List of head transplantation experiments in animal models

In 2017 paper of S.Canavero, Xiaoping Ren et.al.[1] 3 papers are mentioned: "Full cephalic exchanges in animal models have been performed at our center,[9,13,14]"
[9] is [2] where "all rats were euthanized after about 36 hours" (p.5). Also, donor mice weighted 50g while recipient mice weighted 300g to avoid circulatory overload, with blood supply of brain tissue being about 25% of cardiac output. Extra human head also could pose significant energetic cost on the recipient body. Human donor and recipient heads will be of about the same weight.
[13] is [3] where "Forty Kunming mice and forty C57 wild type underwent the AHBR procedure. After transplantation, 18 mice survived for 3 h after the ventilator was disconnected". Btw notice that ~80% mice didn't even survived those 3 hours.
[14] is [4] where "Forty Kunming mice and forty C57 wild-type mice underwent the head transplant procedure. After allograft, 12 pairs of mice survived over 24 h. <...> Within 1.5–2 h after transplantation, the both mice regained consciousness". Btw notice that 70% of mice didn't even survived those 24 hours.
So just 3-24-36 hours here. If anything, [9], [13] and [14] are the strongest arguments against feasibility of human head transplantation. When the two teams of world most active proponents of human head transplantation can't (or don't want to) achieve any decent results on model animals, what to speak about? Xiaoping Ren claims to have >1000 mice heads transplanted[5] so it's strange not to see any long-lived mice. As Xiaoping Ren himself stated in 2015, "We want to do this clinically, but we have to make an animal model with long-term survival first"[6]. So they are trying but failing for some reason. In 2014 paper[7] Xiaoping Ren wrote: "Future studies will use electromyography (EMG) to test the action potential of muscles and extend the survival of the mice for a longer time [28]. This will allow signs of immune rejection to be monitored while using immunotherapy. Once the mouse model has been validated, we will build upon it to establish a primate model". 8 years went by. No long survival results, no primate model. Why?

In 2016, S.Canavero claimed that he performed "successful" head transplantation on monkey (no academic paper followed). Monkey was not regained consciousness and was euthanized 20 hours later [8]. So not even close to 1970y Robert J. White 4 experiments with monkeys (which lived 6 hours to 3 days (or 9 days<ref>https://doi.org/10.1007/s40472-018-0196-7</ref>) after operation and one of them tried to bite experimenter after surgery[9]).

1950s - Vladimir Demikhov grafted dog head and upper body to another intact dog. He performed 20 experiments. One of 20 dogs lived for 29 days, 8 dogs lived 5-7 days, 7 dogs lived 2-4 days<ref>V.P. Demikhov, "Peresadka zhiznenno-vazhnykh organov v eksperimente", p.147. Medgiz, 1960.</ref>. The animals died due to transplant rejection as there were no modern efficient immunosuppressor drugs at that time. Transplanted head was less than recipient head; it was taken from puppy or from smaller breed dog<ref>V.P. Demikhov, "Peresadka zhiznenno-vazhnykh organov v eksperimente", p.143. Medgiz, 1960.</ref>. Which is not exactly what we want (heads would be similar in size in human head transplantation).
1970 - Robert J. White grafted monkey head to another monkey. The transplanted head even tried to bite researcher. There were four experiments; monkeys died between 6 hours and 3 days after operation. Some sources claim that one monkey lived 9 days[10]; original article of R.J.White[11] is unavailable via sci-hub.

/As for now, I didn't find anything better than those Robert J.White and Vladimir Demikhov experiments./

Here<ref>https://pubmed.ncbi.nlm.nih.gov/3261017/</ref>, some mice lived up to 7 weeks after head transplantation (and were sacrificed so could have lived even more).
Drawbacks:
1) donor / recipient mass ratio 20g / 250g = ~12 (it's not donor head/recipient body ratio, it's ratio of mice weights)
2) donor is just 14 days old so everything could be very different
3) authors specially killed brain of donor head (p.6) so donor head was filled with connective tissue instead (p.4)
4) authors used inbred isohistogeneic rats so they were very close genetically
Here<ref>https://pubmed.ncbi.nlm.nih.gov/10416153/</ref> 40 days survival is mentioned. However there is no text of article available anywhere. They also used very young head donor (just 10 days old rats) and they were isohistogeneic. Similar work is <ref>https://pubmed.ncbi.nlm.nih.gov/12023062/</ref> where 12/13 days old donors were used. They were sacrificed 10 days after transplantation but here hippocampal and cerebellum were observed to be normal in histologic and histochemical studies. Rats here also seem to be isohistogeneic.

Miscellaneous

Review on head transplantation in 2016[12] doesn't mention other attempts/papers.

In the last years (like from 2017) S.Canavero seems to be more focused on PEG severed spinal cords fusion than on whole topic of head transplantation as can be seen from https://pubmed.ncbi.nlm.nih.gov/?term=Sergio%20Canavero&sort=date

Can we really trust Demikhov report about one exceptional dog who lived 29 days? For 60+ years nobody could repeat that.

Why Demikhov didn't repeat his head transplantation experiments later? Probably, because of stroke in 1968[13] and problems with mutual understanding with the directors of the institutes where he worked[14].
Why Robert J. White (1926-2010) didn't repeat his head transplantation experiments later? He actually wanted to perform human head transplantation in 1990s[15].

List of articles about restoration of spinal cord with PEG etc

[16](2018y) seems to be interesting. While there is criticism [17] it's still a considerable achievement. Anyway, it's some fusion of spinal cord injury in *the same* dog. To fuse two different dogs spinal cords should be more difficult. As the paper says at p.6: "p.6: The minimally disruptive (nanometers) transection of the spinal cord caused damage to a very thin layer of these interneurons whose cell membranes may have been “resealed” acutely by the topically applied PEG". Can we achieve "minimally disruptive (nanometers)" in fusion of spinal cords of two different dogs?