Nerve growth factor (NGF) is a type of neurotrophin molecule that controls the creation of the nervous system in embryos and regulates the function, growth, and repair of neurons in adults. To execute these roles, an NGF molecule must attach itself to the receptor of a neuron, which is also known as a nerve cell. The symmetrical design of the nerve growth factor molecule enables it to attach to nerve cells by using either side or to attach to two cells at once. Alpha polypeptide chains, beta polypeptide chains and gamma polypeptide chains comprise the protein-based NGF.
Since being discovered in the 1960s, nerve growth factor has been used to treat several disorders and diseases. Most notably, the beta polypeptide chains of NGF have been successful in treating Alzheimer’s disease because they stimulate cellular growth activity in nerves; Alzheimer’s disease is caused by the degeneration and death of cholinergic nerve cells. This decay of nerve cells retards memory and interferes with cognition by scrambling signals sent between neurons that govern sensation, thought and movement. Physical tasks also become more difficult with the loss of these neurons.
The beta polypeptides in nerve growth factor, however, trigger regrowth and repair of neurons, stopping them from dying. NGF cannot create new neurons; they merely cause the existing neurons to grow. When a human is born, they have all the neurons they will ever have, which is more than 100 billion. Over time, trauma, age, and disease cause these neurons to die off, creating disorders like Alzheimer’s disease and dementia.
In medical tests at several universities, Alzheimer’s patients being treated with NGF brain injections demonstrated a nearly 50-percent decrease in nerve cell decay; they also experienced regrowth and repair of damaged neurons. These same patients experienced greater memory and better cognition. The improved neurons were able to build new synapses, or connections, to other cells, improving the brain’s thinking capacity.
NGF has also been used to treat spinal cord injuries, corneal ulcers in the eye, and heart trauma after cardiac surgery or cardiac arrest by stimulating the growth of new blood vessels. The antibodies of nerve growth factor are also used in medical therapy, since too much NGF can be dangerous. Pain such as gout, backaches, and bladder inflammation is often associated with high concentrations of nerve growth factor; the antibodies reduce the pain. Excessively high levels of NGF have also been linked to asthma, cancer tumor growth, and the worsening of acquired immunodeficiency syndrome (AIDS).