Cord blood, as a source of progenitor cells, has been increasingly used in transplant procedures. However, transplant centers typically use cord blood units that have been processed and obtain by collection centers located elsewhere. This means that efficient cryopreservation procedures have to be in place for therapeutic use that lead to minimal cell loss. The key steps in cord blood banking include:
- Planning and preparation for cryopreservation
- Thawing at the transplant center
Typically, most cord blood banks assess potency, viability and hematocrit content prior to cryopreservation. Thawing of cord blood units after cryopreservation is often a tricky procedure, and one that may lead to the biggest variability in preserved cell viability.
Because thawing, washing and transfusion procedures vary among different centers, there has been an increasing call from the scientific community involved in this area for the standardization of these procedures across the industry.
A recent review paper published last month in Transfusion by Jeffrey McCullough and colleagues at the University of Minnesota reviewed current thawing practices performed across cord blood banks and identified inconsistencies among procedures before recommending elements to consider for more standardized thaw procedures across clinics.
Recommendations include decreasing thaw procedures and requiring validation of processing procedures at transplant labs as well as defining standards for processing. While comprehensive standards are currently not in place, there is an increasing need to provide more standardized approaches for the thawing of cryopreserved material. These recommendations are in addition to the standards for processing that organizations like FACT and AABB have have successfully put in place.
Colleagues in the field are echoing these recommendations set forth by Jeffrey McCullough’s manuscript. AABB and FACT have been called on to enhance inspection related to thawing/washing and transfusion and provide training related to these procedures. FACT has released guidelines with relation to administration of cord blood units. Similarly, AABB has been developing standards for blood banks and transfusion services since 1957.
For instance, AABB publishes Standards for Cellular Therapy Product Services which have formed the basis of AABB’s accreditation programs. Similarly, FACT-JACIE has published International Standards for Cord Blood Collection, Banking, and Release for Administration which can be found here. These, in addition to further initiatives aimed at providing guidelines to the industry, are laudable efforts on the part of FACT and AABB to achieve more comprehensive standardization across the industry. Numerous cord blood banks have been accredited for complying with FACT and AABB’s stringent cord blood banking guidelines.
The new recommendation is to apply the same efforts at providing standards for thawing, washing and transplantation.
New procedures that form the basis of the collective pool of scientific data are consistently appearing in the literature: just recently, a research paper was published outlining an improved procedure for the preservation of progenitor cells in preserved cord blood by storage at 4C prior to cryopreservation.
Whether such procedures can form part of cryopreservation approaches is part of the complexity of the assessment, validation and standardization procedure, and part of the reason why efforts in coming up with validated processes and unified standards have been challenging.
We are curious to hear about your experiences and thoughts about the issue of standardization of washing and thawing procedures for therapy. This is a subject that very much relies on user input, and the summary that we presented above all but scrapes the surface of the complexities of this problem. Nonetheless, we thought it worthwhile to draw attention to this issue so that we can begin this collective discussion. We welcome your thoughts as a comment on this blog or via email to firstname.lastname@example.org.
The RIKEN Center for Developmental Biology in Kobe, Japan, has had a tough year. Lauded at the start of the year for their discovery of STAP cells, the Institute later became the subject of controversy after uncertainty surrounding the papers resulted in their retraction and the suicide of one of the paper’s authors.
But now, hopeful news of a scientific move forward is coming from RIKEN. The Institute just started the first human trial using induced pluripotent stem cells, led by ophthalmologist Dr. Masayo Takahashi.
The media is quickly picking up this story, which involves using iPSCs for the treatment of age-related macular degeneration. Using iPSCs avoids the potential pitfalls associated with using embrokyonic stem cells in humans, owing to their improved immunoresponse and the absence of ethical issues.
Back in January, in an interview with New Scientist, Dr. Masayo Takahashi expressed confident optimism about the trials, but also explained that one of the disadvantages of her treatment – the extremely high cost – is because of the cells being derived from the same patient, as opposed to being allogeneic.
After the final safety green light, the first trial was performed on September 12th.
The patient was a Japanese woman in her 70s. According to RIKEN, a 1.3 x 3 mm sheet of retinal pigment epitelium cells was engrafted into the subretinal space of her eye.
The preliminary nature of this study implies an inherent uncertainty about its outcome, as well as potential risks associated with the treatment, which the scientists involved in the study are fully aware of, as was the patient.
Despite Takahashi’s initial optimism, there is no certainty that the study will reveal a successful therapeutic outcome. Nonetheless, this is a tremendous first step that the scientific community has welcomed with cautious, but hopeful, optimism.
