万万没想到，壮阳药居然能抗癌

Due to its distinctive effects on male physiology, Viagra is a drug that has changed the lives of countless men around the world over the last two decades.

由于伟哥对于男性生理的独特效果，在过去的二十多年中，这种神药已经改变了世界各地无数的男性的个人生活。

But an unexpected side effect of the little blue pill hints at even greater transformative potential that scientists never knew about before – and one that could ultimately save thousands of lives.

但是，科学家们直到最近才发现，这种蓝色小药片似乎还有另一种出乎意料的副作用，预示着更大的颠覆性潜能，甚至可能最终拯救数以千计的生命。

Researchers studying the effects of Viagra (aka sildenafil) on mice have discovered a small, daily dose of the medication in the animals’ drinking water significantly reduces their risk of developing colorectal cancer.

科学家在研究伟哥（又称昔多芬）对于小鼠的影响时，发现在动物每天的饮水中加入小剂量药物，可以显著降低它们得结直肠癌的风险。

Giving a baby dose of Viagra can reduce the amount of tumours in these animals by half, says biochemist Darren D. Browning from Augusta University.

“服用很小剂量的伟哥，能将这些动物中的肿瘤数量减半，”来自奥古斯塔大学的生物化学家 Darren D. Browning 说。

We should bear in mind that so far this surprising result has only been demonstrated in the animal model, not in people as yet. But that’s the exact next step the team wants to pursue, saying a clinical trial with patients considered at high risk of colorectal cancer – or with a family history of the disease – should be a research priority.

但有一点我们应该注意，目前这些惊人的结果只来自动物模型，还没有在人体中得到印证。但这正是研究团队下一步的研究方向，对于那些具有结直肠癌高风险的患者，或是有家族病史的患者进行临床试验，应该是研究的首要任务。

If such a trial gets the green light and the effects can be replicated in humans, it could be a huge step forward in saving lives lost to cancer.

如果这样的临床试验获得批准，并且最终证明伟哥可以在人体中得到相同的效果，那么对于挽救那些因癌症而失去生命的人来说，无疑前进了巨大的一步。

In people, colorectal cancer is the third most common cancer worldwide, causing in excess of 1 million cases annually – some 50,000 of which end in death in the US each year.

对于人类，结直肠癌是世界范围内第三大癌症类型，每年超过一百万人被诊断出此病，在美国每年大约五万人死于结直肠癌。

There’s a chance we might be able reduce these grim numbers with Viagra, the researchers think, thanks to the effect the drug appears to have on tissue that can become cancerous.

研究者认为，由于伟哥对那些可能癌变组织的潜在影响，它或许可以帮我们降低这个严酷的统计数字。

In the study, the researchers demonstrated that the daily Viagra dose halved the formation of polyps in mouse tissue: abnormal clumps of cells that form on intestinal lining, which have a tendency to become tumours.

在研究中，科学家们发现，每天服用一定剂量的伟哥，可以让小鼠组织中息肉的形成数量减半：这些息肉就是在小肠内壁形成的异常细胞团，它们有可能变成肿瘤。

Another drug the researchers experimented with, linaclotide – used to treat constipation and irritable bowel syndrome – was even more effective than Viagra.

而研究者们同时试验过另一种药：利那洛肽（linaclotide）。该药常用来治疗便秘和肠易激综合症。它比伟哥的效果更加显著。

But it comes with a nasty drawback: diarrhoea, even in small doses, which makes it ultimately unsuitable for prolonged use, the researchers say.

但研究者发现它有一个非常不好的缺点：即使是小剂量也会导致腹泻，因而并不适合长期服用。

In contrast, Viagra at such low doses isn’t known to produce side effects in humans, which could make it a safe, convenient way to stop the spread of polyps, thanks to it promoting production of a chemical called cyclic GMP inside the body.

相反，低剂量的伟哥则不会对人体产生任何已知的副作用，而且因为它能促进体内产生一种称为环磷酸鸟苷（cGMP）的化学物质，所以是一种既安全又方便阻止息肉扩散的方法。

The exact process by which cyclic GMP benefits the intestinal lining is still being investigated, but the research so far suggests the chemical suppresses excessive cell proliferation – the formation of new cells – in the gut.

对于 cGMP 如何让小肠内壁受益的准确机制尚在研究当中，但目前的研究表明，cGMP 可以抑制肠道内小肠细胞的过度增殖，也就是新细胞的形成。

Seeing as the gut has to deal with whatever we put in our mouths on a daily basis, it experiences high cell turnover – which is why polyp formation is so common. The more new cells forming, the more chance something could go wrong.

由于每一天我们的肠道都需要处理我们吃进嘴里的所有东西，因此肠道细胞的更新速度非常快——这就是为什么息肉的形成如此常见。新生细胞越多，出现差错的概率也就越大。

But cyclic GMP appears to boost normal cell formation while eliminating abnormal counterparts.

但 cGMP 似乎可以在促进正常细胞形成的同时消除异常细胞。

When we give Viagra, we shrink the whole proliferating compartment, says Browning.

Browning说：“当我们给小鼠服用伟哥时，我们让整个增殖区域都缩小了”。

Proliferating cells are more subject to mutations that cause cancer.

“处于增殖期的细胞更容易产生突变，从而导致癌症。”

It’s not the first time Viagra has demonstrated unexpected health benefits a world away from its origins in treating erectile dysfunction – which just goes to show how scientists are continually discovering new molecular mechanisms in old drugs.

对于原本用来治疗勃起障碍的伟哥来讲，这已经不是第一次发现它出人意料的治疗效果，由此也能看出科学家们是如何持续从一些旧药身上发现新的分子机制。

In this case, existing polyps don’t seem to be affected by the drug, so it looks like Viagra can’t be used to fight tissue that has already turned cancerous. But as for cancer prevention, we could be onto a whole new thing here.

在这个例子中，已经存在的息肉并不会受到药物的影响，由此看来，伟哥无法用来对抗那些已经癌变的组织。但是对于癌症预防，我们可能有了全新的办法。

The findings are reported in Cancer Prevention Research.

这一研究成果发表于 Cancer Prevention Research。