Regenerative Medicines _ Tissue Engineering:
Regenerative medicine is the branch of medicine that develops methods to regrow, repair or replace damaged or diseased cells, organs, or tissues. Regenerative medicine includes the generation and use of therapeutic stem cells, tissue engineering, and the production of artificial organs.
The term was coined by William Haseltine in 1999. Objective of this approach is to regain the function of lost, damage or disease part of the body or cells by replacing them with the new ones. It is the major advancement in the field of medical treatment and is based on stem cell technology and tissue engineering.
Strategy of Regenerative Medicines:
To achieve the objective of regenerative medicine it follows the three different approaches
- Cell-based therapy
- Biological and synthetic materials are used to conduct repair process and cell growth
- Cells Seeded scaffolds implantation
Why we need to engineer the tissue?
- Natural repair is challenged by severe trauma or disease state
- Donor tissues cause problems such as immune response and they may be limited in quantity
- Problems associated with autologous tissues (permanent damage at the donor site)
‘Tissue engineering is an interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function’.
There is considerable overlap between the regenerative medicines and tissue engineering. The term regenerative medicine is used in a broader view, covering the engineering principles of tissue for transplantation of cells (stem cells) utilizing nanomaterials (nanotechnology) as the medium for implantation.
3 tools of tissue engineering:
living part of tissue
Provide reparative properties
provide structural support to the construct
Site for cells attachment and proliferation
Biodegradable and biocompatible
- Growth Factors:
Involved in cellular signalling
Direct the cells what to do
Scaffold is the major component of many tissue engineering strategies as it provides architectural support in which ECM, cells and growth factors interact to create the regeneration niche. It provides biocompatible environment required for cell infiltration and reparation of damaged tissue and suitable cues in order to allow regeneration process occur in a controlled manner.
Different sources of cells are autologous-same individual, allogenic-from different individual and xenogenic-from different specie but these cells offer certain problems during the process such as limited proliferative capacity. However, Stem cells improve body owns potential of regeneration. They regenerate the tissue which has no regeneration capacity. Regenerative medicines building blocks are stem cells and are mainly used because of its two capabilities;
- the ability of self-renewal
- the ability to differentiate into different cell lineages upon appropriate signals
They are broadly classified into two types; embryonic stemcells and non-embryonic stem cells or adult stem cells. ES cells are pluripotent and multipotent while non-embryonic are multipotent and have lost their ability of pluripotency. However, ES cells suffer from a number of issues; immune rejection, can develop into cancerous and have a notable ethical and moral issues. Another technique for obtaining Autologous stem cells are obtained through a reprogramming of adult stem cells to get induced pluripotent stem cells (iPSC) which have same potency as ES cells and have no ethical problems.
Nanotechnology in Regenerative Medicine:
Nanotechnology and nano-engineering are the science and engineering involved in the design, synthesis, characterization, and application of materials and devices. The application of nanotechnology in the field of regenerative medicine has opened a new realm of advancement in this field and has provided a controlled biochemical and mechanical micro-environment The nanomaterials used in the field of regenerative medicines and other related areas include their use as:
- Scaffold for cell growth
- Delivery of various drugs, growth factors and genes
- Applications for cellular modification, isolation and tracking
Tissues consist of cells and extracellular matrix ECM. Nano-materials serve as ECM giving both structural and functional support in the form of scaffold. Scaffolds are the 3D constructions that are capable of mimicking the structure of the tissue that requires repair. Nanotechnology can be used to generate nanofibers, nano-patterns and controlled release nanoparticles that mimic native tissues as biomaterials to be engineered is in the nano-meter scale.
- Nano-fibers having high surface area and highly interconnected porous architecture facilitate colonization of the cells in the scaffold and exchange of nutrients and waste between scaffold and its environment.
- Self-assembled nanomaterials: Self-assembly of nanomaterials from nanostructures such as polymersomes, nanofibers or hydrogels from self-assembly of peptides, copolymer amphiphiles or peptide amphiphiles.
- Carbon nanotubes having mechanical strength, high electrical and thermal conductivity which helps in directing cells growth. In regenerative medicines, they are used as scaffold, for delivery of growth factors and involved in cell tracking.
These nanomaterials have a promising hold in the regeneration or engineering of stem cells, cartilage cells, bone cells, vascular cells and hepatic cells and many more.
Major challenges in this field are;
- Development of safety evaluation guidelines
- Industrialization and cost effectiveness
Conclusion and Future:
The development and implementation of nanotechnology and regenerative have brought a major contribution to the field of human diseases. Nano-assisted regenerative medicines have the potential to create a paradigm shift in the healthcare system of the future as they trigger the self-regeneration ability rather than minimizing the symptoms of the traditional approach.
Author: Mushkbar Fatima