Hypoxia – a term referring to an environment of reduced, or inadequate, oxygen supply – is not new to stem cells. In adult tissues, mesenchymal stem cells (MSCs) reside in environments of varying oxygen concentration, which is frequently below that of ambient conditions. This phenomenon has been receiving increased attention for its potential implications in regenerative medicine. A 2013 review suggested hypoxic culture conditions(2–5% O2 concentration) as being a promising alternative to current conditions for expanding MSCs.
Hypoxia is believed to increase MSC-related bone-healing processes, but the exact mechanism is not yet known. Recently, a number of papers have appeared investigating this phenomenon by analyzing osteogenesis under hypoxic conditions.
The first, from the Armed Forces Biomedical Research Institute in France, analyzed bone-healing efficiency in mouse models by subjecting them to hind-limb unloading. The authors found that bone-repair improvement occurred likely as a result of an improvement of natural bone-healing processes owing to the hypoxic conditions during remodeling, rather than the mobilization of an increased number of MSCs.
Elsewhere, researchers from the University of California Davis investigated how culture conditions (1%, 5% and 21% oxygen) affect the osteogenesis process, and found that hypoxia together with serum deprivation improved osteogenic differentiation of MSCs. The condition of 1% FBS and 5%O2 showed the highest concentration of alkaline phosphatase, which was used to characterize osteogenic efficiency.
Both of these papers are part of an increasing body of work showing how conditions far beyond what is currently considered the “norm” may shed light on improved cellular processes leading to tissue repair.
In tissue engineering, the type, composition and properties of biomaterials used as scaffolds have a profound effect on the regeneration of new tissues. In the case of collagen, for example, its structure and fibrillar arrangement in vivo have a direct affect on its function – such as its ability to withstand mechanical stress – and so optimal scaffold mechanics should provide an environment that mimics the molecular arrangement of collagen fibrils.
Continued improvements in biomaterial design have been able to translate some of these structure-function relationships successfully to yield new in vivo models, and new materials have emerged that provide more optimal environments for cellular growth and tissue reconstruction.
These new “smart” scaffolds generally involve combination and hybrid materials coated with growth factors or cells for improved vascularization. The growth factors are usually chosen so that they mimic specific functions of in vivo tissue and are crucial for optimal engrafment of the implanted scaffolds and to support the function of the newly formed tissue.
The trend toward such “smart” scaffolds has created a number of novel biomaterials with promising regenerative behavior.
In a study published last week in the Proceedings of the National Academy of Sciences, a new combination scaffold, made from a combination of silk protein and a collagen-based gel, coated with rat neurons, was developed as a model of 3D brain-like tissue. The authors, led by Dr. David Kaplan of Tufts University, showed that the neurons managed to grow axons through the scaffold, which itself survived for more than two months in the lab. The authors also founds that neurons in their 3D brain-like tissue exhibited higher expression of genes involved in neuron growth and function.
Elsewhere, novel approaches for improved coating of scaffolds are being developed: researchers at the University of Colorado developed a new 3D scaffold based on PLGA coated with growth factors for controllable bone tissue regeneration. Using a layer-by-layer assembly approach, the authors coated the PLGA scaffolds with platelet-derived growth factor (PDGF) first, followed by bone morphogenetic protein 2 (BMP-2), two most important growth factors for bone repair. By coating PDGF first followed by layers of BMP-2, the authors achieved sustained release of the growth factors in a way that mimics the process of in vivo healing.
Nanotechnology is also emerging as a tool to achieve molecular structures of scaffolds closer to those of native tissue – such as the recent development of nanoparticles – published about in Scientific Reports – for the assembly of collagen scaffolds with fibrillar lamellae that resemble native lamellae.
Such examples of new 3D scaffolds emphasize the importance of combination approaches for developing next generation tissue regeneration substrates and show that scaffolds of the future will benefit multipronged development approaches.
A recent editorial in Nature highlighted the murky landscape of patenting induced pluripotent stem cell (IPSC) discoveries, ultimately concluding that patent thickets might stand as one of the central challenges to the smooth patenting of IPSC technologies. This comes on the heels of the controversial news that Dr. Shinya Yamanaka, professor at Kyoto University who shared the 2012 Nobel Prize in Physiology or Medicine with Dr. John B. Gurdon for their discovery of the ability to reprogram adult stem cells to become pluripotent, had her patent for the discovery challenged by an unknown entity called BioGatekeeper. This news is still unraveling, and little else is known about the challenger or what this will ultimately mean for the technology.
On the subject of IPS cells, two interesting papers have appeared in recent weeks which aim to improve on the technology described in Yamanaka’s patent.
One of them, by the lab of Miguel Ramalho-Santos, associate professor of obstetrics, gynecology, and reproductive sciences at University of California – San Francisco, addresses issues that commonly arise during reprogramming of adult cells and result in low reprogramming efficiency. The authors reported on the discovery of “reprogramming barriers”, in the form of genes which regulate, in their own words, transcription, chromatin regulation, ubiquitination, dephosphorylation, vesicular transport, and cell adhesion. These are, they report, disintegrin and metalloproteinase proteins. However, while these barriers appear to prevent complete reprogramming, they also appear to protect the integrity of adult cells, and have furhter protective effects. The study, titled “Systematic Identification of Barriers to Human iPSC Generation” is published in Cell.
