Cachexia and the acute-phase protein response in inflammation are regulated by interleukin-6

Cachexia: A systemic consequence of progressive, unresolved disease

Cachexia, a systemic wasting condition, is considered a late consequence of diseases, including cancer, organ failure, or infections, and contributes to significant morbidity and mortality. The induction process and mechanistic progression of cachexia are incompletely understood. Refocusing academic efforts away from advanced cachexia to the etiology of cachexia may enable discoveries of new therapeutic approaches. Here, we review drivers, mechanisms, organismal predispositions, evidence for multi-organ interaction, model systems, clinical research, trials, and care provision from early onset to late cachexia. Evidence is emerging that distinct inflammatory, metabolic, and neuro-modulatory drivers can initiate processes that ultimately converge on advanced cachexia.

Low skeletal muscle radiodensity and neutrophil-to-lymphocyte ratio as predictors of poor outcome in patients with COVID-19

Inflammatory states and body composition changes are associated with a poor prognosis in many diseases, but their role in coronavirus disease 2019 (COVID-19) is not fully understood. To assess the impact of low skeletal muscle radiodensity (SMD), high neutrophil-to-lymphocyte ratio (NLR) and a composite score based on both variables, on complications, use of ventilatory support, and survival in patients with COVID-19. Medical records of patients hospitalized between May 1, 2020, and July 31, 2020, with a laboratory diagnosis of COVID-19 who underwent computed tomography (CT) were retrospectively reviewed. CT-derived body composition measurements assessed at the first lumbar vertebra level, and laboratory tests performed at diagnosis, were used to calculate SMD and NLR. Prognostic values were estimated via univariate and multivariate logistic regression analyses and the Kaplan–Meier curve. The study was approved by the local Institutional Review Board (CAAE 36276620.2.0000.5404). A total of 200 patients were included. Among the patients assessed, median age was 59 years, 58% were men and 45% required ICU care. A total of 45 (22.5%) patients died. Multivariate logistic analysis demonstrated that a low SMD (OR 2.94; 95% CI 1.13–7.66, P = 0.027), high NLR (OR 3.96; 95% CI 1.24–12.69, P = 0.021) and both low SMD and high NLR (OR 25.58; 95% CI 2.37–276.71, P = 0.008) combined, were associated with an increased risk of death. Patients who had both low SMD and high NLR required more mechanical ventilation (P < 0.001) and were hospitalized for a longer period (P < 0.001). Low SMD, high NLR and the composite score can predict poor prognosis in patients with COVID-19, and can be used as a tool for early identification of patients at risk. Systemic inflammation and low muscle radiodensity are useful predictors of poor prognosis, and the assessment of these factors in clinical practice should be considered.

Alternate-day fasting, a high-sucrose/caloric diet and praziquantel treatment influence biochemical and behavioral parameters during Schistosoma mansoni infection in male BALB/c mice

Schistosoma mansoni-induced granulomas result in severe damage to the host's liver, as well as neurological and metabolic disorders. We evaluated the biochemical and behavioral changes during schistosomiasis under three diet protocols: ad libitum (AL), alternate-day fasting (ADF) and a high-sucrose/caloric diet (HSD). Healthy male BALB/c mice were divided into noninfected, matched infected and infected/treated [praziquantel (PZQ)] groups. Caloric intake and energy efficiency coefficients associated with diets were measured. Behavioral (exploratory and locomotor) and biochemical (glucose, triglycerides, total cholesterol, AST, ALT, ALP, and γ-GT) tests and histological analysis were performed. Fifteen weeks postinfection, HSD and PZQ promoted weight gain, with higher caloric consumption than ADF (p < 0.05), reflecting serum glucose levels and lipid profiles. HSD and PZQ prevented liver dysfunction (AST and ALT) and significantly prevented increases in granuloma area (p < 0.05). HSD and PZQ also significantly improved mouse physical performance in exploratory and locomotor behavior (p < 0.05), reversing the impaired motivation caused by infection. These findings showed that ADF worsened the course of S. mansoni infection, while HSD and PZQ, even with synergistic effects, prevented and/or attenuated biochemical and behavioral impairment from infection.

Malnutrition in Older Adults-Recent Advances and Remaining Challenges

Malnutrition in older adults has been recognised as a challenging health concern associated with not only increased mortality and morbidity, but also with physical decline, which has wide ranging acute implications for activities of daily living and quality of life in general. Malnutrition is common and may also contribute to the development of the geriatric syndromes in older adults. Malnutrition in the old is reflected by either involuntary weight loss or low body mass index, but hidden deficiencies such as micronutrient deficiencies are more difficult to assess and therefore frequently overlooked in the community-dwelling old. In developed countries, the most cited cause of malnutrition is disease, as both acute and chronic disorders have the potential to result in or aggravate malnutrition. Therefore, as higher age is one risk factor for developing disease, older adults have the highest risk of being at nutritional risk or becoming malnourished. However, the aetiology of malnutrition is complex and multifactorial, and the development of malnutrition in the old is most likely also facilitated by ageing processes. This comprehensive narrative review summarizes current evidence on the prevalence and determinants of malnutrition in old adults spanning from age-related changes to disease-associated risk factors, and outlines remaining challenges in the understanding, identification as well as treatment of malnutrition, which in some cases may include targeted supplementation of macro- and/or micronutrients, when diet alone is not sufficient to meet age-specific requirements.

Immune Checkpoint Inhibitors in the Aged

PURPOSE OF REVIEW

Large phase III trials have established the benefit of checkpoint blockade across multiple tumor types, but patient representation is limited in some subgroups including the aged population. There are several changes in the immune system that occur with age (termed immunosenescence) that could potentially limit efficacy in aged populations.

RECENT FINDINGS

Despite the concerns stated above, available evidence from prospective trials, retrospective cohorts, and registry data suggest that elderly patients achieve similar benefit with immune checkpoint blockade in comparison to the general population and do not have increased toxicity. However, as patients age, they are at higher risk of developing a decline in multiple physiologic systems (including the immune system) and reduced ability to recover from illness. Clinical evidence shows that patients who have a poor performance status have inferior outcomes and limited clinical benefit from checkpoint blockade. Clinicians should take an individualized approach that accounts for each patient's health status rather than considering age alone when determining who should be offered checkpoint blockade therapy.

Therapeutic efficacy of IL-17A neutralization with corticosteroid treatment in a model of antigen-driven mixed-granulocytic asthma

Many mouse models of allergic asthma exhibit eosinophil-predominant cellularity rather than the mixed-granulocytic cytology in steroid-unresponsive severe disease. Therefore, we sought to implement a novel mouse model of antigen-driven, mixed-granulocytic, severe allergic asthma to determine biomarkers of the disease process and potential therapeutic targets. C57BL/6J wild-type, interleukin-6 knockout (IL-6-/-), and IL-6 receptor knockout (IL-6R-/-), mice were injected with an emulsion of complete Freund's adjuvant and house dust mite antigen (CFA/HDM) on day 1. Dexamethasone, a lymphocyte-depleting biological, or anti-IL-17A was administered during the intranasal HDM challenge on days 19-22. On day 23, the CFA/HDM model elicited mixed bronchoalveolar lavage (BAL) cellularity (typically 80% neutrophils and 10% eosinophils), airway hyperresponsiveness (AHR) to methacholine, diffusion impairment, lung damage, body weight loss, corticosteroid resistance, and elevated levels of serum amyloid A (SAA), pro-inflammatory cytokines, and T helper type 1/ T helper type 17 (Th1/Th17) cytokines compared with eosinophilic models of HDM-driven allergic airway disease. BAL cells in IL-6- or IL-6R-deficient mice were predominantly eosinophilic and associated with elevated T helper type 2 (Th2) and reduced Th1/Th17 cytokine production, along with an absence of SAA. Nevertheless, AHR remained in IL-6-deficient mice even when dexamethasone was administered. However, combined administration of anti-IL-17A and systemic corticosteroid significantly attenuated both overall and neutrophilic airway inflammation and also reduced AHR and body weight loss. Inhibition of IL-17A combined with systemic corticosteroid treatment during antigen-driven exacerbations may provide a novel therapeutic approach to prevent the pathological pulmonary and constitutional changes that greatly impact patients with the mixed-granulocytic endotype of severe asthma.

