Tissue-Specific Effects of Bariatric Surgery Including Mitochondrial Function

A better understanding of the molecular links between obesity and disease is potentially of great benefit for society. In this paper we discuss proposed mechanisms whereby bariatric surgery improves metabolic health, including acute effects on glucose metabolism and long-term effects on metabolic tissues (adipose tissue, skeletal muscle, and liver) and mitochondrial function. More short-term randomized controlled trials should be performed that include simultaneous measurement of metabolic parameters in different tissues, such as tissue gene expression, protein profile, and lipid content. By directly comparing different surgical procedures using a wider array of metabolic parameters, one may further unravel the mechanisms of aberrant metabolic regulation in obesity and related disorders

Evolution of Biological Bandages as First Cover for Burn Patients.

Significance: Cutaneous wound regeneration is vital to keep skin functions and for large wounds, to maintain human survival. In a deep burn, the ability of the skin to heal is compromised due to the damage of vasculature and resident cells, hindering a coordinated response in the regeneration process. Temporal skin substitutes used as first cover can play a major role in skin regeneration as they allow a rapid wound covering that, in turn, can significantly reduce infection risk, rate of secondary corrective surgeries, and indirectly hospitalization time and costs. Recent Advances: Skin was one of the first tissues to be bioengineered providing thus a skin equivalent; however, what is the current status subsequent to 40 years of tissue engineering? We review the classic paradigms of biological skin substitutes used as first cover and evaluate recent discoveries and clinical approaches adapted for burn injuries cover, with an emphasis on innovative cell-based approaches. Critical Issues: Cell-based first covers offer promising perspectives as they can have an active function in wound healing, such as faster healing minimizing scar formation and prepared wound bed for subsequent grafting. However, cell-based therapies encounter some limitations due to regulatory hurdles, as they are considered as "Advanced Therapy Medicinal Products," which imposes the same industry-destined good manufacturing practices as for pharmaceutical products and biological drug development. Future Directions: Further improvements in clinical outcome can be expected principally with the use of cell-based therapies; however, hospital exemptions are necessary to assure accessibility to the patient and safety without hindering advances in therapies

The good clinical practice guideline and its interpretation - perceptions of clinical trial teams in sub-Saharan Africa

To explore the advantages and challenges of working with the Good Clinical Practice (GCP)-International Conference of Harmonization (ICH) E6 guideline and its interpretation from the perspective of clinical trial teams based in sub-Saharan Africa.; We conducted 60 key informant interviews with clinical trial staff at different levels in clinical research centres in Kenya, Ghana, Burkina Faso and Senegal and thematically analysed the responses.; Clinical trial teams perceived working with ICH-GCP as highly advantageous and regarded ICH-GCP as applicable to their setting and efficiently applied. Only for informed consent did some clinical trial staff (one-third) perceive the guideline as insufficiently applicable. Specific challenges included meeting the requirements for written and individual consent, conditions for impartial witnesses for illiterates or legally acceptable representatives for children, guaranteeing voluntary participation and ensuring full understanding of the consent given. It was deemed important to have ICH-GCP compliance monitored by relevant ethics committees and regulatory authorities, without having guidelines applied overcautiously.; Clinical trial teams in sub-Saharan Africa perceived GCP as a helpful guideline, despite having been developed by northern organisations and despite the high administrative burden of implementing it. To mitigate consent challenges, we suggest adapting GCP and making use of the flexibility it offers

Burn patient care lost in good manufacturing practices?

Application of cell therapies in burn care started in the early 80s in specialized hospital centers world-wide. Since 2007, cell therapies have been considered as "Advanced Therapy Medicinal Products" (ATMP), so classified by European Directives along with associated Regulations by the European Parliament. Consequently, regulatory changes have transformed the standard linear clinical care pathway into a more complex one. It is important to ensure the safety of cellular therapies used for burn patients and to standardize as much as possible the cell sources and products developed using cell culture procedures. However, we can definitely affirm that concentrating the bulk of energy and resources on the implementation of Good Manufacturing Practice (GMP) alone will have a major negative impact on the care of severely burned patients world-wide. Developing fully accredited infrastructures and training personnel (required by the new directives), along with obtaining approval for clinical trials to go ahead, can be a lengthy process.We discuss whether or not these patients could benefit from cell therapies provided by standard in-hospital laboratories, thus avoiding having to meet rigid regulations concerning the use of industrial pharmaceutical products. "Hospital Exemption" could be a preferred means to offer burn patients a customized and safe product, as many adaptations may be required throughout their treatment pathway. Patients who are in need of rapid treatment will be the ones to suffer the most from regulations intended to help them

