Metabolic reprogramming and epigenetic changes of vital organs in SARS-CoV-2-induced systemic toxicity

Extrapulmonary manifestations of COVID-19 are associated with a much higher mortality rate than pulmonary manifestations. However, little is known about the pathogenesis of systemic complications of COVID-19. Here, we create a murine model of SARS-CoV-2-induced severe systemic toxicity and multiorgan involvement by expressing the human ACE2 transgene in multiple tissues via viral delivery, followed by systemic administration of SARS-CoV-2. The animals develop a profound phenotype within 7 days with severe weight loss, morbidity, and failure to thrive. We demonstrate that there is metabolic suppression of oxidative phosphorylation and the tricarboxylic acid (TCA) cycle in multiple organs with neutrophilia, lymphopenia, and splenic atrophy, mirroring human COVID-19 phenotypes. Animals had a significantly lower heart rate, and electron microscopy demonstrated myofibrillar disarray and myocardial edema, a common pathogenic cardiac phenotype in human COVID-19. We performed metabolomic profiling of peripheral blood and identified a panel of TCA cycle metabolites that served as biomarkers of depressed oxidative phosphorylation. Finally, we observed that SARS-CoV-2 induces epigenetic changes of DNA methylation, which affects expression of immune response genes and could, in part, contribute to COVID-19 pathogenesis. Our model suggests that SARS-CoV-2-induced metabolic reprogramming and epigenetic changes in internal organs could contribute to systemic toxicity and lethality in COVID-19.

Kidney cachexia or protein-energy wasting in chronic kidney disease: facts and numbers

BACKGROUND

Weight loss and homeostatic disturbances of both energy and protein balances are characteristics of several illnesses including cancer, heart failure, and chronic kidney disease (CKD). Different definitions have been used to describe this deleterious process. The term protein-energy wasting (PEW) has been proposed for CKD patients by the International Society of Renal Nutrition and Metabolism.

METHODS

We searched the publication in Medline from February 2008 to September 2018 using PEW or cachexia in their title.

RESULTS

Since its inception, the term PEW has been exceptionally successful, highlighted by 327 original publications referenced in PubMed over 10 years. Using this classification, several studies have confirmed that PEW is among the strongest predictors of mortality in CKD patients [hazard ratio of 3.03; confidence interval of 1.69-5.26 in 1068 haemodialysis patients and 1.40 (1.04-1.89) in 1487 non-dialysed patients across PEW stages 0 to 4]. Based on this classification, prevalence of PEW is 28% to 54% among 16 434 adults undergoing maintenance dialysis. PEW prevalence increases when renal function declines, that is, from <2% in CKD stages 1-2 to 11-54% in CKD stages 3-5. A more general definition of cachexia for all chronic diseases proposed by the Society on Sarcopenia, Cachexia and Wasting Disorders was also published concurrently. In the CKD area, we found 180 publications using 'cachexia' underlining that some confusion or overlap may exist. The definitions of PEW and cachexia are somewhat similar, and the main difference is that a loss of body weight >5% is a mandatory criterion for cachexia but supportive for PEW.

CONCLUSIONS

The recent understanding of cachexia physiopathology during CKD progression suggests that PEW and cachexia are closely related and that PEW corresponds the initial state of a continuous process that leads to cachexia, implicating the same metabolic pathways as in other chronic diseases. Despite the success of the definition of PEW, using a more uniform term such as 'kidney disease cachexia' could be more helpful to design future research through collaborative groups of researchers with focus on cachexia.

Implications of low muscle mass across the continuum of care: a narrative review

Abnormalities in body composition can occur at any body weight. Low muscle mass is a predictor of poor morbidity and mortality and occurs in several populations. This narrative review provides an overview of the importance of low muscle mass on health outcomes for patients in inpatient, outpatient and long-term care clinical settings. A one-year glimpse at publications that showcases the rapidly growing research of body composition in clinical settings is included. Low muscle mass is associated with outcomes such as higher surgical and post-operative complications, longer length of hospital stay, lower physical function, poorer quality of life and shorter survival. As such, the potential clinical benefits of preventing and reversing this condition are likely to impact patient outcomes and resource utilization/health care costs. Clinically viable tools to measure body composition are needed for routine screening and intervention. Future research studies should elucidate the effectiveness of multimodal interventions to counteract low muscle mass for optimal patient outcomes across the healthcare continuum. Key messages Low muscle mass is associated with several negative outcomes across the healthcare continuum. Techniques to identify and counteract low muscle mass in clinical settings are needed.

Chronic hyponatremia in a patient with renal salt wasting and without cerebral disease: relationship between RSW, risk of fractures and cognitive impairment

Renal salt wasting syndrome (RSW) is defined as a renal loss of sodium leading to hyponatremia and a decrease in extracellular fluid volume (ECV). Differentiation of this disorder from the syndrome of inappropriate antidiuretic hormone secretion (SIADH), a common cause of hyponatremia, can be difficult because both can present with hyponatremia and concentrated urine with natriuresis. Our clinical case about a 78-year-old woman with a recent fracture of the right femur not only confirms that this syndrome can occur in patients without intracranial pathologies (CT documented), but depicts how the hyponatremia caused by RSW can show a chronic, oscillating course. This is an interesting point of view because it suggests to us to consider RSW in the differential diagnosis of patients with chronic hyponatremia.

Multilevel Analysis of Factors Associated with Wasting and Underweight among Children Under-Five Years in Nigeria

Wasting and underweight reflect poor nutrition, which in children leads to retarded growth. The aim of this study is to determine the factors associated with wasting and underweight among children aged 0-59 months in Nigeria. A sample of 24,529 children aged 0-59 months from the 2013 Nigeria Demographic and Health Survey (NDHS) was used. Multilevel logistic regression analysis that adjusted for cluster and survey weights was used to identify significant factors associated with wasting/severe wasting and underweight/severe underweight. The prevalence of wasting was 18% (95% Confidence Interval (CI): 17.1, 19.7) and severe wasting 9% (95% CI: 7.9, 9.8). The prevalence of underweight was 29% (95% CI: 27.1, 30.5) and severe underweight 12% (95% CI: 10.6, 12.9). Multivariable analysis revealed that the most consistent factors associated with wasting/severe wasting and underweight/severe underweight are: geopolitical zone (North East, North West and North Central), perceived birth size (small and average), sex of child (male), place/mode of delivery (home delivery and non-caesarean) and a contraction of fever in the two weeks prior to the survey. In order to meet the WHO's global nutrition target for 2025, interventions aimed at improving maternal health and access to health care services for children especially in the northern geopolitical zones of Nigeria are urgently needed.

Blood Corticosterone Concentration Reaches Critical Illness Levels Early During Acute Malnutrition in the Weanling Mouse

Acute (i.e., wasting) pediatric malnutrition consistently elevates blood glucocorticoid levels, but neither the magnitude of the rise in concentration nor its kinetics is clear. Male and female C57BL/6J mice, initially 19 days old, and CBA/J mice, initially 23 days old, consumed a complete purified diet either ad libitum (age-matched control) or in restricted daily quantities (mimicking marasmus), or they consumed a purified isocaloric low-protein diet ad libitum (mimicking incipient kwashiorkor). Serum levels of corticosterone were assessed by double antibody radioimmunoassay after 3, 6, and 14 days (C57BLV6J strain) or after 6 and 14 days in the genetically distant CBA/J strain. Age-matched control groups of both strains exhibited mean corticosterone levels of 5–30 ng/ml, whereas the acutely malnourished groups exhibited mean levels of this hormone that were elevated by more than an order of magnitude as early as 3 days after initiation of weight loss. This outcome was confirmed in a second experiment in which the serum corticosterone level of C57BL/6J weanlings was examined by competitive binding enzyme immunoassay 3 and 14 days after initiation of the dietary protocols. Therefore, deficits of protein and/or energy in weanling murine systems relevant to acute pediatric malnutrition elicit early elevations in blood glucocorticoid levels to a magnitude reminiscent of critical illness and multiple trauma. The key to this novel finding was an exsanguination method that permitted accurate assessment of the blood corticosterone level of the healthy, quiescent mouse. Overall, the results of this investigation provide a new perspective on the glucocorticoids as part of the early hormonal response to acute weanling malnutrition coincident with the shift toward catabolic metabolism and the initiation of depression in cellular immune competence.

