**5. The main goal of tissue regeneration**

The main goal of tissue regeneration studies is to acquire knowledge that will enhance the new wide range of regenerative medicine. This information may include evidence to stimulate stem cell activity, structural engineering of better scaffolds or direct initiation of biologic regeneration programs. Scientists already understand some forms of regeneration enough to manipulate and modify major events for therapeutic reasons. For example, the common practice of bone marrow transplantation is to properly guide hematopoietic cells to regenerated blood cells. However, for most examples of innovation, research has begun to acquire knowledge and techniques to try to ban or enhance selective steps selectively during renewal.

#### **5.1. Musculoskeletal tissues**

capacity; importance of stem cells, differentiation and differentiation; how regeneration signals begin and target; and mechanisms that control proliferation and renewed regeneration.

Regenerative medicine is a new branch of medicine that tries to change the course of chronic diseases, and in many cases, regenerates organ systems that fail due to age, disease, damage, or genetic defects. The area has quickly become one of the promising treatment options for patients with tissue failure. It also includes tissue engineering, but also involves the search for self-healing—the body uses its own systems, sometimes with the help of foreign biological materials to reconstitute cells and rebuild tissues and organs. The terms "*tissue engineering*" and "*regenerative medicine*" have become highly interchangeable, with the field hoping to focus

Tissue engineering is an emerging biomedical field aimed at helping to restore physical tissue defects to the point of self-repair as well as replacing the biological functions of damaged and injured members using cells with reproductive and differential abilities. In addition to basic research on these cells, there is no doubt that successful tissue engineering is indispensable for creating an artificial environment that enables cells to stimulate tissue regeneration. Such an environment can be achieved using scaffolds for cell proliferation, differentiation, and growth factors, as well as combining them. Growth factors are often required to promote tissue regeneration, as they can stimulate the formation of blood vessels, which supply oxygen and nutrients to the transplanted cells to replace the organ to

It requires functional platforms or scaffolds with specific properties concerning the morphology, chemistry of the surface, and interconnectivity to promote cell adhesion and proliferation. These requisites are not only important for cellular migration but also to supply nutrients and expulsion of waste molecules. Cell type must be considered when designing of using a specific cellular grown system as scaffold; for instance, if they are autologous, allogeneic, or xenogeneic. The challenge in tissue engineering is to develop an organized three-dimensional architecture with functional characteristics that mimic the extracellular matrix. In this regard, with the advent of nanotechnology, scaffolds are now being developed that meet most of the

The technology of tissue engineering has evolved from the development of biological materials (biomaterials) and refers to the practice of combining scaffolds, cells, and biologically active molecules of functional tissues. The aim of tissue engineering is to gather functional structures that restore, maintain, or improve damaged tissues or full organs. Artificial engineered skin

The operation is usually initiated by building a scaffold from a wide range of potential sources, from proteins to plastics. When scaffolds are created, cells with or without a "mix" of growth factors can be introduced. Assuming that the environment is appropriate, the tissue grows. Sometimes, cells, scaffolds, and growth factors are mixed together simultaneously, giving the

and cartilage tissues are examples that have been recently authorized by the FDA [2].

on treatments rather than complex and often chronic disease treatments.

**4. Regenerative medicine**

6 Tissue Regeneration

maintain its biological functions.

tissue the opportunity to "self-assemble" [2].

requisites.

Musculoskeletal injuries impact millions of people globally and affect their health and well-being as well as of their companion and athletic animals. Soft-tissue injuries represent almost half of these and are associated with unorganized scar tissue formation and long timedepending healing processes. Cell based therapeutic strategies have been developed in the past decades aiming at the treatment and reversion of such disorders. Stem cells are appealing in the field, being a responsive undifferentiated population, with ability to self-renew and differentiate into different lineages. Mesenchymal stem cells can be obtained from several adult tissues, including the synovial membrane. Synovia-derived mesenchymal stem cells can be found in individuals of any age and are associated to intrinsic regenerative processes, through both paracrine and cell-to-cell interactions, thus, contributing to host healing capacity. Studies have demonstrated the potential benefit of synovia-derived mesenchymal stem cells in these regenerative processes in both human and veterinary medicine.

