1 00:00:09,093 --> 00:00:12,693 Speaker 1: You're listening to a podcast from news Talk ZEDB. Follow 2 00:00:12,773 --> 00:00:16,173 Speaker 1: this and our wide range of podcasts now on iHeartRadio. 3 00:00:17,012 --> 00:00:20,052 Speaker 2: So this is fascinating. A University of a Targo study 4 00:00:20,253 --> 00:00:23,293 Speaker 2: found that sterilization boosts life span across one hundred and 5 00:00:23,293 --> 00:00:27,493 Speaker 2: seventeen species. The major international study has found that blocking 6 00:00:27,573 --> 00:00:32,092 Speaker 2: reproduction increases lifespan in both males and females across that 7 00:00:32,133 --> 00:00:35,412 Speaker 2: wide range of species. The lead author is Associate Professor 8 00:00:35,533 --> 00:00:38,772 Speaker 2: Mike Garrett of A. Targo's School of Biomedical Sciences, and 9 00:00:38,853 --> 00:00:41,613 Speaker 2: he joins us on the phone. Now, very good afternoon 10 00:00:41,653 --> 00:00:41,812 Speaker 2: to you. 11 00:00:41,853 --> 00:00:44,453 Speaker 3: Mike, Hi, how's it going good? 12 00:00:44,452 --> 00:00:44,693 Speaker 1: Thanks? 13 00:00:44,853 --> 00:00:46,852 Speaker 4: Could you explain to me, like I'm an idiot, why 14 00:00:46,933 --> 00:00:50,053 Speaker 4: stopping reproduction makes animals live longer? 15 00:00:51,333 --> 00:00:56,093 Speaker 3: Well, reproduction is costly. It has energetic costs, for example, 16 00:00:56,253 --> 00:01:00,253 Speaker 3: and when we inhibit those, it can help animals invest 17 00:01:00,293 --> 00:01:02,853 Speaker 3: in other processes, for example looking after their immune system, 18 00:01:03,173 --> 00:01:04,693 Speaker 3: and this can improve survival. 19 00:01:05,693 --> 00:01:09,293 Speaker 4: Could it be a risky behavior thing? Because you know 20 00:01:09,773 --> 00:01:13,333 Speaker 4: when the you know on that is that it reduces 21 00:01:13,413 --> 00:01:16,973 Speaker 4: risky behavior rather than some sort of deep biological aging effeete. 22 00:01:18,292 --> 00:01:19,893 Speaker 3: So there are a couple of different things that we 23 00:01:19,932 --> 00:01:22,693 Speaker 3: show in this article. In the context of males, we 24 00:01:22,813 --> 00:01:27,733 Speaker 3: show that castration extends lifespan and in part, yes, part 25 00:01:27,773 --> 00:01:29,773 Speaker 3: of the reason they live longer is they're less likely 26 00:01:29,853 --> 00:01:33,773 Speaker 3: to engage in risky behaviors. Although in other contexts where 27 00:01:33,813 --> 00:01:36,693 Speaker 3: we've looked at a sect of castration, for example, in 28 00:01:36,813 --> 00:01:40,693 Speaker 3: lab animals, you also see improvement in improvement in other 29 00:01:40,733 --> 00:01:44,252 Speaker 3: aspects of health. So yes, in part, it can improve 30 00:01:44,292 --> 00:01:47,813 Speaker 3: survival because it reduces investment in risky behaviors, but it 31 00:01:47,893 --> 00:01:51,293 Speaker 3: also provides other benefits late in life as well, at 32 00:01:51,333 --> 00:01:53,893 Speaker 3: least in the animals that have been that's been studied. 33 00:01:54,133 --> 00:01:56,333 Speaker 4: And how long a life span gain is that we're 34 00:01:56,333 --> 00:01:58,453 Speaker 4: talking what teen twenty percent? How long is it? 35 00:01:59,253 --> 00:02:02,373 Speaker 3: Yeah, across the studies, across the species that we looked, 36 00:02:02,413 --> 00:02:04,493 Speaker 3: so you know, we looked at over one hundred different species, 37 00:02:04,533 --> 00:02:07,333 Speaker 3: we found an average increase in life span of about 38 00:02:07,333 --> 00:02:12,013 Speaker 3: ten percent. Those effects were stronger in partigure in the 39 00:02:12,013 --> 00:02:14,972 Speaker 3: context of castration if animals were castrated early in life, 40 00:02:15,093 --> 00:02:17,852 Speaker 3: before they went through puberty. So in those contexts we 41 00:02:17,893 --> 00:02:20,533 Speaker 3: found an average increase in lifespan that was greater, more 42 00:02:20,573 --> 00:02:22,933 Speaker 3: like fifteen to twenty percent, depending on the species. 