N-Terminal Pro-B-Type Natriuretic Peptide as a Biomarker for Loss of Muscle Mass in Prevalent Hemodialysis Patients

Protein-energy wasting (PEW) is common in hemodialysis (HD) patients. A recent study demonstrated that a high level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) may be associated with PEW in those patients. This prospective study aimed to assess the association of NT-proBNP with body composition and muscle loss. A cohort of prevalent HD patients (n = 238) was examined. Blood samples were obtained at baseline to measure high-sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), adiponectin and NT-proBNP. Nutritional status and changes in muscle mass were assessed by subjective global assessment, percentage creatinine generation rate (%CGR), creatinine index (CI) and lean body mass (LBM) estimated by dual-energy X-ray absorptiometry (DXA). The %CGR and CI were calculated five times for one year, and DXA was performed at baseline and one year later. Cardiac function was estimated by ultrasonography at baseline. NT-proBNP was significantly higher in HD patients with PEW. High NT-proBNP was associated with cardiac dysfunction, increased levels of hsCRP and IL-6, and serially decreased levels of the indexes for muscle mass. Multiple regression analysis adjusted with confounders showed that NT-proBNP was an independent predictor for decrease in LBM and serial lower levels of %CGR and CI. In conclusion, the present study demonstrated a novel association between NT-proBNP and muscle loss. NT-proBNP may be an independent biomarker for malnutrition in HD patients, especially in patients with muscles loss, regardless of chronic inflammation, cardiac dysfunction, or overhydration.

Neuromuscular junction degeneration in muscle wasting

PURPOSE OF REVIEW

Denervation is a hallmark of age-related and other types of muscle wasting. This review focuses on recent insights and current viewpoints regarding the mechanisms and clinical relevance of maintaining the neuromuscular junction to counteract muscle wasting resulting from aging or neural disease/damage.

RECENT FINDINGS

Activity-dependent regulation of autophagy, the agrin-muscle specific kinase-Lrp4 signaling axis, and sympathetic modulation are principal mechanisms involved in stabilizing the neuromuscular junction. These findings are derived from several animal models and were largely confirmed by human gene expression analysis as well as insights from rare neuromuscular diseases such as amyotrophic lateral sclerosis and congenital myasthenic syndromes. Based on these insights, agrin-derived fragments are currently being evaluated as biomarkers for age-related muscle wasting. Tuning of autophagy, of the agrin pathway, and of sympathetic input are being studied as clinical treatment of muscle wasting disorders.

SUMMARY

Basic research has revealed that maintenance of neuromuscular junctions and a few signaling pathways are important in the context of age-dependent and other forms of muscle wasting. These findings have recently started to enter clinical practice, but further research needs to substantiate and refine our knowledge.

Could a functional artificial skeletal muscle be useful in muscle wasting?

PURPOSE OF REVIEW

Regardless of the underlying cause, skeletal muscle wasting is detrimental for a person's life quality, leading to impaired strength, locomotion, and physiological activity. Here, we propose a series of studies presenting tissue engineering-based approaches to reconstruct artificial muscle in vitro and in vivo.

RECENT FINDINGS

Skeletal muscle tissue engineering is attracting more and more attention from scientists, clinicians, patients, and media, thanks to the promising results obtained in the last decade with animal models of muscle wasting. The use of novel and refined biomimetic scaffolds mimicking three-dimensional muscle environment, thus supporting cell survival and differentiation, in combination with well characterized myogenic stem/progenitor cells, revealed the noteworthy potential of these technologies for creating artificial skeletal muscle tissue. In vitro, the production of three-dimensional muscle structures offer the possibility to generate a drug-screening platform for patient-specific pharmacological treatment, opening new frontiers in the development of new compounds with specific therapeutic actions. In vivo, three-dimensional artificial muscle biomimetic constructs offer the possibility to replace, in part or entirely, wasted muscle by means of straight reconstruction and/or by enhancing endogenous regeneration.

SUMMARY

Reports of tissue engineering approaches for artificial muscle building appeared in large numbers in the specialized press lately, advocating the suitability of this technology for human application upon scaling up and a near future applicability for medical care of muscle wasting.

VIDEO ABSTRACT

http://links.lww.com/COCN/A9

Magnitude of undernutrition in children aged 2 to 4 years using CIAF and conventional indices in the slums of Mumbai city

Conventional indicators - weight-for-age, height-for-age, weight-for-height and mid-upper arm circumference (MUAC) reflect different facets of the nutritional status. Weight-for-age is the most commonly used indicator. When used individually or in combination, conventional indices fail to depict the overall magnitude of undernutrition in the population. Composite Index of Anthropometric Failure (CIAF) is an alternative classification system which attempts to fill this lacuna. Thus, we undertook this study with the objective to compare the prevalence of undernutrition using CIAF and the conventional indices. We included 634 children aged between 2 to 4 years from anganwadis located in three areas of Mumbai. Weight, height and MUAC measurements were taken. Z scores were computed for weight-for-age (WAZ), height-for-age (HAZ) and weight-for-height (WHZ) using WHO Anthro software. Children were classified as per the conventional indices and CIAF. The prevalence of underweight, stunting and wasting was 35.7%, 33.8% and 18.5% respectively. None of the children had MUAC < 11.5 cm. About 1% of the children were moderately wasted according to MUAC. As per CIAF, 47.8% children were undernourished. According to CIAF, one-third of the undernourished children had single anthropometric failure while half of them had dual failure and 17.1% had multiple failures. When compared with the conventional indices, CIAF could recognize 12.1%, 14.0%, 29.3% and 46.7% more undernourished children than WAZ, HAZ, WHZ and MUAC respectively. In conclusion, CIAF is seen to have many advantages over the conventional indices. CIAF is useful in assessing the overall magnitude of undernutrition and identifying children with multiple anthropometric failures. It also recognizes more undernourished children than all the conventional indices. Therefore, CIAF should be used more widely as a tool for nutritional assessment particularly in developing countries where the burden of undernutrition is high.

Muscle wasting in cancer: the role of mitochondria

PURPOSE OF REVIEW

The aim of the present review is to examine the impact of mitochondrial dysfunction in cancer cachexia.

RECENT FINDINGS

Oxidative pathways are altered in this tissue during muscle wasting and this seems to be a consequence of mitochondrial abnormalities that include altered morphology and function, decreased ATP synthesis and uncoupling.

SUMMARY

An alteration of energy balance is the immediate cause of cachexia. Both alterations in energy intake and expenditure are responsible for the wasting syndrome associated with different types of pathological conditions, such as cancer. Different types of molecular mechanisms contribute to energy expenditure and, therefore, involuntary body weight loss, one of which is mitochondrial dysfunction.

Mitochondrial plasticity in cancer-related muscle wasting: potential approaches for its management

PURPOSE OF REVIEW

Cancer cachexia represents a critical problem in clinical oncology due to its negative impact on patients' quality of life, therapeutic tolerance and survival. This paraneoplasic condition is characterized by significant weight loss mainly from skeletal muscle wasting. Understanding the molecular mechanisms underlying cancer cachexia is urgent in order to develop and apply efficient therapeutic strategies.

RECENT FINDINGS

Mitochondrial dysfunction is an early event in cancer-induced muscle wasting. Decreased ability for ATP synthesis, impaired mitochondrial biogenesis, increased oxidative stress, impairment of protein quality control systems, increased susceptibility to mitophagy and to apoptosis were all shown to mediate contractile dysfunction and wasting in cancer cachexia. Anti-inflammatory therapies as well as exercise training seem to counteract muscle mass loss in part by improving mitochondrial functionality.

SUMMARY

Given its central role in muscle wasting, mitochondrial plasticity should be viewed as a key therapeutic target for the preservation of muscle mass in cancer cachexia. Few studies have addressed the mitochondrial events modulated by cancer cachexia and contradictory data were reported. Scarcer studies have focused on the mitochondrial adaptation to anticancer cachexia strategies.

Involuntary weight loss

Involuntary weight loss remains an important and challenging clinical problem, with a high degree of morbidity and mortality. Because of the frequency of finding a serious underlying diagnosis, clinicians must be thorough in assessment, keeping in mind a broad range of possible causes. Although prediction scores exist, they have not been broadly validated; therefore, clinical judgment remains ever essential.

