Damaged Human Lungs Can Be Repaired by Attaching Them to Pigs, Experiment Shows

Jan 29, 2021 | 🚀 Fathership AI

The sad reality of terminal lung illnesses is that there are simply far more patients than there are donor lungs available. This isn't just because of the low number of donors, which would be problem enough, but many donor lungs are significantly damaged, rendering them unusable.

By using a new experimental technique, though, such a damaged lung has now been restored to function - by sharing its circulatory system with that of a living pig. This leverages the body's self-repair mechanisms to exceed the capabilities of current donor lung restoration techniques.

"It is the provision of intrinsic biological repair mechanisms over long-enough periods of time that enabled us to recover severely damaged lungs that cannot otherwise be saved," say the lead researchers, surgeon Ahmed Hozain and biomedical engineer John O'Neill of Columbia University.

The underlying principle is similar to an existing donor lung restoration technique called ex vivo lung perfusion (EVLP), which involves placing a lung in a sterile dome attached to a ventilator, pump, and filters.

The lung's temperature is maintained at human body temperature, and a bloodless solution containing oxygen, nutrients, and protein is circulated through it. That circulation, when liquid is pumped through the organ, is the perfusion part.

EVLP has helped save lives by keeping donor lungs stable and even repairing them a little. But the time window afforded by the technique is somewhat limited - it can only be conducted for up to eight hours, which is not a lot of time for the biological repair functions to kick in.

It's that precious time that the research team has bought with their pigs, and years of research.

In 2017, O'Neill led the development of the xenogeneic (cross-species) cross-circulation platform. Last year, two of the researchers, biomedical engineer Gordana Vunjak-Novakovic of Columbia University and surgeon Matthew Bacchetta of the Vanderbilt Lung Institute, led a study in which they restored damaged pig lungs by attaching them to other pigs.

Earlier this year, the team extended the operation time of the platform to four days.

Now, the researchers have revealed that they have successfully used the same technique to repair five damaged human lungs by connecting them to pigs, including one severely injured lung that had failed to recover function using EVLP.

"We were able to recover a donor lung that failed to recover on the clinical ex vivo lung perfusion system, which is the current standard of care," Vunjak-Novakovic said. "This was the most rigorous validation of our cross-circulation platform to date, showing great promise for its clinical utility."

In the study, six donor lungs were obtained by the team after being rejected for transplantation. The five lungs in the experiment were attached via a jugular cannula to anaesthetised pigs that had been immunosuppressed, to prevent the pig's immune system from attacking the lungs. The sixth control lung was attached to a pig that was not immunosuppressed.

All of the lungs were subjected to 24 hours of xenogeneic cross-circulation, while the researchers carefully monitored the physiological and biochemical parameters of the organs.

The control lung did not take long to break down. It started developing extra fluid, the circulation broke down, while inflammatory and immune markers rose, blood clots formed, and respiratory function fell - all consistent with hyperacute rejection.

The contrast with the experimental lungs couldn't have been more remarkable. Even though all had previously demonstrated injuries, the lungs showed significant improvement in cellular viability, tissue quality, inflammatory response, and respiratory function.

The change in the lung that had failed EVLP in particular underwent a jaw-dropping turnaround. It had spent a total of 22.5 hours on ice, and received 5 hours of EVLP. After this, the right lung was accepted for transplant, but the left lung was simply too damaged. It had persistent swelling and fluid build-up. Multiple transplant centres had turned it down.

After 24 hours sharing blood with a pig, though, the damaged lung started to show signs of repair; not full recovery, but a lot more than had been thought possible. This suggests, the researchers said, that their cross-circulation platform could be used in conjunction with EVLP to help restore lungs that EVLP can't save alone.

It's not quite ready for clinical use, though. For one, the pigs could share things other than their blood. Like disease, for instance.

Because of this, any clinical use of the technique would require medical-grade animals, which would not be cheap - but it's nonetheless something that is under investigation for use in xenotransplantation, in which pigs' organs can be transplanted in human recipients. (This is currently being tested in baboons.)