Frailty is independently associated with mortality in 11 001 patients with inflammatory bowel diseases

BACKGROUND

The prevalence of older adults with inflammatory bowel diseases (IBD) is increasing. Frailty is an important predictor of outcomes in many chronic disease states. The implications of frailty have not been well-delineated in IBD.

AIMS

To report the prevalence of a frailty-associated diagnosis and determine the association between frailty and mortality in a cohort of IBD patients.

METHODS

In a cohort of 11 001 IBD patients, we applied a validated definition of frailty using International Classification of Disease codes. We compared frail IBD patients to those without a frailty-related code ("fit"). We constructed multivariable logistic regression models adjusting for clinically pertinent confounders (age, gender, race, IBD type, follow-up, IBD-related surgery, ≥1 comorbidity in the Charlson comorbidity index [CCI], and immunosuppression use) to determine whether frailty predicts mortality.

RESULTS

A total of 675 (6%) IBD patients had a frailty-related diagnosis. The prevalence of frailty increased with age, rising from 4% in 20-29 year olds to 25% in patients 90 years or older. The most prevalent frailty diagnosis was protein-energy malnutrition. The strongest predictors of frailty were non-IBD comorbidity, all-cause and IBD-related, hospitalisations. Frailty remained independently associated with mortality after adjusting for age, sex, duration of follow-up, comorbidity, need for IBD-related surgery and immunosuppression (OR: 2.90, 95% CI: 2.29-3.68).

CONCLUSIONS

Frailty is prevalent in IBD patients and increases with age. Frailty nearly triples the odds of mortality for IBD patients. Risk stratifying patients by frailty may improve outcomes.

Aging and nutrition. Paving the way to better health

Sufficient caloric intake is important to maintain the balanced health status, especially during the period of aging, as aging and sickness share paths. Maintaining adequate nutritional balance is the best preventive measure to counteract the risk of malnutrition. There are several causes for malnutrition in elderly people, and some techniques such as anthropometric measurements, laboratory and clinical parameters could help to diagnose malnutrition in these patients. The use of a simple validated questionnaire called the 'Mini Nutritional Assessment' measures the nutritional status of elderly patients. In this review, we discuss about the malnutrition in elderly people with and without a known cause and we present some of nutritional intervention. There are promising strategies that help overcoming malnutrition.

Association between vitamin D and dry eye disease: A systematic review and meta-analysis of observational studies

PURPOSE

A number of studies have examined the association between vitamin D and dry eye disease in different populations, but findings are inconclusive. Herein, available observational studies were systematically reviewed to elucidate the overall relationship between vitamin D and dry eye disease among adult population.

METHODS

PubMed, Scopus, Google scholar and ISI web of science databases were searched until January 2020 for studies assessing the association between vitamin D and dry eye disease. The Newcastle-Ottawa Quality Assessment Scale was used to examine the quality of each study.

RESULTS

A total of 14 studies out of 252 met the inclusion criteria and were included in this systematic review and meta-analysis. Serum 25(OH) D3 was lower in dry eye disease subjects compared to healthy ones (WMD -5.93; 95 % CI, -7.47 to -4.40; P < 0.001) with evidence of significant heterogeneity (I² = 94.6 % p < 0.001). Also, in final analysis, vitamin D correlated significantly with ocular surface disease index (Fisher's Z: -0.26; 95 % CI, -0.48 to -0.04; P = 0.018), with significant heterogeneity between studies (I² = 59.3 %, P = 0.043).

CONCLUSION

It was found that serum vitamin D had a significantly lower level in dry eye disease patients, and correlated with ocular surface disease index but no other dry eye disease parameter. The findings add to the existing literature supporting the concept that nutrition especially vitamin D plays an important role in human eye health. Prospective studies are needed to confirm this relationship.

IL-1α promotes liver inflammation and necrosis during blood-stage Plasmodium chabaudi malaria

Malaria causes hepatic inflammation and damage, which contribute to disease severity. The pro-inflammatory cytokine interleukin (IL)-1α is released by non-hematopoietic or hematopoietic cells during liver injury. This study established the role of IL-1α in the liver pathology caused by blood-stage P. chabaudi malaria. During acute infection, hepatic inflammation and necrosis were accompanied by NLRP3 inflammasome-independent IL-1α production. Systemically, IL-1α deficiency attenuated weight loss and hypothermia but had minor effects on parasitemia control. In the liver, the absence of IL-1α reduced the number of TUNEL⁺ cells and necrotic lesions. This finding was associated with a lower inflammatory response, including TNF-α production. The main source of IL-1α in the liver of infected mice was inflammatory cells, particularly neutrophils. The implication of IL-1α in liver inflammation and necrosis caused by P. chabaudi infection, as well as in weight loss and hypothermia, opens up new perspectives for improving malaria outcomes by inhibiting IL-1 signaling.

The JAK/STAT Pathway in Skeletal Muscle Pathophysiology

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is a key intracellular mediator of a variety of metabolically relevant hormones and cytokines, including the interleukin-6 (IL-6) family of cytokines. The JAK/STAT pathway transmits extracellular signals to the nucleus, leading to the transcription of genes involved in multiple biological activities. The JAK/STAT pathway has been reported to be required for the homeostasis of different tissues and organs. Indeed, when deregulated, it promotes the initiation and progression of pathological conditions, including cancer, obesity, diabetes, and other metabolic diseases. In skeletal muscle, activation of the JAK/STAT pathway by the IL-6 cytokines accounts for opposite effects: on the one hand, it promotes muscle hypertrophy, by increasing the proliferation of satellite cells; on the other hand, it contributes to muscle wasting. The expression of IL-6 and of key members of the JAK/STAT pathway is regulated at the epigenetic level through histone methylation and histone acetylation mechanisms. Thus, manipulation of the JAK/STAT signaling pathway by specific inhibitors and/or drugs that modulate epigenetics is a promising therapeutic intervention for the treatment of numerous diseases. We focus this review on the JAK/STAT pathway functions in striated muscle pathophysiology and the potential role of IL-6 as an effector of the cross talk between skeletal muscle and other organs.

Impact of oral vitamin D supplementation on the ocular surface in people with dry eye and/or low serum vitamin D

PURPOSE

To determine the possible association between serum vitamin D levels and dry eye symptoms, and the impact of an oral vitamin D supplement.

METHODS

Three linked studies were performed. (i) 29 older adult participants, (ii) 29 dry eyed participants, and (iii) 2-month vitamin D supplementation for 32 dry eyed/low serum vitamin D levelled participants. All participants were assessed by the Ocular Surface Diseases Index (OSDI) to determine dry eye symptoms, and the phenol red thread test (PRT) and/or Schirmer's tear test, tear meniscus height, non-invasive tear break up time, grading ocular surface redness and fluorescein staining of the cornea to detect the tear quality and ocular surface conditions. Blood samples were collected for serum vitamin D analysis and interleukin-6 (IL-6) levels.

