Clinical and preclinical approach in AGA treatment: a review of current and new therapies in the regenerative field

Androgenetic alopecia (AGA) is the most prevalent type of hair loss. Its morbility is mainly psychological although an increased incidence in melanoma has also been observed in affected subjects. Current drug based therapies and physical treatments are either unsuccessful in the long term or have relevant side effects that limit their application. Therefore, a new therapeutic approach is needed to promote regenerative enhancement alternatives. These treatment options, focused on the cellular niche restoration, could be the solution to the impact of dihydrotestosterone in the hair follicle microenvironment. In this context emerging regenerative therapies such as Platelet-rich plasma or Platelet-rich fibrine as well as hair follicle stem cells and mesenchymal stem cell based therapies and their derivatives (conditioned medium CM or exoxomes) are highlighting in the evolving landscape of hair restoration. Nanotechnology is also leading the way in AGA treatment through the design of bioinks and nanobiomaterials whose structures are being configuring in a huge range of cases by means of 3D bioprinting. Due to the increasing number and the rapid creation of new advanced therapies alternatives in the AGA field, an extended review of the current state of art is needed. In addition this review provides a general insight in current and emerging AGA therapies which is intented to be a guidance for researchers highlighting the cutting edge treatments which are recently gaining ground.

Efficacy of Adipocyte-Derived Stem Cells-Conditioned Media in Telogen Effluvium

Objectives

To assess the effectiveness of adipocyte-derived mesenchymal stem cells-conditioned media (ADSC-CM) formulation in telogen effluvium patients.

Methods

A retrospective cohort study was conducted at a dermatology clinic in Jeddah, Saudi Arabia. The study included 50 consecutive patients aged 20-70 years, who were diagnosed with telogen effluvium. All patients received five monthly sessions of the same commercial ADSC-CM formulation, using a standardized application protocol. Pre- and post-intervention changes in trichometry parameters were analyzed.

Results

There was a significant increase in mean hair density (up to 29.01 hair/cm2; effect size 0.7-1.0), cumulative hair thickness (up to 2.67 units; effect size 0.7-1.4), and the number of follicular hair units (up to 19.96%; effect size 1.0-1.3) in all scalp regions (p < 0.001), associated with a decrease in mean trichometry-derived Sinclair scale by 0.8-1.3 (p < 0.001). Positive outcomes were observed in 70%-92% of the patients depending on the parameter and scalp region. There was no impact of the patient's age on ADSC-CM efficacy.

Conclusion

ADSC-CM was successfully applied as a new treatment option for patients with telogen effluvium. These findings provide another therapeutic and research area for dermatologists to optimize the management of telogen effluvium and reduce its impact on patients.

Adipose-derived stem cells applied in skin diseases, wound healing and skin defects: a review

Adipose tissue presents a comparably easy source for obtaining stem cells, and more studies are increasingly investigating the therapeutic potential of adipose-derived stem cells. Wound healing, especially in chronic wounds, and treatment of skin diseases are some of the fields investigated. In this narrative review, the authors give an overview of some of the latest studies concerning wound healing as well as treatment of several skin diseases and concentrate on the different forms of application of adipose-derived stem cells.

Tissue Engineering and Regeneration of the Human Hair Follicle in Androgenetic Alopecia: Literature Review

Androgenetic alopecia (AGA) is an androgen-dependent process and represents the most frequent non-scarring alopecia. Treatments for AGA do not always achieve a satisfactory result for the patient, and sometimes cause side effects that lead to discontinuation of treatment. AGA therapeutics currently includes topical and oral drugs, as well as follicular unit micro-transplantation techniques. Tissue engineering (TE) is postulated as one of the possible future solutions to the problem and aims to develop fully functional hair follicles that maintain their cyclic rhythm in a physiological manner. However, despite its great potential, reconstitution of fully functional hair follicles is still a challenge to overcome and the knowledge gained of the key processes in hair follicle morphogenesis and biology has not yet been translated into effective replacement therapies in clinical practice. To achieve this, it is necessary to research and develop new approaches, techniques and biomaterials. In this review, present and emerging hair follicle bioengineering strategies are evaluated. The current problems of these bioengineering techniques are discussed, as well as the advantages and disadvantages, and the future prospects for the field of TE and successful hair follicle regeneration.

Regenerative Medicine Treatments for Androgenetic Alopecia

Regenerative medicine and the role of stem cells are being studied for applications in nearly every field of medicine. The pluripotent nature of stem cells underlies their vast potential for treatment of androgenic alopecia. Several advances in recent years have heightened interest in this field, chief among them are the evolution of simpler techniques to isolate regenerative elements and stems cells. These techniques are easy, outpatient procedures with immediate injection, often single session with harvest, and minimal manipulation (usually physical). This paper seeks to critically review the existing data and determine the current evidence and their role in practice.