The other option is that the human recipients themselves could potentially become the basis for the cross-circulation platform, being attached to the lungs they will themselves receive, and maybe even other kinds of organs one day.

"Modifications to the xenogeneic cross-circulation circuit could enable investigation and recovery of other human organs, including livers, hearts, kidneys and limbs," the researchers wrote in their paper.

"Ultimately, we envision that xenogeneic cross-circulation could be utilised as both a translational research platform to augment transplantation research and as a biomedical technology to help address the organ shortage by enabling the recovery of previously unsalvageable donor organs."

The research has been published in Nature Medicine.


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警员死亡案: 种族歧视字眼并非针对他,除一 名上司 "不专业",其他说法皆不实

Feb 07, 2024 | 🚀 Fathership AI

新加坡警察部队(SPF)已向内政部(MHA)提交了有关警官尤瓦拉贾(Uvaraja S/O Gopal)自杀事件的所有调查结果。

2024 年 2 月 6 日,内政部长尚穆根在国会公布了调查结果,他在部长声明中说,尤瓦拉贾对新加坡警察部队的一些指控属实。

不过,在接到投诉时,警方已经对这些指控进行了调查,并对一些官员采取了纪律处分。

尚穆根说,尤瓦拉贾的其他指控则是虚假的。

他说,最新的调查结果已提交给总检察署(AGC),经过审查,总检察署认为无需采取进一步行动。

警官死前曾多次做出指责

2023 年 7 月 21 日,尤瓦拉贾被发现在义顺组屋楼下一动不动,没有生命迹象。

他生前在脸书上发帖,详细描述了他在工作中遇到的不快和种族歧视。

尤瓦拉贾在帖子中描述了他在工作场所受到欺凌和排挤的情况,声称他遭受种族歧视,并经历了 "恶毒的工作文化"。

警官确实使用了具种族歧视字眼,但并非针对死者

尚穆根说,警方记录显示,尤瓦拉贾确实在 2015 年提出过投诉,当时也进行了内部调查。

调查发现,使用种族不当语言的警官是在相互交谈,这些言论并没有针对尤瓦拉贾。

尚穆根说:"但是,重点是,这些言论是完全不能被接受的。

他指出,这些言论是否针对 尤瓦拉贾并不重要,重要的是 "这些言论过去和现在都是不可接受的"。

尚穆根:不能容忍种族歧视,即使是玩笑也不行

尤瓦拉贾的上司向团队明确表示,不能使用这种语言,即使是开玩笑也不行,说这种话的警员立即向 尤瓦拉贾道了歉。

尤瓦拉贾的上司对情况进行了监控,以确保不再发生类似事件。

尤瓦拉贾的上司提出可以对这名警员提出正式投诉,但 尤瓦拉贾 拒绝进一步投诉。

尚穆根说:"我们不能容忍种族歧视,即使是玩笑话也不行,也不能有冷嘲热讽和带有种族歧视的玩笑"。

对恶毒的工作环境索赔

尤瓦拉贾声称他的上级在 2019 年撕毁了他的请假单,并将这一行为的视频上传到了团队的群聊中。