Multimodal nutrition/anabolic therapy for wasting conditions

PURPOSE OF REVIEW

Significant progress has been made in the field of defining and describing the pathophysiology of wasting conditions such as cachexia. The number of new promising drugs, nutritional therapy alternatives, and exercise/rehabilitation programs is increasing. The purpose of this review is to give an overview of recent clinical findings from intervention studies investigating multimodal anabolic therapies utilizing drug, nutritional, and/or exercise interventions in order to counteract wasting.

RECENT FINDINGS

Anabolic agents such as ghrelin and selective androgen receptor modulators are under late-phase clinical testing and hold promise as new therapies, and their ability to mitigate weight loss and improve muscle mass and physical function is evaluated. In the past 2 years, eight new studies investigating interventions with anabolic potential in wasting have been published, among which three of these studies were multimodal.

SUMMARY

Targeted anabolic therapies aiming to prevent or reverse wasting might involve a combination of anabolic pharmacologic drugs, nutrition, and physical exercise working concurrently to enhance muscle protein synthesis and reduce breakdown. Some anabolic pharmacological interventions demonstrate the potential to improve muscle mass, but the multimodal interventions seem in greater extent to also demonstrate improvement in physical function.

Stunting and wasting are associated with poorer psychomotor and mental development in HIV-exposed Tanzanian infants

Infants born to HIV-infected women are at increased risk of impaired neurodevelopment, but little research has attempted to identify modifiable risk factors. The objective of this prospective cohort analysis was to identify maternal, socioeconomic, and child correlates of psychomotor and mental development in the first 18 mo of life among Tanzanian infants born to HIV-infected women. We hypothesized that child HIV infection, morbidity, and undernutrition would be associated with lower developmental status when taking into consideration maternal health and socioeconomic factors. Baseline maternal characteristics were recorded during pregnancy, birth characteristics were collected immediately after delivery, infant micronutrient status was measured at 6 wk and 6 mo, and anthropometric measurements and morbidity histories were performed at monthly follow-up visits. The Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Development, 2nd edition (BSID-II) were used to assess developmental functioning at 6, 12, and 18 mo of age. Multivariate repeated regression models with time-varying covariates were used to estimate adjusted mean MDI and PDI scores for each level of the variables. A total of 311 infants contributed ≥1 BSID-II assessments for 657 PDI and 655 MDI measurements. Of infants, 51% were male, 23% were born preterm, 7% were low birth weight, and 10% were HIV-positive at 6 wk. Preterm birth, child HIV infection, stunting, and wasting were independently associated with lower PDI and MDI scores. Strategies to lower mother-to-child transmission of HIV, prevent preterm birth, and enhance child growth could contribute to improved child psychomotor and mental development.

Relation of oxidative stress, zinc and alkaline phosphatase in protein energy malnutrition

OBJECTIVE

To determine serum zinc (Zn), total anti-oxidant capacity (TAC), malondialdehyde (MDA), alkaline phosphatase (ALP) and albumin in protein energy malnutrition (PEM) and to analyse the appropriateness of using low weight-for-age for detecting childhood under-nutrition.

METHODS

This study comprised 455 children (355 malnourished and 100 normal). They were classified according to the Nutrition Subcommittee of Indian Academy of Pediatrics, Z-Score Classification and Composite Index of Anthropometric Failure. Serum Zn, TAC, MDA, ALP and albumin levels were determined.

RESULTS

The serum Zn, TAC, ALP and albumin levels were found to be significantly decreased and MDA levels were significantly increased in malnourished children as compared with control (P < 0.001).

CONCLUSION

The significant increase in serum MDA concentration associated with the decrease in serum TAC, Zn and ALP in malnourished children suggest that these children were potentially susceptible to high oxidative stress. Current study also suggest that conventional measures of detecting under-nutrition (low weight-for-age) may be missing out a considerable proportion of undernourished children present in the population.

Combined intensive nutrition education and micronutrient powder supplementation improved nutritional status of mildly wasted children on Nias Island, Indonesia

To assess the impact of intensive nutrition education (INE) with or without the provision of micronutrient powder (MNP) on the nutritional status of mildly wasted children in Nias, Indonesia, two groups of mildly wasted (>=-1.5 to <-1.0 WHZ) children aged >=6 to <60 months in the Church World Service (CWS) project areas were assigned by village randomization to receive INE (n=64) or INE+MNP (n=51) in a weekly program. Another two groups of mildly wasted children who were living at a clear distance from INE and INE+MNP villages were selected to receive a monthly non-intensive nutrition education program (NNE) with or without MNP (n=50 both respectively). WHZ, weight, height, haemoglobin (Hb) level, and morbidity data were assessed at admission, during the study, and at individual discharge. Children's weight gain (g/kg body weight/day) was highest in INE+MNP group (2.2±2.1), followed by INE (1.1±0.9), NNE+MNP (0.3±0.5) and NNE (0.3±0.4) group. In both MNP intervention groups (INE+MNP, NNE+MNP), supplements significantly increased Hb value (g/L) of respective children (10.0±10.0; p<0.001 and 3.0±8.0; p<0.05 respectively). Proportion of children who reached discharge criterion was highest among the INE+MNP (70.6%; n=36), followed by INE (64.1%; n=41), NNE+MNP (26.0%; n=13), and NNE (20.0%; n=10) groups (p<0.001). Shortest length of stay until recovery was observed among children in the INE+MNP group (29.9 days), followed by INE (40.0 days), NNE+MNP (80.6 days), and NNE (86.2 days) respectively (p<0.001). Weekly intensive nutrition education supported by MNP supplementation produced the best results regarding weight gain and haemoglobin status of mildly wasted children.

Leucine-stimulated mTOR signaling is partly attenuated in skeletal muscle of chronically uremic rats

The branched-chain amino acid leucine stimulates muscle protein synthesis in part by directly activating the mTOR signaling pathway. Furthermore, leucine, if given in conjunction with resistance exercise, enhances the exercise-induced mTOR signaling and protein synthesis. Here we tested whether leucine can activate the mTOR anabolic signaling pathway in uremia and whether it can enhance work overload (WO)-induced signaling through this pathway. Chronic kidney disease (CKD) and control rats were studied after 7 days of surgically induced unilateral plantaris muscle WO and a single leucine or saline load. In the basal state, 4E-BP1 phosphorylation was modestly depressed in non-WO muscle of CKD rats, whereas rpS6 phosphorylation was nearly completely suppressed. After oral leucine mTOR, S6K1 and rpS6 phosphorylation increased similarly in both groups, whereas the phospho-4E-BP1 response was modestly attenuated in CKD. WO alone activated the mTOR signaling pathway in control and CKD rats. In WO CKD, muscle leucine augmented mTOR and 4E-BP1 phosphorylation, but its effect on S6K1 phosphorylation was attenuated. Taken together, this study has established that the chronic uremic state impairs basal signaling through the mTOR anabolic pathway, an abnormality that may contribute to muscle wasting. However, despite this abnormality, leucine can stimulate this signaling pathway in CKD, although its effectiveness is partially attenuated, including in skeletal muscle undergoing sustained WO. Thus, although there is some resistance to leucine in CKD, the data suggest a potential role for leucine-rich supplements in the management of uremic muscle wasting.

Hypothalamic actions of tumor necrosis factor alpha provide the thermogenic core for the wastage syndrome in cachexia

TNFalpha is an important mediator of catabolism in cachexia. Most of its effects have been characterized in peripheral tissues, such as skeletal muscle and fat. However, by acting directly in the hypothalamus, TNFalpha can activate thermogenesis and modulate food intake. Here we show that high concentration TNFalpha in the hypothalamus leads to increased O(2) consumption/CO(2) production, increased body temperature, and reduced caloric intake, resulting in loss of body mass. Most of the thermogenic response is produced by beta 3-adrenergic signaling to the brown adipose tissue (BAT), leading to increased BAT relative mass, reduction in BAT lipid quantity, and increased BAT mitochondria density. The expression of proteins involved in BAT thermogenesis, such as beta 3-adrenergic receptor, peroxisomal proliferator-activated receptor-gamma coactivator-1 alpha, and uncoupling protein-1, are increased. In the hypothalamus, TNFalpha produces reductions in neuropeptide Y, agouti gene-related peptide, proopiomelanocortin, and melanin-concentrating hormone, and increases CRH and TRH. The activity of the AMP-activated protein kinase signaling pathway is also decreased in the hypothalamus of TNFalpha-treated rats. Upon intracerebroventricular infliximab treatment, tumor-bearing and septic rats present a significantly increased survival. In addition, the systemic inhibition of beta 3-adrenergic signaling results in a reduced body mass loss and increased survival in septic rats. These data suggest hypothalamic TNFalpha action to be important mediator of the wastage syndrome in cachexia.

