Adipogenic differentiation of human adipose tissue-derived stem cells obtained from cryopreserved adipose aspirates

How to maintain and transport equine adipose tissue for isolating mesenchymal stem cells?

BACKGROUND

Adipose tissue (AT) is one of the most important mesenchymal stem cell (MSC) sources because of its high quantities, availability and ease of collection. After being collected samples, they should be transported to a laboratory for stem cell (SC) isolation, culture and expansion for future clinical application. Usually, laboratories are distant from animal husbandry centers; therefore, it is necessary to provide suitable conditions for adipose tissue transportation, such that adipose-derived MSCs are minimally affected. In the current study, the impact of tissue maintenance under different conditions on MSCs derived from these tissues was evaluated. We aimed at finding suitable and practical transportation methods in which ASCs go through the slightest changes.

RESULTS

In the current study, after being collected, equine AT was randomized into eight groups: four samples were maintained in stem cell culture media at 25 ^οC and 4 ^οC for 6 and 12 hrs. as transportation via SC media groups. Three samples were frozen at three different temperatures (- 20, - 75 and - 196 ^οC) as cryopreserved groups; these samples were defrosted 1 week after cryopreservation. Fresh and unfrozen AT was evaluated as a control group. The tissue samples were then initiated into enzymatic digestion, isolation and the culturing of SCs. Cells at passage three were used to evaluate the ability to form colonies, proliferation rate, plotting of the cell growth curve, and viability rate. All experiments were performed in triplicate. Stem cell isolation was successful in all groups, although purification of SCs from the first series of cryopreservation at - 196 ^οC and two series of - 20 ^οC was unsuccessful. There was no significant difference between the surface area of colonies in all groups except for - 20 ^οC. The growth rate of transportation via stem cell media at 25 ^οC for 6 hrs. was similar to that of the control group. MTT analysis revealed a significant difference between 25 ^οC 12 hrs. Group and other experimental groups except for control, 4 ^οC 12 hrs. and - 196 ^οC group.

CONCLUSION

Data have shown freezing at - 75 ^οC, transportation via stem cell media at 4 ^οC for 12 hrs. and 25 ^οC for 6 hrs. are acceptable tissue preservation and transportation methods due to minor effects on MSCs features.

Cryopreserved human adipose-derived stromal vascular fraction maintains fracture healing potential via angiogenesis and osteogenesis in an immunodeficient rat model

Background

Novel therapeutic strategies for the healing of nonunion, which has serious effects on the quality of life of patients, are needed. We evaluated the therapeutic effect of local transplantation of human stromal vascular fraction (SVF) cells on fracture healing in a rat non-healing fracture model and compared the effects between freshly isolated (F) and cryopreserved (C)-SVFs.

Methods

Non-healing fracture model was induced in the femur of female immunodeficient rats (F344/N Jcl rnu/rnu) with cauterizing periosteum. Immediately after the creation of non-healing fracture, rats received local transplantation of F and C-SVFs suspended in phosphate-buffered saline (PBS) or the same volume of PBS without cells using the same scaffold as a control group. During 8 weeks post-surgery, radiologic, histological, immunohistochemical, and biomechanical analyses were performed to evaluate fracture healing. The comparison of radiological results was performed with a chi-square test, and the multiple comparisons of immunohistochemical, histological, and biomechanical results among groups were made using a one-way analysis of variance. A probability value of 0.05 was considered to denote statistical significance.

Results

At week 8, in 60% of animals receiving F-SVF cells and in 50% of animals receiving C-SVF cells, the fracture radiologically healed with bone union whereas nonunion was observed in the control group. The healing potential was also confirmed by histological and biomechanical assessments. One of the mechanisms underlying healing involving intrinsic angiogenesis/osteogenesis was enhanced in F- and C-SVF groups compared with that in the control group. Human cell-derived vasculogenesis/osteogenesis, which was also confirmed in an in vitro differentiation assay, was also enhanced in the F- and C-SVF groups compared with that in the control groups and could be another mechanism for healing.

Conclusions

SVF cells can enhance bone healing and cryopreserved cells have almost equal potential as fresh cells. SVF cells can be used for improving nonunion bone fracture healing as an alternative to other mesenchymal stem cells and the effect of SVF cells can be maintained under cryopreservation.