尚穆根解释说,尤瓦拉贾申请的是酌情休假,不需要提交休假表。

然而,据了解,尤瓦拉贾非常临时才提交请假单,而其他警员的请假已经获得批准。

调查显示,尤瓦拉贾的上司告诉他,他 "给整个团队带来了不便",但尤瓦拉贾没有撤回休假申请,并在私人聊天中要求上司结束谈话。

这位上司随后录下了自己撕碎 尤瓦拉贾请假单的视频,并将他这样做的视频上传到了团队聊天室。

上级的行为不专业

"上司的行为并不专业。他不应该这样做,尽管我们可以理解他的不快,"尚穆根说。

上司受到了训斥,尤瓦拉贾被暂时调到了另一个单位,以便两名警员都能冷静下来。

尤瓦拉贾的另一个说法是他的上司对他使用了辱骂性语言,尚穆根说,调查结果并不支持这一说法。

尚穆根说,尤瓦拉贾经常直接给上司发信息或打电话,而上司会以专业的口吻回复他。

关于掩盖事实的投诉不成立

尤瓦拉贾还声称,2021 年,他揭发了被他抓到吸电子烟的警官,但案件被 "掩盖 "了。

尚穆根说,根据尤瓦拉贾提供的信息,尤瓦拉贾的上司指示不同单位的一名上级独立对事发地点的所有储物柜和个人物品进行了突击检查。

相关人员也接受了询问。

但是,投诉并不成立。

在 2023 年 1 月的另一起事件中,尤瓦拉贾举报他的一些同事在警署吸烟。

调查发现了相关证据,这些警官被移交给警方内部事务办公室,并对他们采取了纪律处分。

"因此,当投诉被证实后,就会采取纪律处分。没有被证实时他也被告知,没有隐瞒。“

职业生涯受阻的说法不实

尤瓦拉贾声称,他从未得到过上级的良好评价,而且由于 "人力问题",上级不允许他调离岗位。

尚穆根说这是错误的,因为尤瓦拉贾和其他同事一样有机会申请职位。

当他要求调职时,他的上司也会尽可能提供方便,满足他的要求。

在 9 年时间里,尤瓦拉贾被调往 6 个不同的工作单位,尚穆根说,这是相当多的职位调动。

有两次调职与举报涉嫌吸烟违法行为有关,因为他觉得与这些同事共事很不舒服。

调查还发现,他的工作能力获得公平的评估。他还被授予 Covid-19贡献奖章。

同事 "抵制 "他的婚礼并非事实

据尚穆根称,尤瓦拉贾声称同事们 "抵制 "他的婚礼的说法也不属实。

他的上司接受了邀请,但因生病未能出席,他向尤瓦拉贾道了歉。

尤瓦拉贾向他的直属上司告知了婚礼的情况,但没有发出邀请函。这名上司也曾当着队友的面向尤瓦拉贾表示了祝贺。

有三项正在进行的调查

尚穆根说,在尤瓦拉贾去世时,他正接受三项刑事和纪律调查。

他因触犯《刑法典》和《骚扰法》而受到调查。

他还因在 2023 年 7 月一次不服从命令,而受到内部纪律调查。他当时拿了病假却离开家里。

当时他与家人在公寓内发生争执,家人还为此报警。

2023 年 4 月,尤瓦拉贾又一次接受内部纪律调查,原因是他不服从命令,未完成工作且擅离职守。当被要求返回完成任务时,他也拒绝服从。

每年休病假超过 50 天

尚穆根指出,2016 年、2017 年、2021 年、2022 年和 2023 年,乌瓦拉贾分别休了 70 天、56 天、59 天、80 天和 60 天的病假。

2015 年、2016 年和 2022 年,他还休了 100 多天的无薪假。

尚穆根表示,警察部队为满足 尤瓦拉贾的需求,包括他的休假和医疗需求,付出不少努力。

警官的去世影响了同事们

尚穆根说,尤瓦拉贾的去世和他的指控对同事产生了影响。

尚穆根说:“在不同岗位与他共事过的同事们,和了解他的情况的人,对他的自杀感到悲伤。”

"但他们也对他就警察部队提出的不实说法和指控感到失望"。

尚穆根:没有隐瞒

尚穆根说,警方认真对待违规警员的案件,并对他们采取了行动。

"没有所谓掩盖真相。但正如我所说,这些都是特例。只是极少数例外。我们绝大多数警官都是诚实的"。

不过,对于 尤瓦拉贾的案件,他说调查结果与 尤瓦拉贾在帖子中的指控 "截然不同"。

"我们的警员都知道,当出现虚假或不公平的指控时,我们会迅速果断地采取行动,说出真相,并站在警员一边"。


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