Infection, excretion and seroconversion dynamics of porcine circovirus type 2 (PCV2) in pigs from post-weaning multisystemic wasting syndrome (PMWS) affected farms in Spain and Denmark

Longitudinal case-control studies were performed in post-weaning multisystemic wasting syndrome (PMWS) affected farms from Denmark and Spain using similar designs. Fourteen independent batches of 100-154 pigs per batch were monitored from birth to PMWS outbreak occurrence. Pigs displaying PMWS-like signs and matched healthy cohorts were euthanized during the clinical outbreak. PMWS was diagnosed according to internationally accepted criteria and pigs were classified as: (i) PMWS cases, (ii) wasted non-PMWS cases and (iii) healthy pigs. Porcine circovirus type 2 (PCV2) quantitative PCR (qPCR) and serology techniques were applied to analyse longitudinally collected sera and/or nasal and rectal swabs. Results showed that PCV2 load increased in parallel to waning maternal antibody levels, reaching the maximum viral load concurrent with development of clinical signs. PMWS affected pigs had higher PCV2 prevalence and/or viral load than healthy pigs in all collected samples at necropsy (p<0.0001-0.05) and even in sera and nasal swabs at the sampling prior to PMWS outbreak (p<0.01-0.05). Danish farms had a higher PCV2 prevalence in young piglets as well as an earlier PMWS presentation compared to Spanish farms. PMWS diagnoses were confirmed by laboratory tests in only half of pigs clinically suspected to suffer from PMWS. Positive and significant correlations were found among PCV2 viral loads present in sera, nasal swabs, rectal swabs and lymphoid tissues (R=0.289-0.827, p<0.0001-0.01), which indicates that nasal and rectal swabs were suitable indicators of PCV2 excretion. Sensitivity and/or specificity values observed from both tests used separately or combined suggested that qPCR and/or serology tests are not apparently able to substitute histopathology plus detection of PCV2 in tissues for the individual PMWS diagnosis within PMWS affected farms. However, qPCR appears to be a potential reliable technique to diagnose PMWS on a population basis.

The biological mechanisms of cancer-related skeletal muscle wasting: the role of progressive resistance exercise

Cancer results in perturbations in skeletal muscle protein metabolism leading to muscle wasting. Although severe wasting is seen primarily in persons with advanced malignancies, a number of cancer patients show some degree of wasting at presentation. Although cancer-related skeletal muscle wasting is attributable, in part, to decreased muscle protein synthesis, its primary cause appears to be increased muscle protein degradation. Although several proteolytic systems may be involved, compelling evidence suggests that the major system responsible for skeletal muscle protein degradation in cancer is the ATP-dependent ubiquitin- proteasome system. Other contributing factors include proinflammatory cytokines and the tumor-released proteolysis-inducing factor. Decreased physical activity and decreased nutritional intake may also play a role. Cancer-related skeletal muscle wasting is clinically significant because of its profound effects on functional outcomes and quality of life. Nevertheless, no specific interventions have proved to be effective in preventing or reversing the problem. Interventions such as nutritional supplementation and appetite stimulants are only partially helpful. A nonpharmacologic intervention that may attenuate cancer-related skeletal muscle wasting is progressive resistance exercise training (PRT). PRT is a potent stimulus of growth in muscle mass and strength. PRT may attenuate cancer-related skeletal muscle wasting by downregulating the activity of proinflammatory cytokines and by increasing the phosphorylation of intramuscular amino acid-signaling molecules. This article discusses several cancer-related skeletal muscle wasting mechanisms and proposes how PRT might attenuate muscle wasting by counteracting some of these mechanisms.

Undernutrition in early life and body composition of adolescent males from a birth cohort study

The evidence for an association between poor nutrition in early life and subsequent obesity is inconclusive. In the present study, we investigated the associations between stunting, wasting and underweight at 2 and 4 years of age, and body composition in adolescence in male subjects studied since birth. The 1982 Pelotas Birth Cohort Study included all children born in maternity hospitals and living in the urban area of the city of Pelotas, Southern Brazil. All males born in 1982 were legally required to enlist in the army between January and April 2000. We were thus able to track 2250 subjects in 2000 (78.9% of the original cohort). Anthropometric measurements were collected in 1984 and 1986, and body composition was assessed in 2000. In the present analysis, we used as predictors the nutritional indices height-for-age, weight-for-height and weight-for-age presented in six categories. Outcomes included fat, lean and body mass indices and fat:lean mass ratio, derived from anthropometric and bioimpedance measurements. ANOVA and linear regression were used in the analyses to adjust for confounding. All predictors were positively associated with fat and body mass indices. Height-for-age Z score at age 2 or 4 years was not associated with lean mass index, but all other predictors were associated. Fat:lean mass ratio was associated only with weight-for-height Z score. Our results suggest that undernutrition is not a risk factor for overweight and obesity in our population and may partially protect against fatness in adolescence.

[Metabolic frailty in malnourished heart failure patients]

Muscular wasting (MW) and cardiac cachexia (CC) are often present in patients with chronic heart failure (HF).

AIM

To identify whether MW and CC are due to malnutrition or impairment of protein metabolism in HF patients.

MATERIAL AND METHOD

In 78 clinically stable HF patients (NYHA class II-III), aged from 32 to 89 years, we measured anthropometrical parameters and nutritional habits. In the identified 35 malnourished patients, we also measured: insulin resistance, gluconeogenetic amino acids blood concentration and nitrogen balance.

RESULTS

Seventy-five patients had eating-related symptoms. However we found significant nutritional impairment in 35 patients only. In addition, these 35 patients had: 1) significant increase of blood Alanine independently from both presence of insulin resistance or food intake reduction and 2) positive nitrogen balance.

CONCLUSION

Food intake is not impaired in CHF patients. In spite of normal food intake, 35 of 78 patients had nutritional impairment with reduced anthropometric parameters and increased blood Alanine. These findings show alteration of proteins metabolism with proteolysis. We believe that specific physical training with nutritional supplement can be an additional therapy able to prevent protein disarrangement in CHF patients.

Estimation of the risk for nutritional state degradation in patients with cancer: development of a screening tool based on results from a cross-sectional survey

BACKGROUND

In routine practice, the evaluation of the nutritional status of patients with cancer is not always performed although there is frequent modification as disease progresses. The validated screening and evaluation tools currently available are time-consuming and costly. In this study we analysed factors that could be used to identify patients likely to need nutritional surveillance or intervention.

PATIENTS AND METHODS

A cross-sectional survey was carried out for 2 weeks in June 2006 on 477 patients with cancer.

RESULTS

30.2% of the patients had lost more than 10% of their body weight since the start of the illness. After adjustment, the factors significantly associated with weight loss were: depressive state (OR = 3.49; P = 0.002), digestive or ENT tumours (OR = 3.20; P = <0.001), chemotherapy (OR = 2.66; P = 0.011), male gender (OR = 2.30; P = 0.001) and professional status (OR = 2.08; P = 0.02). Using a logistic model, we calculated the risk of weight loss as a function of the presence of the identified predictive factors.

CONCLUSION

We report a simple screening tool, which will not replace the available evaluation methods but will enable targeting of the patients most likely, after a specific evaluation, to benefit from nutritional intervention. This remains to be validated in further prospective studies.

The energetics of wasting diseases

PURPOSE OF REVIEW

Unintentional weight loss or wasting continues to be a nutritional problem in the treatment of HIV/AIDS, cancer and many other diseases. Although wasting is a general sign of energy imbalance, the relative contribution of increased energy demands and decreased energy intake remains incompletely understood.

RECENT FINDINGS

Until the development of the method using doubly labeled water for measuring total energy expenditure, it was difficult to obtain unbiased estimates of total energy expenditure, particularly in clinical populations. Although costly, this technique provides greater insight in the energy requirements of clinical populations and the relative contributions of energy expenditure, energy intake and disease to wasting diseases. Although data are available in only a small portion of wasting diseases, the data suggest that even in the presence of increased demands for resting metabolic rate, total energy expenditure is often reduced because of decreased physical activity.

