12
For the 1st time in Canada, surgeons put teeth in patients' eyes to restore sight (www.cbc.ca)
submitted 2 days ago* (last edited 2 days ago) by otter@lemmy.ca to c/medicine@mander.xyz
4 comments fedilink hide all child comments

cross-posted from: https://lemmy.ca/post/39850196

It involves removing a patient's tooth, usually the canine, installing a plastic optical lens inside it, and then implanting the whole thing into the eye.

top 4 comments
sorted by: hot top controversial new old
[-] isurg@lemm.ee 4 points 2 days ago* (last edited 2 days ago)

I was involved in some research making implants using in part, patients own hair as a support matrix, and I made the 'mistake' or misconception that I think may also be here. That being the concept of it being the 'patients own tissues', and therefore better. However for these more inert tissue types there is no advantage, and you have the disadvantage of not selecting an inert material that might be have more optimal properties, and doesn't require harvesting. So in this example, an artifical bone material, if implanted in the same fashion, would respond in the same way. The notion of it coming from a patients own tooth enamel, might give a 'feel good factor', but in histological terms, does not have the biological advantage you might think it has.

[-] Sal@mander.xyz 2 points 2 days ago

Interesting! I wonder if it is already technically feasible to culture tooth-like pieces from the patient's stem cells. Instead of extracting and carving a tooth, it would be cool to grow the tissue in some kind of structured 3D matrix. Patient gets to keep their canine then.

That said... Do you know if tissue grown from a patient's own stem cells is generally not rejected by the immune system? I am not sure if cells need to differentiate within the body to get labeled by some molecular markers that make them immunocompatible, or if having the same genetic makeup is good enough.

[-] otter@lemmy.ca 1 points 1 day ago* (last edited 1 day ago)

Patient gets to keep their canine then.

That's a good point. I remember seeing an article about tooth re-growing teeth (in ferrets), and while I don't remember if it was stem cells, that might be nicer than having to lose a tooth for an eye.

Do you know if tissue grown from a patient’s own stem cells is generally not rejected by the immune system

My background is a bit limited here, but looking around it seems that it's 'better' but not necessarily 'rejection proof'

HSCT came to mind first, but those are replicated inside the patient:

Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells [...] in order to replicate inside a patient and produce additional normal blood cells. HSCT may be autologous (the patient's own stem cells are used), syngeneic (stem cells from an identical twin), or allogeneic (stem cells from a donor)

Autologous transplants have the advantage of lower risk of infection during the immune-compromised portion of the treatment, since the recovery of immune function is rapid. Also, the incidence of patients experiencing rejection is very rare (and graft-versus-host disease impossible) due to the donor and recipient being the same individual

Induced pluripotent stem cells seem closer:

Since iPSCs can be derived directly from adult tissues, they not only bypass the need for embryos, but can be made in a patient-matched manner, which means that each individual could have their own pluripotent stem cell line. These unlimited supplies of autologous cells could be used to generate transplants without the risk of immune rejection. While the iPSC technology has not yet advanced to a stage where therapeutic transplants have been deemed safe, iPSCs are readily being used in personalized drug discovery efforts and understanding the patient-specific basis of disease.

This other article from 2013 lists a few concerns, and I think this is the closest to what you were looking for: https://pmc.ncbi.nlm.nih.gov/articles/PMC3931018/#sec3

Potential Causes of iPSC Immunogenicity

[...] The first potential cause is immaturity of cells differentiated from iPSCs in vitro. [...] There are a number of human cell types that, to date, can be differentiated only to immature phenotypes in vitro [...] . An immature phenotype poses two risks for immune response, the first being low MHC class I (MHC-I) expression. Natural killer (NK) cells target cells with low MHC-I levels, and although differentiation of iPSCs causes these levels to rise, they may not reach those of adult tissue. [...] Another risk of an immature phenotype is expression of embryonic or fetal proteins. These antigens may not have been present during immune system education to go through negative selection in the thymus, leaving them susceptible to T cell attack. T [...].

A second potential cause of iPSC immunogenicity is genetic and epigenetic changes that arise from reprogramming or adaptation to culture conditions. Recent studies have demonstrated that reprogramming to pluripotency is incomplete and that iPSCs carry an epigenetic memory of their tissue of origin that affects gene expression and can restrict differentiation potential (26–30). [...]

A third potential cause is culturing of iPSCs, or their differentiated progeny, with xenogeneic or non-physiological culture reagents. [...] hESCs take up the non-human sialic acid N-glycolylneuraminic acid (Neu5Gc) from mouse cell feeder layers and animal serum-containing culture media. This represents a risk because humans have circulating antibodies to Neu5Gc (37). Several groups have since developed xeno-free culture conditions for reprogramming and differentiation that reduce or eliminate Neu5Gc expression, although these methods are costly and can be technically challenging (38–40). [...]