RESULTS

Among older adult participants, vitamin D levels were negatively correlated with dry eye symptoms, the severity of dry eye, and associated with tired eye symptom. Vitamin D levels of people with dry eye diagnosis were not correlated with OSDI scores and IL-6 levels; while IL-6 levels showed correlation with tear production. In supplement study, vitamin D levels increased by 29mol/l, while dry eye symptoms and grading of corneal staining appeared significant reductions. No significant changes in IL-6 levels.

CONCLUSIONS

Low vitamin D levels (<50nmol/l) were associated with dry eye symptoms in older individuals but not those diagnosed with dry eye. Vitamin D supplement increased the vitamin D levels, and improved dry eye symptoms, the tear quality and ocular surface conditions.

The MEK-Inhibitor Selumetinib Attenuates Tumor Growth and Reduces IL-6 Expression but Does Not Protect against Muscle Wasting in Lewis Lung Cancer Cachexia

Cachexia, or wasting of skeletal muscle and fat, afflicts many patients with chronic diseases including cancer, organ failure, and AIDS. Muscle wasting reduces quality of life and decreases response to therapy. Cachexia is caused partly by elevated inflammatory cytokines, including interleukin-6 (IL-6). Others and we have shown that IL-6 alone is sufficient to induce cachexia both in vitro and in vivo. The mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) inhibitor Selumetinib has been tested in clinical trials for various cancers. Moreover, Selumetinib has also been shown to inhibit the production of IL-6. In a retrospective analysis of a phase II clinical trial in advanced cholangiocarcinoma, patients treated with Selumetinib experienced significant gains in skeletal muscle vs. patients receiving standard therapy. However, the use of Selumetinib as a treatment for cachexia has yet to be investigated mechanistically. We sought to determine whether MEK inhibition could protect against cancer-induced cachexia in mice. In vitro, Selumetinib induced C2C12 myotube hypertrophy and nuclear accretion. Next we tested Selumetinib in the Lewis lung carcinoma (LLC) model of cancer cachexia. Treatment with Selumetinib reduced tumor mass and reduced circulating and tumor IL-6; however MEK inhibition did not preserve muscle mass. Similar wasting was seen in limb muscles of Selumetinib and vehicle-treated LLC mice, while greater fat and carcass weight loss was observed with Selumetinib treatment. As well, Selumetinib did not block wasting in C2C12 myotubes treated with LLC serum. Taken together, out results suggest that this MEK inhibitor is not protective in LLC cancer cachexia despite lowering IL-6 levels, and further that it might exacerbate tumor-induced weight loss. Differences from other studies might be disease, species or model-specific.

Effects of anti-interleukin 6 on inflammatory responses during murine septic peritonitis

Interleukin (IL)-6 has a limited role in the pathogenesis of the acute systemic inflammatory response syndrome elicited by bolus administration of bacteria or bacterial products. We sought to determine the role of IL-6 in septic peritonitis induced by cecal ligation and puncture (CLP). CLP led to a rapid and sustained induction of IL-6 in plasma and organ homogenates. Pretreatment (-2 h) with an anti-IL-6 mAb (1 mg) resulted in higher plasma and hepatic levels of tumor necrosis factor (TNF), as well as higher plasma concentrations of soluble TNF receptors and IL-10, while attenuating the acute phase protein response. Administration of anti-IL-6 did not influence survival. These results suggest that IL-6 production during septic peritonitis serves to inhibit the appearance of both agonist and antagonist members of the cytokine network. The importance of IL-6 in mediating the cytokine response to infection may be underestimated in more acute sepsis models.

Sex Differences in Severity of Inflammation-Induced Anorexia and Weight Loss

Food intake and body weight changes in response to induction of acute inflammation were examined in intact cycling females, ovariectomized females, and sham-operated male rats. In intact females, body weight and feeding responses were compared between rats in which inflammation was induced on day of estrus with rats in which inflammation was induced on day of diestrus. Anorexia and weight loss were more severe in the female rats with inflammation induced on estrus day, which coincides with peak serum estrogen levels. In ovariectomized females, inflammation was induced the day after rats received injections of estrogen, progesterone, or sesame oil (vehicle). Males received vehicle injections. Among female rats, the group that received estradiol injections the previous day displayed the most severe anorexia. The least severe anorexia was observed in female rats that received progesterone the previous day. Food intake of female rats that received vehicle injections prior to induction of inflammation was greater than the rats receiving estrogen but less than the rats receiving progesterone. Male rats displayed the most severe anorexia and greatest weight loss. These data suggest that, although females exposed to estradiol prior to induction of acute inflammation display more severe anorexia than those exposed to progesterone, it may be that progesterone attenuates severity of anorexia rather than estrogen solely potentiating severity. Male rats, however, appear to experience the most severe anorexia in response to this form of inflammation.

Acquired Muscle Weakness in the Surgical Intensive Care Unit

Muscle weakness is common in the surgical intensive care unit (ICU). Low muscle mass at ICU admission is a significant predictor of adverse outcomes. The consequences of ICU-acquired muscle weakness depend on the underlying mechanism. Temporary drug-induced weakness when properly managed may not affect outcome. Severe perioperative acquired weakness that is associated with adverse outcomes (prolonged mechanical ventilation, increases in ICU length of stay, and mortality) occurs with persistent (time frame: days) activation of protein degradation pathways, decreases in the drive to the skeletal muscle, and impaired muscular homeostasis. ICU-acquired muscle weakness can be prevented by early treatment of the underlying disease, goal-directed therapy, restrictive use of immobilizing medications, optimal nutrition, activating ventilatory modes, early rehabilitation, and preventive drug therapy. In this article, the authors review the nosology, epidemiology, diagnosis, and prevention of ICU-acquired weakness in surgical ICU patients.

Reduced cerebellar gray matter is a neural signature of physical frailty

Physical frailty has been recognized as a clinical syndrome resulting from declines in various physiological systems; however, the role of the central nervous system in the pathophysiology of frailty remains unclear. The I-Lan Longitudinal Aging Study randomly sampled community-dwelling people aged 50 or older for a brain magnetic resonance imaging study. All participants were assessed for frailty status (robust, prefrail, and frail) based on the presence of five frailty components: slow walking speed, muscle weakness, low physical activity, exhaustion and weight loss (Fried criteria). Gray matter volume (GMV) changes associated with frailty status and individual frailty components were examined. Overall, 456 participants (64.0 ± 8.5 years, 47.6% women) were included in this study. The prefrail (n = 178, 39.0%) and frail (n = 19, 4.2%) subjects were grouped for analysis. The prefrail-frail group showed reduced GMV, compared to the robust group (n = 259, 56.8%), in the cerebellum, hippocampi, middle frontal gyri, and several other cerebral regions (corrected P < 0.05). Each frailty component was associated with GMV changes in functionally related brain areas. Hierarchical cluster analysis categorized these components into three subsets. Motor-related components, including weakness, low activity, and slowness, comprised one subset with a common cerebellar involvement. Exhaustion and weight loss were the other two subsets without cerebellar changes. To conclude, physical frailty is associated with a decreased reserve in specific brain regions, especially cerebellum. Further longitudinal studies are needed to explore if the cerebellum- and noncerebellum-based frailty components reflect a distinctive future risk for developing frailty.

