Distinguishing starvation from cachexia

Safety of elective enteral access in elderly patients: a comparative analysis of perioperative risk

BACKGROUND

Elderly patients can experience torpid hospitalization that is often characterized by malnutrition. In this setting, enteral feeding may facilitate improvement in nutritional status. This study aimed to compare the perioperative outcomes between elderly (age of ≥65 years old) and nonelderly (age of <65 years old) patients undergoing elective enteral access placement.

METHODS

Adult patients who underwent enteral access procedures between 2018 and 2020 at a tertiary care facility were retrospectively reviewed. Differences in baseline characteristics between nonelderly and elderly patients were adjusted using entropy-balanced weights. Subsequently, multivariate logistic and linear regression models were developed to evaluate the association between elderly status and outcomes of interest.

RESULTS

Overall, 914 patients with enteral access met the inclusion criteria, of whom 471 (51.5%) were elderly. Elderly patients more commonly received percutaneous gastrostomy and had a higher burden of comorbidities as measured using the Charlson Comorbidity Index than nonelderly patients. Multivariate risk adjustment generated a strongly balanced distribution of baseline covariates between patient groups. After adjustment, despite no significant association with inhospital mortality, reoperation, or time to feeding goals, elderly status was linked to an approximately 8-day reduction in length of stay (95% CI, -14.28 to -2.30; P = .007) and significantly lower odds of total parenteral nutrition (adjusted odds ratio [AOR], 0.59; 95% CI, 0.37-0.94; P = .026) and nonelective readmission (AOR, 0.65; 95% CI, 0.49-0.86; P = .003). In addition, elderly status was associated with significantly greater odds of nonhome discharge (AOR, 1.58; 95% CI, 1.17-2.13; P = .003).

CONCLUSION

Despite having more comorbidities than their nonelderly counterparts, elderly patients experienced favorable nutritional and perioperative outcomes after enteral access placement.

Microgliosis: a double-edged sword in the control of food intake

Maintaining energy balance is essential for survival and health. This physiological function is controlled by the brain, which adapts food intake to energy needs. Indeed, the brain constantly receives a multitude of biological signals that are derived from digested foods or that originate from the gastrointestinal tract, energy stores (liver and adipose tissues) and other metabolically active organs (muscles). These signals, which include circulating nutrients, hormones and neuronal inputs from the periphery, collectively provide information on the overall energy status of the body. In the brain, several neuronal populations can specifically detect these signals. Nutrient-sensing neurons are found in discrete brain areas and are highly enriched in the hypothalamus. In turn, specialized brain circuits coordinate homeostatic responses acting mainly on appetite, peripheral metabolism, activity and arousal. Accumulating evidence shows that hypothalamic microglial cells located at the vicinity of these circuits can influence the brain control of energy balance. However, microglial cells could have opposite effects on energy balance, that is homeostatic or detrimental, and the conditions for this shift are not totally understood yet. One hypothesis relies on the extent of microglial activation, and nutritional lipids can considerably change it.

Targeting Gut Microbiota in Cancer Cachexia: Towards New Treatment Options

Cancer cachexia is a complex multifactorial syndrome whose hallmarks are weight loss due to the wasting of muscle tissue with or without the loss of adipose tissue, anorexia, systemic inflammation, and multi-organ metabolic alterations, which negatively impact patients' response to anticancer treatments, quality of life, and overall survival. Despite its clinical relevance, cancer cachexia often remains an underestimated complication due to the lack of rigorous diagnostic and therapeutic pathways. A number of studies have shown alterations in gut microbiota diversity and composition in association with cancer cachexia markers and symptoms, thus supporting a central role for dysbiosis in the pathogenesis of this syndrome. Different tools of microbiota manipulation, including probiotics, prebiotics, synbiotics, and fecal microbiota transplantation, have been investigated, demonstrating encouraging improvements in cachexia outcomes. Albeit pioneering, these studies pave the way for future research with the aim of exploring the role of gut microbiota in cancer cachexia more deeply and setting up effective microbiota-targeting interventions to be translated into clinical practice.

