Sarcopenia, obesity, and natural killer cell immune senescence in aging: altered cytokine levels as a common mechanism. Aging (Albany NY). 2012;4:535-546. [PMID: 22935594 PMCID: PMC3461341 DOI: 10.18632/aging.100482]

GIT2-A keystone in ageing and age-related disease

Since its discovery, G protein-coupled receptor kinase-interacting protein 2, GIT2, and its family member, GIT1, have received considerable interest concerning their potential key roles in regulating multiple inter-connected physiological and pathophysiological processes. GIT2 was first identified as a multifunctional protein that is recruited to G protein-coupled receptors (GPCRs) during the process of receptor internalization. Recent findings have demonstrated that perhaps one of the most important effects of GIT2 in physiology concerns its role in controlling multiple aspects of the complex ageing process. Ageing can be considered the most prevalent pathophysiological condition in humans, affecting all tissue systems and acting as a driving force for many common and intractable disorders. The ageing process involves a complex interplay among various deleterious activities that profoundly disrupt the body's ability to cope with damage, thus increasing susceptibility to pathophysiologies such as neurodegeneration, central obesity, osteoporosis, type 2 diabetes mellitus and atherosclerosis. The biological systems that control ageing appear to function as a series of interconnected complex networks. The inter-communication among multiple lower-complexity signaling systems within the global ageing networks is likely coordinated internally by keystones or hubs, which regulate responses to dynamic molecular events through protein-protein interactions with multiple distinct partners. Multiple lines of research have suggested that GIT2 may act as one of these network coordinators in the ageing process. Identifying and targeting keystones, such as GIT2, is thus an important approach in our understanding of, and eventual ability to, medically ameliorate or interdict age-related progressive cellular and tissue damage.

Proposal for new selection criteria considering pre-transplant muscularity and visceral adiposity in living donor liver transplantation

BACKGROUND

The significance of pre-operative body composition has recently attracted much attention in various diseases. However, cut-off values for these parameters remain undetermined, and these factors are not currently included in selection criteria for recipients of living donor liver transplantation (LDLT).

METHODS

Using computed tomography of 657 donors for LDLT, skeletal muscle mass, muscle quality, and visceral adiposity were evaluated by using skeletal muscle mass index (SMI), intramuscular adipose tissue content (IMAC), and visceral-to-subcutaneous adipose tissue area ratio (VSR). Sex-specific cut-offs for SMI, IMAC, and VSR were determined, and correlations with outcomes after LDLT in 277 recipients were examined with the aim of establishing new selection criteria for LDLT.

RESULTS

On the basis of younger donor data, we determined sex-specific cut-off values for low SMI, high IMAC, and high VSR (mean ± 2 standard deviations). Patients with all three factors showed the lowest survival rate after LDLT (1 year survival rate, 41.2%; P < 0.001). On multivariate analysis, low SMI (P = 0.002), high IMAC (P = 0.002), and high VSR (P = 0.001) were identified as independent risk factors for mortality after LDLT. Based on these findings, we have excluded patients showing all three factors (low SMI, high IMAC, and high VSR) as candidates for LDLT since October 2016.

CONCLUSIONS

Using cut-off values determined from healthy donors, we have established new selection criteria for LDLT including body composition, which should improve post-transplant outcomes.

Immune System Dysfunction in the Elderly

Human aging is characterized by both physical and physiological frailty that profoundly affects the immune system. In this context aging is associated with declines in adaptive and innate immunity established as immunosenescence. Immunosenescence is a new concept that reflects the age-associated restructuring changes of innate and adaptive immune functions. Thus elderly individuals usually present chronic low-level inflammation, higher infection rates and chronic diseases. A study of alterations in the immune system during aging could provide a potentially useful biomarker for the evaluation of immune senescence treatment. The immune system is the result of the interplay between innate and adaptive immunity, yet the impact of aging on this function is unclear. In this article the function of the immune system during aging is explored.

Human Body Composition and Immunity: Visceral Adipose Tissue Produces IL-15 and Muscle Strength Inversely Correlates with NK Cell Function in Elderly Humans

