不久前的一則新聞讓整個(gè)互聯(lián)網(wǎng)沸騰了——意大利神經(jīng)外科醫(yī)生塞爾吉奧?卡納韋羅和中國(guó)哈爾濱醫(yī)科大學(xué)的任曉平醫(yī)生實(shí)施了世界首例成功的人類頭部移植手術(shù)（不過(guò)此次手術(shù)是在尸體上進(jìn)行的，讓人不免聯(lián)想到弗蘭肯斯坦和他的怪物）?？{韋羅稱，此次手術(shù)是成功的，它標(biāo)志著完整的甚至是活體的頭部移植術(shù)可能“即將來(lái)臨了”，將來(lái)，由于種種疾病導(dǎo)致身體徹底損壞的病人或許將能等來(lái)一具新的身體。

不過(guò)近幾年來(lái)，卡納韋羅和任曉平的研究也為他們招來(lái)了不少懷疑聲浪，有不少學(xué)者既質(zhì)疑換頭術(shù)在科學(xué)上是否可行，同時(shí)又對(duì)它的倫理影響提出擔(dān)憂。一些知名醫(yī)生甚至公然否定了“換頭術(shù)”的可行性。不過(guò)在各種批評(píng)聲中，據(jù)稱卡納韋羅和任曉平已經(jīng)相繼在老鼠甚至猴子身上成功進(jìn)行了頭部移植手術(shù)。

可以想見(jiàn)，要成功實(shí)施“換頭術(shù)”，必然會(huì)面臨很多重大阻礙。且不說(shuō)要對(duì)頭部和頸部組織、神經(jīng)細(xì)胞和脊髓進(jìn)行橋接，確保新的身體“能用”，患者能不能挺過(guò)這樣一次耗時(shí)極長(zhǎng)的手術(shù)也是個(gè)大問(wèn)題，就算堅(jiān)持下來(lái)了，腦袋和新身體會(huì)不會(huì)產(chǎn)生嚴(yán)重的排異反應(yīng)也是個(gè)未知數(shù)。

拿目前極具開(kāi)拓性且已經(jīng)經(jīng)過(guò)臨床驗(yàn)證的生物工程為例——比如用基因技術(shù)操縱血癌患者的免疫細(xì)胞，將其變成抗癌細(xì)胞，然后重新注入患者體內(nèi)。就是這種貌似理論上無(wú)懈可擊的技術(shù)，也會(huì)導(dǎo)致嚴(yán)重的毒副作用。而一個(gè)新的頭部和大腦會(huì)給身體帶來(lái)什么樣的長(zhǎng)期影響，或者反過(guò)來(lái)，一具新身體會(huì)給頭部和大腦帶來(lái)什么樣的長(zhǎng)期影響，也依然是未知數(shù)，結(jié)果是高度難以預(yù)測(cè)的。

神經(jīng)科學(xué)家迪恩?伯內(nèi)特就在一篇專欄文章里指出，卡納韋羅聲稱的一些以往的成功案例，其實(shí)與現(xiàn)實(shí)情況并不完全相符。比如那只實(shí)施了換頭術(shù)的猴子并沒(méi)有恢復(fù)真正的意識(shí)。

不過(guò)好消息是，器官移植領(lǐng)域最近確實(shí)也是喜訊不斷。比如最近世界上的首例換臉術(shù)宣告成功了。另外，未來(lái)人們很有可能能夠用上從轉(zhuǎn)基因的豬身上培養(yǎng)的器官。

作者：Sy Mukherjee

譯者：賈政景

The Internet was abuzz on Friday with news that famed—and controversial—Italian neurosurgeon Sergio Canavero and partner Dr. Xiaoping Ren of Harbin Medical University in China had performed the world’s first successful human head transplant(albeit with the major caveat that it was done on a corpse, raising comparisons to Dr. Frankenstein and his monster). Canavero claims the procedure was a success and a sign that full-on, presumably live head transplant surgeries are “imminent,” with the potential to help people who suffer from diseases which have caused their bodies to waste away.

But Canavero and Ren have prompted plenty of skepticism over the years from critics challenging both the scientific feasibility and ethical implications of head transplants, with some prominent doctors rejecting the notion that such a procedure is even possible. Canavero and Ren have played up reported successes in performing mice, monkey, and even rat head transplant operations.

There are, as you might imagine, a number of massive obstacles to successfully completing a head transplant surgery. Not only would head and neck tissue, nerve cells, and spinal cords have to be grafted together to create functional units; the patient going through such an extensive procedure would have to stay alive for long enough for it to work and then have to hope that his or her new body doesn’t reject the head of a biological stranger.

Considering that even groundbreaking, clinically proven biological re-engineering—like new genetic technologies which involve manipulating blood cancer patients’ immune cells into becoming cancer killers before re-inserting them into the body—can cause serious, toxic side effects, it’s an open question what the long-term effects of an entirely new head and brain would have on a body (or vic versa); such interactions would be highly unpredictable.

And as neuroscience Dr. Dean Burnett points out in a scathing op-ed, Canavero’s outsized claims about past successes may not exactly align with the realities of his accomplishments. For instance, Burnett notes, the monkey head transplant procedure didn’t result in a being with actual consciousness.

There have, however, been other kinds of recent milestones in the transplant space, including one of the most extensive face transplants ever done and the prospect of human organ donations from genetically modified pigs.