Novel role for tumor-induced expansion of myeloid-derived cells in cancer cachexia

Cancer progression is associated with inflammation, increased metabolic demand, infection, cachexia, and eventually death. Myeloid-derived suppressor cells (MDSCs) commonly expand during cancer and are associated with adaptive immune suppression and inflammatory metabolite production. We propose that cancer-induced cachexia is driven at least in part by the expansion of MDSCs. MDSC expansion in 4T1 mammary carcinoma-bearing hosts is associated with induction of a hepatic acute-phase protein response and altered host energy and fat metabolism, and eventually reduced survival to polymicrobial sepsis and endotoxemia. Similar results are also seen in mice bearing a Lewis lung carcinoma and a C26 colon adenocarcinoma. However, a similar cachexia response is not seen with equivalent growth of the 66C4 subclone of 4T1, in which MDSC expansion does not occur. Importantly, reducing MDSC numbers in 4T1-bearing animals can ameliorate some of these late responses and reduce susceptibility to inflammation-induced organ injury and death. In addition, administering MDSCs from both tumor- and nontumor-bearing mice can produce an acute-phase response. Thus, we propose a previously undescribed mechanism for the development of cancer cachexia, whereby progressive MDSC expansion contributes to changes in host protein and energy metabolism and reduced resistance to infection.

Hepcidin-dependent and hepcidin-independent regulation of erythropoiesis in a mouse model of anemia of chronic inflammation

Increased hepcidin antimicrobial peptide correlates with hypoferremia and anemia in various disease states, but its requirement for anemia of inflammation has not been adequately demonstrated. Anemia of inflammation is usually described as normocytic and normochromic, while diseases associated with over expression of hepcidin, alone, are often microcytic and hypochromic. These differences in erythrocyte parameters suggest anemia in many inflammatory states may not be fully explained by hepcidin-mediated iron sequestration. We used turpentine-induced sterile abscesses to model chronic inflammation in mice with targeted disruption of Hepcidin 1 [Hepc1 (-/-)] or its positive regulator, Interleukin-6 [IL-6 (-/-)], to determine whether these genes are required for features characteristic of anemia of inflammation. Although hemoglobin levels did not decline in Hepc1 (-/-) mice with sterile abscesses, erythrocyte numbers were significantly reduced compared to untreated Hepc1 (-/-) mice. In contrast, both hemoglobin concentration and erythrocyte number declined significantly in wild type and IL-6 (-/-) mice with sterile abscesses. Both Hepc1 (-/-) and IL-6 (-/-) mice had increased erythrocyte mean cell volume and mean cell hemoglobin following sterile abscesses, while wild types had no change. Thus, IL-6 (-/-) mice with sterile abscesses exhibit an intermediate phenotype between wild type and Hepc1 (-/-). Our results demonstrate the requirement of Hepc1 for the development of anemia in this rodent model. Simultaneously, our results demonstrate hepcidin-independent effects of inflammation on the suppression of erythropoiesis. Our results suggest chronic anemia associated with inflammation may benefit from interventions protecting erythrocyte number in addition to anti-hepcidin interventions aimed at enhancing iron availability.

Drugs in development for treatment of patients with cancer-related anorexia and cachexia syndrome

Cancer-related anorexia and cachexia syndrome (CACS) is a complex multifactorial condition, with loss of lean body mass, chronic inflammation, severe metabolic derangements, reduced food intake, reduced physical activity, and poor quality of life as key symptoms. Cachexia recognizes different phases or stages, moving from precachexia through overt cachexia to advanced or refractory cachexia. The purpose of this review is to describe currently effective approaches for the treatment of cachexia, moving forward to drugs and treatments already shown to be effective but needing further clinical trials to confirm their efficacy. We then introduce novel promising investigational drugs and approaches which, based on a strong rationale from the most recent data on the molecular targets/pathways driving the pathophysiology of cachexia, need to be tested either in currently ongoing or appropriate future clinical trials to confirm their clinical potential. Although different drugs and treatments have been tested, we can speculate that a single therapy may not be completely successful. Indeed, considering the complex clinical picture and the multifactorial pathogenesis of CACS, we believe that its clinical management requires a multidisciplinary and multitargeted approach. In our opinion, appropriate treatment for cachexia should target the following conditions: inflammatory status, oxidative stress, nutritional disorders, muscle catabolism, immunosuppression, quality of life, and above all, fatigue. A comprehensive list of the most interesting and effective multitargeted treatments is reported and discussed, with the aim of suggesting the most promising with regard to clinical outcome. A critical issue is that of testing therapies at the earliest stages of cachexia, possibly at the precachexia stage, with the aim of preventing or delaying the development of overt cachexia and thereby obtaining the best possible clinical outcome for patients.

Interleukin-6 myokine signaling in skeletal muscle: a double-edged sword?

Interleukin (IL)-6 is a cytokine with pleiotropic functions in different tissues and organs. Skeletal muscle produces and releases significant levels of IL-6 after prolonged exercise and is therefore considered as a myokine. Muscle is also an important target of the cytokine. IL-6 signaling has been associated with stimulation of hypertrophic muscle growth and myogenesis through regulation of the proliferative capacity of muscle stem cells. Additional beneficial effects of IL-6 include regulation of energy metabolism, which is related to the capacity of actively contracting muscle to synthesize and release IL-6. Paradoxically, deleterious actions for IL-6 have also been proposed, such as promotion of atrophy and muscle wasting. We review the current evidence for these apparently contradictory effects, the mechanisms involved and discuss their possible biological implications.

Bilateral cataract induced by unilateral UVR-B exposure -- evidence for an inflammatory response

PURPOSE

To investigate whether unilateral in vivo UVR-B exposure of one eye affects the fellow eye in a co-cataractogenic, sympathetic reaction and to determine whether an inflammatory response could be involved in the pathogenesis.

METHODS

C57BL/6 mice were unilaterally exposed in vivo to UVR-B for 15 min. In the group of 24 animals each received 0×/2×/3×/or 4× cataract threshold equivalent dose. Following 48-hr UVR-B exposure, cataract morphology was documented in dark-field illumination photography, and light scattering was quantified, in both lenses in vitro. Serum levels of pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α were analysed with ELISA. Immunohistochemistry was performed for inflammatory infiltration in exposed and contralateral eyes.

RESULTS

UVR-B exposure induced cataract in all exposed lenses. There was additionally a significant UVR dose-dependent increase in light scattering in the lenses of the non-exposed fellow eye. Inflammatory infiltration was detected immunohistochemically in the anterior segment of both eyes. IL-1β serum concentration increased with increasing UVR-B exposure dose. There was a similar trend for serum IL-6 but not for TNF-α.

CONCLUSION

Unilateral UVR-B exposure to one eye is associated with intraocular inflammation and an increase in lens light scattering also in the unexposed, fellow eye. A resulting systemic inflammatory response might be mediated by IL-1β and possibly IL-6. The finding that an inflammatory response may play a role in UVR-B-induced cataract development might initiate new strategies in the prevention of the disease.