Understanding Metabolic Alterations in Cancer Cachexia through the Lens of Exercise Physiology

Cancer cachexia is one of the leading causes of mortality for late-stage cancer patients. One of its key characteristics is abnormal metabolism and loss of metabolic flexibility, i.e., loss of ability to switch between use of fats and carbohydrates as needed. Here, it is hypothesized that late-stage systemic cancer creates a chronic resource drain on the body that may result in the same metabolic adaptations that occur during intense endurance exercise, activating some of the same mechanisms of nutrient consumption that are supposed to be transient during strenuous physical activity. This hypothesis is evaluated by creating a mathematical model that characterizes the relationships between increased exercise intensity and carbohydrate and fat oxidation. The model is parametrized using published data on these characteristics for a group of professional athletes, moderately active individuals, and individuals with metabolic syndrome. Transitions between different zones of relative nutrient consumption as a function of increased effort are captured through explicitly modeling ventilatory thresholds, particularly VT1 and VT2, where fat is primarily used below VT1, both carbohydrates and fats are used between VT1 and VT2, and where carbohydrates become the primary source of fuel above VT2. A simulation is conducted of projected patterns of nutrient consumption when simulated “effort” remains between VT1 and VT2, or above VT2, and it is proposed that it is the scenario when the simulated effort is maintained primarily above VT2 that most closely resembles metabolic patterns characteristic of cachexia. A discussion of a broader framework for understanding cachectic metabolism using insights from exercise physiology, including potential intervention strategies, concludes this paper.

Chemotherapy-Induced Myopathy: The Dark Side of the Cachexia Sphere

Simple Summary

In addition to cancer-related factors, anti-cancer chemotherapy treatment can drive life-threatening body wasting in a syndrome known as cachexia. Emerging evidence has described the impact of several key chemotherapeutic agents on skeletal muscle in particular, and the mechanisms are gradually being unravelled. Despite this evidence, there remains very little research regarding therapeutic strategies to protect muscle during anti-cancer treatment and current global grand challenges focused on deciphering the cachexia conundrum fail to consider this aspect—chemotherapy-induced myopathy remains very much on the dark side of the cachexia sphere. This review explores the impact and mechanisms of, and current investigative strategies to protect against, chemotherapy-induced myopathy to illuminate this serious issue.

Abstract

Cancer cachexia is a debilitating multi-factorial wasting syndrome characterised by severe skeletal muscle wasting and dysfunction (i.e., myopathy). In the oncology setting, cachexia arises from synergistic insults from both cancer–host interactions and chemotherapy-related toxicity. The majority of studies have surrounded the cancer–host interaction side of cancer cachexia, often overlooking the capability of chemotherapy to induce cachectic myopathy. Accumulating evidence in experimental models of cachexia suggests that some chemotherapeutic agents rapidly induce cachectic myopathy, although the underlying mechanisms responsible vary between agents. Importantly, we highlight the capacity of specific chemotherapeutic agents to induce cachectic myopathy, as not all chemotherapies have been evaluated for cachexia-inducing properties—alone or in clinically compatible regimens. Furthermore, we discuss the experimental evidence surrounding therapeutic strategies that have been evaluated in chemotherapy-induced cachexia models, with particular focus on exercise interventions and adjuvant therapeutic candidates targeted at the mitochondria.

A Pound of Flesh: What Cachexia Is and What It Is Not

Body weight loss, mostly due to the wasting of skeletal muscle and adipose tissue, is the hallmark of the so-called cachexia syndrome. Cachexia is associated with several acute and chronic disease states such as cancer, chronic obstructive pulmonary disease (COPD), heart and kidney failure, and acquired and autoimmune diseases and also pharmacological treatments such as chemotherapy. The clinical relevance of cachexia and its impact on patients’ quality of life has been neglected for decades. Only recently did the international community agree upon a definition of the term cachexia, and we are still awaiting the standardization of markers and tests for the diagnosis and staging of cancer-related cachexia. In this review, we discuss cachexia, considering the evolving use of the term for diagnostic purposes and the implications it has for clinical biomarkers, to provide a comprehensive overview of its biology and clinical management. Advances and tools developed so far for the in vitro testing of cachexia and drug screening will be described. We will also evaluate the nomenclature of different forms of muscle wasting and degeneration and discuss features that distinguish cachexia from other forms of muscle wasting in the context of different conditions.

