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Researchers rejuvenate aging mice with stem cell genes

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Required fields are indicated by an asterisk (*) Email Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwecenter_img Stem cells can spawn other types of body cells, but they have another striking capability—they remain young. Researchers have now harnessed this ability to boost the life spans of mice and refurbish some of their tissues. Although the approach won’t work in humans, it could lead to ways to keep our bodies vigorous even as we get older.“It’s a beautiful piece of work,” says genome scientist Howard Chang of Stanford University School of Medicine in Palo Alto, California, who wasn’t connected to the research. The study, he adds, reinforces the idea that “aging is not just a passive process. We can intervene to change the outcome.”Like our hair and skin, our chromosomes show our age. Chromosomes carry molecular attachments, known as epigenetic marks, that help control how tightly DNA coils and how active genes are. As we get older, the arrays of these marks change, potentially fouling up the precisely coordinated patterns of gene activity that keep our cells working. Epigenetic modifications aren’t permanent, however. By turning on a few genes normally active only in embryos, researchers can “reprogram” adult body cells into stem cells. This process returns epigenetic marks to their youthful settings and seems to rejuvenate even elderly cells. In one 2011 study, scientists reprogrammed cells from people as old as 101 in the lab, resetting their epigenetic marks and tuning up their metabolism. But could this chromosomal reboot provide similar benefits outside the lab dish?To find out, developmental biologist Juan Carlos Izpisúa Belmonte of the Salk Institute for Biological Studies in San Diego, California, and colleagues genetically modified mice to respond to the antibiotic doxycycline by switching on four key genes that—in the lab—can turn adult cells into stem cells. The researchers tried their approach in mutant mice with symptoms of Hutchinson-Guilford progeria syndrome (HGPS), a rare genetic disease that resembles premature aging. Children with HGPS develop health problems typical of senior citizens, such as weak bones and atherosclerosis, and they usually die of heart attacks or strokes in their teens.Dosing the animals with doxycycline reduced several signs of old age, including thinning of the skin. It also delayed the deterioration of the animals’ kidneys and spleens and kept their hearts beating at a sprightly pace. In addition, switching on the stem cell genes boosted the mutant mice’s life spans by more than one-third, the researchers report online today in Cell.As we get older, our ability to replace dead or injured cells declines. To determine whether activating stem cell genes restores this capacity, the researchers tested healthy, middle-aged mice whose insulinmaking β cells they had removed. Turning on the stem cell genes increased the rodents’ ability to replace their lost β cells. Izpisúa Belmonte and colleagues also tested how well a different group of middle-aged mice could repair muscle damage. If the stem cell genes were active, the animals were better at mending muscle injuries caused by an injection of cobra venom. “We believe that cellular reprogramming has the capacity to convert an old epigenetic program into a young program, slowing down the aging process,” Izpisúa Belmonte says.But tampering with epigenetic marks could have a price. Previous studies have found that turning on the stem cell genes in adult mice can lead to cancer or teratomas, abnormal growths that sometimes sprout teeth or hair. The researchers found, however, that they could prevent tumors and teratomas by giving the mice fewer doses of doxycycline.“I think it’s a proof of concept that partial reprogramming can rejuvenate some tissues,” says regeneration biologist Clive Svendsen of Cedars-Sinai Medical Center in Los Angeles, California, who was not involved with the work. But he says he wants to see evidence that resetting the epigenetic marks increases longevity in healthy animals and that it works in parts of the body, such as the central nervous system, where cell replacement is limited. “Who wants to have a young heart and an old brain?”last_img read more

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