43 00:02:23,573 --> 00:02:25,252 Speaker 4: Now I was thinking about this when I was walking 44 00:02:25,333 --> 00:02:27,813 Speaker 4: my dog Colin the other day, and you know, he's 45 00:02:28,093 --> 00:02:33,013 Speaker 4: he's castrated, and he seems pretty pretty happy in his life. 46 00:02:33,013 --> 00:02:35,973 Speaker 4: But part of me feels a bit said because you know, 47 00:02:36,013 --> 00:02:37,933 Speaker 4: that's the end of his line and he's such a 48 00:02:38,972 --> 00:02:41,132 Speaker 4: great dog. But it made me think as well, is 49 00:02:41,173 --> 00:02:44,453 Speaker 4: he happier because he has been fixed, or is he 50 00:02:44,532 --> 00:02:46,373 Speaker 4: still part of them that feels like he's missing out 51 00:02:46,413 --> 00:02:51,093 Speaker 4: on something you know, deep in his you know instincts. 52 00:02:52,133 --> 00:02:54,573 Speaker 3: Well, it's an interesting question, I think if we're talking 53 00:02:54,573 --> 00:02:56,732 Speaker 3: about so you seem to be focusing on the castration 54 00:02:56,893 --> 00:03:00,413 Speaker 3: component here. You know, once you're castrated, you don't have 55 00:03:00,453 --> 00:03:03,532 Speaker 3: the same drive to reproduce. So actually you probably are 56 00:03:03,573 --> 00:03:06,813 Speaker 3: happier if you're not castrated, but you're kept in an 57 00:03:06,853 --> 00:03:10,373 Speaker 3: environment where you can't reproduce. Yeah, that could also be stressful. 58 00:03:10,413 --> 00:03:13,053 Speaker 3: So actually, in that situation, you know, you might have 59 00:03:13,413 --> 00:03:15,933 Speaker 3: be exposed to androgens. You've got this drive to reproduce, 60 00:03:15,972 --> 00:03:18,573 Speaker 3: but that's not met with the actual reward of mating. 61 00:03:18,773 --> 00:03:21,412 Speaker 3: So actually that could potentially be more stressful for the 62 00:03:21,453 --> 00:03:25,533 Speaker 3: animal than actually being castrated. And then you don't necessarily 63 00:03:25,532 --> 00:03:28,053 Speaker 3: need those reproductive opportunities or you don't want them. 64 00:03:28,453 --> 00:03:30,333 Speaker 4: Now, the obvious question in the Elephant and the Room, 65 00:03:30,373 --> 00:03:34,573 Speaker 4: I guess is should I castraight myself? Can you interpret 66 00:03:34,893 --> 00:03:38,053 Speaker 4: anything meaningful around humans from the study or is it 67 00:03:38,133 --> 00:03:38,853 Speaker 4: a bridge too far? 68 00:03:39,813 --> 00:03:43,253 Speaker 3: Well, in our study, we did try to extrapolate some 69 00:03:43,293 --> 00:03:45,453 Speaker 3: of our results to humans. There've been a couple of 70 00:03:45,453 --> 00:03:50,173 Speaker 3: studies that have been conducted on historical data sets where 71 00:03:50,213 --> 00:03:53,013 Speaker 3: people have been castrated for various different reasons. There was 72 00:03:53,013 --> 00:03:55,453 Speaker 3: a study on Korean unix from I think that the 73 00:03:55,453 --> 00:03:59,733 Speaker 3: seventeenth eighteenth century. That data has been quite controversial. But 74 00:03:59,933 --> 00:04:02,293 Speaker 3: the mean increase in life as you would expect, but 75 00:04:02,333 --> 00:04:05,053 Speaker 3: the mean increase in lifespan that was reported in those 76 00:04:05,093 --> 00:04:09,093 Speaker 3: studies actually matches what we report in after so you know, 77 00:04:09,133 --> 00:04:12,573 Speaker 3: it's potential that these benefits might extend to humans. However, 78 00:04:12,773 --> 00:04:15,933 Speaker 3: we also find in our study that the effects of 79 00:04:16,293 --> 00:04:19,733 Speaker 3: sterilization and castration are stronger when you keep animals in 80 00:04:19,853 --> 00:04:23,493 Speaker 3: wild environments where they have to, you know, invest heavily 81 00:04:23,573 --> 00:04:25,653 Speaker 3: in different things. We don't have as many resources, right, 82 00:04:25,813 --> 00:04:28,413 Speaker 3: so I think actually the society that we're living means 83 00:04:28,413 --> 00:04:31,293 Speaker 3: that probably we wouldn't necessarily get those benefits because we 84 00:04:31,333 --> 00:04:34,253 Speaker 3: have really good healthcare. You know, we're largely protected from 85 00:04:34,333 --> 00:04:38,253 Speaker 3: infectious disease. You know, we aren't exposed to the same 86 00:04:38,373 --> 00:04:41,733 Speaker 3: level of mortality from risky behavior, from aggression, from things 87 00:04:41,773 --> 00:04:44,933 Speaker 3: like that. So yeah, so don't go out and castrate yourself. 