What point are you trying to make with that abstract? That skin is part of the integumentary system so it also has a correlation with hair? That would just further prove my argument as valid. This is what your abstract says:
"This bioengineered 3D integumentary organ system was fully functional following transplantation into nude mice" so that would include hair and skin.
Incase you want to try and counter argue that I'll go ahead and 1up you right now.
Here is what Dr. Costarelis from Follica (another major researcher in the hair loss industry) has to say:
http://www.healthline.com/health-news/re-growing-teeth-and-healing-wounds-without-scars#5
"Our study showed hair and fat develop separately but not independently"
Before you go and say fat is not skin, read all of the information he provides from the site I linked and you'll understand why he's simply breaking it down by talking about adipose fat which then allows skin to regenerate as new and healthy instead of scarred tissue.
Myofibroblasts can be converted to adipocytes by wounding and it instructs the skin to regenerate instead of scar which also allows generates hair.
Here is further proof for you.
https://www.google.com/amp/s/futuri...-discovered-how-to-regenerate-human-skin/amp/
And on this next site down below he clearly states there's a link between skin and hair which of course makes sense because after all, they are part of your "integumentary organ system" that your abstract talks about which btw further validates my assumption.
Here is one more site and I'll give you a quote from it since I know you won't read it.
http://www.xconomy.com/boston/2013/06/03/hair-raising-follica-study-could-point-to-baldness-therapy/
“It draws a very clear link between tissue regeneration and the skin immune system"
Based on all my sources and your abstract I will say: "yes it is skin we're talking about." Both skin and hair in fact because yes they are both part of the integumentary system.