Sarcopenia

Andropause: Symptom Management for Prostate Cancer Patients Treated With Hormonal Ablation

Andropause, or the age-related decline in serum testosterone, has become a popular topic in the medical literature over the past several years. Andropause includes a constellation of symptoms related to lack of androgens, including diminished libido, decreased generalized feeling of well-being, osteoporosis, and a host of other symptoms. The andropause syndrome is very prominent in men undergoing hormonal ablation therapy for prostate cancer. Most significant in this population are the side effects of hot flashes, anemia, gynecomastia, depression, cognitive decline, sarcopenia, a decreased overall quality of life, sexual dysfunction, and osteoporosis with subsequent bone fractures. The concept of andropause in prostate cancer patients is poorly represented in the literature. In this article, we review the current literature on the symptoms, signs, and possible therapies available to men who cannot take replacement testosterone.

Female sexuality

Female sexuality is an extraordinarily complex process. The physician needs to be aware of the patient's sexuality and whether or not there are sexual concerns. Physiologic changes over the lifespan can interact with sexual performance as can a variety of disease processes. Partner and relationship issues must also be taken into account. Physicians need to include a sexual history as part of their general history and should not be judgmental of their patients' sexual practices. Sexual disorders in women are defined and delineated by those issues causing personal distress. Again, one person's distress may be quite normal to another. The important aspects of care consist of listening, educating, and providing support to the patient. There is increasing interest but a continued need for data in the use of testosterone in women with decreased libido. The use of sildenafil for female sexual dysfunction remains controversial as a benefit. Overall, there is a need for the development of well-organized, randomized, controlled studies on appropriate assessment and intervention for sexual dysfunction in women.

Andropause:

There is increasing evidence that the common condition of hypogonadism in older men when associated with symptoms responds well to testosterone replacement. Over the last few years there has been a marked increase in the awareness and treatment of the andropause [137]. Long-term side effects of testosterone are uncertain with only eight people over 50 years having been studied for 10 years [138]. Testosterone needs to be considered a quality-of-life drug, similar to sildenafil, and at present it should be used only if it produces symptomatic improvement. There is a need for a men's health study to determine the long-term efficacy and safety of testosterone replacement in older persons.

Oral testosterone supplementation increases muscle and decreases fat mass in healthy elderly males with low-normal gonadal status

BACKGROUND

Loss of muscle mass (sarcopenia) leads to frailty in older men. The decline in testosterone over the life span may contribute to this muscle loss. We studied the ability of oral testosterone to prevent muscle loss in older men over a 12-month period.

METHODS

A standard dose (80 mg twice daily) of testosterone undecanoate or placebo was administered for 1 year to 76 healthy men aged 60 years or older. All men had a free testosterone index of 0.3-0.5, which represents a value below the normal lower limit for young men (19-30 years), but remains within the overall normal male range. Measurements of body composition, muscle strength, hormones, and safety parameters were obtained at 0, 6, and 12 months.

RESULTS

Lean body mass increased (p =.0001) and fat mass decreased (p =.02) in the testosterone as compared with the placebo-treated group. There were no significant effects on muscle strength. There was a significant increase in hematocrit (0.02%) in the testosterone-treated group (p =.03). Plasma triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels were similar in both groups, but there was a decrease in high-density lipoprotein cholesterol (-0.1 mmol/L) at 12 months in the testosterone group as compared to the placebo group (p = 0.026). There were no differences in prostate-specific antigen or systolic or diastolic blood pressure between the groups.

CONCLUSION

Oral testosterone administration to older relatively hypogonadal men results in an increase in muscle mass and a decrease in body fat.

Evaluation of body composition: practical guidelines

The measurement of body composition in the truest sense allows for the estimation of body tissues, organs, and their distributions in living persons without inflicting harm. It is important to recognize that there is no single measurement method that is error-free. Furthermore, bias can be introduced if a measurement method makes assumptions related to body composition proportions and characteristics that are inaccurate across different populations. Some methodologic concerns include hydration of fat-free body mass changes with age and differences across ethnic groups [73]; the density of fat-free body mass changes with age and differences between men and women [74, 75]; total body potassium decreases with age [73] and fatness [76] and differences between African Americans and Caucasians [77]; the mass of skeletal muscle differences across race group [63]; and VAT differences across sex [78] and race [67, 79, 80] groups, independent of total adiposity. These between-group differences influence the absolute accuracy of methods for estimating fatness or FFM that involve the two-compartment model approach. The clinical significance of the body compartment to be measured should be determined before a measurement method is selected, because the more advanced techniques are less accessible and more costly.

