Tissue engineered cartilage from autologous, dermis-isolated, adult, stem (DIAS) cells
Grant Award Details
Tissue engineered cartilage from autologous, dermis-isolated, adult, stem (DIAS) cells
- This project is developing skin-derived stem cells for engineered cartilage. They have identified a cell population they refer to as dermis isolated adult stem (DIAS) cells. They are using these cells to develop autologous skin cell-derived articular cartilage to use for cartilage injury repair. The objective of this DCF project is to first demonstrate a comparable cell population from human skin and then to show safety and efficacy of DIAS cell-engineered cartilage in vivo in small and large animal models.
Bone or Cartilage Disease
Cartilage degeneration resulting from injuries or wear-and-tear leads to osteoarthritis, which impacts millions and costs in excess of $65B per annum. No long-term solutions exist for cartilage degeneration, but cellular therapies hold promise toward replacing degenerated cartilage with healthy tissue. This Development Candidate Feasibility Award is a first step toward the overall goal of developing a cell-based cartilage repair therapy using stem cells derived from the skin. The therapy would consist of using a skin biopsy to harvest dermis-isolated, adult stem cells (DIAS cells), which will undergo processing to yield neocartilage. This neocartilage will then be implanted into the patient’s joint to restore or improve mobility.
Work during this progress report period has been divided into project preparation and scientific progress. Project preparation includes setting up facilities and approvals for work with human DIAS cells, identifying sources and acquiring human skin for DIAS cell isolation, and hiring and training personnel. Scientific progress includes a publication on co-cultures using stem cells, work on culturing larger numbers of cells using low oxygen tension, comparing stem cells from human skin of different anatomical locations, and gaining an understanding of the niches where skin stem cells may reside.
The project now has a consistent source of human dermis tissue from which stem cells can be isolated. This includes skin containing hair follicles and also skin without follicles. Spherical culture of human skin-derived stem cells has been performed. It was found that directing stem cells into cells that make cartilaginous matrix can be more efficacious if done under low oxygen tension. Since much of the prior work on directing stem cells from the skin to form neocartilage has been done using animal-derived stem cells, in the next project period neocartilage will be formed using human stem cells instead. Technologies developed using animal models can thus be translated toward human use.
Resulting from injuries or wear-and-tear that leads to osteoarthritis, cartilage degeneration is a problem that costs in excess of $65B per annum. Toward developing a long-term solution for this vexing problem, cellular therapies hold the promise of replacing degenerated cartilage with healthy tissue. This Development Candidate Feasibility Award is a first step toward the overall goal of developing a cell-based cartilage repair therapy using stem cells derived from the skin. The therapy would begin with a biopsy of the patient’s own skin to harvest dermis isolated, adult stem cells (DIAS cells), which will undergo processing to yield neocartilage. This neocartilage will then be implanted into the patient’s joint to restore or improve mobility.
During this progress report period, a major milestone has been completed. Previously, DIAS cells have been isolated from various animal models, including sheep, goat, and rabbit. Comparing animal skin and human skin showed notable differences, including morphology, response to enzymatic digestion, and the rate at which cells attach to tissue culture plastic. As a result, protocols that successfully yielded DIAS cells using animal models could not be directly applied to isolating DIAS cells from human skin. During the first six months of this reporting period, human DIAS cells were isolated and used to engineer neocartilage. Characterizing the human DIAS cell population showed that cells shared similar characteristics with stem and progenitor cells previously identified by other groups as originating from various niches of the skin. Neocartilage constructs formed using human DIAS cells were found to contain twice as much glycosaminoglycans and three times more collagen; these are cartilage extracellular matrix component important in imparting mechanical function to the tissue. Neocartilage constructs generated from human DIAS cells also contained five times higher compressive modulus and close to twice the tensile modulus of constructs generated using sheep DIAS cells. The completion of this important milestone allowed for progression to the next milestones of this award.
Milestone 2 of this award consists of examining safety of the engineered constructs in a small animal model. For the scaling-up of constructs to be used in an athymic mouse study, an experiment was conducted to finalize our protocol for generating human DIAS cell constructs, using what have been learned both from Milestone 1 and also from literature sources. Three methods for generating neocartilage constructs were examined. While the resultant constructs did not differ in mechanical properties, one method nonetheless yielded constructs of more uniform size and greater cell and glycosaminoglycan content.
For milestones 3 and 4, the originally proposed studies were to implant autologous neocartilage constructs in intermediate and large animal studies to examine efficacy of repair. To improve the translational potential of this project, CIRM has requested that neocartilage constructs of human origin be used instead. To ensure that the implanted constructs are not rejected, progress during this reporting period also includes identifying methods to immunosuppress intermediate and large animal models.
To summarize, progress during this reporting period includes the completion of Milestone 1 and work toward all other milestones of this award. Additionally, two papers have been published thus far to disseminate scientific findings to the public.
Articular cartilage injuries and degeneration eventually lead to osteoarthritis, costing $65B per year and affecting over 25% of adults over the age of 65. This Development Candidate Feasibility (DCF) Award seeks to address cartilage defects classified by the International Cartilage Repair Society (ICRS) as grades II-IV with the intent of halting the progression of cartilage damage before it creates arthritic changes in joint compartments. The therapy would begin with a biopsy of the patient’s own skin to harvest dermis isolated, adult stem cells (DIAS cells), which will undergo processing to yield neocartilage. This neocartilage will then be implanted into the patient’s joint to restore or improve mobility. The project objective has not changed from previous progress reports, though new milestones have been proposed during this reporting period and approved by CIRM, as described below.