Inflammation and Skeletal Muscle Wasting During Cachexia

Cachexia is the involuntary loss of muscle and adipose tissue that strongly affects mortality and treatment efficacy in patients with cancer or chronic inflammatory disease. Currently, no specific treatments or interventions are available for patients developing this disorder. Given the well-documented involvement of pro-inflammatory cytokines in muscle and fat metabolism in physiological responses and in the pathophysiology of chronic inflammatory disease and cancer, considerable interest has revolved around their role in mediating cachexia. This has been supported by association studies that report increased levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in some, but not all, cancers and in chronic inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis (RA). In addition, preclinical studies including animal disease models have provided a substantial body of evidence implicating a causal contribution of systemic inflammation to cachexia. The presence of inflammatory cytokines can affect skeletal muscle through several direct mechanisms, relying on activation of the corresponding receptor expressed by muscle, and resulting in inhibition of muscle protein synthesis (MPS), elevation of catabolic activity through the ubiquitin-proteasomal system (UPS) and autophagy, and impairment of myogenesis. Additionally, systemic inflammatory mediators indirectly contribute to muscle wasting through dysregulation of tissue and organ systems, including GCs via the hypothalamus-pituitary-adrenal (HPA) axis, the digestive system leading to anorexia-cachexia, and alterations in liver and adipocyte behavior, which subsequently impact on muscle. Finally, myokines secreted by skeletal muscle itself in response to inflammation have been implicated as autocrine and endocrine mediators of cachexia, as well as potential modulators of this debilitating condition. While inflammation has been shown to play a pivotal role in cachexia development, further understanding how these cytokines contribute to disease progression is required to reveal biomarkers or diagnostic tools to help identify at risk patients, or enable the design of targeted therapies to prevent or delay the progression of cachexia.

Guidelines for the Use of Orexigenic Drugs in Long-Term Care

Undernutrition is defined as a state induced by nutrient deficiency that may be improved solely by administration of nutrients. By this definition, provision of adequate protein and energy sources should reverse the clinical presentation and correct the problem. However, a large number of patients who seem to be undernourished fail to respond to refeeding. A developing understanding of the acute-phase inflammatory response to illness and the role of cytokines in the pathophysiology of chronic illness has challenged the current diagnostic paradigm of undernutrition. In the presence of adequate food, weight loss is most often due to cytokine-associated cachexia and anorexia. Failure of appetite, or anorexia, may play a role in involuntary weight loss. Intervention for involuntary weight loss should aim first at the provision of adequate calories and protein, often in the form of high-density nutrition supplements. However, cytokine-mediated cachexia is remarkably resistant to hypercaloric feeding. With continued weight loss, the use of an orexigenic drug should be considered. Orexigenic drugs have been demonstrated to improve appetite and produce weight gain. The mechanism is unknown but may relate to suppression of proinflammatory cytokines. General guidelines for the use of orexigenic agents are presented. Although much work remains to be done, anticytokine drugs seem to be a promising avenue for the treatment of involuntary weight loss.

Effects of Ramadan fasting on glucose homeostasis and adiponectin levels in healthy adult males

BACKGROUND

Adiponectin is a hormone secreted by adipocytes during the fasting phase of the fast-fed cycle. Ramadan fasting involves prolonged fasting for up to twelve hours and thus could lead to increased secretion of adiponectin by adipocytes. However, studies on the role of adiponectin on glucose and body weight homeostasis during Ramadan fasting is still a matter of controversy. Thus the specific aim of this study was to assess the effect of fasting during Ramadan on the adiponectin levels, body weight and glucose homeostasis in healthy male Malaysian subjects.

METHODS

Twenty healthy male (19-23 years) Muslim subjects were followed up during the fasting month of Ramadan. Anthropometry and blood samples were taken one week before and during the fourth week of fasting. Plasma glucose, insulin and adiponectin were estimated and insulin sensitivity indices were estimated using the Homeostasis Model Assessment.

RESULTS

Subjects experienced a significant decrease in body weight (2.4 %, p < 0.001) and body mass index (5.5 %, p < 0.01). There was also a significant decrease of 12.3 %, 52.8 % and 45.6 % of plasma glucose, insulin and adiponectin respectively (p < 0.01). The drop in adiponectin was positively correlated with the decrease in body weight (r = 0.45, p < 0.05). There was also a significant increase in insulin sensitivity and a decrease in insulin resistance (p < 0.01).