Natural killer (NK) lymphocyte-mediated cytotoxicity and cytokine secretion control infections and cancers, but these crucial activities decline with age. NK cell development, homeostasis, and function require IL-15 and its chaperone, IL-15 receptor alpha (IL-15Rα). Macrophages and dendritic cells (DC) are major sources of these proteins. We had previously postulated that additional IL-15 and IL-15Rα is made by skeletal muscle and adipose tissue. These sources may be important in aging, when IL-15-producing immune cells decline. NK cells circulate through adipose tissue, where they may be exposed to local IL-15. The objectives of this work were to determine (1) if human muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) are sources of IL-15 and IL-15 Rα, and (2) whether any of these tissues correlate with NK cell activity in elderly humans. We first investigated IL-15 and IL-15Rα RNA expression in paired muscle and SAT biopsies from healthy human subjects. Both tissues expressed these transcripts, but IL-15Rα RNA levels were higher in SAT than in skeletal muscle. We also investigated tissue obtained from surgeries and found that SAT and VAT expressed equivalent amounts of IL-15 and IL-15Rα RNA, respectively. Furthermore, stromal vascular fraction cells expressed more IL-15 RNA than did adipocytes. To test if these findings related to circulating IL-15 protein and NK cell function, we tested 50 healthy adults aged > 70 years old. Plasma IL-15 levels significantly correlated with abdominal VAT mass in the entire cohort and in non-obese subjects. However, plasma IL-15 levels did not correlate with skeletal muscle cross-sectional area and correlated inversely with muscle strength. Plasma IL-15 did correlate with NK cell cytotoxic granule exocytosis and with CCL4 (MIP-1β) production in response to NKp46-crosslinking. Additionally, NK cell responses to K562 leukemia cells correlated inversely with muscle strength. With aging, immune function declines while infections, cancers, and deaths increase. We propose that VAT-derived IL-15 and IL-15Rα is a compensatory NK cell support mechanism in elderly humans.

Temporospatial Analysis and New Players in the Immunology of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive loss of lower and upper motor neurons (MN) leading to muscle weakness, paralysis and eventually death. Although a highly varied etiology results in ALS, it broadly manifests itself as sporadic and familial forms that have evident similarities in clinical symptoms and disease progression. There is a tremendous amount of knowledge on molecular mechanisms leading to loss of MNs and neuromuscular junctions (NMJ) as major determinants of disease onset, severity and progression in ALS. Specifically, two main opposing hypotheses, the dying forward and dying back phenomena, exist to account for NMJ denervation. The former hypothesis proposes that the earliest degeneration occurs at the central MNs and proceeds to the NMJ, whereas in the latter, the peripheral NMJ is the site of precipitating degeneration progressing backwards to the MN cell body. A large body of literature strongly indicates a role for the immune system in disease onset and progression via regulatory involvement at the level of both the central and peripheral nervous systems (CNS and PNS). In this review, we discuss the earliest reported immune responses with an emphasis on newly identified immune players in mutant superoxide dismutase 1 (mSOD1) transgenic mice, the gold standard mouse model for ALS.

The Relation between Sarcopenia and Mortality in Patients at Intensive Care Unit

Background and Aim

Psoas muscle area (PMA) can reflect the status of skeletal muscle in the whole body. It has been also reported that decreased PMA was associated with postoperative mortality or morbidity after several surgical procedures. In this study, we aimed to investigate the relation between PMA and mortality in all age groups in intensive care unit (UNIT).

Materials and Method

The study consists of 362 consecutive patients. The demographic characteristics of patients, indications for ICU hospitalization, laboratory parameters, and clinical parameters consist of mortality and length of stay, and surgery history was obtained from intensive care archive records.

Results

The mean age was 61.2 ± 18.2 years, and the percentage of female was 33.3%. The mean duration of stay was 10.3 ± 24.4 days. Exitus ratio, partial healing, and healing were 25%, 70%, and 5%, respectively. The mean right, left, and total PMA were 8.7 ± 3.6, 8.9 ± 3.4, and 17.6 ± 6.9, respectively. The left and total PMA averages of the nonoperation patients were statistically significantly lower (p = 0.021  p = 0.043). The mean PMA between the ex and recovered patients were statistically significantly lower (p = 0.001, p = 0.001, p < 0.001). Dyspnoea, renal insufficiency, COPD, transfusion rate, operation rate, ventilator needy, and mean duration of hospitalization were statistically significant higher in patients with exitus. There is a significant difference in operation types, anesthesia type, and clinic rates.

Conclusion

Our data suggest that sarcopenia can be used to risk stratification in ICU patients. Future studies may use this technique to individualize postoperative interventions that may reduce the risk for an adverse discharge disposition related to critical illness, such as early mobilization, optimized nutritional support, and reduction of sedation and opioid dose.