Opportunities and challenges for decentralised clinical trials in sub-Saharan Africa: a qualitative study

IntroductionDigital health has gained traction in research and development, and clinical decision support systems. The COVID-19 pandemic accelerated the adoption of decentralised clinical trials (DCTs) as a mitigation and efficiency improvement strategy. We assessed the opportunities and challenges of a digital transformation in clinical research in sub-Saharan Africa from different stakeholders’ perspectives.MethodsA qualitative study, including 40 in-depth semi structured interviews, was conducted with investigators of three leading research institutions in sub-Saharan Africa and Switzerland, contract research organisations and sponsors managing clinical trials in sub-Saharan Africa. A thematic approach was used for the analysis.ResultsInterviewees perceived DCTs as an opportunity for trial efficiency improvement, quality improvement and reducing the burden of people participating in clinical trials. However, to gain and maintain an optimal quality of clinical trials, a transition period is necessary to tackle contextual challenges before DCTs are being implemented. The main challenges are categorised into four themes: (1) usability and practicability of the technology; (2) paradigm shift and trial data quality; (3) ethical and regulatory hurdles and (4) contextual factors (site-specific research environment and sociocultural aspects).ConclusionThe transformation from a site to a patient-centric model with an increased responsibility of participants should be context adapted. The transformation requires substantial investment, training of the various stakeholders and an efficient communication. Additionally, commitment of sponsors, investigators, ethics and regulatory authorities and the buy-in of the communities are essential for this change

Decellularised tissues obtained by a CO2-philic detergent and supercritical CO2

Tissue decellularisation has gained much attention in regenerative medicine as an alternative to synthetic materials. In decellularised tissues, biological cues can be maintained and provide cellular environments still unmet by synthetic materials. Supercritical CO2 (scCO2 ) has recently emerged as a promising alternative decellularisation technique to aggressive detergents; in addition, scCO2 provides innate sterilisation. However, to date, decellularisation with scCO2 is limited to only a few tissue types with low cellular density. In the current study, a scCO2 technique to decellularise high density tissues, including articular cartilage, tendon and skin, was developed. Results showed that most of the cellular material was removed, while the sample structure and biocompatibility was preserved. The DNA content was reduced in cartilage, tendon and skin as compared to the native tissue. The treatment did not affect the initial tendon elastic modulus [reduced from 126.35 ± 9.79 MPa to 113.48 ± 8.48 MPa (p 〉 0.05)], while it reduced the cartilage one [from 12.06 ± 2.14 MPa to 1.17 ± 0.34 MPa (p 〈 0.0001)]. Interestingly, cell adhesion molecules such as fibronectin and laminin were still present in the tissues after decellularisation. Bovine chondrocytes were metabolically active and adhered to the surface of all decellularised tissues after 1 week of cell culture. The developed method has the potential to become a cost-effective, one-step procedure for the decellularisation of dense tissues

Development, characterization, and use of a fetal skin cell bank for tissue engineering in wound healing.

Wound healing in fetal skin is characterized by the absence of scar tissue formation, which is not dependent on the intrauterine environment and amniotic fluid. Fetal cells have the capacity of extraordinary expansion and we describe herein the development of a fetal skin cell bank where from one organ donation (2-4 cm2) it is possible to produce several hundred million fetal skin constructs of 9 x 12 cm2. Fetal cells grow three to four times more rapidly than older skin cells cultured in the same manner and these banked fetal cells are very resistant against physical and oxidative stress when compared to adult skin cells under the same culture conditions. They are up to three times more resistant to UVA radiation and two times more resistant towards hydrogen peroxide treatment. This mechanism may be of major importance for fetal cells when they are delivered to hostile wound environments. For fetal cell delivery to patients, cells were associated with a collagen matrix to form a three-dimensional construct in order to analyze the capacity of these cells for treating various wounds. We have seen that fetal cells can modify the repair response of skin wounds by accelerating the repair process and reducing scarring in severe bums and wounds of various nature in children. Hundreds of thousands of patients could potentially be treated for acute and chronic wounds from one standardized and controlled cell bank

Efficient decellularization of equine tendon with preserved biomechanical properties and cytocompatibility for human tendon surgery indications.