[...]

A fun fact I came across on that wikipedia article:

Yamanaka named iPSCs with a lower case "i" due to the popularity of the iPod and other products.

[-] otter@lemmy.ca 2 points 2 days ago

See the crosspost where someone commented a summary of the procedure

this post was submitted on 28 Feb 2025
12 points (92.9% liked)

Medicine

1224 readers
128 users here now

This is a community for medical professionals. Please see the Medical Community Hub for other communities.

Official Lemmy community for /r/Medicine.

!medicine@mander.xyz is a virtual lounge for physicians and other medical professionals from around the world to talk about the latest advances, controversies, ask questions of each other, have a laugh, or share a difficult moment.

This is a highly moderated community. Please read the rules carefully before posting or commenting.

Related Communities

See the pinned post in the Medical Community Hub for links and descriptions. link (!medicine@lemmy.world)

Rules

Violations may result in a warning, removal, or ban based on moderator discretion. The rule numbers will correspond to those on /r/Medicine, and where differences are listed where relevant. Please also remember that instance rules for mander.xyz will also apply.

  1. Flairs & Starter Comment: Lemmy does not have user flairs, but you are welcome to highlight your role in the healthcare system, however you feel is appropriate. Please also include a starter comment to explain why the link is of interest to the community and to start the conversation. Link posts without starter comments may be temporarily or permanently removed. (rule is different from /r/Medicine)

  2. No requests for professional advice or general medical information: You may not solicit medical advice or share personal health anecdotes about yourself, family, acquaintances, or celebrities, seek comments on care provided by other clinicians, discuss billing disputes, or otherwise seek a professional opinion from members of the community. General queries about medical conditions, prognosis, drugs, or other medical topics from the lay public are not allowed.

  3. No promotions, advertisements, surveys, or petitions: Surveys (formal or informal) and polls are not allowed on this community. You may not use the community to promote your website, channel, community, or product. Market research is not allowed. Petitions are not allowed. Advertising or spam may result in a permanent ban. Prior permission is required before posting educational material you were involved in making.

  4. Link to high-quality, original research whenever possible: Posts which rely on or reference scientific data (e.g. an announcement about a medical breakthrough) should link to the original research in peer-reviewed medical journals or respectable news sources as judged by the moderators. Avoid login or paywall requirements when possible. Please submit direct links to PDFs as text/self posts with the link in the text. Sensationalized titles, misrepresentation of results, or promotion of blatantly bad science may lead to removal.

  5. Act professionally and decently: /c/medicine is a public forum that represents the medical community and comments should reflect this. Please keep disagreement civil and focused on issues. Trolling, abuse, and insults (either personal or aimed at a specific group) are not allowed. Do not attack other users' flair. Keep offensive language to a minimum and do not use ethnic, sexual, or other slurs. Posts, comments, or private messages violating Reddit's content policy will be removed and reported to site administration.

  6. No personal agendas: Users who primarily post or comment on a single pet issue on this community (as judged by moderators) will be asked to broaden participation or leave. Comments from users who appear on this community only to discuss a specific political topic, medical condition, health care role, or similar single-topic issues will be removed. Comments which deviate from the topic of a thread to interject an unrelated personal opinion (e.g. politics) or steer the conversation to their pet issue will be removed.

  7. Protect patient confidentiality: Posting protected health information may result in an immediate ban. Please anonymize cases and remove any patient-identifiable information. For health information arising from the United States, follow the HIPAA Privacy Rule's De-Identification Standard.

  8. No careers or homework questions: Questions relating to medical school admissions, courses or exams should be asked elsewhere. Links to medical training communitys and a compilation of careers and specialty threads are available on the /r/medicine wiki. Medical career advice may be asked. (rule is different from /r/Medicine)

  9. Throwaway accounts: There are currently no limits on account age or 'karma'. (rule is different from /r/Medicine)

  10. No memes or low-effort posts: Memes, image links (including social media screenshots), images of text, or other low-effort posts or comments are not allowed. Videos require a text post or starter comment that summarizes the video and provides context.

  11. No Covid misinformation, conspiracy theories, or other nonsense

Moderators may act with their judgement beyond the scope of these rules to maintain the quality of the community. If your post doesn't show up shortly after posting, make sure that it meets our posting criteria. If it does, please message a moderator with a link to your post and explanation. You are free to message the moderation team for a second opinion on moderator actions.

founded 2 years ago
MODERATORS
otter@lemmy.ca
otter@mander.xyz
medgremlin@midwest.social