Acute Sarcopenia Secondary to Hospitalisation - An Emerging Condition Affecting Older Adults

There has been increasing interest and research into sarcopenia in community-dwelling older adults since the European Working Group on Sarcopenia in Older People (EWGSOP) agreed a consensus definition in 2010. Sarcopenia has been defined as loss of muscle mass with loss of muscle function (strength or physical performance), with measurements two Standard Deviations (SDs) below the mean of a young reference population. This definition does not necessitate longitudinal measurements, or the absence of acute illness and diagnosis can be made from single measurements. We hypothesise that hospitalisation, due to a combination of acute inflammatory burden and muscle disuse, leads to an acute decline in muscle mass and function and may lead to some individuals meeting criteria for sarcopenia, acutely, based on the EWGSOP definition. This may be partially recoverable or may lead to increased risk of developing sarcopenia long-term. We have denoted the term “acute sarcopenia” to refer to acute loss of muscle mass and function associated with hospitalisation. This review discusses some of the current available research in this context and also identifies some of the knowledge gaps and potential areas for future research.

High Intensity Interval Training Increases Natural Killer Cell Number and Function in Obese Breast Cancer-challenged Mice and Obese Women

High intensity interval training (HIIT) boosts natural killer (NK) cell number and activity in normal weight breast cancer patients; however, whether this occurs in obese individuals is not well established. The goal of this study was to determine whether HIIT effectively boosts NK cells as a therapeutic strategy against breast cancer in an obese mouse model and in overweight/obese women. Diet induced female C57Bl/6 obese mice were assigned to undergo HIIT for four weeks or remain sedentary. Female participants were subjected to a six weeks HIIT protocol. HIIT mice acclimatized to treadmill running were subsequently injected with 5 × 10⁵ polyoma middle T (MT) breast cancer cells intravenously. NK cell number and activation were monitored using flow cytometry, and tumor burden or lipid content evaluated from histological lung and liver tissues, respectively. In both mice and humans, circulating NK cell number and activation (CD3−NK1.1+CD27+ and CD3−CD56+, respectively) markedly increased immediately after HIIT. HIIT obese mice had reduced lung tumor burden compared to controls following MT challenge, and had diminished hepatic lipid deposition despite minimal body weight loss. Our findings demonstrate that HIIT can benefit obese individuals by enhancing NK cell number and activity, reducing tumor burden, and enhancing metabolic health.

Aging promotes neoplastic disease through effects on the tissue microenvironment

A better understanding of the complex relationship between aging and cancer will provide important tools for the prevention and treatment of neoplasia. In these studies, the hypothesis was tested that aging may fuel carcinogenesis via alterations imposed in the tissue microenvironment. Preneoplastic hepatocytes isolated from liver nodules were orthotopically injected into either young or old syngeneic rats and their fate was followed over time using the dipeptidyl-peptidase type IV (DPPIV) system to track donor-derived-cells. At 3 months post-Tx, the mean size of donor-derived clusters was 11±3 cells in young vs. 42±8 in old recipients. At 8 months post-Tx, no visible lesion were detected in any of 21 young recipients, while 17/18 animals transplanted at old age displayed hepatic nodules, including 7 large tumors. All tumors expressed the DPPIV marker enzyme, indicating that they originated from transplanted cells. Expression of senescence-associated β-galactosidase was common in liver of 18-month old animals, while it was a rare finding in young controls. Finally, both mRNA and IL6 protein were found to be increased in the liver of aged rats compared to young controls. These results are interpreted to indicate that the microenvironment of the aged liver promotes the growth of pre-neoplastic hepatocytes.

Muscle Steatosis is an Independent Predictor of Postoperative Complications in Patients with Hepatocellular Carcinoma

BACKGROUND

Skeletal muscle depletion, referred to as sarcopenia, has been shown to be an independent predictor of lower disease-free and overall survivals in various kinds of diseases. The quality of skeletal muscle has recently attracted much attention as a new parameter of sarcopenia, but its impact on surgical complications is still unknown.

METHODS

A retrospective analysis of 492 patients undergoing hepatectomy for hepatocellular carcinoma (HCC) in our institution between April 2005 and December 2014 was performed. The quality of skeletal muscle was evaluated by intramuscular adipose tissue content (IMAC) using preoperative CT imaging at the umbilical level. The impact of sarcopenia on postoperative complications and the predictors of surgical complications after hepatectomy for HCC were analyzed.

RESULTS

Patients with high IMAC were older and had higher body mass index, higher indocyanine green retention test at 15 min, and more operative blood loss. Among 492 patients, 108 (22 %) patients had major postoperative complications (Clavien grade ≥ III), and infectious complications were found in 74 (15 %) patients. Twelve (2 %) patients died from postoperative complications. On multivariate analysis, preoperative high IMAC was an independent risk factor for increased major postoperative complications [odds ratio (OR) 1.580; P = 0.049] and infectious complications (OR 1.903; P = 0.021).