Frailty in elderly people

Frailty is the most problematic expression of population ageing. It is a state of vulnerability to poor resolution of homoeostasis after a stressor event and is a consequence of cumulative decline in many physiological systems during a lifetime. This cumulative decline depletes homoeostatic reserves until minor stressor events trigger disproportionate changes in health status. In landmark studies, investigators have developed valid models of frailty and these models have allowed epidemiological investigations that show the association between frailty and adverse health outcomes. We need to develop more efficient methods to detect frailty and measure its severity in routine clinical practice, especially methods that are useful for primary care. Such progress would greatly inform the appropriate selection of elderly people for invasive procedures or drug treatments and would be the basis for a shift in the care of frail elderly people towards more appropriate goal-directed care.

Current pharmacotherapy options for cancer anorexia and cachexia

INTRODUCTION

Anorexia and cachexia syndrome represents a complex clinical picture that occurs in the late stage of several chronic inflammatory diseases, including cancer. Unless counteracted cancer-related anorexia and cachexia syndrome affects quality of life (QL) and survival. However, to date a standard effective treatment is lacking.

AREAS COVERED

The aim of this review is to describe the current pharmacological approaches for anorexia and cachexia syndrome, focusing on cancer-related syndrome. The several pharmacological agents tested so far are discussed, distinguishing them in unproven drugs, effective drugs, and drugs under investigation. Moreover, a section is devoted to the promising use of nutritional supplements and nutraceuticals. The emerging role of a multitargeted combined treatment approach is exhaustively reviewed.

EXPERT OPINION

Considering the complex clinical picture and the multifactorial pathogenesis of anorexia and cachexia syndrome, we believe that its clinical management requires a multidisciplinary and multipharmacological approach. In our opinion the anorexia and cachexia syndrome treatment should include drugs that target the following conditions: inflammatory status, oxidative stress, nutritional disorders, muscle catabolism, anemia, immunosuppression, and fatigue. The multidimensional therapies for anorexia and cachexia syndrome should ideally be introduced within a context of the "best supportive care," which includes optimal symptom management and careful psychosocial counseling.

Late stage erythroid precursor production is impaired in mice with chronic inflammation

BACKGROUND

We and others have shown previously that over-expression of hepcidin antimicrobial peptide, independently of inflammation, induces several features of anemia of inflammation and chronic disease, including hypoferremia, sequestration of iron stores and iron-restricted erythropoiesis. Because the iron-restricted erythropoiesis evident in hepcidin transgenic mice differs from the normocytic, normochromic anemia most often observed in anemia of inflammation, we tested the hypothesis that chronic inflammation may contribute additional features to anemia of inflammation which continue to impair erythropoiesis following the acute phase of inflammation in which hepcidin is active.

DESIGN AND METHODS

We compared erythropoiesis and iron handling in mice with turpentine-induced sterile abscesses with erythropoiesis and iron handling in hepcidin transgenic mice. We compared erythrocyte indices, expression of genes in the hepcidin regulatory pathway, tissue iron distribution, expression of heme and iron transport genes in splenic macrophages, the phenotype of erythroid maturation and chloromethyl dichlorodihydrofluorescein diacetate, acetyl ester fluorescence.

RESULTS

Mice with sterile abscesses exhibited an intense, acute inflammatory phase followed by a mild to moderate chronic inflammatory phase. We found that erythrocytes in mice with sterile abscesses were normocytic and normochromic in contrast to those in hepcidin transgenic mice. We also observed that although hypoferremia resolved in the late phases of inflammation, erythropoiesis remained suppressed, with evidence of inefficient maturation of erythroid precursors in the bone marrow of mice with sterile abscesses. Finally, we observed increased oxidative stress in erythroid progenitors and circulating erythrocytes of mice with sterile abscesses which was not evident in hepcidin transgenic mice.

CONCLUSIONS

Our results suggest that chronic inflammation inhibits late stages of erythroid production in the turpentine-induced sterile abscess model and induces features of impaired erythropoiesis which are distinct from those in hepcidin transgenic mice.

Evaluation of clumping factor A binding region A in a subunit vaccine against Staphylococcus aureus-induced mastitis in mice

The present study evaluated the potential of recombinant binding region A of clumping factor A (rClfA-A) to be an effective component of a vaccine against mastitis induced by Staphylococcus aureus in the mouse. rClfA-A and inactivated S. aureus were each emulsified in Freund's adjuvant, mineral oil adjuvant, and Seppic adjuvant; phosphate-buffered saline was used as a control. Seven groups of 12 mice each were immunized intraperitoneally three times at 2-week intervals. The titers of IgG and subtypes thereof (IgG1 and IgG2a) in the rClfA-A-immunized group were more than 1,000-fold higher than those in the killed-bacteria-immunized group (P < 0.01). Of the three adjuvants used, mineral oil adjuvant induced the highest antibody levels for both antigens (P < 0.001). Furthermore, the anti-rClfA-A antibody capacities for bacterial adhesion and opsonizing phagocytosis were significantly greater in the rClfA-A-immunized group than in the killed-bacteria-immunized group (P < 0.05). Lactating mice immunized with either rClfA-A or inactivated vaccine were challenged with S. aureus via the intramammary route. The numbers of bacteria recovered from the murine mammary glands 24 h after inoculation were significantly lower in the rClfA-A group than in the killed-bacteria-immunized group (P < 0.001). Histologic examination of the mammary glands showed that rClfA-A immunization effectively preserved tissue integrity. Thus, rClfA-A emulsified in an oil adjuvant provides strong immune protection against S. aureus-induced mastitis in the mouse.

Treatment strategies for amyloid A amyloidosis

BACKGROUND

Amyloid A (AA) amyloidosis is a serious complication of a wide range of chronic inflammatory, infectious and neoplastic diseases. A longstanding overproduction of the liver-synthesised cytokine-induced acute phase serum amyloid A (SAA) protein is a key event in the pathogenetic cascade leading to the deposition of AA amyloid in tissues and organs.

OBJECTIVE

The aim of the study was to critically review treatment strategies in AA amyloidosis.

METHODS

A systematic literature review was conducted based on PubMed (January 1980 - April 2008) and selected conference abstracts.

RESULTS/CONCLUSIONS

The current strategy for the treatment of AA amyloidosis is firmly based on the knowledge of the underlying pathogenetic mechanism and aims at reducing the amyloid precursor (SAA) load by intensive anti-inflammatory/immunosuppressive therapy and, in selected instances, anticytokine (TNF-alpha, IL-1beta or IL-6 blockade) therapy, or, when applicable, the eradication of an existing infectious focus (surgery, antimicrobial drugs). Emerging strategies focus on the dissolution of the amyloid deposits using small molecules that either interact with the glycosaminoglycans or the fibril component of the deposits, or deplete amyloid P component.

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.

Corticotropin-releasing hormone deficiency is associated with reduced local inflammation in a mouse model of experimental colitis

CRH, the hypothalamic component of the hypothalamic-pituitary adrenal axis, attenuates inflammation through stimulation of glucocorticoid release, whereas peripherally expressed CRH acts as a proinflammatory mediator. CRH is expressed in the intestine and up-regulated in patients with ulcerative colitis. However, its pathophysiological significance in intestinal inflammatory diseases has just started to emerge. In a mouse model of acute, trinitrobenzene sulfonic acid-induced experimental colitis, we demonstrate that, despite low glucocorticoid levels, CRH-deficient mice develop substantially reduced local inflammatory responses. These effects were shown by histological scoring of tissue damage and neutrophil infiltration. At the same time, CRH deficiency was found to be associated with higher serum leptin and IL-6 levels along with sustained anorexia and weight loss, although central CRH has been reported to be a strong appetite suppressor. Taken together, our results support an important proinflammatory role for CRH during mouse experimental colitis and possibly in inflammatory bowel disease in humans. Moreover, the results suggest that CRH is involved in homeostatic pathways that link inflammation and metabolism.

