Since the development of the regenerative medicine field in the early 90s, tissue engineering and cell therapy have evolved from benchtop ideas into commercially available products validated by clinical studies. Currently, searching the terms ‘‘tissue engineering’’ and “regenerative medicine’’ in Google Scholar brings up, respectively, nearly 3.4 and 1.2 million results. This reflects how this field has been traveling a path toward success, experiencing a continuous maturation and a rapid rise over the last 25 years [1,2].
Tissue engineering techniques have the potential to create several patient-specific treatments to improve the quality of life of thousands of people that are in the waiting list for organ transplantation worldwide. The expansion of tissue engineering sales and revenue are a consequence of a number of completed and ongoing clinical trials investigating acellular and cellular solutions to treat various conditions [3]. According to ClinicalTrials.gov, in 2021, there are 100 clinical studies registered using tissue engineering, from which 25 are currently active or recruiting patients. The European continent hosts the largest share of tissue engineering clinical trials. Among the conditions related to clinical studies, the most recurrent are wounds and injuries, eye diseases, congenital abnormalities, and musculoskeletal diseases [4].
Figure 1: A map that indicates the number of studies located in each region [4].
Most of the clinical studies conducted in South America are located in Brazil [4]. Here we will provide an overview of the studies being conducted on tissue engineering in Brazil.
Use of Mesenchymal Stem Cells for Alveolar Bone Tissue Engineering for Cleft Lip and Palate Patients (NCT01932164)
In this study, the researchers aimed to performed bone tissue engineering to reconstruct the alveolar bone defect in cleft lip and palate patients using mesenchymal stem cells from deciduous dental pulp associated with a collagen and hydroxyapatite biomaterial through prospective qualitative and quantitative analysis of bone neoformation.
Bone Tissue Engineering With Dental Pulp Stem Cells for Alveolar Cleft Repair (NCT03766217)
In this method, mesenchymal stem cells associated with biomaterials have been used to rehabilitate the alveolar bone cleft of patients with cleft lip and palate. This randomized controlled trial compared mesenchymal stem cells obtained from autogenous deciduous dental pulp associated with biomaterials versus iliac crest autogenous bone graft for secondary alveolar cleft repair.
Effects of Simvastatin Gel on Bone Neoformation in Post-extraction Sockets: a Randomized Controlled Trial (NCT04149080)
This study seeks to evaluate dimensional changes, level of soft tissue healing, pain/discomfort, and newly formed tissues in post-extraction sockets (holes in the bone where teeth have been removed) filling with Simvastatin (SIM) gel covered with polypropylene membranes. Thirty post-extraction sockets of posterior teeth will be randomized allocated in two groups: 1) extractions and socket filling with 1.2% SIM gel and membrane and 2) extraction and socket filling with placebo gel and membrane. The evaluation will be done through clinical analyzes, histomorphometry, and micro-computed tomographic images, considering the dimensional changes, the quantity, and the quality of tissue formation after extractions.
Clinical Trial of Fat Grafts Supplemented With Adipose-derived Regenerative Cells (NCT01674439)
This study focused on investigating whether a novel protocol for isolation of adipose-derived regenerative cells and their use in combination with fat tissue improve the long-term retention of the grafts in patients with craniofacial microsomia since first reports of the clinical use of adipose-derived regenerative cells suggest that this approach may be feasible and effective for soft tissue augmentation.
Autogenous Mesenchymal Stem Cell Culture-Derived Signalling Molecules as Enhancers of Bone Formation in Bone Grafting (NCT04998058)
This study aims to evaluate bone formation in grafts in terms of its density, quantity, and maturation obtained using a tissue-engineered bone grafting compound containing concentrated autogenous cell culture medium and a synthetic bone substitute. After protocol approval by the Research Ethics Committee, a total of 20 consecutive participants in need of maxillary reconstruction aiming at implant-supported oral rehabilitation will be invited to join the study. To collect autogenous adipose tissue-derived mesenchymal stem cells, an outpatient lipoplasty procedure at the abdominal area of each patient will be performed.
REFERENCES
1. Kim, Y. S., Smoak, M. M., Melchiorri, A. J. & Mikos, A. G. An Overview of the Tissue Engineering Market in the United States from 2011 to 2018. Tissue Eng. Part A 25, 1–8 (2019).
2. Jaklenec, A., Stamp, A., Deweerd, E., Sherwin, A. & Langer, R. Progress in the Tissue Engineering and Stem Cell Industry ‘Are we there yet?’ Tissue Eng. Part B Rev. 18, 155–166 (2012).
3. Hoffman, T., Khademhosseini, A. & Langer, R. Chasing the Paradigm: Clinical Translation of 25 Years of Tissue Engineering. Tissue Eng. Part A 25, 679–687 (2019).
4. ClinicalTrials.gov. Clinical Trials on Tissue Engineering (last accessed on November 2021).