Milestone 1 was completed and, after reporting of preliminary data from Milestone 2, a prior approval request was submitted with a description of critical path experiments to amend the milestones, and a no cost extension was also submitted. These have been approved by CIRM. The new, remaining milestones to be completed consist of: three studies in the athymic mice using human DIAS neocartilage generated from foreskin, breast skin, and abdominal skin, from multiple donors (Milestone 2); a study to apply aggregate redifferentiation to human DIAS cells to yield cells with a chondrogenic phenotype (Milestone 3), and the rabbit study as initially approved, using human DIAS cells and with an abridged timeline (Milestone 4).
As proposed and approved, the three athymic mouse studies are currently in progress. The mouse portion of the first study, using breast skin-derived DIAS cells, has been completed. Studies using abdominal skin- and foreskin-derived DIAS cells are on track for completion in March and April, 2016. The aggregation redifferentiation study is currently ongoing, and neocartilage constructs have yet to be generated. The rabbit study is under planning for its immunosuppression component. Additionally, a paper was published during this reporting period to disseminate scientific findings to the public.
This Development Candidate Feasibility (DCF) Award seeks to address cartilage defects classified by the International Cartilage Repair Society (ICRS) as grades II-IV with the intent of halting the progression of cartilage damage before it creates arthritic changes in joint compartments. The medical significance of this project is that articular cartilage injuries and degeneration eventually lead to osteoarthritis, which costs $65B per year and affects over 25% of adults over the age of 65. The envisioned therapy would begin with a biopsy of the patient’s own skin to harvest dermis isolated, adult stem cells (DIAS cells), which would undergo processing to yield neocartilage. This neocartilage would then be implanted into the patient’s joint to restore or improve mobility.
Milestone 1 was completed, and, after reporting of preliminary data from Milestone 2, a prior approval request was submitted and approved with revised milestones. These, too, have now been completed.
For Milestone 2, three studies in the athymic mice using human DIAS neocartilage generated from foreskin, breast skin, and abdominal skin, from multiple donors were conducted to determine whether variability existed due to anatomical location and different donors. The goal was to determine whether engineered constructs would maintain stability, integrity, and viability in vivo without eliciting adverse effects. Anatomical and donor variability were found, with foreskin-derived human DIAS cells displaying constructs with the lowest level of donor variability; all of the foreskin-derived constructs retained stability, integrity, and viability. Regardless of anatomical location and donors, no DIAS cell-derived constructs elicited adverse host responses.
Milestone 3 consisted of a study to apply aggregate redifferentiation to human DIAS cells to yield cells with a chondrogenic phenotype. The aggregate redifferentiation technique, previously optimized in animal models, has also shown efficacy with human marrow-derived mesenchymal stem cells. Applied to constructs formed using human foreskin-derived DIAS cells, aggregate redifferentiation was shown to be efficacious in improving the biochemical and biomechanical properties of the constructs. Specifically, the constructs contained more cells and extracellular matrix. The compressive properties of constructs that had been formed with aggregate redifferentiated human DIAS cells were also higher than those of controls.
Milestone 4 consisted of determining whether over 75% of the engineered constructs would retain mechanical integrity after orthotopic implantation in a rabbit model. The mechanical properties of the engineered constructs were not sufficiently high to survive cycling within rabbit knees ex vivo after being placed in cartilage defects. Additional work needs to be performed to strengthen the human DIAS cell constructs for implantation; the goal would be to attain the mechanical properties currently achievable with differentiated cartilage cells derived from animal models.
Grant Application Details
- Tissue engineered cartilage from autologous, dermis-isolated, adult, stem (DIAS) cells
This study addresses the cartilage defects resulting from injuries or from wear-and-tear that can eventually degenerate to osteoarthritis. This is a significant problem that impacts millions and costs in excess of $65B per annum in the US alone. Addressing this indication successfully holds potential for halting the progression of cartilage damage before it destroys the entire joint. We have shown that articular cartilage can be engineered with properties on par with native tissues using chondrocytes. Also, skin derived stem cells can be used to engineer new cartilage with significant mechanical integrity. Combining these findings, the new cellular therapy that this proposal seeks to develop is an autologous skin cell-derived combination product for articular cartilage repair. Three aims are proposed to advance this autologous, adult stem cell-based method: First, protocols shown to be efficacious in cartilage tissue engineering will be applied to skin-derived stem cells and show safety in the mouse model. Then, using a preclinical model, the desired biological response, toxicology, and durability will be verified. Finally, short-term safety and efficacy of cartilage repair will be examined in a different preclinical model. Successful completion of this DCF project will allow the start of preclinical studies in the sheep that demonstrate long-term safety and efficacy, as specified by the FDA.
Statement of Benefit to California:
Arthritis is the leading cause of disability in the US, affecting over 46 million Americans. Of these, over 5 million Californians are affected by this debilitating disease, with roughly 3 million that are women and over 2 million that are men. Additionally, Californian youth is also included in the estimated 30 million children who participate in organized sports activities, whose yearly costs for injuries have been projected to be $1.8 billion. For young patients with knee injuries, 75% exhibit superficial (grade I–II) and 25% exhibit deep (grade III–IV) cartilage lesions. Young patients not only need to retain mobility for many years in life but also new, tissue-sparing techniques. This proposal seeks to develop an autologous, adult stem cell-based therapy that addresses grade II-IV cartilage lesions. The source of these cells will be the skin, using minimally invasive procedures. The development of such a therapy would expand the clinical options available to Californians. The assembled team of academics, orthopaedic surgeons, and veterinary surgeons are based in the [REDACTED]. The refinement of this research will not only benefit [REDACTED] in terms of increasing competitiveness for NIH funding, but it will also allow for Californian companies to license the technology and therefore benefit economically.
Source URL: https://www.cirm.ca.gov/our-progress/awards/tissue-engineered-cartilage-autologous-dermis-isolated-adult-stem-dias-cells