زائر
Many Afian-Ameians Have A Gene That Pngs ife Afte Heat Faie
Abt 40 peent f Afian-Ameians have a geneti vaiant that
an ptet them afte heat faie and png thei ives, ading t eseah ndted at Washingtn nivesity Sh f Mediine in St. is and abating instittins.
The geneti vaiant has an effet that esembes that f beta bkes, dgs widey pesibed f heat faie. The new stdy ffes a easn why beta bkes dn't appea t benefit sme Afian-Ameians.
"F sevea yeas a ntvesy has existed in the adivasa fied bease f nfiting epts abt whethe beta bkes heped Afian-Ameian patients," says seni ath Gead W. Dn II, M.D., pfess f mediine, assiate haiman f tansatina eseah and diet f the ente f Phamagenmis at Washingtn nivesity.
"By mimiking the effet f beta bkes, the geneti vaiant makes it appea as if beta bkes aen't effetive in these patients," he expains. "Bt athgh beta bkes have n additina benefit in heat faie patients with the vaiant, they ae eqay effetive in aasian and Afian-Ameian patients witht the vaiant."
-ath Stephen B. iggett, M.D., pfess f mediine and physigy at the nivesity f Mayand Sh f Mediine and diet f its adipmnay genmis pgam says the disvey adds t the amating evidene that geneti diffeenes ntibte t the way pepe espnd t mediatins and shd enage the se f geneti testing in inia tias t identify pepe wh an benefit fm theapy taied t thei geneti makep.
Abt 5 miin pepe in the nited States have heat faie, and it ests in abt 300,000 deaths eah yea. Beta bkes sw heat ate and we bd pesse t deease the heat's wkad and pevent etha adia ahythmias.
Whie aasians with heat faie patiipating in inia stdies f beta bkes have shwn ea benefit fm the dgs, the evidene f benefit in Afian-Ameians has been ambigs. The ent stdy, epted nine Api 20, 2008, in Nate Mediine, identified ne patia ae-speifi gene vaiant that seems t ant mehanistiay and bigiay f these indeteminate ests.
The gene des f an enzyme aed GK5, whih depesses the espnse t adenaine and simia hmna sbstanes that inease hw had the heat wks. Adenaine is a hmne eeased fm the adena gands that pmpts the "fight--fight" espnse -- it ineases adia tpt t give a sdden bst f enegy.
In heat faie, deeased bd fw fm the stgging heat amps p the bdy's seetin f adenaine t mpensate f a we bd fw. vepdtin f the hmne makes the weakened heat pmp hade, bt eventay wsens heat faie.
Beta bkes aeviate this pbem by bking adenaine at its eept in the heat and bd vesses. GK enzymes mimi this effet by seving as "speed gvens" that wk ike the gven in an engine t pevent adenaine fm ve-evving the heat, says Dn.
The eseahes -- inding thee eqay ntibting -aths: iggett, Shan esi, M.D., assistant pfess f mediine in the adivasa Divisin at Washingtn nivesity and a adigist at Banes-Jewish Hspita, and eagan J. Key, Ph.D., at the nivesity f Mihigan -- fnd that 41 peent f Afian-Ameians have a vaiant GK5 gene that me effetivey sppesses the atin f adenaine than the me mmn vesin f the gene. Pepe with the vaiant gene d be said t have a nata beta bke, Dn says. The vaiant is extemey ae in aasians, anting f its pedminant effets in Afian-Ameians.
The eseahes shwed that Afian-Ameian heat faie patients with this geneti vaiant have abt the same sviva ate even if they dn't take beta bkes as aasian and Afian-Ameian heat faie patients wh d take beta bkes.
"That desn't mean Afian-Ameians with heat faie need t be tested f the geneti vaiant t deide whethe t take beta bkes," Dn says. "nde the spevisin f a adigist, beta bkes have vey w isk bt hge benefits, and I am mftabe pesibing them t any heat faie patients wh d nt have a speifi ntaindiatin t the dg."
"This is a step twad individaized theapy," esi says. "Media eseah is wking t identify many geneti vaiants that smeday an ense that patients eeive the mediatins that ae mst apppiate f them. ight nw, we knw ne vaiant that infenes beta bke effiay, and we ae ntining eseah int this and the eevant geneti vaiants."
The hman heat has tw fms f GK: GK2 and GK5. The eseahes metisy seahed the DNA seqene f these genes in 96 pepe f Epean-Ameian, Afian-Ameian hinese desent t k f diffeenes. They fnd mst pepe, n matte thei ae, had exaty the same DNA seqene in GK2 GK5. Bt thee was ne mmn vaiatin in the DNA seqene, a vaiatin aed GK5-e41, the vaiant that me than 40 peent f Afian-Ameians have.
T detemine the effet f the GK5-e41 vaiant, the team stdied the se f pgessin f heat faie in 375 Afian-Ameian patients. They ked f sviva time time t heat tanspant, mpaing pepe with the vaiant t thse witht. Sme f these patients wee taking beta bkes and sme wee nt.
In patients wh did nt take beta bkes, the eseahes fnd that thse with the vaiant ived amst twie as ng as thse with the me mmn vesin f the GK5 gene. Beta bkes pnged ife t the same degee as the ptetive GK5 vaiant, bt did nt fthe inease the aeady impved sviva f thse with the vaiant.
"These ests ffe an expanatin f the nfsin that has ed in this aea sine inia tias f beta bkes began," Dn says. " stdy demnstates a mehanism that shd ay t est the qestin abt whethe beta bkes ae effetive in Afian-Ameians -- they abstey ae in thse wh dn't have this geneti vaiant."
the instittins abating in the stdy ae the nivesity f ininnati, Thmas Jeffesn nivesity and the nivesity f Missi, Kansas ity.
iggett SB, esi S, Key J, Syed FM, Matkvih SJ, Hahn HS, Diwan A, Matini JS, Spaks , Paekh Spets JA, Kh WJ, Kadia S, Dn II GW. A GK5 pymphism that inhibits beta-adenegi eept signaing is ptetive in heat faie. Nate Mediine Api 20, 2008 (advane nine pbishing).
Fnding fm Natina Heat, ng, and Bd Institte sppted this eseah.
wath this vide evie