp\u011b\u0161n\u00fdch. Tyto negativn\u00ed zm\u011bny ve slo\u017een\u00ed mikrobioty se pod\u00edlej\u00ed na st\u00e1rnut\u00ed mimo jin\u00e9 podporou\u00a0rozvoje z\u00e1n\u011btliv\u00fdch st\u0159evn\u00edch onemocn\u011bn\u00ed \u010di syndromu propustn\u00e9ho st\u0159eva.<\/p>\n
Mgr. Lenka Gmiterkov\u00e1<\/p>\n
8.3.2023<\/p>\n
<\/p>\n
Zdroj:<\/p>\n
L\u00f3pez-Ot\u00edn C, Blasco MA, Partridge L, Serrano M, Kroemer G. (2023): Hallmarks of aging: An expanding universe. Cell, 186, 243-278.<\/p>\n","protected":false},"excerpt":{"rendered":"
St\u00e1rnut\u00ed pat\u0159\u00ed mezi p\u0159irozen\u00e9 procesy, kter\u00e9 oded\u00e1vna fascinovaly lidstvo. M\u00edsto hled\u00e1n\u00ed z\u00e1zra\u010dn\u00fdch recept\u016f na nesmrtelnost […]<\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"image","meta":{"_uag_custom_page_level_css":""},"categories":[1],"tags":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"boldthemes_grid":false,"boldthemes_grid_11":false,"boldthemes_grid_22":false,"boldthemes_grid_21":false,"boldthemes_grid_12":false,"boldthemes_latest_posts":false,"boldthemes_grid_gallery":false},"uagb_author_info":{"display_name":"Ane\u017eka Klubalov\u00e1","author_link":"https:\/\/www.mc-praha.cz\/mcp\/author\/aklubalova\/"},"uagb_comment_info":0,"uagb_excerpt":"St\u00e1rnut\u00ed pat\u0159\u00ed mezi p\u0159irozen\u00e9 procesy, kter\u00e9 oded\u00e1vna fascinovaly lidstvo. M\u00edsto hled\u00e1n\u00ed z\u00e1zra\u010dn\u00fdch recept\u016f na nesmrtelnost […]","post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/posts\/4304"}],"collection":[{"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/comments?post=4304"}],"version-history":[{"count":1,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/posts\/4304\/revisions"}],"predecessor-version":[{"id":4306,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/posts\/4304\/revisions\/4306"}],"wp:attachment":[{"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/media?parent=4304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/categories?post=4304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mc-praha.cz\/mcp\/wp-json\/wp\/v2\/tags?post=4304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}