Mesothelial Stem Cells and Stromal Vascular Fraction for Skin Rejuvenation

The use of stem cells in regenerative medicine and specifically facial rejuvenation is thought provoking and controversial. Today there is increased emphasis on tissue engineering and regenerative medicine, which translates into a need for a reliable source of stem cells in addition to biomaterial scaffolds and cytokine growth factors. Adipose tissue is currently recognized as an accessible and abundant source for adult stem cells. Cellular therapies and tissue engineering are still in their infancy, and additional basic science and preclinical studies are needed before cosmetic and reconstructive surgical applications can be routinely undertaken and satisfactory levels of patient safety achieved.

Successful isolation of viable adipose-derived stem cells from human adipose tissue subject to long-term cryopreservation: positive implications for adult stem cell-based therapeutics in patients of advanced age

We examined cell isolation, viability, and growth in adipose-derived stem cells harvested from whole adipose tissue subject to different cryopreservation lengths (2–1159 days) from patients of varying ages (26–62 years). Subcutaneous abdominal adipose tissue was excised during abdominoplasties and was cryopreserved. The viability and number of adipose-derived stem cells isolated were measured after initial isolation and after 9, 18, and 28 days of growth. Data were analyzed with respect to cryopreservation duration and patient age. Significantly more viable cells were initially isolated from tissue cryopreserved <1 year than from tissue cryopreserved >2 years, irrespective of patient age. However, this difference did not persist with continued growth and there were no significant differences in cell viability or growth at subsequent time points with respect to cryopreservation duration or patient age. Mesenchymal stem cell markers were maintained in all cohorts tested throughout the duration of the study. Consequently, longer cryopreservation negatively impacts initial live adipose-derived stem cell isolation; however, this effect is neutralized with continued cell growth. Patient age does not significantly impact stem cell isolation, viability, or growth. Cryopreservation of adipose tissue is an effective long-term banking method for isolation of adipose-derived stem cells in patients of varying ages.

Microfat Grafting in Nasal Surgery

BACKGROUND

Injectable fillers are sometimes necessary to correct slight skin irregularities. However, there have been reports of necrosis after injection of alloplastic materials and heterogeneous transplants. On the other hand, the advantages of autogenous tissue grafts over those fillers are well established. Volumetric reshaping of the face with autologous tissue injection is a popular and reliable method with good long-term results. However, procedures performed on the fragile skin of the nose are prone to complications.

OBJECTIVES

The author conducted a study of injectable autologous microfat grafting to the nose in patients with secondary nasal deformities.

METHODS

During a 5-year period, 313 patients who had secondary nasal deformities with slight skin irregularities or severe nasal skin damage were treated with microfat grafting. At each patient's first injection session, excess harvested fat was cryopreserved for subsequent injection. To correct minor irregularities, 0.3 to 0.8 mL of microfat was injected during each session; for major irregularities or defects, 1 to 6 mL was required for each session.

RESULTS

One to 3 injections of microfat provided satisfactory results in all patients who had minor irregularities. For patients with multiple and severe irregularities, 3 to 6 injections were necessary and resulted in high patient satisfaction. In another group of patients, with severe traumatic skin damage, 6 to 16 injections were necessary for reconstruction. After repeated injections, each patient's skin damage was repaired.

CONCLUSIONS

Autologous microfat injection appears to be safe and effective for correcting slight irregularities of the nose.

LEVEL OF EVIDENCE

4.

The effect of lipoaspirates cryopreservation on adipose-derived stem cells

BACKGROUND

Autologous fat grafting has gained popularity, particularly with the discovery of adipose-derived stem cells (ADSC). The possibility of freezing lipoaspirates (LA) for later use has intriguing clinical potential. However, the effect of LA cryopreservation on ADSC is unclear.

OBJECTIVES

The authors explore the effect of LA cryopreservation on ADSC viability.