Androgen treatment of male hypogonadism in older males

The treatment of primary and secondary hypogonadism with testosterone is well established. Recently, there has been increased awareness that low testosterone levels also occur in chronically ill persons and aging males. Because of sex hormone binding globulin changes, it is more appropriate to make the diagnosis using either free or bioavailable testosterone. A small number of controlled studies have suggested that testosterone replacement in older men improves libido, quality of erections, some aspects of cognition, muscle mass, muscles strength, and bone mineral density. It also decreases fat mass and leptin levels. A number of screening questionnaires for the andropause have been developed. Insufficient numbers of older men have been treated with testosterone to characterize the true incidence of side effects. There is a desperate need for well designed, large controlled trials to establish the value or otherwise of testosterone treatment in older males.

Handgrip strength and cause-specific and total mortality in older disabled women: exploring the mechanism

OBJECTIVES

To examine the association between muscle strength and total and cause-specific mortality and the plausible contributing factors to this association, such as presence of diseases commonly underlying mortality, inflammation, nutritional deficiency, physical inactivity, smoking, and depression.

DESIGN

Prospective population-based cohort study with mortality surveillance over 5 years.

SETTING

Elderly women residing in the eastern half of Baltimore, Maryland, and part of Baltimore County.

PARTICIPANTS

Nine hundred nineteen moderately to severely disabled women aged 65 to 101 who participated in handgrip strength testing at baseline as part of the Women's Health and Aging Study.

MEASUREMENTS

Cardiovascular disease (CVD), cancer, respiratory disease, other measures (not CVD, respiratory, or cancer), total mortality, handgrip strength, and interleukin-6.

RESULTS

Over the 5-year follow-up, 336 deaths occurred: 149 due to CVD, 59 due to cancer, 38 due to respiratory disease, and 90 due to other diseases. The unadjusted relative risk (RR) of CVD mortality was 3.21 (95% confidence interval (CI) = 2.00-5.14) in the lowest and 1.88 (95% CI = 1.11-3.21) in the middle compared with the highest tertile of handgrip strength. The unadjusted RR of respiratory mortality was 2.38 (95% CI = 1.09-5.20) and other mortality 2.59 (95% CI = 1.59-4.20) in the lowest versus the highest grip-strength tertile. Cancer mortality was not associated with grip strength. After adjusting for age, race, body height, and weight, the RR of CVD mortality decreased to 2.17 (95% CI = 1.26-3.73) in the lowest and 1.56 (95% CI = 0.89-2.71) in the middle, with the highest grip-strength tertile as the reference. Further adjustments for multiple diseases, physical inactivity, smoking, interleukin-6, C-reactive protein, serum albumin, unintentional weight loss, and depressive symptoms did not materially change the risk estimates. Similar results were observed for all-cause mortality.

CONCLUSION

In older disabled women, handgrip strength was a powerful predictor of cause-specific and total mortality. Presence of chronic diseases commonly underlying death or the mechanisms behind decline in muscle strength in chronic disease, such as inflammation, poor nutritional status, disuse, and depression, all of which are independent predictors of mortality, did not explain the association. Handgrip strength, an indicator of overall muscle strength, may predict mortality through mechanisms other than those leading from disease to muscle impairment. Grip strength tests may help identify patients at increased risk of deterioration of health.