SUMMARY

Wasting is often the result of endocrine disorders accompanying the disease process itself. This, coupled with reduced energy intake, is often the primary contributor to wasting.

The molecular mechanisms of skeletal muscle wasting: Implications for therapy

Skeletal muscle wasting is an important systemic manifestation of a wide range of diseases, including trauma, sepsis and cancer. The clinical consequences of muscle wasting undoubtedly include significant patient morbidity and worsened survival. Recently, there has been important progress in our understanding of the molecular mechanisms behind muscle wasting. In this review, the common systemic mediators, intracellular signalling pathways and effector mechanisms of skeletal muscle wasting are discussed with particular reference to different models of wasting and the development of novel therapeutic strategies.

Cytokine and C-reactive protein profiles induced by porcine circovirus type 2 experimental infection in 3-week-old piglets

The purpose of this study was to determine serum profiles of cytokines at a protein level and Creactive protein (CRP) during the development of postweaning multisystemic wasting syndrome (PMWS) in experimentally inoculated pigs. Levels of serum IFN-alpha, IL-6, IL-10, and CRP were examined for a 35-day period in 10 piglets experimentally infected with PCV2 at 3 weeks of age. Four of the infected piglets developed severe PMWS at 14 to 21 days post-infection (d.p.i.) and died prior to termination of the experiment. The remaining six PCV2-infected piglets experienced transient fever, but did not display overt clinical signs of PMWS and were considered as subclinically infected. A bioassay was used to detect IL-6 and ELISAs were used to detect IFN-alpha, IL-10, and CRP. There were no significant differences in cytokine or CRP expression from 0 to 7 d.p.i. between the PMWS-affected and the subclinically infected piglets. Levels of IL-10 and CRP were elevated from 10 and 14 d.p.i. respectively in the PMWS-affected piglets compared to the subclinically infected piglets. There were no significant differences in IFN-alpha and IL-6 expression between the PMWS-affected piglets and the subclinically infected piglets. The present study shows that elevated levels of serum CRP and IL-10 were associated with PCV2-infected piglets that subsequently developed severe PMWS. This may help to provide further insight into the immunoaetiogenesis of this syndrome.

Comparison of body composition assessment methods in patients with human immunodeficiency virus-associated wasting receiving growth hormone

CONTEXT

Bioelectrical impedance spectroscopy (BIS) and skinfold anthropometry (SKF) have been used to monitor body composition among patients with HIV wasting; however, validation of these techniques during recombinant human GH (rhGH) treatment has not been performed.

OBJECTIVE

Our objective was to evaluate the degree of agreement between criterion measurements of dual-energy x-ray absorptiometry (DXA) and those of BIS and SKF in patients with HIV wasting treated with rhGH.

DESIGN AND SETTING

We conducted a randomized, double-blinded, placebo-controlled, two-period crossover trial at the University of Toronto and Mount Sinai Hospital (Toronto, Canada).

PATIENTS

A referred sample of 27 community-dwelling men with HIV-associated weight loss (> or =10% over preceding 12 months) despite optimal antiretroviral therapy participated in the study.

INTERVENTION

Intervention was one daily injection of rhGH (6 mg) or placebo self-administered for 3 months in a crossover fashion with a 3-month washout.

MAIN OUTCOME MEASURES

Fat-free mass (FFM) and fat mass (FM) were measured by BIS, SKF, and DXA before and after rhGH and placebo treatment.

RESULTS

FFM(BIS) was not significantly different from FFM(DXA) after rhGH treatment (P = 0.10). Mean differences (bias +/- sd) according to Bland-Altman analysis were smaller for SKF than for BIS (P < 0.05) at all time points, yet treatment-induced change in FM was better detected with BIS than with SKF. BIS estimates of FFM and FM showed better agreement with those of DXA after rhGH treatment (1.6 +/- 4.6 kg and -2.1 +/- 3.9 kg) compared with baseline (3.8 +/- 3.5 kg and -4.1 +/- 3.6 kg) and placebo (2.7 +/- 4.4 kg and -3.1 +/- 4.6) (P < 0.05). BIS overestimated and SKF underestimated the treatment-induced changes in FFM and FM.

CONCLUSIONS

SKF was more accurate than BIS when measuring body composition in patients with HIV wasting before and after rhGH treatment; nonetheless, the accuracy of BIS increased after treatment. Change in FM because of treatment was not accurately assessed with SKF.

Body composition studies in patients with wasting associated with tuberculosis

OBJECTIVE

Wasting is a well-recognized manifestation of tuberculosis (TB), but little is known about the alterations in body composition that occur. Therefore, we measured regional and whole-body composition in patients with TB and wasting.

METHODS

Body composition was measured by dual-energy x-ray absorptiometry in 18 patients with newly diagnosed TB and wasting (10 coinfected with human immunodeficiency virus [HIV]) and 22 controls (10 coinfected with HIV).

RESULTS

Patients with TB and wasting had significantly lower body weight (48.6 versus 62.0 kg), lean body mass (39.6 versus 45.6 kg), and fat mass (6.2 versus 12.6 kg) than did controls. Patients with TB had significantly reduced lean tissue in the limbs (15.2 versus 19.1 kg) and trunk (21.3 versus 23.2 kg) and significantly higher trunk-to-limb lean ratio (1.41 versus 1.22) compared with controls. Patients with TB had significantly reduced fat in the limbs (3.4 versus 6.1 kg) and trunk (2.1 versus 5.7 kg) and significantly lower trunk-to-limb fat ratio (0.52 versus 0.92) compared with controls. Body composition measurements were no different in patients with and without HIV coinfection.

CONCLUSIONS

Wasting in TB is associated with depletion of whole-body lean and fat tissue in approximately equal proportions overall, but lean tissue depletion is greater in the limbs and fat tissue depletion is greater in the trunk. HIV coinfection does not affect the magnitude or distribution of the body composition changes.

TH1/TH2-mediated colitis induced by adoptive transfer of CD4+CD45RBhigh T lymphocytes into nude mice

BACKGROUND

Transfer of CD4CD45RB T cells from normal donors to SCID/Rag-1, 2-deficient mice, which lack T and B cells, leads to the development of a TH1-mediated inflammatory bowel disease (IBD)-like syndrome characterized by extensive mononuclear cell infiltrates and epithelial cell hyperplasia. Because it is well known that B cells are also involved in a multitude of mechanistic pathways in human IBD, this study attempts to establish a new model of colitis in nude mice.

METHODS

We transferred CD4CD45RB T cells into athymic nude mice, which lack thymus-dependent T cells but retain normal B cells, to establish and investigate a B cell-involving chronic colitis model. As a control, CD4CD25 T cells were also used.

RESULTS

Mice reconstituted with CD4CD45RB but not CD4CD25 T cells developed a wasting disease, with severe infiltrates of B cell aggregates as well as T cells, macrophages, and dendritic cells into the colon and elevated levels of interferon-gamma, tumor necrosis factor-alpha, interleukin (IL)-4, IL-5, and IL-10, by 7 weeks after T cell transfer. Furthermore, the infiltrated lamina propria B cells in colitic nude mice consisted predominantly of massive aggregated immunoglobulin (Ig) M- and scattered IgG-positive cells, but not IgA-positive cells. In contrast, mice reconstituted with CD4CD45RB and CD4CD45RB did not develop wasting disease or colitis.

CONCLUSIONS

Collectively, the power of the colitis model induced by the adoptive transfer of CD4CD45RB T cells into nude mice is that one can investigate the roles of TH2-type cells and B cells in a regulatory T cell-depleted condition.