CONCLUSIONS

These results indicate that Ramadan fasting in young healthy individuals has a positive impact on the maintenance of glucose homeostasis. It also shows that adiponectin levels dropped along with significant loss in weight. We feel caloric restriction during the Ramadan fasting is in itself sufficient to improve insulin sensitivity in healthy individuals.

Identifying geriatric malnutrition in nursing practice: the Mini Nutritional Assessment (MNA®)-an evidence-based screening tool

Protein calorie malnutrition (PCM) is common and often undiagnosed in older adults. Left untreated, PCM carries both clinical and financial risks, including decreased quality of life, declining functionality, the inability to live independently, and increased health care costs. The prevalence of PCM in older adults calls for a systematic and standardized approach to nutrition screening that includes the use of a validated screening tool. Recommended by international organizations, the Mini Nutritional Assessment® (MNA) is highly specific and reliable and the most well-validated nutrition screening tool for adults 65 and older. Simple, noninvasive, inexpensive, and easy for nurses and other clinicians to use, the newest MNA-short form (MNA-SF) can quickly and easily identify older adults who are at risk for malnutrition or malnourished. Nurses are key players in successful malnutrition screening in hospitals, long-term care, home care, and community settings. It is strongly recommended that nurses incorporate the newest MNA-SF into all practice settings where older adults receive care.

Pharmacological interventions for geriatric cachexia: a narrative review of the literature

OBJECTIVE

The objective of this review was to investigate the range of pharmacological interventions that have been studied for treatment of geriatric cachexia, and to evaluate their effect on selected clinical outcomes in this population.

METHODS

Databases including Medline and Cochrane Central Register of Controlled Trials were searched up to March 2010 with search terms including "cache*", "intervention", "megestrol acetate" and "cytokine inhibitors". Studies investigating subjects with mean age <60y or disease-related cachexia were excluded. Outcomes assessed were weight or BMI, body composition, appetite and laboratory parameters indicative of cachexia.

RESULTS

Fifteen publications met the selection criteria, reporting on ten studies. Seven studies investigated use of megestrol acetate (MA): two randomised controlled trials, one case control study, two pre-test/post-test studies and two retrospective chart reviews. Weight/BMI was common amongst outcomes and these studies showed an improvement in weight compared with baseline. MA studies which investigated body composition, appetite and/or laboratory parameters provided some evidence for improvement in these outcomes. Three randomised controlled trials investigated the use of other interventions: ghrelin, growth hormone and vitamin supplementations. All demonstrated a significant increase in lean body mass. The only other outcome of interest in these three trials was weight in one study with a significant increase demonstrated.

CONCLUSION

Little investigation has been conducted in this population and the diagnosis of cachexia is problematic however these trials provide preliminary evidence for beneficial outcomes in older adults likely to have cachexia. Further high quality adequately powered prospective studies are necessary to provide effective treatment for geriatric cachexia.

A randomised feasibility study of EPA and Cox-2 inhibitor (Celebrex) versus EPA, Cox-2 inhibitor (Celebrex), resistance training followed by ingestion of essential amino acids high in leucine in NSCLC cachectic patients--ACCeRT study

Background

Cancer cachexia is a syndrome of progressive weight loss. Non-small cell lung cancer patients experience a high incidence of cachexia of 61%. Research into methods to combat cancer cachexia in various tumour sites has recently progressed to the combination of agents.

The combination of the anti-cachectic agent Eicosapentaenoic acid (EPA) and the cyclo-oxygenase-2 (COX-2) inhibitor celecoxib has been tested in a small study with some benefit. The use of progressive resistance training (PRT) followed by the oral ingestion of essential amino acids (EAA), have shown to be anabolic on skeletal muscle and acceptable in older adults and other cancer groups.

The aim of this feasibility study is to evaluate whether a multi-targeted approach encompassing a resistance training and nutritional supplementation element is acceptable for lung cancer patients experiencing cancer cachexia.

Methods/Design

Auckland's Cancer Cachexia evaluating Resistance Training (ACCeRT) is an open label, prospective, randomised controlled feasibility study with two parallel arms. All patients will be treated with EPA and the COX-2 inhibitor celecoxib on an outpatient basis at the study site. In the experimental group patients will participate in PRT twice a week, followed by the ingestion of essential amino acids high in leucine. A total of 21 patients are planned to be enrolled. Patients will be randomised using 1:2 ratio with 7 patients enrolled into the control arm, and 14 patients into the treatment arm. The primary endpoint is the acceptability of the above multi-targeted approach, determined by an acceptability questionnaire.

