Q&A with Dr. Aaron Gardner

[Arashi]

what? jahoda's DSC cells only? and in his wife's arm? what about rejection? why did jahoda do that? why not in his own arm?

Good question (about rejection). This experiment "demonstrated a unique immunological privilege of the donor cells". They're not 100% sure why this is, but it seems that molecule "CD200" causes this. This molecule is expressed by by follicle stem cells.

and if DSC cells could do that trick alone, why not concentrate on multiplying those cells and inject them instead?

Also a good question Would also love to hear Aaron's answer. But I think it doesn't really matter if you take DP or DSC cells: both are equally difficult to culture (at least that's what I would think, might be wrong here of course)

[hellouser]

what? jahoda's DSC cells only? and in his wife's arm? what about rejection? why did jahoda do that? why not in his own arm?

and if DSC cells could do that trick alone, why not concentrate on multiplying those cells and inject them instead?

man, i'm totally confused now. i'm lost. it feels like the cure is here already but nobody is willing to go the final step =D

You should ask Dr. Rolf Hoffman and Kevin McElwee from Replicel, thats what they're doing; multiplying DSC cells and injecting them back into the scalp.

[joachim]

ok, so then it absolutely makes sense what Replicel does. i was wondering why they were going the way with DSC cells.

i'm not sure if DSC cells are also that difficult do expand like DP cells.

but the big difference here: if DSC cells could do that trick ALONE, it would be a much easier way i assume, because no need for complex 3D culturing of more than one different cells. (3D spheres, with coating of epithelial cells, and maybe even add DSC cells into the mix).

we need more information about that experiment. it seems too good to be true.

and maybe Dr. Xu is able to convert iPS cells into DSC cells already. if not, who knows... maybe he can figure it out faster than converting to DP cells.

[Arashi]

ok, so then it absolutely makes sense what Replicel does. i was wondering why they were going the way with DSC cells.

i'm not sure if DSC cells are also that difficult do expand like DP cells.

but the big difference here: if DSC cells could do that trick ALONE, it would be a much easier way i assume, because no need for complex 3D culturing of more than one different cells. (3D spheres, with coating of epithelial cells, and maybe even add DSC cells into the mix).

we need more information about that experiment. it seems too good to be true.

and maybe Dr. Xu is able to convert iPS cells into DSC cells already. if not, who knows... maybe he can figure it out faster than converting to DP cells.

I'd say that if the DSC route was easier, then Aaron's group wouldnt be focussing on DP cells, so there's most probably a good reason for it. I would love to hear it anyway !!

[agardner]

with what cell types are currently working in the lab? (of which cells does the follicle consist?)

DP cells
DSC cells
Epithelial cells
ECM? we heard the extracellular matrix is build up automatically when the DP cells come and interact together (according to team Lauster)

are you able (and other researches too) to isolate EVERY different cell type out of the follicle? or is there still a cell type which makes problems and can't be isolated for multiplitication?

Culture of the varying dermal populations is possible, dermal papilla, dermal sheath and inter-follicular dermal fibroblasts. These populations are also relatively easy to expand.

Epithelial cells are more tricky as they tend to terminally differentiate in culture (they are alive, but they do not multiply, they are also less likely to respond to inductive stimuli). Keratinocytes, outer root sheath and hair matrix epithelial cells are all able to be cultured.

Other cells such as melanocytes (for colouration), sebocytes (from the sebaceous gland) and immune system cells is also possible, but again their expansion potential is limited.

[agardner]

Dr. Gardner,

Have you read much about the PGD2 research (eg http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319975/ and http://www.ncbi.nlm.nih.gov/pubmed/24521203 ) and if so may we have your opinion on the potential of this pathway?

Thanks a lot.

Yes, it’s very interesting work. I could see research like this being very important in priming the scalp for transplantation and also maintaining existing follicles and those that have been transplanted/implanted as well as any lab developed constructs.

[agardner]

Dr. Gardner,

Have you read much about the PGD2 research (eg http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319975/ and http://www.ncbi.nlm.nih.gov/pubmed/24521203 ) and if so may we have your opinion on the potential of this pathway?

Thanks a lot.

That paper is describing a technique of growing micro-follicles in the lab, in the same way as that described by the Lauster group. They do not demonstrate complete restoration of in vivo DP character. But I don’t think 100% restoration is required in culture, it won’t hurt but a lot of the character of the DP in vivo is generated by its interactions with surrounding tissue. All we and the other groups are attempting to do is restore enough character to the DP cells to kick start this interaction with a high efficiency.

[agardner]

Aaron, some time ago Desmond posted this link: http://online.liebertpub.com/doi/abs....TEA.2013.0547 and we thought that hairloss was cured since it seemed these guys could now culture cells while keeping all genes expressed. But re-reading that abstract they dont specifically say that 100% genes were expressed. What do you think ? Cause if I understand correctly, once we can culture dp cells (enough of them) while retaining 100% gene expression, then we've overcome a major hurdle and you guys can focus on things like hair growth direction etc, right ?

That paper is describing a technique of growing micro-follicles in the lab, in the same way as that described by the Lauster group. They do not demonstrate complete restoration of in vivo DP character. But I don’t think 100% restoration is required in culture, it won’t hurt but a lot of the character of the DP in vivo is generated by its interactions with surrounding tissue. All we and the other groups are attempting to do is restore enough character to the DP cells to kick start this interaction with a high efficiency.

[agardner]

Dr. Gardener, Has there been any thought regarding your research about injecting the 40% of cultured cells that have reclaimed their genetic character into a balding scalp to see if they can rejuvenate miniaturized follicles, as opposed to creating follicles denovo? And do you have any thoughts as to whether this might be effective, at least to an extent far greater than what Aderans and Replicel have been able to achieve to date? My understanding is that these concepts have been in large part unsuccessful because the cells they are culturing have lost their inductivity. If this is indeed the reason, perhaps the rejuvenation concept is the quickest way forward.

It’s not that 40% of the cells have reclaimed in vivo DP character, rather that the spheres have reclaimed 40% of the character of the DP. There is a group in Taiwan that are undertaking this work as a clinical trial but I don’t know anything about that beyond what is readily available.

[agardner]

I don't quite understand this;

3D culture as we currently do it is relatively laborious. For example creating ~500 spheres would take about an hour. These need to be fed manually every 3 days which would take several hours. There are ways of automating this though, we just don't do this.

Does this mean that the spheres after about an hour would be ready to implant into the scalp, but if held for preservation to implant at a later date, they must be fed every 3 days?

Would this then mean from culturing to implanting we could see all of it done in a matter of hours?

Sorry, I was thinking from a research perspective where we are testing the spheroid cultures. Sphere formation occurs after approximately 24 hours, but I would expect they would be left longer to adhere more tightly to each other.
The DP cell number needs to be increased in 2D expansion culture first which is the time consuming step, so from isolation to re-implantation I think a timeline of 6-8 weeks would be feasible.