Skeletal muscle apoptosis is not increased in gastric cancer patients with mild–moderate weight loss

Numerous experimental and clinical studies have shown that skeletal muscle apoptotis may increase in wasting conditions and suggest that apoptosis might contribute to the loss of lean body mass. Data in cancer patients are still lacking. The present study aimed at verifying whether apoptosis was enhanced in the skeletal muscle of 16 patients with gastric cancer with respect to controls. A biopsy specimen was obtained from the rectus abdominis muscle. The occurrence of apoptosis in muscle biopsies was determined morphologically by the fluorescent transferase-mediated dUTP nick end labeling assay and by immunohistochemistry for caspase-3 and caspase-1. Mean weight loss was 6+/-2% in cancer patients and 0.5+/-0.1% in controls (p<0.0001). Serum albumin levels (g/dL) were 3.7+/-0.3 in cancer patients and 4.1+/-0.2 in controls (p<0.05). The percentage of apoptotic myonuclei was similar in cancer patients and in controls (1.5+/-0.3 versus 1.4+/-0.2, respectively; p=ns), in gastric cancer patients with mild (1.6+/-0.4) or moderate-severe weight loss (1.4+/-0.5) (p=ns), and in the different stages of disease (stages I-II: 1.5+/-0.7; stage III: 1.3+/-0.4; stage IV: 1.6+/-0.3; p=ns). By immunohistochemistry, caspase-1 and caspase-3 positive fibers were absent in controls and in neoplastic patients. Poly-ADP-ribosyl polymerase, a typical caspase-3 substrate whose processing is indicative of caspase-3 activation, was not cleaved in muscle biopsies of cancer patients. These data suggest that skeletal muscle apoptosis is not increased in neoplastic patients with mild-moderate weight loss and argue against the hypotheses that caspase-3 activation might be an essential step of myofibrillar proteolysis in cancer-related muscle wasting.

Parathyroid hormone-related protein (PTHrP) as a causative factor of cancer-associated wasting: possible involvement of PTHrP in the repression of locomotor activity in rats bearing human tumor xenografts

Nude rats bearing the LC-6-JCK human lung cancer xenograft displayed cancer-associated wasting syndrome in addition to humoral hypercalcemia of malignancy. In these rats, not only PTHrP but also several other human proinflammatory cytokines, such as IL-6, leukemia-inducing factor, IL-8, IL-5 and IL-11, were secreted to the bloodstream. Proinflammatory cytokines induce acute-phase reactions, as evidenced by a decrease of serum albumin and an increase in alpha1-acid glycoprotein. Tumor resection abolished the production of proinflammatory cytokines and improved acute-phase reactions, whereas anti-PTHrP antibody affected neither proinflammatory cytokine production nor acute-phase reactions. Nevertheless, tumor resection and administration of anti-PTHrP antibody similarly and markedly attenuated not only hypercalcemia but also loss of fat, muscle and body weight. Body weight gain by anti-PTHrP antibody was associated with increased food consumption; increased body weight from anti-PTHrP antibody was observed when animals were freely fed but not when they were given the same feeding as those that received only vehicle. Furthermore, nude rats bearing LC-6-JCK showed reduced locomotor activity, less eating and drinking and low blood phosphorus; and anti-PTHrP antibody restored them. Although alendronate, a bisphosphonate drug, decreased blood calcium, it affected neither locomotor activity nor serum phosphorus level. These results indicate that PTHrP represses physical activity and energy metabolism independently of hypercalcemia and proinflammatory cytokine actions and that deregulation of such physiologic activities and functions by PTHrP is at least in part involved in PTHrP-induced wasting syndrome.

Polyunsaturated fatty acids improve exercise capacity in chronic obstructive pulmonary disease

BACKGROUND

Muscle wasting and decreased muscle oxidative capacity commonly occur in patients with chronic obstructive pulmonary disease (COPD). Polyunsaturated fatty acids (PUFA) have been shown to mediate several inflammatory and metabolic pathways which may be involved in the pathogenesis of muscle impairment in COPD. The aim of this study was to investigate the effect of PUFA modulation on systemic inflammation, reversal of muscle wasting, and functional status in COPD.

METHODS

Eighty patients with COPD (57 men) with forced expiratory volume in 1 second (FEV1) 37.3 (13.8)% predicted received 9 g PUFA or placebo daily in a double blind randomised fashion during an 8 week rehabilitation programme. Body composition (bioelectrical impedance), functional capacity (lung function, incremental cycle ergometry test, submaximal cycle test, isokinetic quadriceps strength) and inflammatory markers (C-reactive protein (CRP), interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha) were assessed at baseline and after 8 weeks.

RESULTS

Both groups had similar increases in weight, fat-free mass (FFM), and muscle strength. The peak load of the incremental exercise test increased more in the PUFA group than in the placebo group (difference in increase 9.7 W (95% CI 2.5 to 17.0), p = 0.009) even after adjustment for FFM. The duration of the constant work rate test also increased more in patients receiving PUFA (difference in increase 4.3 min (95% CI 0.6 to 7.9), p = 0.023). The positive effects of PUFA could not be attributed to a decrease in systemic levels of CRP, IL-6 and TNF-alpha.

CONCLUSIONS

This is the first study to show beneficial effects of PUFA on exercise capacity in patients with COPD.

Two amino acid mutations in the capsid protein of type 2 porcine circovirus (PCV2) enhanced PCV2 replication in vitro and attenuated the virus in vivo

Porcine circovirus type 2 (PCV2) is the primary causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. To identify potential genetic determinants for virulence and replication, we serially passaged a PCV2 isolate 120 times in PK-15 cells. The viruses harvested at virus passages 1 (VP1) and 120 (VP120) were biologically, genetically, and experimentally characterized. The PCV2 VP120 virus replicated in PK-15 cells to a titer similar to that of the PK-15 cell line-derived nonpathogenic PCV1 but replicated more efficiently than PCV2 VP1 with a difference of about 1 log unit in the titers. The complete genomic sequences of viruses at passages 0, 30, 60, 90, and 120 were determined. After 120 passages, only two nucleotide mutations were identified in the entire genome, and both were located in the capsid gene: the mutations were located at nucleotide positions 328 (C328G) and 573 (A573C). The C328G mutation, in which a proline at position 110 of the capsid protein changed to an alanine (P110A), occurred at passage 30 and remained in the subsequent passages. The second mutation, A573C, resulting in a change from an arginine to a serine at position 191 (R191S), appeared at passage 120. To experimentally characterize the VP120 virus, 31 specific-pathogen-free pigs were randomly divided into three groups. Ten pigs in group 1 received phosphate-buffered saline as negative controls. Each pig in group 2 (11 pigs) was inoculated intramuscularly and intranasally with 10(4.9) 50% tissue culture infective doses (TCID(50)) of PCV2 VP120. Each pig in group 3 (10 pigs) was similarly inoculated with 10(4.9) TCID(50) of PCV2 VP1. Viremia was detected in 9 of 10 pigs in the PCV2 VP1 group with a mean duration of 3 weeks, but in only 4 of 11 pigs in the PCV2 VP120 group with a mean duration of 1.6 weeks. The PCV2 genomic copy numbers in serum in the PCV2 VP1 group were significantly higher than those in the PCV2 VP120 group (P < 0.0001). Gross and histopathologic lesions in pigs inoculated with PCV2 VP1 were more severe than those inoculated with PCV2 VP120 at both day 21 and 42 necropsies (P = 0.0032 and P = 0.0274, respectively). Taken together, the results from this study indicated that the P110A and R191S mutations in the capsid of PCV2 enhanced the growth ability of PCV2 in vitro and attenuated the virus in vivo. This finding has important implications for PCV2 vaccine development.

Function and bulk of respiratory and limb muscles in patients with cystic fibrosis

Inspiratory muscle weakness due to lung hyperinflation and muscle wasting may occur in cystic fibrosis. We therefore measured diaphragm function and bulk in 18 stable patients with cystic fibrosis and 15 matched control subjects; the abdominal and quadriceps muscles were studied for comparison. We assessed diaphragm mass, abdominal muscle thickness, twitch transdiaphragmatic and gastric pressures, quadriceps cross-section and isokinetic strength, and lean body mass. Lean body mass, quadriceps strength, and quadriceps cross-section were lower in patients with cystic fibrosis. Twitch transdiaphragmatic pressure was 23% lower and twitch gastric pressure was 22% greater in patients with cystic fibrosis than in control subjects, but diaphragm mass and abdominal muscle thickness were similar in the two groups. For any given lean body mass and quadriceps cross-section, patients with cystic fibrosis had greater diaphragm mass and abdominal muscle thickness. Diaphragm mass had greater intersubject variability in patients with cystic fibrosis than in control subjects. We conclude that diaphragm strength is decreased but abdominal muscle strength is increased in patients with cystic fibrosis. Diaphragm and abdominal muscle bulk are not affected by the general muscle wasting, which suggests that there may be a training effect of cystic fibrosis on respiratory muscles. However, the variability of diaphragm mass indicates that this beneficial response does not occur in all patients with cystic fibrosis.