Interleukin-6 and leptin as markers of energy metabolic changes in advanced ovarian cancer patients

The progression of the neoplastic disease is characterized by specific alterations of energy metabolism and by symptoms like fatigue, anorexia, nausea, anaemia, immunodepression and poor performance status (PS). The main cause of these symptoms and metabolic abnormalities is the chronic action of proinflammatory cytokines released both by tumour and immune cells. The present study aimed to assess the relationship between markers of inflammation (C-Reactive Protein, Fibrinogen, proinflammatory cytokines) and energy metabolic status (BMI, leptin, oxidative stress) according to clinical parameters in 104 ovarian cancer patients at different stage and, moreover, to evaluate prospectively the changes of these parameters in accordance to tumour response in a subgroup of 70 advanced stage ovarian cancer patients. Advanced stage and poor PS were associated to high-grade inflammation and impaired energy metabolism. Among inflammatory mediators, interleukin (IL)-6 had a central role as predictive factor of leptin, reactive oxygen species and glutathione peroxidase. In turn, leptin considered the key marker of the nutritional status and energy metabolism, was independently determined from stage and IL-6, not only from BMI. Moreover, the evaluation of the changes of these parameters during the course of the neoplastic disease in the subgroup of advanced ovarian cancer patients clearly unveils the central role of IL-6 and leptin as early markers of the metabolic alterations and symptoms associated to disease progression in advanced stage ovarian cancer. Their assessment should be included in monitoring disease outcome, especially when cancer is no longer curable and quality of life becomes the primary endpoint.

Discography in practice: a clinical and historical review

Chronic low back pain is the most common cause of disability in individuals between the ages of 45 and 65. Given the variety of anatomic and pathophysiologic causes of persistent low back pain, it is a difficult diagnosis for clinicians to treat. Discography is a diagnostic option that may link a patient's subjective complaints of spinal pain to symptomatic disk disease when non-invasive imaging, such as magnetic resonance imaging (MRI), does not find structural abnormalities. A controversial procedure, discography is only necessary to assess painful discs prior to surgical interventions. For accurate discogram interpretation an experienced spine interventionalist must be careful to exclude false positive results and be aware of the patient's underlying psychological state. This literature review will discuss the following: anatomy and function of the spine and intervertebral disc, intervertebral disc degeneration and discogenic pain, history of discography, indications and contraindications, a description of the procedure, complications, and the current debate regarding its outcomes.

Is the interleukin-6 haplotype a prognostic factor for sciatica?

AIMS

We have shown in a cross-sectional setting that an IL6 haplotype (GGGA) is associated with intervertebral disc disease (IDD) characterized by sciatica. The aim of this study was to evaluate the prognostic role of the GGGA haplotype in IDD.

METHODS

DNA from 153 sciatica patients who participated in a randomized controlled trial of periradicular infiltration was analysed for IL6 variations rs1800797 (-596A>G), rs1800796 (-572G>C), rs1800795 (-174G>C), and rs13306435 (+15T>A). The patients recorded back and leg pain intensity and duration, disability by Oswestry Index and back-related sickness absence over a three-year follow-up. Repeated measures and univariate analysis of variance with adjustment for age, gender and physical work load were used in statistical analyses for the last two-years of the follow-up.

RESULTS

The prevalence of the GGGA haplotype was 9% (14/153). Subjects with the GGGA haplotype did not differ from those without the haplotype with respect to pain intensity, or disability score, but days with back and leg pain and days on sick leave were significantly higher among subjects with the IL6 haplotype after adjustment for occupation (p=0.006, 0.001 and 0.002, respectively). An interaction between the IL6 haplotype and physical work load was significant for the duration of back and leg pain and sick leave (p=0.038, 0.011 and 0.006, respectively).

CONCLUSIONS

This is the first observation of any prognostic genotype among sciatica patients. The IL6 haplotype GGGA predicted the number of days with back or leg pain and also sickness absence. Subjects with the IL6 haplotype may be more vulnerable when doing physically demanding jobs.

Acute phase response impairs host defense against Pseudomonas aeruginosa pneumonia in mice

OBJECTIVE

Pseudomonas aeruginosa is a common pathogen in hospital-acquired pneumonia. Especially trauma and postsurgical patients display a profound acute phase protein response and are susceptible to acquiring pneumonia. The objective was to study the influence of the acute phase response induced by sterile tissue injury on pulmonary host defense.

DESIGN

Laboratory investigation.

SETTING

Academic medical center.

SUBJECTS

Female C57Bl/6 wild-type mice, 8-10 wks old.

INTERVENTIONS

Mice were injected subcutaneously with either turpentine or sterile saline (control) in both hind limbs 1 day before intranasal infection with P. aeruginosa.

MEASUREMENTS AND MAIN RESULTS

The turpentine-induced acute phase response was associated with 100% lethality after induction of pneumonia, whereas control mice all survived the Pseudomonas infection. In addition, turpentine-injected mice demonstrated much higher bacterial loads in their lungs and an increased dissemination of the infection. The acute phase reaction attenuated lung inflammation during pneumonia, as reflected by histopathology, reduced pulmonary levels of proinflammatory cytokines, and a strongly diminished recruitment of neutrophils to the site of infection. Blood neutrophils harvested from turpentine injected mice displayed a reduced capacity to up-regulate their CD11b/CD18 expression upon stimulation with Pseudomonas ex vivo and during Pseudomonas pneumonia in vivo. Administration of a blocking anti-CD11b antibody to turpentine-injected and control mice almost completely abrogated the difference in bacterial outgrowth, whereas inhibition of the sympathetic nervous system did not affect the impaired pulmonary host defense in mice with an acute phase response.

CONCLUSIONS

These data suggest that a systemic acute phase response might impair host defense against P. aeruginosa pneumonia, possibly in part by inhibition of CD11b/CD18-dependent neutrophil recruitment.

The interleukin-6 (IL6)-174 G/C promoter genotype is associated with the presence of septic shock and the ex vivo secretion of IL6

Septic shock is associated with a high mortality and an excessive activation of immune cascades. Interleukin (IL)-6 has been found to be a key cytokine in the pathogenesis of severe sepsis, but the importance of a regulatory polymorphism within the IL6 promoter has been controversial in these patients. The aim of the study was therefore to systematically investigate the IL6-174 G/C promoter genotype with regard to the presence of shock in patients with sepsis, the IL6 serum levels, and the ex vivo secretion of IL6, respectively. Overall, 112 consecutive subjects with severe sepsis and septic shock according to consensus criteria were enrolled. The ex vivo secretion of IL6 after stimulation with lipopolysaccharide (LPS) in a whole blood assay and the IL6 serum concentrations were determined after admission of the patients. Among the 112 subjects with severe sepsis, 85 patients fulfilled the criteria of septic shock. In these patients, the frequency of the mutated C-allele of the IL6 promoter polymorphism was significantly (P = 0.04) higher compared to that in individuals without shock. IL6 serum concentrations were highest in patients with the GG genotype (mean 2209 pg mL(-1)), followed by CG genotype (mean 1113 pg mL(-1)), and lowest in individuals with the CC genotype (mean 256 pg mL(-1)). Interestingly, a significantly (P = 0.005) higher ex vivo secretion of IL6 is detected in heterozygote individuals (535 pg mL(-1)) and patients with the IL6 CC genotype (555 pg mL(-1)) compared to patients with the -174 GG genotype (276 pg mL(-1)). In conclusion, the IL6-174 G/C promoter genotype is associated with shock in patients with sepsis. Functionally, the mutated C-allele is correlated with low IL6 serum concentrations, but a high ex vivo secretion after LPS stimulation. These results further indicate a complex regulation of the expression of IL6 during infection and have implications for the design of immune intervention trials.