#### **5.2. Bone regeneration**

Bone regeneration is a surgical technique (**Figure 4**) that uses barrier membranes to direct, or guide, the growth of new bone at the site of the defect. The principle is that the barrier

The development of implantable tissue to replace renal function permanently is a promising hope in overcoming donor deficiency problems and morbidity associated with immunosup-

Introductory Chapter: Concepts of Tissue Regeneration http://dx.doi.org/10.5772/intechopen.76996 9

One of the main challenges researchers face when trying to cultivate tissue engineering organs is to produce a scaffold, in which new cells can be implanted. While some scientists have followed three-dimensional printed scaffolds, many others focused on decellularization of local tissues to produce non-cellular scaffolds. The decellularization process typically consists of a series of perfused detergents through the organ, stripping the cells and nuclear material behind, and leaving the extracellular matrix. When developing decellularization protocols, researchers must balance the need for cellular material elimination with the need to maintain

Humans have limited regeneration ability, all the organ tissues can regrow, but it is very limited except the liver. Studies can find new methods to deal with regeneration. Recently, scientists are investigating the genes and factors which are active during regeneration. Scientists already understand some forms of regeneration sufficiently to manipulate and modify key events for therapeutic causes. So, in future, people will not need to use prosthesis, it will be more comfortable than using prosthesis because limbs will not lose their function and the

Department of Hygiene and Management, Faculty of Veterinary Medicine, Cairo University,

[1] Lina MQ, Kristen ML, Christopher HA, Stephen FB, Tabassum A. Looking ahead to engineering epimorphic regeneration of a human digit or limb. Tissue Engineering Part

[2] National Institute of Biomedical Imaging and Bioengineering (NIH). 2018. Available

[3] Kaoud H. Principles of Medical Biotechnology. CreateSpace-eStore. 2015. Available

[4] Li JJ, Kaplan DL, Zreiqat H. Scaffold-based regeneration of skeletal tissues to meet clinical challenges. Journal of Materials Chemistry B. 2014;**2**:7272-7306. DOI: 10.1039/

pression in transplantation.

regeneration of disabled people.

Hussein Abdelhay El-Sayed Kaoud

Address all correspondence to: ka-oud@outlook.com

from: https://www.nibib.nih.gov/

B: Reviews. 2016;**3**:251-262. DOI: 10.1089/ten.teb.2015.0401

from: https://www.createspace.com/5849816. pp. 68 and 163

**Author details**

El-Giza, Egypt

**References**

C4TB01073F

the properties of an extracellular matrix important.

**Figure 4.** Bone scaffold: the bone capacity or the osteogenic potential of a bone graft is given by cells involved in bone formation, such as mesenchymal stem cells, osteoblasts, and osteocytes. The term osteoconductive refers to the scaffold or matrix which stimulates bone cells to grow on its surface [4].

membranes create and maintain a space above the bone defect; this allows the slower mesenchymal cells with osteogenic potential to populate the defect and regenerate without interference from the more quickly proliferating overlying soft tissues. Protection of the clot in the defect, exclusion of gingival connective tissue cells, and preparation of an enclosed space in which osteogenic cells can migrate from the bone are three essential elements of a successful outcome. Many types of grafts have been used as space maintainers between the membrane and the bone defect. Autografts, allografts, and xenografts have all been used successfully, either alone or in combination, for bone regeneration using particulate materials.

#### **5.3. Applications**

Tissue engineering currently plays a relatively small role in treating patients. Additional bladder, small arteries, skin grafts, cartilage, and even the entire trachea have been implanted in patients but the operation is still experimental and of high cost. While the more complex organ tissues such as heart, lung, and hepatic tissue have been successfully reconstituted in the laboratory, they are far from being entirely cloned and ready for transplantation in a patient. These tissues, however, can be very useful in research, especially in drug research [2].

Researchers have developed multi-capacity (pluripotent) stem cells that can be transformed into any type of cell in different types of specific areas and found that they controlled by very specific gene networks that determine the fate of cells. Most other medical research has focused on multivariate stem cells to modify the range of growth solutions in which cells are placed. Bone marrow stem cells in mature cells have been able to take stem cells along the way from multiple-capacity to bone maturation that can be implanted in a patient.

The ability to regenerate a new kidney from a patient's own cells would provide major relief for the hundreds of thousands of patients suffering from kidney disease. The resulting organ tissue was able to remove metabolites, re-absorb nutrients, and produce urine both in vitro and in vivo in rats. This process has been used previously in the heart, liver, and lung tissue. The development of implantable tissue to replace renal function permanently is a promising hope in overcoming donor deficiency problems and morbidity associated with immunosuppression in transplantation.

One of the main challenges researchers face when trying to cultivate tissue engineering organs is to produce a scaffold, in which new cells can be implanted. While some scientists have followed three-dimensional printed scaffolds, many others focused on decellularization of local tissues to produce non-cellular scaffolds. The decellularization process typically consists of a series of perfused detergents through the organ, stripping the cells and nuclear material behind, and leaving the extracellular matrix. When developing decellularization protocols, researchers must balance the need for cellular material elimination with the need to maintain the properties of an extracellular matrix important.

Humans have limited regeneration ability, all the organ tissues can regrow, but it is very limited except the liver. Studies can find new methods to deal with regeneration. Recently, scientists are investigating the genes and factors which are active during regeneration. Scientists already understand some forms of regeneration sufficiently to manipulate and modify key events for therapeutic causes. So, in future, people will not need to use prosthesis, it will be more comfortable than using prosthesis because limbs will not lose their function and the regeneration of disabled people.