Exercise treatment to counteract protein wasting of chronic diseases

PURPOSE OF REVIEW

The objective is to summarize the findings from recent (June 2001-2002) studies that have examined the potential benefits of exercise training for the treatment of wasting associated with sarcopenia, cancer, chronic renal insufficiency, rheumatoid arthritis, osteoarthritis and HIV. In many clinical conditions, protein wasting and unintentional weight loss are predictors of morbidity and mortality. The pathogenesis of protein wasting in these conditions can be different, but the fundamental mechanism is an imbalance between muscle protein synthetic and proteolytic processes. The muscle proteins most affected and the precise alterations in their synthetic and proteolytic rates that occur in each cachectic condition are still under investigation.

RECENT FINDINGS

Regular exercise, or sometimes just a modest increase in physical activity, can mitigate muscle protein wasting. Aerobic exercise training primarily alters mitochondrial and cytosolic proteins (enzyme activities), while progressive resistance exercise training predominantly increases contractile protein mass. Previous studies indicate that resistance exercise acutely increases the muscle protein synthetic rate more than muscle proteolysis such that the muscle amino acid balance is increased for up to 2 days after exercise. Progressive resistance exercise training increases muscle protein synthesis and muscle mass, but attenuates the increment in proteolysis that results from a single bout of resistance exercise. The cellular mechanisms that produce these adaptations are not entirely clear.

SUMMARY

In general, patients with wasting conditions who can and will comply with a proper exercise program gain muscle protein mass, strength and endurance, and, in some cases, are more capable of performing the activities of daily living.

Acute phase protein levels and thymus, spleen and plasma protein synthesis rates differ in adult and old rats

Aging induces a dysregulation of immune and inflammation functions that may affect protein synthesis rates in lymphoid tissue and plasma proteins. We quantified in vivo synthesis rates of thymus, spleen and plasma proteins, including albumin and acute phase proteins, in adult (8 mo old) and old (22 mo old) rats using the flooding dose method [L-(1-(13)C) phenylalanine]. Immunosenescence was reflected by thymus atrophy and spleen hypertrophy in old rats but not in adult rats. A low albumin plasma level associated with high concentrations of fibrinogen, alpha(2)-macroglobulin, alpha(1)-acid glycoprotein and proteins other than albumin revealed a low grade inflammation in old rats. Protein fractional synthesis rates (FSR) and protein synthesis efficiencies of thymus were 29 and 26% lower in old than in adult rats, respectively; these variables did not differ in spleen. Protein absolute synthesis rates (ASR) of the thymus and spleen were 76% lower and 67% greater in old than adult rats, respectively. The FSR and ASR of albumin and other plasma proteins were greater in old than in adult rats. Protein synthesis measurement is a valuable nonimmunological tool to assess, in vivo, immune and inflammatory variables. Alterations in secondary lymphoid organs and plasma protein synthesis may contribute to the significant repartitioning of amino acids in old compared with adult rats and may be involved in sarcopenia.

Orexigenic and anabolic agents

Anorexia and weight loss represent a major cause of morbidity and mortality. At present in the United States two effective anorectic agents are commonly used, namely, megestrol acetate and dronabinol. These two agents are compared in Table 1. In persons with a large excess cytokine production. megestrol acetate should be tried at a does of 800 mg per day for no longer than 3 months. Megestrol acetate should be administered with testosterone in men. It should be avoided in persons who are bed-bound because of the risk of deep vein thrombosis. Dronabinol should be used for most anorectic patients. Dronabinol should initially be given in a low dose (2.5 mg) in the evening. The dose should be increased to 5 mg per day if no improvement in appetite is seen after 2 to 4 weeks. Dronabinol can be continued indefinitely. It seems to have a particularly good profile for persons with anorexia who are at the end of life. In persons with depression and anorexia. mirtazapine seems to be the antidepressant of choice. In addition, the use of taste enhancers can be considered in persons who complain that the food does not taste good. The appropriate use of anabolic agents in older persons with weight loss is controversial. Certainly all older men who are losing weight should have bioavailable testosterone measured and, if the testosterone level is low, should receive testosterone replacement therapy. Women who are losing weight may benefit from the use of low-dose testosterone (eg, Estratest). Anabolic agents, such as oxandrolone, should be reserved for those who have profound cachexia. An approach to the management of anorexia and weight loss in older persons is given in Fig. 1. Thomas et al have provided a more complex algorithm the management of weight loss in nursing home residents.

