A degenerative disease is defined as a disease characterized by the worsening condition due to the deterioration of the function and structure of the affected body part, thus causing disability, mortality, and morbidity, which could be prematurely.(1, 2) Aging is a natural phase in life. At the organism level, the body tends to undergo and accumulate changes over time and these changes are usually degenerative. The body degenerates from its former prime condition, especially in terms of speed, efficiency, and repair. Inopportunely, there are also instances when certain individuals undergo degenerative changes prematurely. Over time, these degenerative changes lead to symptoms and disease. Such disease is referred to as degenerative disease. Many of these diseases are associated with aging, genetics, and lifestyle choices. Many of these conditions, too, are incurable and can only be managed to alleviate symptoms.
Aging is one of the common risk factors for many degenerative diseases. It entails diverse biological changes. At the cellular level, a cell is aging when it loses its ability to divide and yet remain metabolically active. At the tissue and organ level, an aged biological structure is one that eventually wears off. Their structure and function are no longer as potent as they were when they were young. This is often attributed to the genetic changes inside the cell, particularly the shortening of the telomeres. Deterioration over time can occur as a result of telomere degeneration. Consequently, the cell loses its ability to function upon reaching a certain point. When several cells lose their capacity to divide and to function effectively, the body would, therefore, be impaired. Disease manifests as symptoms appear. Apart from natural degenerative changes caused by DNA damage accumulation from aging, the body may also be susceptible when exposed to many stressors, e.g. oxidative stress. Mitochondrial DNA mutations are also an important risk factor.
Examples of degenerative disease
Neurons tend to deteriorate or degenerate over time. Neurodegeneration is the progressive loss of structure and function as well as the death of neurons. The condition may progress to neurodegenerative disease. Many of them are associated with aging, genetics, and lifestyle choices. Some have no cures but can be managed to ease symptoms. Examples of neurodegenerative diseases are Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, Amyotrophic lateral sclerosis, multiple sclerosis, and Batten disease.
Alzheimer’s disease is a progressive neurodegenerative disease caused by the degeneration of the neurons. The individual with this disease may have several areas of brain affected. As such, the brain may progressively lose its cognitive function, such as memory and language.
Parkinson’s disease is another progressive neurological disease involving the melanin-containing nerve cells in the brainstem. Individuals with this disease exhibit symptoms such as shuffling gait, stooped posture, resting tremor, speech impediments, movement difficulties and an eventual slowing of mental processes and dementia.
Huntington’s disease is a disease characterized by mental and physical deterioration leading to death. The individual with this disease initially lacks coordination and then eventually loses a steady gait, coordinated movement, and mental abilities.
Amyotrophic lateral sclerosis (ALS) is a disease caused by the death of neurons that control the voluntary muscles. Initially, there is a weakening of the arms or legs. Eventually, the person with ALS will lose the ability to use hands and feet, speak, and swallow.
Multiple sclerosis is a neurodegenerative disease characterized by the gradual accumulation of focal plaques of demyelination particularly in the periventricular areas of the brain.
Batten disease is a neurodegenerative disorder characterized by an excessive accumulation of lipofuscin in cells and tissues. The accumulation of lipofuscin is due to a pathological mutation in gene (e.g. CLN3 gene, in juvenile type of the disease). The disease starts at the age of five to eight years. Some of the symptoms include seizures, ataxia, vision impairment, and clumsiness.
Cancers are characterized by a malignant growth of cells (from uncontrolled cell division) that can be invasive (metastasis). There are over a hundred types of cancers in humans.(3) Many of them are due to poor lifestyle habits, e.g. tobacco use, poor diet, and lack of physical activities. Other risk factors are exposure to ionizing radiation and environmental pollutants. Infections caused by certain viruses (e.g. Epstein-Barr virus, HIV, hepatitis B virus, hepatitis C virus, human papillomavirus, and Helicobacter pylori) may also increase the risk to developing cancer. Cancers are a degenerative disease because the cancer growth could affect the function of adjacent cells. In the lungs, for instance, a lump could take up space and consequently prevent lung cells to absorb sufficient oxygen. The presence of malignant cells in the lungs could also impair the immune response and thereby increase the risk of acquiring lung infections.
Coronary artery disease
Coronary artery disease is a condition characterized by the progressive narrowing or the eventual occlusion of the coronary artery. It is the underlying cause of a heart attack. Risk factors are hypertension, smoking, diabetes, lack of physical activities, poor diet, and excessive alcohol.
Macular degeneration is a medical condition caused by macular damage. The affected individual may experience blurred vision in the center of the visual field. Over time, the vision worsens and may end up in blindness. Risk factors include genetic factors, poor diet, lack of physical activities, and smoking.
Osteoarthritis is a non-inflammatory degenerative joint disease occurring chiefly in older persons. It is characterized by the degeneration of the articular cartilage, hypertrophy of bone at the margins, and changes in the synovial membrane. It is accompanied by pain and stiffness, particularly after prolonged activity.
Osteoporosis is a degenerative disease involving the bones. The condition is characterized by the extremely porous bones. Thus, an individual with osteoporosis has an increased risk of fracture. It commonly affects elderly women. It causes a curved back due to the compression fractures of the backbones.
- NCI Dictionary of Cancer Terms. (2019). Retrieved from National Cancer Institute website: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/degenerative-disease
- What are degenerative diseases? Department of Health website. (2010). Retrieved December 17, 2019, from Doh.gov.ph website: https://www.doh.gov.ph/faqs/What-are-degenerative-diseases
- What Is Cancer? (2015, February 9). Retrieved from National Cancer Institute website: https://www.cancer.gov/about-cancer/understanding/what-is-cancer
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