[Wasting syndrome in cancer patients: pathophysiology, clinical manifestations and drug therapy]

Wasting is a syndrome related to patient functional impairment that characterizes many conditions, including cancer. The development of wasting includes changes in the metabolism, as well as in hormones and other cell mediators, which trigger a syndrome that cannot be solved by forced nutrient ingestion. The goal of this study is to review the pathophysiological components of wasting, as well as its clinical manifestations and the available specific drug therapy options for the treatment of this condition. To this end, a review of papers published during the last four years has been carried out. The treatment of wasting with drugs includes a number of combination therapies for the underlying condition, nutritional support administration, and specific drug therapy for the wasting clinical picture. Currently, the clinical efficacy of cyproheptadine, hydrazine and pentoxyfilline in the treatment of anorexia is uncertain. Only progestagen derivatives have shown to increase appetite and food intake, and to improve nutritional status, in these patients. Corticoids also appear to increase appetite, but their effects are short-lasting.

Cytokine mRNA expression profiles in lymphoid tissues of pigs naturally affected by postweaning multisystemic wasting syndrome

Fifteen 8-week-old conventional pigs were selected from a farm where pigs were suffering from postweaning multisystemic wasting syndrome (PMWS). Ten of the animals were diseased pigs showing typical signs of PMWS (wasting and respiratory disorders) and positive for infection with porcine circovirus type 2 (PCV2), and the other five animals selected as controls were pen-mate, apparently healthy pigs. Blood samples and lymphoid tissues were taken from each animal for haematological, serological and histopathological studies. Also, cytokine mRNA expression of IL-1beta, IL-2, IL-4, IL-8, IL-10, IL-12p40 and IFN-gamma from inguinal and bronchial lymph nodes, tonsils, spleen and thymus was determined by semi-quantitative RT-PCR. Pigs suffering from PMWS showed severe alterations of haematological parameters such as anaemia, lymphopenia with decrease of CD8(+) and IgM(+) cells, monocytosis and neutrophilia. Also, extensive lymphocyte depletion and altered cytokine mRNA expression patterns were seen in most of the examined lymphoid organs. Those cytokine mRNA alterations were characterized by an overexpression of IL-10 mRNA in thymus and IFN-gamma mRNA in tonsils, and by decreases in the mRNA expression of several cytokines as IL-2 and IL-12p40 in the spleen, IL-4 in tonsils, and IFN-gamma, IL-10, IL-12p40 and IL-4 in inguinal lymph nodes. Also, the IL-10 mRNA overexpression was histologically associated with the thymic depletion and atrophy observed in PMWS pigs. In conclusion, the cytokine mRNA imbalance, specially the increased mRNA levels of IL-10 in the thymus, jointly with the histopathological and haematological disorders, are highly indicative of a T-cell immunosuppression, enhancing the notion that the immune system of PMWS-affected pigs is severely impaired.

Endocrine evaluation of patients with critical illness

Prolonged critical illness has a high morbidity and mortality. The acute and chronic phases of critical illness are associated with distinct endocrine alterations. The acute neuroendocrine response to critical illness involves an activated anterior pituitary function. In prolonged critical illness, however, a reduced pulsatile secretion of anterior pituitary hormones and the so-called "wasting syndrome" occur. The impaired pulsatile secretion of GH, thyrotropin and gonadotropin can be re-amplified by relevant combinations of releasing factors, which also substantially increase circulating levels of IGF-1, GH-dependent IGFBPs, thyroxin, tri-iodothyronine and testosterone. Anabolism is clearly re-initiated at the time GH secretagogues, thyrotropin-releasing hormone and gonadotropin-releasing hormone are coadministered but the effect on survival remains unknown. A lethal outcome of critical illness is predicted by a high serum concentration of IGFBP-1, pointing to impaired insulin effect rather than pituitary function, and survival was recently shown to be dramatically improved by strict normalization of glycemia with exogenous insulin. In addition to the illness-induced endocrine alterations, patients may have pre-existing central or peripheral endocrine diseases, either previously diagnosed or unknown. Hence, endocrine function testing in a critically ill patient represents a major challenge and the issue of treatment remains controversial. The recent progress in knowledge of the neuroendocrine response to critical illness and its interrelation with peripheral hormonal and metabolic alterations during stress, allows for potential new therapeutic perspectives to safely reverse the wasting syndrome and improve survival.

T helper type-2 cells induce ileal villus atrophy, goblet cell metaplasia, and wasting disease in T cell-deficient mice

BACKGROUND & AIMS

T helper (Th) 1 and Th2 cell subsets significantly influence the pathological features of inflammation in the gastrointestinal tract in a distinct manner. It is now established that the transfer of CD4(+)CD45RB(Hi) (RB(Hi)) T cells to either severe combined immunodeficient (SCID) or recombinase activation gene 2-deficient (RAG(-/-)) mice results in a severe granulomatous hypertrophic colitis mediated by Th1 cells. We have modified this approach to address the role of Th2 cells.

METHODS

RB(Hi) T cells from wild-type (Wt) mice or mice genetically predisposed to Th2 responses (interferon-gamma-defective [IFN-gamma(-/-)]) with or without B cells were transferred to T cell receptor (TCR)-beta and delta-chain-defective (TCR(-/-)) or SCID mice.

RESULTS

Transfer of Wt RB(Hi) T cells induced wasting disease with severe colitis in the TCR(-/-) mice. In contrast, IFN-gamma(-/-) RB(Hi) T cells induced severe weight loss and hypoalbuminemia without significant inflammation in the colon. The small intestine of these mice exhibited villus atrophy, a decrease in brush-border enzymes, reduced enterocyte proliferation, and an increased number of goblet cells. The presence of B cells was necessary for these changes, because SCID recipients required cotransfer of B cells, together with IFN-gamma(-/-) RB(Hi) T cells for ileal lesions to develop. Treatment of TCR(-/-) recipients of IFN-gamma(-/-) RB(Hi) T cells with anti-IL-4 mAb abrogated both the wasting disease and the villus atrophy.

CONCLUSIONS

Dysregulated Th2 cells cause atrophic changes and goblet cell transformation in the small intestinal epithelium and wasting disease mediated by excess interleukin-4 and B cells.

Experimental reproduction of postweaning multisystemic wasting syndrome in cesarean-derived, colostrum-deprived piglets inoculated with porcine circovirus type 2 (PCV2): investigation of quantitative PCV2 distribution and antibody responses

Sixteen cesarean-derived, colostrum-deprived piglets were inoculated intranasally with porcine circovirus type 2 (PCV2), originally isolated from a pig affected with postweaning multisystemic wasting syndrome (PMWS). At 1 day postinoculation (PI), 3 of the 5 piglets in the uninoculated control group were moved to the room of inoculated piglets for contact exposure. Porcine circovirus type 2 was detected by polymerase chain reaction (PCR) in swabs from inoculated piglets from 1 day PI and from contact piglets from 2 days after cohabitation. Porcine circovirus type 2 was also detected in all serum samples but not in control piglets 7 days PI. Until the end of study, PCV2 was detected in swabs and serum samples by PCR but not in the control piglets. One inoculated piglet died suddenly without clinical signs 19 days PI. Beginning at 14 days PI, 5 piglets, including 1 contact piglet, had clinical signs of depression, anorexia, and icterus, and 1 inoculated piglet died 21 days PI. Most of the piglets exhibiting the above clinical signs became moribund and were necropsied 21 and 28 days PI. In the piglets that showed clinical signs, gross lesions, including icterus of liver and hemorrhage in stomach, and typical histopathological lesions of PMWS, such as lymphoid depletion and basophilic intracytoplasmic inclusion bodies in lymph nodes and other tissues, were observed. Porcine circovirus type 2 was detected by PCR in all tissue samples except in those of the control piglets. Porcine circovirus type 2 was recovered from several tissue samples of the piglets necropsied until 35 days PI. In particular, PCV2 was recovered in high titer from most of the tissue samples of the piglets exhibiting clinical signs. Serum antibody against PCV2 was mostly detected in inoculated piglets and in contact piglets 14 and 21 days PI by an indirect fluorescence antibody test but was not detected in the piglets exhibiting clinical signs until 28 days PI. These results indicate that PCV2 was able to induce clinical PMWS in the absence of other swine pathogens and that there were significant differences in both the quantitative PCV2 distribution in tissues and the antibody response between the piglets that were infected and developed PMWS and those that were infected but remained healthy.