Pathophysiology of anorexia

A physiologic decline in food intake occurs with advancing age. The physiologic anorexia of aging and its associated weight loss predispose older persons to develop protein-energy malnutrition. In older persons a variety of social and psychologic factors, diseases, and medications can aggravate the physiologic anorexia and lead to severe weight loss. Many of these factors are amenable to treatment, resulting in a reversal of the underlying malnutrition. This article first reviews the physiologic factors responsible for anorexia in older persons. It then reviews the major pathologic processes responsible for producing protein-energy malnutrition in older persons.

Molecular-based therapeutic approaches in treatment of anorexia of aging and cancer cachexia

Loss of appetite, or anorexia, has profound implications for older persons, altering social interactions, reducing quality of life, and leading to weight loss with grave health consequences. Two conditions associated with anorexia considered in this article are the multidetermined anorexia of aging and the wasting syndrome termed cachexia induced by cancer. Nutritional interventions may have some benefit in the former, but are of limited value in the latter. Emerging studies at the molecular level relating to appetite regulation and energy balance may offer new approaches to arrest progressive weight loss in the anorexia of aging and cancer cachexia.

Low relative skeletal muscle mass (sarcopenia) in older persons is associated with functional impairment and physical disability

OBJECTIVES

To establish the prevalence of sarcopenia in older Americans and to test the hypothesis that sarcopenia is related to functional impairment and physical disability in older persons.

DESIGN

Cross-sectional survey.

SETTING

Nationally representative cross-sectional survey using data from the Third National Health and Nutrition Examination Survey (NHANES III).

PARTICIPANTS

Fourteen thousand eight hundred eighteen adult NHANES III participants aged 18 and older.

MEASUREMENTS

The presence of sarcopenia and the relationship between sarcopenia and functional impairment and disability were examined in 4,504 adults aged 60 and older. Skeletal muscle mass was estimated from bioimpedance analysis measurements and expressed as skeletal muscle mass index (SMI = skeletal muscle mass/body mass x 100). Subjects were considered to have a normal SMI if their SMI was greater than -one standard deviation above the sex-specific mean for young adults (aged 18-39). Class I sarcopenia was considered present in subjects whose SMI was within -one to -two standard deviations of young adult values, and class II sarcopenia was present in subjects whose SMI was below -two standard deviations of young adult values.

RESULTS

The prevalence of class I and class II sarcopenia increased from the third to sixth decades but remained relatively constant thereafter. The prevalence of class I (59% vs 45%) and class II (10% vs 7%) sarcopenia was greater in the older (> or = 60 years) women than in the older men (P <.001). The likelihood of functional impairment and disability was approximately two times greater in the older men and three times greater in the older women with class II sarcopenia than in the older men and women with a normal SMI, respectively. Some of the associations between class II sarcopenia and functional impairment remained significant after adjustment for age, race, body mass index, health behaviors, and comorbidity.

CONCLUSIONS

Reduced relative skeletal muscle mass in older Americans is a common occurrence that is significantly and independently associated with functional impairment and disability, particularly in older women. These observations provide strong support for the prevailing view that sarcopenia may be an important and potentially reversible cause of morbidity and mortality in older persons.

A conceptual framework of frailty: a review

This article presents an overview of the increasingly common condition of frailty, which by and large lacks clarity of definition. A variety of sources provide this statement regarding definition, incidence, causation, rate, and time of appearance. Utilizing the newly elaborated process of symmorphosis, which explains the coadaptation of structure and function secondary to altered energy loads, I propose that frailty is a body-wide set of linked deteriorations including, but not confined to, musculoskeletal, cardiovascular, metabolic, and immunologic systems. The common final pathway that leads to this constellation of findings is usually keyed to a decline in physical activity either as a result of habit or disease inputs. As such, the state of frailty is largely separable from the process of aging and should thereby be susceptible to active intervention and reversal.