METHODS

Human LA (n = 8) were harvested using a standard technique. Lipoaspirate samples were either processed immediately as fresh LA (A) or stored at -20°C and then at -80°C for 30 days with (B) or without (C) freezing medium. Stromal vascular fraction (SVF) was separated from adipocytes and either cultured to obtain purified ADSC or processed for the isolation of 3 distinct ADSC subpopulations (CD90(+)/CD45(-), CD105(+)/CD45(-), and CD34(+)/CD31(-)). Apoptosis and necrosis were determined by an annexin V/propidium iodide assay and quantified by flow cytometry. The capability of ADSC for long-term proliferation and differentiation was also examined.

RESULTS

There were no significant differences in the apoptosis and necrosis of adipocytes, SVF, or ADSC between groups A and B. However, cell viability in SVF and ADSC was significantly compromised in group C as compared with group B (P < .01) due to higher ADSC apoptosis but not necrosis. The viable ADSC isolated from fresh or frozen LA were cultured for more than 20 passages and demonstrated similar patterns and speed of proliferation with strong capability to differentiate, evidenced by cell doubling time and positive staining with Oil Red O (Sigma-Aldrich, St Louis, Missouri) and alkaline phosphatase.

CONCLUSIONS

Lipoaspirates cryopreservation had a significant impact on ADSC apoptosis but not on ADSC necrosis, proliferation, or differentiations. Freezing medium provides significant protection against ADSC apoptosis.

Porcine adipose tissue-derived mesenchymal stem cells retain their proliferative characteristics, senescence, karyotype and plasticity after long-term cryopreservation

We and others have provided evidence that adipose tissue-derived mesenchymal stem cells (ASCs) can mitigate rat cardiac functional deterioration after myocardial ischemia, even though the mechanism of action or the relevance of these findings to human conditions remains elusive. In this regard, the porcine model is a key translational step, because it displays heart anatomic-physiological features that are similar to those found in the human heart. Towards this end, we wanted to establish the cultural characteristics of porcine ASCs (pASCs) with or without long-term cryostorage, considering that allogeneic transplantation may also be a future option. Compared to fresh pASCs, thawed cells displayed 90-95% viability and no changes in morphological characteristics or in the expression of surface markers (being pASCs characterized by positive markers CD29(+); CD90(+); CD44(+); CD140b(+); CD105(+); and negative markers CD31(-); CD34(-); CD45(-) and SLA-DR(-); n = 3). Mean population doubling time was also comparable (64.26±15.11 hours to thawed cells vs. 62.74±18.07 hours to fresh cells) and cumulative population doubling increased constantly until Passage 10 (P10) in the entire cell population, with a small and gradual increase in senescence (P5, 3.25%±0.26 vs. 3.47%±0.32 and P10, 9.6%±0.29 vs. 10.67%±1.25, thawed vs. fresh; SA-β-Gal staining). Chromosomal aberrations were not observed. In addition, under both conditions pASCs responded to adipogenic and osteogenic chemical cues in vitro. In conclusion, we have demonstrated the growth characteristics, senescence, and the capacity of pASCs to respond to chemical cues in vitro and have provided evidence that these properties are not influenced by cryostorage in 10% DMSO solution.

Facial rejuvenation with staged injections of cryopreserved fat and tissue cocktail: clinical outcomes in the past 10 years

BACKGROUND

Facial rejuvenation by autologous fat transfer is common in aesthetic plastic surgery. The main drawback is progressive resorption, requiring repeated harvesting and microfat grafting.

OBJECTIVE

The authors present a method for cryopreservation of excess harvested fat and tissue to enable subsequent use of previously harvested excess material.

METHODS

Fat grafts were harvested using a 50-mL syringe and a 3- or 4-mm cannula. A tissue "cocktail" composed of dermis, fascia, and fat was prepared from excised scar tissue, tissue from abdominoplasty, or tissue from reduction mammaplasty. Cocktail specimens were placed in sterile tubes, immersed in a liquid nitrogen tank (-196°C), and stored at -80°C. At 3- to 6-month intervals, repeated cryopreserved fat graft injections were performed. Patients were evaluated by comparing preoperative and postoperative photographs.

RESULTS

Between 2000 and 2010, a total of 5199 cryopreserved fat or tissue injections were performed in 2439 consecutive patients (age range, 19-80 years). Nasolabial folds and lips were the most common injection sites. Clinical outcomes were satisfactory, and improved contour was achieved in most patients after repeated injections.