88 00:04:45,613 --> 00:04:46,093 Speaker 3: Very interesting. 89 00:04:46,533 --> 00:04:50,653 Speaker 4: I was sitting on the fience but ye, leaving things things, Mike. 90 00:04:50,973 --> 00:04:54,773 Speaker 2: So when you look at vasikamese, Mike, it's obviously different 91 00:04:54,773 --> 00:04:58,133 Speaker 2: to castration, and according to the study there, there wasn't 92 00:04:58,173 --> 00:05:01,053 Speaker 2: those same finding. So any human out there right now 93 00:05:01,093 --> 00:05:02,613 Speaker 2: that's head of the seek to me and hoping to 94 00:05:02,613 --> 00:05:05,413 Speaker 2: live a bit longer, it might not be that they're simple. 95 00:05:06,893 --> 00:05:09,973 Speaker 3: Yes, that's right. So there's there's little data available in 96 00:05:10,053 --> 00:05:14,373 Speaker 3: animals and definitely little experimental data. So the two in zoos, 97 00:05:14,413 --> 00:05:16,533 Speaker 3: and a lot of our analysis has conducted on zoo 98 00:05:16,533 --> 00:05:20,093 Speaker 3: house species, so we were able to look retrospectively at 99 00:05:20,213 --> 00:05:22,493 Speaker 3: zoo records. Now there are only a couple of species 100 00:05:22,533 --> 00:05:26,253 Speaker 3: where they routinely do vasectomy rather castration. That's lions, because 101 00:05:26,373 --> 00:05:28,373 Speaker 3: they want to maintain the lion's main and if you 102 00:05:28,413 --> 00:05:31,373 Speaker 3: castrate then that goes away. Also, baboons, you know, they 103 00:05:31,413 --> 00:05:35,013 Speaker 3: have this big kind of secondary sexual coloration, so to 104 00:05:35,133 --> 00:05:37,653 Speaker 3: use theseectomy in those contexts, and in those contexts we 105 00:05:37,773 --> 00:05:40,933 Speaker 3: see no effects on survival. There've also been a couple 106 00:05:40,973 --> 00:05:43,613 Speaker 3: of laboratory studies of laboratory life and there they also 107 00:05:43,653 --> 00:05:46,573 Speaker 3: see no effect on survival. So evidence would suggest that 108 00:05:46,573 --> 00:05:49,333 Speaker 3: it needs to be castration in the context of males. 109 00:05:49,653 --> 00:05:52,773 Speaker 4: And what do you see me and what do you see? 110 00:05:52,773 --> 00:05:56,693 Speaker 4: As a nixt big question, this research opens up what's 111 00:05:56,693 --> 00:05:58,173 Speaker 4: the practical implications for this? 112 00:05:59,333 --> 00:06:01,773 Speaker 3: Well, I mean, we'd really like to understand the effects 113 00:06:01,813 --> 00:06:04,133 Speaker 3: on the biology of aging, So what's actually happening, How 114 00:06:04,133 --> 00:06:06,933 Speaker 3: does this occur? In particular, we found that the effects 115 00:06:06,933 --> 00:06:09,973 Speaker 3: of castration are stronger when they're cur before puberty, So 116 00:06:10,053 --> 00:06:14,613 Speaker 3: there's something that must occur through puberty where testosterone has 117 00:06:14,653 --> 00:06:17,413 Speaker 3: effects on the body. It potentially helps you to show 118 00:06:17,493 --> 00:06:20,893 Speaker 3: kind of male specific growth, male specific behavior, but then 119 00:06:20,933 --> 00:06:24,093 Speaker 3: reduces lifespan. And trying to understand the mechanisms of that, 120 00:06:24,693 --> 00:06:27,733 Speaker 3: you know, how they interact with other pathways that influence aging. 121 00:06:28,173 --> 00:06:31,693 Speaker 3: Other hormones might ultimately allow us to understand the aging 122 00:06:31,733 --> 00:06:34,453 Speaker 3: process aging process better and you might be able to 123 00:06:34,453 --> 00:06:37,173 Speaker 3: get the benefits of those things without castration. 