Short-Term Efficacy of Autologous Cellular Micrografts in Male and Female Androgenetic Alopecia: A Retrospective Cohort Study

Purpose

Autologous cellular micrografts (ACM) is a novel treatment method in hair loss, and few data are available regarding its efficacy. The present study was carried out to assess the short-term clinical efficacy of a single application of ACM in the treatment of male and female androgenetic alopecia (AGA).

Materials and Methods

This was a single-center retrospective study involving 140 consecutive adults with confirmed AGA, who received a single session of ACM (Regenera Activa®). Efficacy was evaluated 1–6 months after treatment, by analyzing the change of trichometry parameters, which were assessed using TrichoScan digital image analysis.

Results

Depending on the scalp region, there was increase in mean hair density by 4.5–7.12 hair/cm², average hair thickness by 0.96–1.88 μm, % thick hair by 1.74–3.26%, and mean number of follicular units by 1.30–2.77, resulting in an increase of cumulative hair thickness by 0.48–0.56 unit. Additionally, the frontal region showed a significant decrease in % thin hair (−1.81%, p = 0.037) and yellow dots (−1.93 N/cm², p = 0.003). A favorable response was observed in 66.4% of the participants in the frontal region. Further, a gender-specific effect of treatment was observed.

Conclusion

ACM is a promising treatment in AGA with a short-term favorable response observed in up to approximately two-thirds of patients.

Autologous micrografts from the palatal mucosa for bone regeneration in calvarial defects in rats: a radiological and histological analysis

BACKGROUND

The application of dental implants is often restricted by bone volume. In such cases, bone grafts are required, although bone graft materials have some disadvantages. Therefore, other effective approaches are needed. Our previous study showed that the autologous micrograft, a dissociated cell suspension made out of palatal connective tissue grafts, promoted bone-marrow cell proliferation and differentiation under osteogenic conditions. In this study, we aimed to evaluate the effects of dissociated soft-tissue suspensions relevant to bone regeneration in animal model.

MATERIAL AND METHODS

Twelve-week-old male Wistar rats were used in the study. Defects were created in rat calvaria, and were filled with hydrogel containing either dissociated soft-tissue suspension (test) or sucrose (control). The new bone formation was evaluated at 1 and 2 weeks after surgery (n = 16) by radiological and histological analysis.

RESULTS

The conducted radiological analysis showed that the new bone volume was significantly greater in the dissociated soft-tissue suspension group. This finding was further confirmed by the conducted histological analysis.

CONCLUSIONS

The dissociated mucosa tissue suspension enhanced bone regeneration in vivo; thus, it is a promising potential method to aid the successful application for bone augmentation in the implant practice.

Progenitor-cell-enriched micrografts as a novel option for the management of androgenetic alopecia

Regenerative medicine is a multidisciplinary field that combines engineering and life science principles to promote regeneration, potentially restoring the physiological condition in diseased tissues. Specifically, the developments of complex grafts enhance the intrinsic regenerative capacity of the host by altering its environment. Autologous micrografts obtained through Rigenera® micrografting technology are able to promote derma and bone regeneration. Androgenetic alopecia (AGA) leads to a progressive thinning of scalp hair affecting 60-70% of the adult population worldwide. Pharmacological treatment offers moderate results and hair transplantation represents the only permanent treatment option. The aim of this study was to demonstrate the role of dermis micrografting in the treatment of AGA by clinical and histological evaluations after 4, 6, and 12 months. Hair growth and density were improved at all indicated times. Those outcomes were also confirmed by the TrichoScan® analysis, reporting an increase of total hair count and density with an increase and reduction of anagen and telogen phases, respectively. Scalp dermoscopic analysis showed an improvement of hair density and histological analysis indicated a clear amelioration of the scalp, development of hair follicles, and a beginning of cuticle formation. Collectively, those results suggest a possible use of the micrografts as a novel therapeutic option in the management of AGA.

Micrografting chronic lower extremity ulcers with mechanically disaggregated skin using a micrograft preparation system

OBJECTIVE

The Rigenera system is a new standardised micrograft preparation system. It works by means of automated mechanical disaggregation of small tissue samples, extracting only the smallest cells (<50µm). The aim of this study was to retrospectively evaluate patients affected by chronic ulcers and who were treated with the micrograft preparation method.

METHOD

Chronic ulcers have been included regardless of the cause. The specimen was collected with a 3mm diameter biopsy punch and immediately dissociated by means of the Rigenera System. The obtained suspension was placed on a scaffold of equine collagen.