The biochemistry of aging muscle

Between the ages of 20 and 80, humans lose approximately 20-30% of their skeletal muscle mass. This age-related loss of muscle mass, sometimes described as 'sarcopenia of old age', is the consequence of complicated multifactorial processes and is commonly associated with osteopenia or osteoporosis. Consequences of the aging changes in muscle are declining physiological function and loss of muscle strength, typically associated with reduced physical activities. Consequently, falls and subsequent serious injuries are prevalent in the elderly. Thus, it is imperative to try and understand the processes, leading to age-related muscle loss, in order to develop means to retard this phenomenon leading to improved quality of life in the elderly. It is possible to divide the causes of muscle aging to intrinsic factors, involving changes at the molecular and cellular levels, and to extrinsic or environmental factors. The purpose of this review is to describe some of the biochemical processes and the possible mechanisms of muscle aging and to evaluate the importance of various extrinsic factors such as nutrition, exercise and limb immobilization. Changes in the aging skeletal muscle are reviewed with regard to: (a) enzyme activities, protein turnover and repair capacities (b) mitochondrial functioning and energy reserve systems (c) ion content and regulation (d) oxidative stress and free radicals (e) nutrition and caloric restriction (f) exercise and limb immobilization.

Exercise-induced modulation of antioxidant defense

Maintaining mobility is a critical element for the quality of life. Skeletal muscle, the primary organ for locomotion, undergoes age-associated deterioration in size, structure, and function. Recent research suggests that oxidative stress is an important etiology for sarcopenia. The level of oxidative stress imposed on aging muscle is influenced by two fundamental biological processes: the increased generation of reactive oxygen species (ROS) and age-associated changes in antioxidant defense. It appears that despite increased ROS production, aging muscle has a decreased gene expression of antioxidant enzymes possibly due to a diminished ability for cell signaling. A major benefit of nonexhaustive exercise is to induce a mild oxidative stress that stimulates the expression of certain antioxidant enzymes. This is mediated by the activation of redox-sensitive signaling pathways. For example, gene expression of muscle mitochondrial (Mn) superoxide dismutase is enhanced after an acute bout of exercise preceded by an elevated level of NF-kappaB and AP-1 binding. An increase in de novo protein synthesis of an antioxidant enzyme usually requires repeated bouts of exercise. Aging does not abolish but seems to attenuate training adaptations of antioxidant enzymes. Thus, for senescent muscle, training should be assisted with supplementation of exogenous antioxidants to research the optimal level of defense.

Nutrition in the elderly

It is now well accepted that older persons experience a physiologic anorexia, the anorexia of aging, which is caused by alterations in hedonic qualities of food, fundal compliance, and increased leptin levels. Depression is the most common pathologic cause of weight loss in older persons. Older persons fail to recognize thirst and as such have an increased risk of dehydration. Alterations in brain membrane fatty acids can lead to cognitive impairment in older persons.

The biomechanics of adiposity--structural and functional limitations of obesity and implications for movement

Obesity is a significant health problem and the incidence of the condition is increasing at an alarming rate worldwide. Despite significant advances in the knowledge and understanding of the multifactorial nature of the condition, many questions regarding the specific consequences of the disease remain unanswered. For example, there is a dearth of information pertaining to the structural and functional limitations imposed by overweight and obesity. A limited number of studies to date have considered plantar pressures under the feet of obese vs. non-obese, the influence of foot structure on performance, gait characteristics of obese children and adults, and relationships between obesity and osteoarthritis. A better appreciation of the implications of increased levels of body weight and/or body fat on movement capabilities of the obese would provide an enhanced opportunity to offer more meaningful support in the prevention, treatment and management of the condition.

Joint tests of linkage and association for quantitative traits

In this paper we describe various study designs and analytic techniques for testing the joint hypothesis that a genetic marker is both linked to and associated with a quantitative phenotype. Issues of power and sampling are addressed. The distinction between methods that explicitly examine association and those that infer association by examining the distribution of allelic transmissions from a heterozygous parent is examined. Extensions to multivariate, multiallelic, and multilocus situations are addressed. Recent approaches that combine variance-components-based linkage analyses with joint tests of linkage in the presence of association for disentanglement of the linkage and association and the application of such methods to fine mapping are discussed. Finally, new classes of joint tests of linkage and association that do not require samples of related individuals are described.