Discussion

To our knowledge ACCeRT offers for the first time the opportunity to investigate the effect of stimulating the anabolic skeletal muscle pathway with the use of PRT along with EAA alongside the combination of EPA and celecoxib in this population.

Trial registration

Netherlands Trial Register (NTR): ACTRN12611000870954

Senile anorexia in different geriatric settings in Italy

OBJECTIVES

Anorexia is the most frequent modification of eating habits in old age, which may lead to malnutrition and consequent morbidity and mortality in older adults. We aimed to estimate the prevalence and factors associated to anorexia in a sample of Italian older persons living in different settings. Our secondary aim was to evaluate the impact of senile anorexia on nutritional status and on eating habits, as well as on functional status.

DESIGN AND SETTING

Observational study in nursing homes, in rehabilitation and acute geriatric wards, and in the community in four Italian regions (Lazio, Sicily, Emilia-Romagna, and Veneto).

PARTICIPANTS

526 over 65 years old participants were recruited; 218 free-living subjects, 213 from nursing homes, and 96 patients from rehabilitation and acute geriatric wards in the context of a National Research Project (PRIN) from the Italian Ministry of Instruction, University and Research (2005-067913 "Cause e Prevalenza dell'Anoressia senile").

MEASUREMENTS

Anthropometric and nutritional evaluation, olfactory, chewing, and swallowing capacity, food preferences, cognitive function, functional status, depression, quality of life, social aspects, prescribed drugs, and evaluation of gastrointestinal symptoms and pain. Laboratory parameters included prealbumin, albumin, transferrin, C-reactive protein, mucoprotein, lymphocyte count, as well as neurotransmitters leptin, and ghrelin. Anorexia was considered as ≥50% reduction in food intake vs. a standard meal (using 3-day "Club Francophone de Gériatrie et Nutrition" form), in absence of oral disorders preventing mastication.

RESULTS

The overall prevalence of anorexia was 21.2% with higher values among hospitalized patients (34.1% women and 27.2% men in long-term facilities; 33.3% women and 26.7% men in rehabilitation and geriatric wards; 3.3% women and 11.3% men living in the community) and in the oldest persons. Anorexic subjects were significantly less self-sufficient and presented more often a compromised nutritional and cognitive status. Diet composition analyses of anorexic older adults revealed a lower intake of all food groups and a general tendency to a monotonous diet.

CONCLUSION

Anorexia is a frequent condition in older Italians, particularly those hospitalized, with important consequences in the nutritional and functional status. The analysis of dietary components and its quality along with the frequency of intake of single food groups may be useful to plan intervention strategies aiming to improve the nutritional and health status of older adults with anorexia. An early detection of anorexia followed by an adequate intervention in older hospitalized patients to avoid further worsening of clinical and functional status is warranted.

[Nutritional assessment in oncogeriatrics]

Geriatric patients are not defined by their age but by their general profile. Ageing is characterized by loss of organ function together with a reduced capability for adapting to changes in the environment (loss of homeostatic mechanisms) leading to frailty. In the older patient with cancer, there can be problems of dietary intake next to the effects of ageing per se. On top of this situation, the deleterious effects of the inflammatory processes induced by the tumour are superimposed. When these changes are translated into nutritional concepts, it is clear that, in the older cancer patient, there is a strong overlap of starvation, sarcopenia, and cachexia. Nutritional assessment should be part of the routine preliminary evaluation of the older oncology patient. Difference should be made between assessment of risk and actual nutritional status, which should be assessed with specific malnutrition indices. Body weight assessment with specific attention to unintended weight loss is essential in this evaluation. One should recognise the fact that body mass index (BMI) should be interpreted with caution, but that a low value for BMI still heralds an increased malnutrition risk. This increased alertness for nutritional problems has a lot to offer in the willingness for early intervention. The nutritional assessment, however, must be framed in a larger comprehensive geriatric assessment addressing several functional domains.

Body composition among HIV-seropositive and HIV-seronegative adult patients with pulmonary tuberculosis in Uganda

PURPOSE

We determined whether human immunodeficiency virus (HIV) infection affects body cell mass and fat mass wasting among adults with pulmonary tuberculosis (PTB).