Genetic characterization and phylogenetic analysis of porcine circovirus type 2 (PCV2) strains from cases presenting various clinical conditions

Porcine circovirus type 2 (PCV2) has been associated with a newly identified and described disease in swine called the postweaning multisystemic wasting syndrome (PMWS). An association of PCV2 with various other clinical conditions in pigs are also increasingly being reported. To date molecular studies to determine the extent of genetic variations of this virus have been limited. To more fully understand the extent of genetic diversity we report the sequencing of 34 PCV2 strains from Eastern Canada originating from a variety of clinical conditions spanning years 1990-2001 along with the phylogenetic analysis of these strains and that of 36 PCV2 sequences published in GenBank. Sequence analysis of the complete genome indicated that the Canadian PCV2 strains analyzed in the present study are closely related to each other but also to other PCV2 strains originating from Western Canada, US, Europe and Asia. Sequence analysis of ORF1 and ORF2 genes of the 34 strains revealed that the extent of nucleotide variation was greater for the ORF2 than for the ORF1. The amino acid sequences alignment of the PCV2 capsid protein identified three major regions of amino acid heterogeneity, two of which correspond with dominant immunoreactive areas. No repeatable amino acid motifs for these two regions could be associated with PCV2 strains identified from cases of PMWS or other clinical conditions. Phylogenetic analysis of all 70 strains revealed one large cluster composed of strains from Europe, Taiwan, China and Canada. This large cluster could be divided in several sub clusters, in two of which Canadian strains were found closely related to strains from Germany. The remaining strains from Canada and the US were spread in small groupings along the phylogenetic tree and an association with geographic origin could not be established. The genomic characterizations performed in this study indicate that PCV2 strains associated with PMWS are scattered throughout the phylogenetic tree often in groupings including PCV2 strains identified from cases other that PMWS such as, porcine reproductive and respiratory syndrome (PRRS), generalized tremors, porcine dermatitis and nephropathy syndrome (PDNS), arthritis, nervous signs, erysipelas and even healthy pigs.

Epidemiology of weight loss in humans with special reference to wasting in the elderly

Unintentional weight loss in older adults is a problem that occurs frequently in clinical practice. Although slight declines in weight have been observed with aging alone, clinically important weight loss (decrements of 5% or more of usual body weight) is almost always the result of disease, disuse, and/or psychosocial factors. Adverse health outcomes associated with weight loss include decreased functional abilities and increased morbidity and mortality. Case series and prospective studies have helped to identify the most common causes of weight loss in older adults, and are reviewed herein. Knowledge of these frequent underlying etiologies can help guide an appropriate and cost-effective evaluation of patients presenting with weight loss. In many cases the causes are remediable and weight loss may slow or reverse with appropriate intervention. In some cases no clear etiology can be identified but the patient may still respond to nutritional support therapies that include hypercaloric feeding and appetite stimulants. Increasing caloric intake alone, however, is usually not sufficient to mitigate against losses in body mass (especially muscle mass) that are the result of chronic inflammatory or other severe disease states (cachexia). Potential strategies to help reduce losses in lean body mass and the functional decline that often accompanies weight loss include anabolic agents, exercise/physical activity, and cytokine inhibition. This article reviews the epidemiology of weight loss in older adults with special attention to the problem of cachexia. Diagnostic and treatment algorithms are provided to help guide clinical evaluation of, and therapeutic interventions for, older adults presenting with weight loss.

Prevalence of malnutrition in rural Karnataka, South India: a comparison of anthropometric indicators

Malnutrition is a problem at varying proportions in developing countries, and anthropometry is a simple tool to assess its magnitude in children. This study was aimed at identifying the prevalence of malnutrition among 256 children of rural areas of Karnataka in South India, who attended the aanganwadis. The value of using various field-based formulae and of various anthropometric indicators used for classification of malnutrition was also studied. The children, aged 12-60 months, came from villages located at the outskirts of Bangalore city. The prevalence of wasting, stunting, and wasting and stunting was 31.2%, 9.4%, and 29.2% respectively. Wasting was more predominant among the younger age groups (p<0.01). To detect wasting (acute malnutrition), the best indicator was a comparison with the reference weight calculated using Weech's formula. However, the age of child had to be rounded off to the nearest quarter of a year. Results of the study showed that indicators, such as mid-upper arm circumference (MUAC), needed to be used with caution since they are not sensitive enough to detect all cases of malnutrition. However, the MUAC-for-height (quac stick) method could be used since it was more sensitive. For detection of stunting, if reference tables are not available, Weech's formula can be used for calculation of expected height taking care to account for age to the nearest quarter, although the sensitivity of this indicator is not very high.

Central mechanisms involved with catabolism

PURPOSE OF REVIEW

Catabolism conjures up an end-metabolic process in which muscle and fat tissue are broken down into their constituent parts to provide nutrients for the body, secondary to a noxious stimulus that prevents the organism from adequately nourishing itself. However, catabolism is a primary event, initiated in the brain in response to perceived or real stresses or noxious stimuli, which has a secondary effect of inhibiting food intake and consequently the break down of skeletal muscle and adipose tissues to provide nutrients for the body to survive.

RECENT FINDINGS

This is achieved via a cascade of neurohormonal monoaminergic and peptidergic mediators in the central nervous system, invoking the cortex, the limbic system and the hypothalamus. Among the most detailed mediators studied are corticotropin-releasing factor and serotonin which, via the hypothalamic-pituitary-adrenal axis and the sympathetic and parasympathetic nervous system, stimulate catecholamines and cortisol and inhibit anabolic hormones, insulin, leptin, ghrelin, including neuropeptide Y and other neuropeptides, among them the paracrine-acting cytokines. Simultaneously, there occurs stimulation of the counter-regulatory hormones cortisol, glucagon and the melanocortin family of neuropeptides.

SUMMARY

The net effect is anorexia, with the inhibition of food intake, body weight loss, delayed gastric emptying and functions, the stimulation of gluconeogenesis, glycogenolysis and ketogenesis as sources of metabolic fuel, which if unabated leads ultimately to cachexia. The use of antagonists and the removal of stress or noxious stimuli experimentally test different pathways of this dynamic metabolic picture. Several studies have demonstrated important progress towards our understanding of the central mechanisms involved in anorexia and weight loss, which we summarize in this review.

Eicosanoid-dependent cancer cachexia and wasting

The reversal of catabolic processes remains a significant challenge related, in part, to their complexity and our incomplete understanding of the mechanisms involved. The eicosanoids are key players in the inflammatory process and have been implicated in the process of cancer cachexia. They are unsaturated C20 fatty acids which can be separated into two main groups: the lipoxygenase products including leukotrienes and lipoxins, and the prostanoids including prostaglandins, prostacyclin and thromboxane. This review examines the biology of the eicosanoids and the evidence of a role for the eicosanoids in cancer cachexia and wasting.

Regional study of nutritional status of urban primary schoolchildren. 3. Kuala Lumpur, Malaysia

A total of 5,995 (7.8% of all 7- to 10-year-old primary schoolchildren in Kuala Lumpur), randomly selected from 166 schools (97.6% of all schools), were measured for their weight and height. The analyses of all weight and height data, including the cutoffs used for defining stunting, underweight, and wasting and for thinness and overweight, were carried out as recommended by the World Health Organization (WHO). The prevalances of stunting (height-for-age Z score < -2 SD), underweight (weight-for-age Z score < -2 SD) and wasting (weight-for-height Z score < -2 SD) among all the children studies were 6.7%, 7.1%, and 4.5%, respectively. Undernutrition among boys was more serious than among girls according to all three indicators. Because it was not possible to analyze the weight-for-height data for most of the children above 8.5 years of age, body mass index (BMI)-for-age was used to determine the prevalences of thinness and overweight for all the children. Based on the reference data, the prevalence of overweight (at or above the 95th percentile) was 9.7% and 7.1% for boys and girls, respectively, and 8.4% overall.