{"id":1136,"date":"2023-03-13T01:04:52","date_gmt":"2023-03-13T01:04:52","guid":{"rendered":"https:\/\/joshmitteldorf.peachpuff-wolverine-566518.hostingersite.com\/?p=1136"},"modified":"2023-03-13T14:44:18","modified_gmt":"2023-03-13T14:44:18","slug":"harold-katchers-last-rat","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/joshmitteldorf\/2023\/03\/13\/harold-katchers-last-rat\/","title":{"rendered":"Harold Katcher’s Last Rat"},"content":{"rendered":"

Experience tells us that it is much easier to extend median lifespan than maximum lifespan. Katcher\u2019s trial of E5 in 8 rats breaks this expectation. The last of Harold Katcher\u2019s rats has died, and she outlived her sisters by 7 months. Compared to controls, the average lifespan of treated rats increased 9.6%, while the maximum lifespan increased 22.0%. (For reasons unknown, the control rats lived longer than most Sprague-Dawley rats.)<\/p>\n

When I last wrote about Katcher\u2019s rats<\/a>, there were just two left alive, and the survival curve conformed well to the Gompertz rule, which says that mortality rates increase exponentially with age. (There is no theoretical basis for the Gompertz rule, but it has been found to be a good empirical model for aging in many species.) From a Gompertz fit to the first 6 rats, I was projecting a maximum lifespan of 1250 days. The 7th rat wasn\u2019t far off from that estimate, but the last of the 8 has lived just over 4 years (1464 days), breaking the record for lab rats. \u201cSima\u201d lived 5% longer than the previous\u00a0 longest-lived Sprague-Dawley rat.<\/p>\n

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Write-up in The Guardian<\/a><\/p>\n

Sima received five infusions during her lifetime at intervals of 3 months. A sixth scheduled treatment was held on the judgment of the experimenters, so that at Sima’s death she was more than six months out from her last infusion. The fact that one rat lived longer than the rest is an invitation to experiment with optimization of the E5 protocol. All the rats were genetically identical and raised in the same lab. All received their first treatment around 2 years of age. Perhaps there are physiological tests that would offer suggestions why Sima responded better to the treatment.<\/p>\n

Where does this project need to go?<\/span><\/h2>\n

It has been almost three years since I wrote up (breathlessly) the results of Katcher\u2019s first study. I called it an\u00a0Age Reduction Breakthrough<\/a>. I still believe that plasma transfusions are the most promising path toward real, practical rejuvenation in the near-term. It is frustrating how little has happened in the intervening years. This should be a crash project for laboratories around the world, and instead it is being confined to a small group of scientists in Mumbai and Baltimore who are holding the IP.<\/p>\n

Edison invented the lightbulb in 1879, and the first commercial units went on sale to the public in 1880.<\/p>\n

We all should be demanding of Katcher and Sanghavi and our funding agencies a full-scale research program.<\/p>\n