Along similar lines, another new collaborative study published in Stem Cells Translational Medicine titled “Removal of Reprogramming Transgenes Improves the Tissue Reconstitution Potential of Keratinocytes Generated From Human Induced Pluripotent Stem Cells” by Ken Igawa’s lab at Tokyo Medical and Dental University and collaborators at Osaka university, compared the efficiency of reprogrammed human skin cells after removing reprogramming transgenes to reprogrammed cells containing the transgenes. Interestingly, after the cells were differentiated into keratinocytes, the authors observed that reprogramming material-free cells were functionally and morphologically more similar to normal human keratinocytes than cells still containing the genetic reprogramming material. The implications for clinical use are potentially significant, although further investigations should be untertaken to elucidate the exact long-term effect of the removal of such genes. Moreover, studies on additional cell lines should also be carried out and investigated.
To answer the question in the title, can we make IPS cells better? Taken together, these two studies highlight the significance of the presence of genetic material in directing reprogramming and the subsequent fate of reprogrammed cells after differentiation, and it will be interesting to see how they impact further growth of the prolific IPSC field.
Last week, Cytori Therapeutics made news when they announced they had suddenly halted their ATHENA and ATHENA II clinical trials. The company announced the news in a press release, following what it described as “safety review of reported cerebrovascular events.” The company reported that certain patients had observed complications with blood flow to the brain following administration of the therapy. The company claimed:
“Symptoms occurred in three patients, of which two patients’ symptoms fully resolved within a short period of time and the third patient has had substantial resolution of symptoms.“
While it is promising that two of the three patients recovered quickly, the concern is significant enough to put a dent in the proceedings (Cytori’s shares fell by more than 13% following the announcement).
The trials aim to investigate the safety and feasibility of adipose-derived stem cells for the treatment of chronic myocardial ischemia. Speaking to Forbes, Timothy Henry, the co-principal investigator of the trials, claimed that the complications were from the “use of electroanatomical mapping,” which facilitates the intervention and expressed hope for the studies to resume once issues are resolved.
Elsewhere, Bioheart announced that it had successfully completed a combination stem cell treatment using AdipoCell and MyoCell on a patient with congestive heart failure. AdipoCell are Bioheart’s proprietary adipose-derived stem cells, and the news comes on the heels of the successful clinical results on AdipoCell the company reported earlier this year.
These are two examples of the more high-profile trials approved by the FDA that have recently made headlines.
Clearly, isolating stem cells from fat is a growing industry that is expanding in multiple areas: the market for medical devices devoted to the isolation of stem cells from adipose tissue is serious business, with over a dozen companies developing products to enable more efficient isolation of such cells.
On the therapy side, the tide may be turning: Just like the two examples mentioned above indicate, treatments involving the use of adipose-derived stem cells are also growing – however, many of them are still controversial. There have been reported to be over 100 clinics currently administering stem cell treatments around the USA. Many of them, under the umbrella of the Cell Surgical Network, have attracted a lot of interest recently when their practices were brought into question. The specifics were discussed at length elsewhere, but the Network made news recently when Nature Medicine reported on the scientific community’s efforts to pressure the FDA’s Center for Biologics Evaluation and Research to investigate whether the CSN was violating federal regulations governing the administration of stem cell–based products.
Whatever the legalities end up being, we are at an intriguing point for the field of adipose-derived stem cells: both legally as well as from a scientific perspective, the tide is moving forward rapidly.
For more on these cells, we devoted a blog entry on the isolation of stem cells from adipose tissue, wherein we also introduced Matrixyme, Akron’s entry into the adipose tissue derived-stem cell arena. More to follow…
Akron Biotech and Vivex Biomedical, Inc. have just announced a strategic collaboration on the use of Akron’s next-generation line of cryopreservation media, CryoNovo™ in one of Vivex’ therapeutic applications.
CryoNovo™ is Akron’s brand new range of DMSO-free cryopreservation media. Developed to meet the growing needs for efficient cryopreservation of a variety of cells, the CryoNovo™ line includes three products, each tailored to a specific application:
- CryoNovo™ X12 – for the preservation of specialized biological cells
- CryoNovo™ P24 – for the preservation of mesenchymal stem cells
- CryoNovo™ T82 – for the preservation of biological cells
CryoNovo™ media are DMSO-, serum- and glycerol- free. They are also non-toxic and developed from completely natural components.
In the collaboration, Akron’s CryoNovo™ T82 is used in the Vivex process of viable bone allograft preparation.