Stem cell therapies
The current medical practice for proximal femoral fracture is dependent on the degree of damage that is caused to the bone structure. For more severe injury, hip replacement surgeries are used. This entails an artificial hip implant replacing the damaged hip joint, most commonly performed on adults between the ages of 60 and 80 (NHS, 2019). Modern artificial hip joints are designed to last at least 15 years, generally restricted by the frame’s degradation in the body. After surgery, a course of physical therapy is standard protocol, and following this process of treatment, reports suggest reduction in pain and improved range of movement. However, there are a variety of complications following hip surgery. Implantations of artificial hip joints can result in secondary surgeries due to infection that is a consequence of surgery. There are also the extensive recovery times of 4-6 weeks before regaining enough strength to mobilize the hip joint. (Hecht, 2021). Bedsores or pressure ulcers can easily develop during this waiting period, after which proceeds an intense course of physical therapy. On top of this, hip replacements cannot offer the same mobility as experienced before the hip fracture. For more active and youthful patients, this is far from ideal as outdoor lifestyles will be heavily reduced (Tomaszewski, 2018). Stem cell therapies can offer an alternative to treating proximal femoral fractures. For healing hips, stem cells are combined with another field of regenerative medicine named tissue engineering. This technique involves creating a scaffold that mimics the shape of the desired tissue and placing it into the site of cellular damage (Wagner, 2021). Next, stem cells are transplanted into this scaffold with a medium that contains chemical signals and growth factors that will enhance the rate of proliferation and differentiation of the stem cells (Figure 2.1). This medium composition will be tailored specifically to produce a certain tissue type, result ing in the repairment of the body’s damaged tissues. This technique uses scaffolds to regrow cells into specific structures.
Figure 2.1 – The principle of tissue engineering in bone repairment.
For tissue engineering, a scaffold must be both biocompatible and biodegradable so it will naturally hydrolyse after the tissue structure has grown. Furthermore, it must allow the movement of cells and molecules, so the
tissues grow evenly. The extracellular matrix is the most commonly used biological scaffold as it satisfies these criteria. The extracellular matrix is the extensive network that contains cells and macromolecules such as proteins and cell receptors (Kusindarta, 2018). Naturally produced, the extracellular matrix is both biocompatible and biodegradable, so it will eventually degrade. Additionally, the extracellular matrix is porous, resulting in well-balanced stem cell dispersion that promotes healthy tissue growth (Brockett, 2020).
Typically, the extracellular matrix is isolated through the process of decellularization (Brockett, 2020). Tissues are put through cycles of freezing and thawing to loosen the tissue fibres before being washed in hypertonic solution to lyse cells, which destroys excessive cells, so they are easily removed. A
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