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.

[agardner]

Thanks Dr. Gardner for your time and patience.

It seems to me that all the research teams are tackling hair growth one step at a time, as would be expected. I'm glad that you've cleared up the fact that no one has achieved full inductivity retention, or full gene expression (many on here didn't seem to understand the difference).

Two ideas as far as restoring characteristics is concerned
a) would it be of any use to not only combine cells, but also add growth factors such as fg9, or whatever compounds are implicated in the wnt pathway, which seems so crucial to follicle growth?
b) shape-wise, and from a designer's perspective, the sheath cup cells seem to be the most crucial as far as keeping everything in line, would it not make sense to start incorporating these into your mix right away? Maybe your epithelial cells are not "sticky" enough because they are only a second part of the puzzle, and you need all the pieces. Just a thought.

Another thing that I'm curious about is if any of you research teams have any solid ideas of why baldness actually happens in a broader sense. I know it is activated by androgens, but is it a matter of every cell in the scalp being programmed and implicated in these changes, or is it just the DP cells that have the receptors, and are sending signals to the environment- or is it the fat cells controlling the game? It seems a big effort has been made to understand the interaction between fat cells and DP cells, and I'm wondering if the key to retaining inductivity and maintaining hair growth doesn't lie in the interaction with the fat in the skin.

The epithelial, DP, and other hair follicle cells seem to be able to work together to create a follicle, but the fact that these follicles are small in vitro, and not the same as healthy hairs begs the question of what it is that they are missing. I doubt full gene expression is the complete answer, and my guess would be that they need to interact with not only epithelial cells, but also whatever other cells are in the scalp. are fat cells the answer? If so, can you guys begin to culture DP spheroids in a way where they are exposed to healthy fat cells?

I think you're right about it being hard to induce and maintain hair in a balding scalp, and thus I don't think any of the research will go anywhere as far as curing alopecia until the roots of the condition are understood (are they?) . A workaround solution could be the creation of follicles in engineered skin, and then the implantation of these follicles with new surrounding tissue, similar to current transplants.

No one has presented, or published work demonstrating full retention of inductivity or gene expression. As I said above “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.”

The addition of growth factors is not desirable for clinical practice. Producing these factors to a clinical standard is very difficult and expensive, it is better to try and induce the cells to make these factors themselves.

I’m not sure what you mean about the sheath cells, do you mean are they important for hair follicle orientation?

The interaction of any constructs with the surrounding tissues is key yes, as I’ve mentioned previously implanting these constructs into skin which has underlying problems will not “cure” baldness. Co-therapies limiting the degradation of any new follicles would be required.

Multi-cell models including adipocytes (fat cells) and melanocytes (cells that provide colouration) are in the works, but I can’t talk about those at the moment .

[agardner]

Are these guys working on an actual cure or treatment, or they only doing research on hair follicle and skin?

Prof. Jahoda’s lab is a research lab not clinical, so we are not directly working towards a clinical trial. However there is nothing limiting other groups more set up to perform clinical trials from using Prof. Jahoda's research in their trials.

[hellouser]

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.

Here's some more info DSC cells;

Some time before 2003 Dr. Rolf Hoffman & Dr. Kevin McElwee published a study on Dermal Sheath Cup Cells inducing hair follicles;

http://www.ncbi.nlm.nih.gov/pubmed/14675169

Shortly after that, the method was patented by Dr. Rolf Hoffman & Dr. Kevin McElwee.

http://www.google.com/patents/US8431400

They're now the guys behind Replicel.

[hellouser]

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.

Bummer, 6-8 weeks to deliver a treatment is almost certainly going to be expensive. Thanks for the clarity!

[agardner]

Thanks for answering questions Dr. Gardner!

Will the color of these new hairs match the existing hairs?

If you have a head of gray hair will the new hair come out gray?

Thanks again!

At the moment they would come out un-pigmented. Incorporation of patient melanocytes (the cells that provide the colouration) is something that is in the works.