CONCLUSIONS

Cryopreservation of excess tissue for future injection is promising since repetitive injections are often required after resorption of microfat grafts. In our study, the survival of cryopreserved tissue cocktail or fat was comparable to that of fresh fat grafts and is therefore an effective adjuvant method for facial rejuvenation.

Non-invasive cryolipolysis for body contouring in Chinese--a first commercial experience

BACKGROUND

The objective of the study is to determine the clinical efficacy and patient satisfaction of a novel cryolipolysis device (Zeltiq®) for body contouring in Chinese after a single treatment and after 2 treatments at a commercial setting.

MATERIALS AND METHODS

Two groups of patients were recruited for this procedure at their own cost. Group A, 21 subjects, received a single treatment and group B, 12 subjects, received 2 treatments, average 3 months apart using the Zeltiq Breeze System®. The thickness of fat at the treatment site was measured by a caliper and the data were collected at baseline and 2 months post-treatment. Standardized clinical photos were also taken at baseline and follow-up visits. Subjective assessment was carried out in the form of a questionnaire. Any adverse effects were documented. Statistical analyses were performed on the data to compare the efficacy after a single treatment and after 2 treatments.

RESULTS

The first group of subjects, received a single treatment, showed that there was a significant improvement (P < 0.0001). The second group of subjects showed that the improvement was significant after 1 and 2 treatments when compared to the baseline. The extent of improvement after the second treatment however, was not as dramatic as the first treatment.

CONCLUSION

Non-invasive cryolipolysis is effective for body contouring in Chinese. It is shown to have a further improvement with subsequent treatment sessions but of a lesser extent. The second treatment was statistically significant for abdomen, though not for love handles.

Current methods of adipogenic differentiation of mesenchymal stem cells

There has been a recent increase in our understanding in the isolation, culture, and differentiation of mesenchymal stem cells (MSCs). Concomitantly, the availability of MSCs has increased, with cells now commercially available, including human MSCs from adipose tissue and bone marrow. Despite an increased understanding of MSC biology and an increase in their availability, standardization of techniques for adipogenic differentiation of MSCs is lacking. The following review will explore the variability in adipogenic differentiation in vitro, specifically in 3T3-L1 and primary MSCs derived from both adipose tissue and bone marrow. A review of alternative methods of adipogenic induction is also presented, including the use of specific peroxisome proliferator-activated receptor-gamma agonists as well as bone morphogenetic proteins. Finally, we define a standard, commonly used adipogenic differentiation medium in the hopes that this will be adopted for the future standardization of laboratory techniques--however, we also highlight the essentially arbitrary nature of this decision. With the current, rapid pace of electronic publications, it becomes imperative for standardization of such basic techniques so that interlaboratory results may be easily compared and interpreted.

Effects of expanded human adipose tissue-derived mesenchymal stem cells on the viability of cryopreserved fat grafts in the nude mouse

Adipose-derived mesenchymal stem cells (AdMSCs) augment the ability to contribute to microvascular remodeling in vivo and to modulate vascular stability in fresh fat grafts. Although cryopreserved adipose tissue is frequently used for soft tissue augmentation, the viability of the fat graft is poor. The effects of culture-expanded human adipose tissue-derived mesenchymal stem cells (hAdMSCs) on the survival and quality of the cryopreserved fat graft were determined. hAdMSCs from the same donor were mixed with fat tissues cryopreserved at -70 °C for 8 weeks and injected subcutaneously into 6-week-old BALB/c-nu nude mice. Graft volume and weight were measured, and histology was evaluated 4 and 15 weeks post-transplantation. The hAdMSC-treated group showed significantly enhanced graft volume and weight. The histological evaluation demonstrated significantly better fat cell integrity compared with the vehicle-treated control 4 weeks post-transplantation. No significant difference in graft weight, volume, or histological parameters was found among the groups 15 weeks post-transplantation. The hAdMSCs enhanced the survival and quality of transplanted cryopreserved fat tissues. Cultured and expanded hAdMSCs have reconstructive capacity in cryopreserved fat grafting by increasing the number of stem cells.