METHODS

We screened 967 Ugandan adults for PTB and HIV infection in a cross-sectional study. We compared anthropometric and bioelectric impedance analysis (BIA) body composition parameters among HIV-seropositive and HIV-seronegative men and women with or without PTB by using a non-parametric test.

RESULTS

We found that poor nutritional status associated with TB differed among men and women. Anthropometric and BIA body composition did not differ between HIV-seropositive and HIV-seronegative patients regardless of gender. Average weight group difference in men consisted of body cell mass and fat mass in equal proportions of 43%. In women, average weight group difference consisted predominantly of fat mass of 73% and body cell mass of 13%. Compared to individuals without TB, patients with TB had lower body mass index, weight, body cell mass, and fat mass regardless of gender and HIV status.

CONCLUSIONS

Gender, but not HIV status, was associated with body composition changes in TB. TB appears to be the dominant factor driving the wasting process among co-infected patients.

[Association between aspiration pneumonia and malnutrition in patients from active geriatric units]

PURPOSE

To study the association between malnutrition and aspiration pneumonia (AP) in patients from active geriatric units and describe patients who developed AP.

METHODS

Cases of AP were identified from archived medical charts of two active geriatric units between 2001 and 2007 (n=2238). The prevalence of neurologic disorders, dysphagia and malnutrition was assessed in patients who developed AP and those who did not.

RESULTS

Cumulative incidence of AP was low in both units investigated (1.1%). Aspiration pneumonia was highly associated with neurologic disorders (stroke and Parkinson's disease) and dysphagia (p<0.01), and tended to be more prevalent in those who were malnourished (p<0.10). In AP cases, about 80% of patients were malnourished as assessed by the dietitians, a result supported by a high prevalence of nutritional risk indicators.

CONCLUSIONS

Results support the hypothesis that malnutrition could have contributed to AP in these two active geriatric units. Prevention and treatment of malnutrition, especially in dysphagic patients, could reduce risk of AP in hospitalized elderly.

Nutritional assessment in geriatric cancer patients

INTRODUCTION

Geriatric patients are not defined by their age but by their general profile. Aging is characterized by loss of organ function together with a reduced capability for adapting to changes in the environment (loss of homeostatic mechanisms) leading to frailty. In the older patient with cancer, there can be problems of dietary intake next to the effects of aging per se. On top of this situation, the deleterious effects of the inflammatory processes induced by the tumor are superimposed. When these changes are translated into nutritional concepts, it is clear that, in the older cancer patient, there is a strong overlap of starvation, sarcopenia, and cachexia.

DISCUSSION

Nutritional assessment should be part of the routine preliminary evaluation of the older oncology patient. Difference should be made between assessment of risk and actual nutritional status, which should be assessed with specific malnutrition indices. Body weight assessment with specific attention to unintended weight loss is essential in this evaluation. One should recognize the fact that body mass index (BMI) should be interpreted with caution, but that a low value for BMI still heralds an increased malnutrition risk. This increased alertness for nutritional problems has a lot to offer in the willingness for early intervention. The nutritional assessment, however, must be framed in a larger comprehensive geriatric assessment addressing several functional domains.

Powerful signals for weak muscles

The aim of the present review is to summarise, evaluate and critique the different mechanisms involved in anabolic growth of skeletal muscle and the catabolic processes involved in cancer cachexia and sarcopenia of ageing. This is highly relevant, since they represent targets for future promising clinical investigations. Sarcopenia is an inevitable process associated with a gradual reduction in muscle mass and strength, associated with a reduction in motor unit number and atrophy of muscle fibres, especially the fast type IIa fibres. The loss of muscle mass with ageing is clinically important because it leads to diminished functional ability and associated complications. Cachexia is widely recognised as severe and rapid wasting accompanying disease states such as cancer or immunodeficiency disease. One of the main characteristics of cancer cachexia is asthenia or lack of strength, which is directly related to the muscle loss. Indeed, apart from the speed of loss, muscle wasting during cancer and ageing share many common metabolic pathways and mediators. In healthy young individuals, muscles maintain their mass and function because of a balance between protein synthesis and protein degradation associated with rates of anabolic and catabolic processes, respectively. Muscles grow (hypertrophy) when protein synthesis exceeds protein degradation. Conversely, muscles shrink (atrophy) when protein degradation dominates. These processes are not occurring independently of each other, but are finely coordinated by a web of intricate signalling networks. Such signalling networks are in charge of executing environmental and cellular cues that ultimately determine whether muscle proteins are synthesised or degraded. Increasing our understanding for the pathways involved in hypertrophy and atrophy and particularly the interaction of these pathways is essential in designing therapeutic strategies for both prevention and treatment of muscle wasting conditions with age and with disease.

