Researchers recreate rat heart

Courtesy University of Minnesota and World Science staff

Re­search­ers re­port that they have ar­ti­fi­cially cre­at­ed a beat­ing rat heart, with help from na­ture.

Through a pro­cess called whole or­gan de­cel­lu­lar­iz­a­tion, Uni­vers­ity of Min­ne­so­ta sci­en­tists said they grew the or­gans by tak­ing dead ani­mal hearts and re-seed­ing them with live cells. The re­sults are de­scribed in the Jan­u­ary 13 on­line is­sue of the re­search jour­nal Na­ture Med­i­cine.

Al­though re-cre­ating hu­man hearts may be years away, the work seems to be a prom­is­ing start, said the prin­ci­pal in­ves­ti­ga­tor, Do­ris Tay­lor of the uni­vers­ity. “The idea would be to de­vel­op trans­plantable blood ves­sels or whole or­gans that are made from your own cells.”

An estimated 550,000 heart failure cases are di­ag­nosed yearly in the Un­ited States, and some 50,000 U.S. pa­tients die an­nu­ally wait­ing for a do­nor heart.

A so­lu­tion may be “de­cel­lu­lar­iz­a­tion,” us­ing na­ture’s plat­form to cre­ate a heart, Tay­lor said. De­cel­lu­lar­iz­a­tion is the pro­cess of re­mov­ing all of the cells from an or­gan—in this case a dead an­i­mal’s heart—leav­ing in­tact the so-called ex­tra­cel­lu­lar ma­trix, the frame­work be­tween cells.

Af­ter re­mov­ing all cells from rat and pig hearts by bath­ing them in de­ter­gents, re­search­ers in­jected the re­main­ing scaf­fold with a mix­ture of pro­gen­i­tor cells from new­born rat hearts. The sci­ent­ists then placed the struc­ture in a ster­ile set­ting to grow. With­in eight days, the re­search­ers said, the hearts were pump­ing, though only at two per­cent strength com­pared to adult hearts. “The cells have many of the mark­ers we as­so­ci­ate with the heart and seem to know how to be­have like heart tis­sue,” Tay­lor said.

“We just took na­ture’s own build­ing blocks to build a new or­gan,” said Har­ald C. Ott, co-in­ves­ti­ga­tor of the stu­dy, who now works at Mas­sa­chu­setts Gen­er­al Hos­pi­tal. “When we saw the first con­trac­tions we were speech­less.”

Re­search­ers said they’re op­ti­mis­tic the dis­cov­ery could help in­crease the do­nor or­gan pool. The supply of do­nor or­gans is lim­it­ed. And once a heart is trans­planted, pa­tients may have to take life­long im­mune-sup­press­ing drugs, of­ten trad­ing heart fail­ure for high blood pres­sure, di­a­be­tes, and kid­ney fail­ure, Tay­lor said.

Scientists hope de­cel­lu­lar­iz­a­tion could be used to make new do­nor or­gans. Be­cause a new heart could be filled with the re­cip­i­en­t’s cells, re­search­ers hy­poth­e­size it’s much less likely to be re­jected by the body, and would be nour­ished, reg­u­lat­ed, and re­gen­er­ated in a na­tur­al way.