Serum concentrations of C-reactive protein, serum amyloid A, and haptoglobin in pigs inoculated with African swine fever or classical swine fever viruses

OBJECTIVE

To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses.

ANIMALS

8 crossbred (Large White x Landrace) 10-week-old pigs.

PROCEDURES

Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other groupwas inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses.

RESULTS

Serum concentrations of APPs increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.

Comparison of inflammatory responses after off-pump and on-pump coronary surgery using surface modifying additives circuit

BACKGROUND

Cardiac surgery is followed by various degrees of inflammation, which have harmful consequences. Because of the central role of extracorporeal circulation (EC), off-pump coronary bypass surgery is deemed preferable. Do different modalities of EC challenge this view?

METHODS

Four groups of similar patients underwent coronary surgery: (group 1) on-pump, EC with closed surface modifying additives (SMA) circuit and no pump suckers (n = 20); (group 2) on-pump, EC with open SMA circuit and pump suckers (n = 20); (group 3) off-pump (beating heart) and heparin 3 mg/kg (n = 20); (group 4) off-pump (beating heart) and heparin 1 mg/kg (n = 20). Interleukins (IL)-6, IL-8, IL-10, myeloperoxidase, elastase, and terminal complex of the complement (TCC) were analyzed at various times: at induction (time I); after heparin (time II); after complete revascularization (time III); after protamine (time IV); and 24 hours later (time V).

RESULTS

The TCC was significantly higher in groups 1 and 2 at time III. The pattern of IL-6 was the same for the four groups. No significant difference in myeloperoxydase content was noted; however, elastase was significantly higher in the two EC (on-pump) groups.

CONCLUSIONS

Except for the complement system and elastase, on-pump surgery with SMA-coated circuits did not elicit any greater inflammatory response than off-pump surgery.

Dietary problems in patients with severe chronic obstructive pulmonary disease

BACKGROUND AND AIMS

Low body weight and low fat-free mass-index (FFMI) are common in patients with severe chronic obstructive pulmonary disease (COPD). Several factors seem to contribute. The aims of the present observational study were to investigate dietary problems in patients with severe COPD and to compare dietary problems to nutritional status, energy intake and smoking habits.

METHODS

Nutritional status was assessed in 73 stable outpatients using body mass index and FFMI by single-frequency bioelectrical impedance. Lung function, smoking habits, energy intake and dietary problems were also assessed.

RESULTS

The most frequently reported dietary problems were 'anorexia', 'dyspeptic symptoms other than diarrhoea', 'slimming', 'fear of gaining weight', 'dyspnoea', 'diarrhoea', 'depression, anxiety, solitude'. Smoking habits and gender had impact on the kind of dietary problems reported. Reporting two dietary problems correlated to low FFMI, whereas reporting one or more dietary problems correlated to decreased energy intake.

CONCLUSION

Dietary problems are common in the group studied and related to smoking habits and gender. Dietary problems affect energy intake and FFMI negatively. It is important to recognize dietary problems and to offer intervention of the dietary problems as a part of the dietary intervention.

The role of plasminogen activator inhibitor type 1 in the inflammatory response to local tissue injury

BACKGROUND

The plasma levels of the plasminogen activator-inhibitor type 1 (PAI-1) are consistently elevated in patients with sterile tissue injury, often accompanied by a systemic acute phase protein response. It remains unknown, however, whether and to what extent PAI-1 affects the host response to trauma.

METHODS AND RESULTS

By using the well-established murine model of turpentine-induced tissue injury we compared local and systemic inflammatory responses in PAI-1 gene-deficient (PAI-1-/-) and normal wild-type (Wt) mice. Subcutaneous turpentine injection elicited strong increases in PAI-1 protein concentration in plasma and at the site of injury, but not in liver. PAI-1 mRNA was locally increased and expressed mainly by macrophages and endothelial cells. PAI-1 deficiency greatly enhanced the early influx of neutrophils to the site of inflammation, which was associated with increased edema and necrosis at 8 h after injection. Furthermore, PAI-1-/- mice showed a reduced early interleukin (IL)-6 induction with subsequently lower acute phase protein levels and a much slower recovery of body weight loss.

CONCLUSION

These findings suggest that PAI-1 is not merely a marker of tissue injury but plays a functional role in the local and systemic host response to trauma.

Inhibition of the development of collagen-induced arthritis in rhesus monkeys by a small molecular weight antagonist of CCR5

OBJECTIVE

Collagen-induced arthritis (CIA) in the rhesus monkey is a nonhuman primate model of rheumatoid arthritis (RA). The close phylogenetic relationship between humans and the rhesus monkey makes this model useful for the preclinical safety and efficacy testing of new therapies that are inactive in animals more distinctly related to humans. In this study, we tested the therapeutic potential of a novel, small molecular weight antagonist of CCR5, SCH-X, in this model.

METHODS

CIA was induced in 10 rhesus monkeys. The animals were allocated to receive SCH-X or saline as the control (n = 5 in each group). Treatment was initiated on the day of CIA induction and continued for 45 days. Monkeys were monitored before and 63 days after CIA induction for macroscopic signs of clinical arthritis, such as soft-tissue swelling and body weight. Furthermore, markers of inflammation and joint degradation were monitored to follow the disease course.

RESULTS

Only 2 of 5 animals in the SCH-X-treated group displayed prominent soft-tissue swelling, compared with all 5 saline-treated monkeys. In addition to the suppression of joint inflammation, treatment with SCH-X resulted in a reduction in joint destruction, as demonstrated by lower rates of urinary excretion of collagen crosslinks, with confirmation by histology. Whereas in all saline-treated monkeys, marked erosion of joint cartilage was observed, this was absent in 4 of the 5 SCH-X-treated monkeys.

CONCLUSION

The systemic effects of treatment with SCH-X were a suppressed acute-phase reaction (reduction in C-reactive protein level) in the 3 treated monkeys with CIA that remained asymptomatic, and an altered antibody response toward type II collagen. The results suggest that the CCR5 antagonist SCH-X might have a strong clinical potential for treatment during periods of active inflammation, as seen in RA.

Interleukin-6 is an afferent signal to the hypothalamo-pituitary-adrenal axis during local inflammation in mice

The cytokines IL-1 and IL-6 are able to induce prostaglandin (PG)-dependent activation of the hypothalamo-pituitary-adrenal axis (HPAA) and are thought to play key roles in immune-neuroendocrine interactions during inflammation. The present study shows that inflammation induced by im injection of turpentine (TPS) in the hind limb of mice causes an increase in the plasma concentration of IL-6, but not that of IL-1 alpha or IL-1 beta, together with a prolonged (>18-h) activation of the HPAA. IL-6 plays a causal role in the TPS-induced elevation in HPAA activity, because the sustained (8-18 h) increases in 1) plasma corticosterone, 2) plasma ACTH, and 3) induction of c-Fos in the hypothalamic paraventricular nucleus are all markedly blunted in IL-6-deficient (IL-6(-/-)) mice. Peripheral administration of a neutralizing IL-6 antiserum inhibited the plasma corticosterone response of normal (C57BL/6) mice to hind limb inflammation to an extent similar to that seen in IL-6(-/-) mice, suggesting that the IL-6 responsible for the increased HPAA activity is produced, or acts, on the blood side of the blood-brain barrier. We also show that IL-6 in the circulation is induced almost exclusively at the local inflammatory site, where IL-1 beta is produced. Induction of IL-6 and activation of the HPAA are dependent upon prior activation of an IL-1 type I receptor, as both are inhibited in type I IL-1 receptor-deficient mice. Furthermore, hind limb inflammation induced cyclooxygenase-2 protein expression around the cerebrovasculature of normal (IL-6(+/+)), but not IL-6(-/-), mice. Based on these data, we propose that IL-6 is produced at the local inflammatory site under the control of IL-1 beta and is the circulating afferent signal that is in part responsible for elevated HPAA activity, possibly acting via eicosanoid production within the cerebrovasculature.