Chronic and acute tendon injuries are frequent afflictions, for which treatment is often long and unsatisfactory. When facing extended injuries, matrices and scaffolds with sufficient biomechanical properties are required for surgical repair and could additionally serve as supports for cellular therapies to improve healing. In this study, protocols of either commonly used detergents only (SDS 1%, Triton 1%, TBP 1%, and Tween-20 1%) or a combination of freeze/thaw (F/T) cycles with decellularization agents (NaCl 1M, ddH <sub>2</sub> O) were evaluated for the decellularization of horse equine superficial digital flexor tendon (SDFT) for hand flexor or extensor tendon reconstruction. Decellularization efficiency was assessed microscopically by histological staining (HE, DAPI) and DNA quantification. Macroscopical structure and biomechanical integrity of the tendon matrices were further assessed by gross observation, histological staining (SR), and mechanical testing (ultimate strain and stress, Young's modulus, energy to failure) for select protocols. Decellularization with hypertonic NaCl 1M in association with F/T cycles produced the most robust tendon matrices, which were nontoxic after 10 days for subsequent recellularization with human fetal progenitor tendon cells (hFPTs). This standardized protocol uses a less aggressive decellularization agent than current practice, which allows subsequent reseeding with allogenic cells, therefore making them very suitable and bioengineered tendon matrices for human tendon reconstruction in the clinic

Cell therapies for skin regeneration: an overview of 40 years of experience in burn units.

The earliest attempts at cell therapy can be attributed to Charles-Edward Brown-Séquard (1817–1894), who sought to treat senescence and aging by injecting animal gonad shreds into his contemporaries, a practice that was widespread in late 19th century. Since then, advances in science have enabled the development of biological substitutes to restore the function of various tissues. Skin was one of the first tissues to be regenerated. For severe burns, patient survival depends on the restoration of skin function as a barrier against pathogens and control of body temperature and fluid loss. We aim here to overview the different cell therapy techniques implemented at the University Hospital of Lausanne (CHUV), one of the two Swiss national centres of highly specialised medicine for burn care. In particular, we will describe the specific indications for each of the different therapies as well as future perspectives

Optimized Manufacture of Lyophilized Dermal Fibroblasts for Next-Generation Off-the-Shelf Progenitor Biological Bandages in Topical Post-Burn Regenerative Medicine.

Cultured fibroblast progenitor cells (FPC) have been studied in Swiss translational regenerative medicine for over two decades, wherein clinical experience was gathered for safely managing burns and refractory cutaneous ulcers. Inherent FPC advantages include high robustness, optimal adaptability to industrial manufacture, and potential for effective repair stimulation of wounded tissues. Major technical bottlenecks in cell therapy development comprise sustainability, stability, and logistics of biological material sources. Herein, we report stringently optimized and up-scaled processing (i.e., cell biobanking and stabilization by lyophilization) of dermal FPCs, with the objective of addressing potential cell source sustainability and stability issues with regard to active substance manufacturing in cutaneous regenerative medicine. Firstly, multi-tiered FPC banking was optimized in terms of overall quality and efficiency by benchmarking key reagents (e.g., medium supplement source, dissociation reagent), consumables (e.g., culture vessels), and technical specifications. Therein, fetal bovine serum batch identity and culture vessel surface were confirmed, among other parameters, to largely impact harvest cell yields. Secondly, FPC stabilization by lyophilization was undertaken and shown to maintain critical functions for devitalized cells in vitro, potentially enabling high logistical gains. Overall, this study provides the technical basis for the elaboration of next-generation off-the-shelf topical regenerative medicine therapeutic products for wound healing and post-burn care