124 00:06:37,493 --> 00:06:39,373 Speaker 2: Interesting, so how would you do that? You know, This 125 00:06:39,413 --> 00:06:43,053 Speaker 2: is hYP thetical, of course, but potentially talking about after 126 00:06:43,093 --> 00:06:46,213 Speaker 2: that puberty period some sort of medication to balance out 127 00:06:46,253 --> 00:06:48,892 Speaker 2: testosterone levels to allow people to live a bit longer. 128 00:06:50,213 --> 00:06:51,533 Speaker 3: So I mean, I could try and go into a 129 00:06:51,533 --> 00:06:54,133 Speaker 3: little bit of detail with you, but there are other parts. 130 00:06:54,133 --> 00:06:59,053 Speaker 3: So we've said in our study that androgen's testosterone influences 131 00:06:59,093 --> 00:07:02,333 Speaker 3: aging in males. There are other pathways that we also 132 00:07:02,453 --> 00:07:05,973 Speaker 3: know influence lifespan in animals. There's some other hormones like 133 00:07:06,013 --> 00:07:10,773 Speaker 3: growth hormone and some some proteins in cells that also 134 00:07:10,893 --> 00:07:13,533 Speaker 3: influence the aging process while at the same time helping 135 00:07:13,573 --> 00:07:15,933 Speaker 3: you grow. So there are other hormones that make you grow, 136 00:07:15,973 --> 00:07:17,533 Speaker 3: but I make you have a short live span. We 137 00:07:17,613 --> 00:07:22,973 Speaker 3: know that, so androgens probably feed in to that pathway. 138 00:07:23,093 --> 00:07:27,733 Speaker 3: How it influences cells influence aspects of stress resistance, but 139 00:07:27,853 --> 00:07:29,933 Speaker 3: also influence aspects of growth, and we can try to 140 00:07:30,053 --> 00:07:34,253 Speaker 3: understand those trade offs, those actual mechanisms, those things that 141 00:07:34,333 --> 00:07:37,133 Speaker 3: go on in cells that mean that the cells grow 142 00:07:37,813 --> 00:07:40,773 Speaker 3: but they're less protected against stress, if that makes sense 143 00:07:40,813 --> 00:07:43,173 Speaker 3: to mean, can really just try and delve into the 144 00:07:43,213 --> 00:07:44,973 Speaker 3: actual mechanisms at the level of a cell. 145 00:07:45,373 --> 00:07:47,373 Speaker 4: It's an interesting one because I would say that my 146 00:07:47,453 --> 00:07:50,253 Speaker 4: kids have definitely aged me with worry, but they've also 147 00:07:50,413 --> 00:07:52,733 Speaker 4: added a lot of meaning and happiness to my life. 148 00:07:52,813 --> 00:07:57,533 Speaker 4: So I would say having my children, I may die earlier, 149 00:07:57,973 --> 00:08:01,373 Speaker 4: but my overall happiness well has been increased by them. 150 00:08:01,373 --> 00:08:03,773 Speaker 4: So they've definitely a trade off from a human bespeaktive, 151 00:08:03,773 --> 00:08:04,973 Speaker 4: isn't it well? 152 00:08:05,013 --> 00:08:06,493 Speaker 3: I mean, how old are your children at the moment? 153 00:08:06,533 --> 00:08:12,413 Speaker 3: Minor four and six and they're definitely aging. It's not 154 00:08:12,493 --> 00:08:15,333 Speaker 3: it doesn't feel it quite as worthwhile at the moment. 155 00:08:15,213 --> 00:08:19,893 Speaker 4: Well, teenagers and it's moved into the pure happiness stage 156 00:08:19,933 --> 00:08:20,453 Speaker 4: at this point. 157 00:08:21,893 --> 00:08:22,653 Speaker 3: I'll hold you for that. 158 00:08:24,933 --> 00:08:28,173 Speaker 2: Yeah, Mike, you've been brilliant. Thank you very much for 159 00:08:28,453 --> 00:08:31,013 Speaker 2: joining us and having a chat. It's fascinating research and 160 00:08:31,093 --> 00:08:32,493 Speaker 2: we're interested to see where it goes. 161 00:08:33,653 --> 00:08:34,933 Speaker 3: Nice to speak to you, that is. 162 00:08:34,933 --> 00:08:39,573 Speaker 2: Associate Professor Mike Garrett out of the Otago University. Fascinating stuff. 163 00:08:40,133 --> 00:08:43,053 Speaker 1: For more from News Talks B listen live on air 164 00:08:43,252 --> 00:08:45,933 Speaker 1: or online, and keep our shows with you wherever you 165 00:08:46,012 --> 00:08:48,453 Speaker 1: go with our podcast on iHeartRadio.