Atrophy

Jump to: navigation, search

WikiDoc Resources for Atrophy

Articles

Most recent articles on Atrophy

Most cited articles on Atrophy

Review articles on Atrophy

Articles on Atrophy in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Atrophy

Images of Atrophy

Photos of Atrophy

Podcasts & MP3s on Atrophy

Videos on Atrophy

Evidence Based Medicine

Cochrane Collaboration on Atrophy

Bandolier on Atrophy

TRIP on Atrophy

Clinical Trials

Ongoing Trials on Atrophy at Clinical Trials.gov

Trial results on Atrophy

Clinical Trials on Atrophy at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Atrophy

NICE Guidance on Atrophy

NHS PRODIGY Guidance

FDA on Atrophy

CDC on Atrophy

Books

Books on Atrophy

News

Atrophy in the news

Be alerted to news on Atrophy

News trends on Atrophy

Commentary

Blogs on Atrophy

Definitions

Definitions of Atrophy

Patient Resources / Community

Patient resources on Atrophy

Discussion groups on Atrophy

Patient Handouts on Atrophy

Directions to Hospitals Treating Atrophy

Risk calculators and risk factors for Atrophy

Healthcare Provider Resources

Symptoms of Atrophy

Causes & Risk Factors for Atrophy

Diagnostic studies for Atrophy

Treatment of Atrophy

Continuing Medical Education (CME)

CME Programs on Atrophy

International

Atrophy en Espanol

Atrophy en Francais

Business

Atrophy in the Marketplace

Patents on Atrophy

Experimental / Informatics

List of terms related to Atrophy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself. Hormonal and nerve inputs that maintain an organ or body part are referred to as trophic. Atrophy is a general physiological process of reabsorption and breakdown of tissues, involving apoptosis on a cellular level. When it occurs as a result of disease or loss of trophic support due to other disease, it is termed pathological atrophy, although it can be a part of normal body development and homeostasis as well.

Types of Atrophy

Normal Development

Examples of atrophy as part of normal development include shrinkage and involution of the thymus in early childhood and the tonsils in adolescence.

Breast Atrophy

Atrophy of the breasts can occur with prolonged estrogen reduction, as with anorexia nervosa or menopause. Atrophy of the testes occurs with prolonged use of enough exogenous sex steroid (either androgen or estrogen) to reduce gonadotropin secretion. The adrenal glands atrophy during prolonged use of exogenous glucocorticoids like prednisone.

Muscle Atrophy

Disuse atrophy of muscles (muscle atrophy) and bones, with loss of mass and strength, can occur after prolonged immobility, such as extended bedrest, or having a body part in a cast (living in darkness for the eye, bedridden for the legs, etc). This type of atrophy can usually be reversed with exercise unless severe. Astronauts must exercise regularly to minimize atrophy of their limb muscles while they are in microgravity.

There are many diseases and conditions which cause atrophy of muscle mass. For example diseases such as cancer and AIDS induce a body wasting syndrome called "cachexia", which is notable for the severe muscle atrophy seen. Other syndromes or conditions which can induce skeletal muscle atrophy are congestive heart failure and liver disease.

During aging, there is a gradual decrease in the ability to maintain skeletal muscle function and mass. This condition is called "sarcopenia", and may be distinct from atrophy in its pathophysiology. While the exact cause of sarcopenia is unknown, it may be induced by a combination of a gradual failure in the "satellite cells" which help to regenerate skeletal muscle fibers, and a decrease in sensitivity to or the availability of critical secreted growth factors which are necessary to maintain muscle mass and satellite cell survival.[1]

Dystrophies, Myosities, and Motor Neuron Conditions

Pathologic atrophy of muscles can occur due to diseases of the motor nerves, or due to diseases of the muscle tissue itself. Examples of atrophying nerve diseases include CMT (Charcot Marie Tooth syndrome) poliomyelitis, amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), and Guillain-Barre syndrome. Examples of atrophying muscle diseases include muscular dystrophy, myotonia congenita, and myotonic dystrophy.

Vaginal Atrophy

In post-menopausal women, the walls of the vagina atrophy and become thinner. The mechanism for the age-related condition is not yet clear, though there are theories that the effect is caused by decreases in estrogen levels.[2]

Research

It has been reported that Astemizole might prevent 97% of the muscle wasting that occurs in immobile, bedridden patients.[3]Testing upon mice showed that it blocked the activity of a protein present in the muscle that is involved in muscle atrophy.[4] However the concerns for the drug's longterm effects on the heart preclude its routine use in humans for this indication and further alternative drugs are being sought.[3]

Related Chapters

References

  1. Campellone, Joseph V. (2007-05-22). "Muscle atrophy" (html). MedlinePlus. Retrieved 2007-10-02. 
  2. "Types of Atrophy" (html). Retrieved 2007-10-02. 
  3. 3.0 3.1 "Drug could stop muscle wasting'". NetDoctor.co.uk. 25 May,2006. Retrieved 2006-05-27. 
  4. Wang X, Hockerman GH, Green Iii HW, Babbs CF, Mohammad SI, Gerrard D, Latour MA, London B, Hannon KM, Pond AL (2006). "Merg1a K+ channel induces skeletal muscle atrophy by activating the ubiquitin proteasome pathway". FASEB J. PMID 16723379. 




Linked-in.jpg