REPAIR HORMONE OF THE HEART
Importance of Growth Hormone, IGF-1,
in Cardiovascular Function and Cardiovascular Disease
Growth Hormone (GH) is made in the anterior pituitary in the brain. It goes to the liver to stimulate Insulin-like Growth Factor-1 (IGF-1) production. Hence, IGF-1 mediates many of GH’s actions. IGF-1 receptors are found in almost every cell in our body.
IGF-1 is a poly-peptide growth factor responsible for cell differentiation, maturation, growth and proliferation in nearly every tissue and organ in our body.
A brilliantly written and eye-opening 2023 review article eliciting the importance of IGF-1 on our cardiovascular system and suggesting IGF-1as a possible therapeutic agent for cardiovascular disease is entitled, ‘New Insights on the Cardiovascular Effects of IGF-1’.
The article was published February 9, 2023, in the journal, ‘Frontiers in Endocrinology’, with a massive 229 references. The authors were from multiple departments at King Abdullah University of Science and Technology, Thuwal, Saudi Arabia. The review included all research papers on IGF-1 and cardiovascular disease from 1957 to present concentrating on articles in the last 5 years. This landmark review article is one of the best review articles found on IGF-1 and cardiovascular function, opening the possibility of using IGF-1 as a therapeutic agent for cardiovascular disease and cardiovascular protection.
The authors state, “IGF-1, an anabolic growth factor, regulates cell division, proliferation, and survival…there is mounting evidence IGF-1 plays a specialized role in the complex activities that underpin cardiovascular (CV) function. “
IGF-1’s effects on cardiovascular function are truly profound. Review of research on GH/ IGF-1 on cardiovascular health shows definitive support for the following roles IGF-1 plays in CV function.
IGF-1:
- Promotes cardiac development
- Improves cardiac output
- Improves stroke volume
- Improves contractility
- Improves ejection fraction
- Improves cardiac function after heart attacks by stimulating tissue remodeling and contractility
- Has a pro-survival effect on cardiac cells and VSMC (vascular smooth muscle cells)
- Stimulates collagen type I synthesis in VSMC
- Stimulates angiogenesis, an increase blood supply to tissues
- Improves lipid profile
- Lowers insulin levels
- Increases insulin sensitivity
- Promotes glucose metabolism
- Stimulates NO (nitric oxide) production to dilate vessels
- Protects endothelial lining against oxLDL via NO signaling pathway
- Ameliorates acute renal failure via the NO-mediated pathway
- Decreases blood pressure via the NO pathway
- Low IGF-1 is associated with high blood pressure, High IGF-1 associated with decreased risk of high blood pressure
- Regulates peripheral resistance
- Decreases heart failure
- Has anti-inflammatory effects on vasculature
- Decreases atherosclerotic lesions
- If IGF-1 is low, there is an increase in atherosclerosis in carotids
- Decreased IGF-1 levels are associated with increased incidence of ischemic heart and cerebrovascular stroke
- Increased IGF-1 levels protect against ischemic strokes.
- Protects endothelial lining of coronary arteries and veins
- Inhibits apoptosis or cell death, in cardiac cells with low oxygen supply
- Coordinates protein, fat, and carbohydrate metabolism
- Stimulates amino acid transport and protein synthesis in skeletal muscle while inhibiting muscle break down.
- Decreased IGF levels lead to increased cardiovascular morbidity and mortality.
It is clear from the list above, IGF-1 maintains homeostasis in the CV system and is a critical and necessary hormone at optimal levels for CV function and CV repair.
Why is not everyone with low GH being treated with GH or IGF-1? Especially the elderly? Why are growth hormone reference ranges decreased to reflect the deterioration of GH with age? The squeed reference range level of a 60, 70, 80 year old is not in the range for optimal health.
IGF-1, which mediates the action of GH, is crucial in maintaining organ integrity and function, especially in the cardiovascular system. An easy way to maintain optimal levels of growth hormone is by taking specific amino acids. Eating protein is also important in delivering amino acids to the brain to stimulate optimal growth hormone function.
No matter what age, our brains can produce optimal growth hormone production with proper stimulation. An amazing way to stay healthy!
Have an awesome day, Dr. D
(excerpt from Growth Hormone, An Eternal Life Hormone PhD thesis by Valerie P. Donaldson, MD) copywrite September 2024