The aging population--is there a role for endocrine interventions?

The expected increase in the aging population will have a significant impact on society and the health system in the coming years and decades. Enhancing healthspan, "healthy aging", and thus extending the time that the elderly are able to function independently is a significant task and is imperative. Age-dependent changes such as weight loss, sarcopenia and anorexia, which contribute to the development of frailty in the elderly are discussed. The role of the age-dependent decrease in growth hormone secretion in this process and the potential benefits and risks of hormonal interventions to delay, prevent or reverse frailty in the elderly are reviewed.

The evolution of nutritional status of geriatric patients without cachexia is associated with food intake in sub-acute care

OBJECTIVES

To determine if changes in patients' nutritional status during hospitalization are related to daily energy and protein intakes when cachectic/inflammatory conditions are controlled for.

DESIGN

Prospective study.

SUBJECTS

A total of 32 non-cachectic patients (21 women; 65-92 y).

METHODS

Nutritional status was evaluated at admission and discharge using the Protein-Energy Malnutrition Index which includes BMI, %IBW, TS, MAC, albumin, hemoglobin and lymphocyte count. Food intake was assessed 3 meals/day every other day for an average of 46.2 +/- 14.6 meals/participant.

RESULTS

In all, 47% of the study sample was malnourished at admission. Nutritional status improved in 73% of patients who had been identified as malnourished and in 30 % of non-malnourished patients at admission. Total energy intake correlated with improvements in BMI, %IBW and total lymphocyte count (all p < 0.04). Improvement in PEMI score for the whole group was associated with functional status (p < 0.05). Controlling for this variable, energy (kj/kg body weight) and protein (g/kg body weight) intakes correlated positively with improvements in BMI, %IBW and MAC (Energy: partial r = 0.644, 0.624, 0.466 respectively; Protein: partial r = 0.582, 0.554, 0.433 respectively; all p < 0.05).

CONCLUSIONS

Results from this study offer strong evidence that when cachectic/inflammatory conditions are controlled for, standard nutrition care is compatible with the maintenance or improvement of nutritional status during the hospital stay.

Nutrition assessment in long-term care

Assessment of nutrition status is necessary in long-term care settings for both optimal patient care and to meet regulatory standards. Careful nutrition assessment leads to development of an individual plan of care to optimize nutrition status. Although the Minimum Data Set is mandated as the nutrition assessment tool in long-term care settings, published studies show that the use of the Minimum Data Set to assess nutrition status is problematic. Two types of nutrition assessment instruments have been developed. The first type aims to identify those at risk for malnutrition but is not used to diagnose clinical malnutrition, whereas the second type has been designed to diagnose malnutrition. A number of commonly used nutrition assessment tools have not been validated in long-term care populations. This review focuses on the available tools used in the long-term care setting and provides an overview of their characteristics and performance measures.

The cytokine basis of cachexia and its treatment: are they ready for prime time?

Cachexia is a hypercatabolic condition that is often associated with the terminal stages of many diseases, in which the patient's resting metabolic rate is high and loss of muscle and fat tissue mass occur at an alarming rate. The patient also usually has concurrent anorexia, amplifying the wasting syndrome that is cachexia. The greater the extent of cachexia (regardless of underlying disease), the worse the prognosis. Efforts to treat cachexia over the years have fallen short of satisfactorily reversing the wasting syndrome. This article reviews the pathophysiology of cachexia, enumerating the different pro-inflammatory cytokines that contribute to the syndrome and attempting to illustrate their interwoven pathways. We also review the different treatments that have been explored, as well as the recent literature addressing the use of anti-cytokine therapy to treat cachexia.

Hypermetabolic syndrome as a consequence of repeated psychological stress in mice

Stress is a powerful modulator of neuroendocrine, behavioral, and immunological functions. After 4.5-d repeated combined acoustic and restraint stress as a murine model of chronic psychological stress, severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with the severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turnover, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure, changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice. Thus, in our murine model, repeated stress caused severe metabolic dysregulations, leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.