RESULTS

We included 15 patients (four males, 11 females) with a mean age of 72.2±8.41 (mean±standard deviation) years. In seven patients the ulcers were related to the complications of diabetes, post-traumatic in a further three diabetic patients, vasculitis in one patient, and four patients had venous leg ulcers (VLUs). The median main diameter was 5.0cm and the median estimated area was 43.96cm². The ulcers were present from a mean of 4.50±2.30 months before inclusion in this study. At the second week the wounds were reduced by 37.33%±19.35%, at the week eight, nine patients (60.0%) were healed, and at week 16, 13 (86.7%) were healed. The quality of scars was good and did not deteriorate at the six month follow-up.

CONCLUSION

The simplicity of the approach, the minimal invasiveness of the specimen collection, and the good quality of scarring of healed wounds, confirmed in the follow-up, makes this micrograft preparation method a useful tool to use on large or complex wounds.

Advances in Regenerative Stem Cell Therapy in Androgenic Alopecia and Hair Loss: Wnt pathway, Growth-Factor, and Mesenchymal Stem Cell Signaling Impact Analysis on Cell Growth and Hair Follicle Development

The use of stem cells has been reported to improve hair regrowth in several therapeutic strategies, including reversing the pathological mechanisms, that contribute to hair loss, regeneration of hair follicles, or creating hair using the tissue-engineering approach. Although various promising stem cell approaches are progressing via pre-clinical models to clinical trials, intraoperative stem cell treatments with a one-step procedure offer a quicker result by incorporating an autologous cell source without manipulation, which may be injected by surgeons through a well-established clinical practice. Many authors have concentrated on adipose-derived stromal vascular cells due to their ability to separate into numerous cell genealogies, platelet-rich plasma for its ability to enhance cell multiplication and neo-angiogenesis, as well as human follicle mesenchymal stem cells. In this paper, the significant improvements in intraoperative stem cell approaches, from in vivo models to clinical investigations, are reviewed. The potential regenerative instruments and functions of various cell populaces in the hair regrowth process are discussed. The addition of Wnt signaling in dermal papilla cells is considered a key factor in stimulating hair growth. Mesenchymal stem cell-derived signaling and growth factors obtained by platelets influence hair growth through cellular proliferation to prolong the anagen phase (FGF-7), induce cell growth (ERK activation), stimulate hair follicle development (β-catenin), and suppress apoptotic cues (Bcl-2 release and Akt activation).

Therapeutic Potential of Stem Cells in Follicle Regeneration

Alopecia is caused by a variety of factors which affect the hair cycle and decrease stem cell activity and hair follicle regeneration capability. This process causes lower self-acceptance, which may result in depression and anxiety. However, an early onset of androgenic alopecia is associated with an increased incidence of the metabolic syndrome and an increased risk of the cardiac ischaemic disease. The ubiquity of alopecia provides an encouragement to seek new, more effective therapies aimed at hair follicle regeneration and neoregeneration. We know that stem cells can be used to regenerate hair in several therapeutic strategies: reversing the pathological mechanisms which contribute to hair loss, regeneration of complete hair follicles from their parts, and neogenesis of hair follicles from a stem cell culture with isolated cells or tissue engineering. Hair transplant has become a conventional treatment technique in androgenic alopecia (micrografts). Although an autologous transplant is regarded as the gold standard, its usability is limited, because of both a limited amount of material and a reduced viability of cells obtained in this way. The new therapeutic options are adipose-derived stem cells and stem cells from Wharton's jelly. They seem an ideal cell population for use in regenerative medicine because of the absence of immunogenic properties and their ease of obtainment, multipotential character, ease of differentiating into various cell lines, and considerable potential for angiogenesis. In this article, we presented advantages and limitations of using these types of cells in alopecia treatment.

Rigenera protocol in the treatment of surgical wound dehiscence

The effective management of post-operative wounds is important to prevent potential complications such as surgical-site infections and wound dehiscence. The purpose of this study was to treat wound dehiscence in elderly patients who were subjected to orthopaedic surgical interventions. The dehisced wounds were treated with autologous micro-grafts obtained using a promising CE-certified medical device called Rigeneracons. This instrument is a biological disruptor of human tissues able to specifically select progenitor cells that, as already reported in previous studies, maintain high cell viability but mainly have a high regenerative potential, allowing the repair of damaged tissues. Autologous micro-grafts obtained by Rigeneracons are ready to use and can be applied alone or in combination with biological scaffolds directly on the injured area. We observed in our patients a complete remission of dehisced wounds, on average, after 30 days from micro-grafts application and a total wound re-epithelialisation after 1 year from the surgical intervention. In conclusion, although we reported only three patients, autologous micro-grafts can be considered a promising approach for the treatment of dehisced wounds, improving the wound-healing process and in general the patient's quality of life without using other dressings.