Increased serum leptin concentrations correlate with soluble tumour necrosis factor receptor levels in patients with cirrhosis

OBJECTIVE

Several reports have documented the involvement of hyerleptinaemia in malnutrition associated with liver cirrhosis. However, the mechanisms of elevated leptin levels remains unclear. Serum concentrations of tumour necrosis factor-alpha (TNF-alpha), and two soluble TNF receptors (sTNF-RI and sTNF-RII) are increased in patients with liver cirrhosis. In rodents, administration of TNF-alpha has been shown to stimulate plasma leptin concentration, suggesting that a cytokine-leptin link may mediate anorexia and weight loss during chronic inflammation. In this study, we investigate the potential interaction of the TNF-alpha system with leptin in the development of malnutrition in liver cirrhosis.

STUDY DESIGN

A total of 26 male patients with liver cirrhosis and 25 healthy people were recruited at an outpatient clinic at the Veterans General Hospital in Taiwan. Serum biochemistry and anthropometric measurement by bioelectrical impedance analysis were used to assess nutrition status, and immunoassay was used to determine serum leptin, TNF-alpha sTNF-RI and sTNF-RII concentrations.

RESULTS

In cirrhotic patients, the body fat mass (FM) and serum albumin levels were both lower than control subjects [15.8 (13.2-19.5) kg vs. 18.9 (16.2-20.1) kg; 35 (33-41) g/l vs. 43 (41-45) g/l, respectively; P < 0.05]. Serum TNF-alpha sTNF-RI and sTNF-RII were significantly elevated in cirrhotic patients compared to healthy controls [9.8 (7.2-13.5) ng/l vs. 4.3 (3.4-7.3) ng/l; 1682.1 (1344.8-2179.4) ng/l vs. 1319.6 (1037.7-1632.1) ng/l; 4462.2 (3748.5-5159.4) ng/l vs. 3559.8 (2506.9-3988.9 ng/l, respectively; P < 0.01] and correlated with disease severity (graded by Pugh-Child's scores). An inverse correlation was observed between circulating sTNF-RI and sTNF-RII to serum albumin levels (r =-0.42, r = -0.398; P < 0.05). The serum leptin levels in cirrhotic patients were significantly higher [6.0 (3.6-7.7) (g/l vs. 3.4 (2.9-4.3) (g/l; P < 0.01) and correlated with body FM (r = 0.52; P < 0.01]. Using a multiple linear regression analysis with leptin as dependent variable and FM and TNF-alpha, sTNF-R as independent variables, FM and serum sTNF-RI concentrations were found to predict independently the leptin levels in cirrhotic patients.

CONCLUSION

Our study demonstrated that serum levels of TNF-alpha, sTNF-RI, sTNF-RII and leptin were all elevated in cirrhotic patients. The severity of liver cirrhosis was an important factor for the activation of TNF-alpha system. The activated TNF-alpha system conjointly with hyperleptinaemia might mediate malnutrition in patients with liver cirrhosis.

Sarcopenia, weight loss, and nutritional frailty in the elderly

The progression of the aging process leads to a decreased margin of homeostatic reserve and a reduced ability to accommodate metabolic challenges, including nutritional stress. Nutritional frailty refers to the disability that occurs in old age owing to rapid, unintentional loss of body weight and loss of lean body mass (sarcopenia). Sarcopenia, a loss of muscle mass and strength, contributes to functional impairment. Weight loss is commonly due to a reduction in food intake; its possible etiology includes a host of physiological and nonphysiological causes. The release of cytokines during chronic disease may also be an important determinant of frailty. In addition to being anorectic, cytokines also contribute to lipolysis, muscle protein breakdown, and nitrogen loss. Whereas the multiple causes of nutritional frailty are not completely understood, clinical interventions for weight loss, sarcopenia, and cytokine alterations have been used with modest success.

Inflammatory signals associated with hemodialysis

BACKGROUND

Inflammation is highly prevalent in chronic hemodialysis patients. Because hemodialysis involves the contact of blood with "foreign" surfaces, and the documented activation of several humoral and cellular pathways during the procedure, the hemodialysis procedure has been suggested as a potential source of inflammation in this patient population. Earlier studies did not provide clear-cut evidence of the potential contribution of the hemodialysis procedure to inflammation, as assessed by markers of inflammation such as cytokine levels and acute-phase protein production.

METHODS

Nine patients were studied using primed-constant infusion of l-(l-13C) leucine 2 hours before, during, and 2 hours after a single hemodialysis session. We evaluated the effects of hemodialysis on induction of interleukin-6 (IL-6) production as well as the fractional synthetic rates (FSR) of albumin and fibrinogen, two well-known acute-phase proteins.

RESULTS

During hemodialysis, albumin FSR and fibrinogen FSR increased significantly compared to the measurements obtained during baseline period. During this period, albumin and fibrinogen FSR increased 64% and 34%, respectively, compared to baseline (P < 0.05). While the increase in IL-6 concentration was modest during hemodialysis (14%), the levels further increased at the end of the 2-hour post-hemodialysis period (68% higher compared to baseline, P < 0.05). Fibrinogen FSR also demonstrated a further increase during the post-dialysis period (17% higher compared to the intradialytic period and 58% higher compared to baseline), while albumin FSR stabilized during this period.

CONCLUSIONS

The results provide clear evidence of hemodialysis-induced inflammatory response. The process is most notable during the 2-hour post-hemodialysis period.

Invited review: cytokine regulation of fever: studies using gene knockout mice

Fever is defined as a regulated rise in body temperature. The regulation of this phenomenon is accomplished by the actions of two types of endogenous cytokines, some functioning as pyrogens and others as antipyretics. Previous data obtained with the use of traditional pharmacological techniques, such as the injection of neutralizing antibodies, implicate interleukin (IL)-1 and IL-6 as endogenous pyrogens or inducers of fever. In almost all instances in which the endogenous actions of IL-1 or IL-6 are antagonized, fevers are attenuated. Other cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and IL-10, are thought to act as endogenous antipyretics or inhibitors of fever. In several studies, the inhibition of TNF action has enhanced fever. Recently, mice genetically engineered to lack cytokines or their receptors in all tissues of the body have been used to examine the regulation of IL-1, IL-6, TNF, and IL-10 on fever. Data obtained with these mice shed new light on our understanding of cytokine interactions in fever and, in some instances, contradict data obtained with pharmacological methods. This review summarizes the responses of cytokine and cytokine receptor knockout mice to fevers induced by lipopolysaccharide, turpentine, and sepsis.