BIOGERNOTOLOGY-2

R.A.S HEMAT, MB;BCh, FRCSI, DUL.

Aging is a process characterised by several changes that include a reduced capacity to use oxygen along with impaired cardiocirculatory capacity and respiratory adaptation; deterioration of the nervous system.

A decline in the rate of total protein synthesis is one of the most common age-associated biochemical changes that has been observed in a wide variety of cells, tissues, organs.

Consequences of slowing-down of protein synthesis
1- Decrease in the availability of enzymes.
2- Inefficiency in the removal of intracellular damage.
3- Accumulation of abnormal and defective molecules.
4- Inefficient intra- and inter-cellular communication.
5- Decrease in the production of hormones and growth factors.
6- Decrease in production of antibodies.
7- Decrease in the production of ECM.

There is increased membrane rigidity of erythrocytes during ageing due to increased methylation of proteins. Antiageing replacement therapy should include calorie restriction, antioxidants, and gene therapy.

Altered cellular responsiveness is one of the critical aspects of cellular ageing. Instability of the genome is an important aspect of the failure of homeostasis, as the survival and continued existence of any lifeform depends upon the stability of its genome. Mitochondria posses an independent genetic system necessary for the morphogenesis of the energy transduction system consisted of the respiratory chain and ATP synthetase. mtDNA random mutations that occur throughout human life in the population of mtDNA molecules of each cell are major contributor to the gradual loss of cellular bioenergy capacity within tissues and organs associated with general senescence and diseases of aging.

During the life of an individual, a vast sum of the redox energy produced in mitochondria is converted to activate the molecular oxygen to ROS that seems to be utilised in the process of cellular apoptosis. Decline in the mitochondrial respiratory chain activity associated with age or premature aging due to the mitochondrial diseases, lead to the expression of the geriatric process, such as mental retardation, progressive decline of heart performance, muscle weakness, and clinical signs of degenerative diseases.

Older patients are known to have platelet-rich plasma with enhanced platelet aggregation. The older patient is at increased risk for iatrogenic and nosocomial complications. There is decreased response to aldosterone in tubules, which causes an increase in sodium excretion and may predispose the geriatric patient to the effect of hyponatraemia. Erythropoietin production in the kidney is also altered with ageing. Glomerular filtration and glomerular blood flow rise with a high protein diet. The muscle mass decreases with aging, with corresponding decrease in creatinine clearance. The decline in creatinine clearance associated with aging is intrinsically renal in origin. There is a tendency in the older adult to develop acidosis, which contributes to the rise in serum potassium. Increased glomerular pressures/flow induces cell injury and platelet aggregation, leads to permeability changes, and glomerular hyperfiltration.

Lifestyle activities are necessary for successful ageing. Perceived memory change is influenced by ageing. Activity and frequent contact with friends and family increase the chance for good memory capacity.

Age-associated decline in levels of scavenging enzymes, due to declining lean body mass, and changes in nutritional status.

Partial obstruction of the urethra is found in 20-30% of men >65 y and in 11-14% of incontinent women.

Ageing leads to diminished secretion of gastric acid, with or without accompanying decline in availability of intrinsic factor (IF). Suboptimal levels of cobalamin may produce neuropsychiatric manifestations without the development of the classic peripheral blood picture of magloblastic anaemia. Relative achlorhydria reduces calcium absorption.

Age-related organ changes affecting the CVS are mostly anatomic and include fibrosis, calcification, and the deposition of lipofucin, amyloid, and cholesterol..etc.

Serum albumin levels decline by 10-15% between the ages of 30 to 80 years. The change in ESR is not related to mortality. Hepatic enzymes may increase, decrease, or show no change during aging. The thyroid becomes more nodular with age.

Headache is independently associated with depression in the elderly. Depression in late life is widely acknowledged as a serious public health problem with considerable morbidity and mortality.

Many of the elderly individuals are good candidates for surgical procedure. More than 50% of elderly people have significant coronary artery disease. Potential for cardiac arrhythmias is greater at rest, during normal activity, and during vigorous exercise or stressful situations. The APACHE II score lacks objective measurement in the immunocompromised patients and the severely malnourished patient. The perioperative period is associated with major metabolic, haemodynamic, haemostatic, and neurohumoral stressors.

The elderly are at risk for adverse effects of polypharmacy. They frequently take multiple drugs for multiple diseases, are prescribed medications by a number of providers, and may receive care in many different settings.

JULY, 2002

Note: The information in this article has been excerpted from the following books: urotext-ebook simplifying urology, Principles of modern urology, Principles of Orthomolecularism, Andropathy, by Dr. R.A.S HEMAT. Permission is granted to copy and redistribute this document electronically as long as it is unmodified. This article may not be sold in any medium, including electronic, CD-ROM, or database, or published in print, without the explicit, written permission of Dr. R. A. S. Hemat.

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Dr. R.A.S HEMAT declares no conflicts of interest or financial interests in any product or service mentioned in this article, including grants, employment, stock holdings, gifts, or honoraria.