Unintended weight loss in older persons

Unintended weight loss has a profound effect on morbidity and mortality in older persons. A therapeutic approach to unintended weight loss in older persons depends on correct classification. A careful differential diagnostic approach is mandatory, combined with nutritional and often pharmacological interventions. While starvation due to protein-energy undernutrition is widely regarded as the primary cause of loss of fat and fat-free mass in older persons, a failure to improve with nutritional replacement should trigger a consideration of other causes. Both sarcopenia and cachexia are resistant to hypercaloric feeding. Cachexia may be amenable to suppression of proinflammatory cytokines in known inflammatory disease states.

Intensive Session: New Approaches to Medical Issues in Long-Term Care

This article, based on a series of presentations at the American Medical Directors Association, briefly highlights new advances in medical areas of interest to long-term care physicians. The areas discussed are heart failure, vitamin D, falls, new treatments for diabetes mellitus, blood pressure measurement, anemia, clinical nutrition, pressure ulcers, Clostridium difficile, insomnia, and antipsychotic therapy.

Loss of skeletal muscle mass in aging: Examining the relationship of starvation, sarcopenia and cachexia

A loss of body weight or skeletal muscle mass is common in older persons and is a harbinger of poor outcome. Involuntary weight loss can be categorized into three primary etiologies of starvation, sarcopenia, and cachexia. Starvation results in a loss of body fat and non-fat mass due to inadequate intake of protein and energy. Sarcopenia is associated with a reduction in muscle mass and strength occurring with normal aging, associated with a reduction in motor unit number and atrophy of muscle fibers, especially the type IIa fibers. The loss of muscle mass with aging is clinically important because it leads to diminished strength and exercise capacity. Cachexia is widely recognized as severe wasting accompanying disease states such as cancer or immunodeficiency disease, but does not have a universally accepted definition. The key clinical question is whether these changes in body composition are distinct entities or represent an interdependent continuum. The importance of defining the distinction lies in developing a targeted therapeutic approach to skeletal muscle loss and muscle strength in older persons. Failure to distinguish among these causes of skeletal muscle loss often results in frustration over the clinical response to therapeutic interventions.

Cachexia: pathophysiology and clinical relevance

Cachexia causes weight loss and increased mortality. It affects more than 5 million persons in the United States. Other causes of weight loss include anorexia, sarcopenia, and dehydration. The pathophysiology of cachexia is reviewed in this article. The major cause appears to be cytokine excess. Other potential mediators include testosterone and insulin-like growth factor I deficiency, excess myostatin, and excess glucocorticoids. Numerous diseases can result in cachexia, each by a slightly different mechanism. Both nutritional support and orexigenic agents play a role in the management of cachexia.

Vitamins in aging, health, and longevity

Evidence of epidemiological associations of vitamins and disease states have been found for nine vitamins. In observational studies, people with a high intake of antioxidant vitamins by regular diet or as food supplements generally have a lower risk of major chronic disease, such as myocardial infarction or stroke, than people who are low consumers of antioxidant vitamins. Prospectively, folate appears to reduce the incidence of neural tube defects. Vitamin D is associated with a decreased occurrence of fractures when taken with calcium. Zinc, betacarotene, and vitamin E appear to slow the progression of macular degeneration, but do not reduce the incidence. Vitamin E and lycopene may decrease the risk of prostate cancer. In other randomized controlled trials, the apparent beneficial results of a high intake of antioxidant vitamins seen in observational studies have not been confirmed. There is increasing concern from these trials that pharmacological supplementation of vitamins may be associated with a higher mortality risk.

Disorders of Fuel Metabolism: Medical Complications Associated with Starvation, Eating Disorders, Dietary Fads, and Supplements

Disorders of fuel metabolism as they relate to abnormal fuel intake,abnormal fuel expenditure, and dietary supplements are the focus of this article. The emergency physician should be aware of the medical complications that can occur as a result of starvation states,eating disorders, fad diets, hypermetabolic states, and ergogenic aids. Knowledge and understanding of the complications associated with these disorders will facilitate the diagnosis and management of patients who present to the emergency department with any of the disorders reviewed.