The physiological mechanisms stem cells regenerate joints are continually being researched and understood. Because of the current understanding of research findings and consistent testimonials of improvement by patients, doctors and patients continue to request and apply this revolutionary, safe treatment. We learn more detailed benefits and a deeper understanding of the healing mechanisms every year. But before we explain how stem cells help cartilage regeneration, let's look at cartilage and how it degenerates in the first place.

Cartilage is a flexible yet strong connective tissue found in various body parts. Its composition allows it to function in areas where rigidity, combined with some degree of flexibility or cushioning, is needed. Cartilage is primarily composed of chondrocytes, the cells responsible for synthesizing and maintaining the cartilage matrix. Cartilage (and chondrocytes) have a very poor blood supply and require a process called imbibition to maintain a healthy integrity. Imbibition makes regeneration slow and difficult unless specific technique methods and nutrients are available.

Cartilaginous imbibition refers to how cartilage absorbs nutrients. Unlike most tissues in the body, cartilage is avascular, meaning it does not contain blood vessels. As a result, it cannot receive nutrients or remove waste products through the usual circulatory methods. Instead, cartilage relies on a process called imbibition to obtain the necessary nutrients to remain functional and healthy.

Imbibition: When joints move, the pressure within the joint changes. This change in pressure causes the synovial fluid to be squeezed out of the cartilage when pressure is applied and reabsorbed when the pressure is released. This action is like a sponge being compressed and then released, allowing the cartilage to absorb the nutrients dissolved in the synovial fluid.

Nutrient Absorption: As the synovial fluid moves in and out of the cartilage, the cartilage cells (chondrocytes) absorb the necessary nutrients to maintain health and function. Because of this reliance on imbibition, regular joint movement is vital. Without movement, cartilage does not get the necessary nutrients it needs, therefore leading to degeneration or other common joint issues. It's one reason why joint mobility exercises and maintaining an active lifestyle (yet limiting impact beyond its capability) can be essential for joint health. In the case of acute trauma, the joint and tissue are injured or may even show compression fractures, Schmorl's nodes, and the imbibition mechanism are injured, and even faster degeneration occurs.

Stem cells (and a combination of exosomes and peptides by some clinicians) are currently used for spinal disc degenerative diseases, meniscus in the knee, and shoulders most commonly, but also used for tennis elbow, carpal tunnel, and any other area of connective tissue, muscle, and neurological compromise.

This cartilage matrix is made of:

• Water: The majority of cartilage's composition is water, which aids in its resilience by allowing it to compress and then spring back.
• Collagen: A protein that provides cartilage with strength and rigidity. The type of collagen can vary depending on the specific type of cartilage (e.g., Type II collagen is predominant in articular cartilage).
• Proteoglycans: Large molecules are made of protein cores with long chains of sugars attached. They attract and hold water, giving cartilage its resilience.
• Elastin fibers: Present in elastic cartilage, these fibers allow for even greater flexibility. This type of cartilage is found in areas like the external ear.

Where is cartilage found in the body?

• Joints: As articular cartilage, it covers the ends of bones where they come together to form joints (knees, hips, shoulders, and spinal vertebrae as major examples). Cartilage should provide a smooth surface and cushion the ends of bones, reducing friction and absorbing shock during movement.
• Intervertebral discs: The discs between the vertebrae in our spine have cartilage, which provides cushioning and flexibility.
• Epiphyseal plates: In growing bones, cartilage forms the growth plates, which eventually ossify (turn to bone) as the individual reaches adulthood. Growth plates can be injured in adolescent years (without catastrophic injury), and asymmetrical growth can be measured. An anatomical short leg validated by a standing x-ray shoes off easily seen in teens and adults (not a neurological short leg that practitioners reference lying face up or face down on a therapy table) is a common example of this.

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• Rib cage: Cartilage connects the ribs to the sternum (breastbone) and maintains the flexibility and elasticity of the rib cage.
• Respiratory tract: Cartilage provides structure to the trachea (windpipe) and bronchi, ensuring they remain open for airflow.
• Ears and Nose: The external parts of our ears (the pinna or auricle) and the tip of our nose are primarily composed of cartilage, which gives them their shape yet allows for flexibility.

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Although the hip with yellow arrows will need replacement, some people and surgeons prefer integrating stem cells with surgery to enhance the outcome, especially for those wanting to remain very active. The other hip has significant degeneration and would benefit significantly from a cell therapy program.  

Here are several key processes and factors that research explains in the potential regenerative effects of stem cells on joints:

• Anti-Inflammatory Effects: Stem cells, including those derived from umbilical cord sources, can modulate the immune response and reduce inflammation. In joints affected by conditions like osteoarthritis, rheumatoid arthritis, or injuries, inflammation is a significant contributor to pain and tissue damage. By modulating inflammation, stem cells can create a more conducive tissue repair and regeneration environment.
• Cell Differentiation: Stem cells possess the remarkable ability to differentiate into various cell types. In joint regeneration, stem cells can potentially transform into chondrocytes, which are the specialized cells responsible for producing and maintaining cartilage. This is crucial because cartilage is the smooth, flexible tissue that cushions and protects the ends of bones within a joint. Cartilage is easily weakened or damaged in impact injuries. When disruption to the cartilaginous imbibition occurs, it loses the ability to rehydrate and decreases nutrient absorption. The cartilage deteriorates, and it is common to see osseous degeneration of the entire joint capsule, including vertebra, facets, ligaments, tendons, and connective tissue.  
• Paracrine Signaling: Stem cells release signaling molecules known as growth factors and cytokines. These molecules have the ability to attract other natural healing cells involved in tissue repair and regeneration, such as fibroblasts, endothelial cells, and a variety of immune cells. By recruiting these cells to the damaged joint area, stem cells contribute to the healing process.
• Extracellular Matrix Production: Stem cells can also promote the production of the extracellular matrix, a network of proteins and other molecules that provide structural support to tissues. A healthy extracellular matrix in joint regeneration is crucial for the proper functioning and durability of cartilage and other joint components. Wharton’s Jelly from the umbilical cord has been shown to have the most beneficial lattice structure of joint and connective tissue regeneration when comparing various stem cell sources.
• Angiogenesis: Stem cells can stimulate the growth of new blood vessels (angiogenesis). Improved blood supply to the joint and surrounding vascular tissue can provide the necessary nutrients and oxygen for healing and tissue regeneration.
• Immunomodulation: Stem cells can modulate the immune response, which is especially important in conditions where the immune system is involved in joint inflammation and damage, such as rheumatoid arthritis. By regulating immune activity, stem cells can help prevent further deterioration of joint tissues.
• Microenvironment Enhancement: Stem cells create a favorable microenvironment within the joint, promoting cell survival and tissue regeneration. They help regulate the balance between cell growth and cell death, which is essential for healthy tissue renewal.

It's important to note that while these mechanisms hold promise for joint regeneration, the effectiveness of stem cell therapies can vary from person to person and is influenced by factors such as the patient's overall health, the specific joint condition, and the quality of the stem cell source. Additionally, the field of regenerative medicine is continuously evolving, and ongoing research is focused on optimizing techniques and understanding the long-term effects of these therapies.

Before considering any stem cell-based treatment for joint regeneration, it's essential to consult with a qualified medical professional who specializes in regenerative medicine or orthopedics. They can provide personalized guidance based on your specific condition and medical history.