CONCLUSIONS

Preoperative muscle steatosis evaluated with IMAC was closely correlated with increased postoperative complications, especially infectious complications. The preoperative nutritional intervention and rehabilitation might lead to the improvement of postoperative outcomes after hepatectomy for HCC.

Posttherapeutic skeletal muscle mass recovery predicts favorable prognosis in patients with advanced urothelial carcinoma receiving first-line platinum-based chemotherapy

OBJECTIVES

Sarcopenia, decreased skeletal muscle mass (SMM), is an adverse prognostic factor in patients with advanced urothelial carcinoma (aUC). Given that SMM is variable depending on disease and patient conditions, changes in SMM over the course of treatments may be also prognostic. We investigated the prognostic role of posttherapeutic SMM recovery (PSR) in patients with aUC receiving first-line platinum-based chemotherapy.

MATERIALS AND METHODS

This retrospective study included 72 consecutive patients with aUC receiving first-line platinum-based chemotherapy. Skeletal muscle index (SMI) was measured on computed tomography images taken before the initiation of and immediately after 2 cycles of chemotherapy. ΔSMI was calculated as [(posttherapeutic SMI - pretherapeutic SMI)/pretherapeutic SMI] × 100, and PSR was defined as ΔSMI >0. Variables associated with progression-free survival (PFS) and overall survival (OS) were evaluated.

RESULTS

During the follow-up (median, 18mo for survivors), 60 (83%) patients progressed (2-year PFS, 17%) and 55 (76%) died (2-year OS, 24%). ΔSMI was significantly associated with chemotherapy response (P = 0.012), and was an independent predictor for both PFS (hazard ratio [HR] = 0.94, P<0.001) and OS (HR = 0.93, P<0.001). A total of 15 (21%) patients with PSR demonstrated significantly longer PFS and OS than those without PSR (both P<0.001). On multivariate analysis, PSR was an independent favorable predictor for both PFS (HR = 0.24, P<0.001) and OS (HR = 0.21, P<0.001). Incorporation of PSR into the Bajorin's and Galsky's models improved their c-indices (0.611-0.650, and 0.690-0.708, respectively).

CONCLUSIONS

PSR is a novel prognostic factor in patients with aUC receiving first-line platinum-based chemotherapy.

IL-15 promotes human myogenesis and mitigates the detrimental effects of TNFα on myotube development

Studies in murine cell lines and in mouse models suggest that IL-15 promotes myogenesis and may protect against the inflammation-mediated skeletal muscle atrophy which occurs in sarcopenia and cachexia. The effects of IL-15 on human skeletal muscle growth and development remain largely uncharacterised. Myogenic cultures were isolated from the skeletal muscle of young and elderly subjects. Myoblasts were differentiated for 8 d, with or without the addition of recombinant cytokines (rIL-15, rTNFα) and an IL-15 receptor neutralising antibody. Although myotubes were 19% thinner in cultures derived from elderly subjects, rIL-15 increased the thickness of myotubes (MTT) from both age groups to a similar extent. Neutralisation of the high-affinity IL-15 receptor binding subunit, IL-15rα in elderly myotubes confirmed that autocrine concentrations of IL-15 also support myogenesis. Co-incubation of differentiating myoblasts with rIL-15 and rTNFα, limited the reduction in MTT and nuclear fusion index (NFI) associated with rTNFα stimulation alone. IL-15rα neutralisation and rTNFα decreased MTT and NFI further. This, coupled with our observation that myotubes secrete IL-15 in response to TNFα stimulation supports the notion that IL-15 serves to mitigate inflammatory skeletal muscle loss. IL-15 may be an effective therapeutic target for the attenuation of inflammation-mediated skeletal muscle atrophy.

Impact of sarcopenia on outcomes of locally advanced esophageal cancer patients treated with neoadjuvant chemoradiation followed by surgery

Background

Sarcopenia is an independent predictor of clinical outcomes in multiple gastrointestinal cancers. Total psoas area (TPA), as measured on a single cross-sectional CT image at the L4 vertebral body level, has been correlated with sarcopenia. We sought to evaluate whether TPA was predictive of acute grade ≥3 toxicity, pathologic response, and overall survival in patients with locally advanced esophageal cancer receiving tri-modality therapy.

Methods

An institutional database of esophageal cancer patients treated with neoadjuvant chemoradiation followed by surgery was queried. Of 77 patients treated from 2008 to 2012 with intensity modulated radiation therapy (IMRT) and image guided radiation therapy (IGRT), 56 patients were eligible based on having CT imaging that included the L4 vertebral body. The L4 vertebra was identified on axial CT and the psoas muscle was manually contoured bilaterally to determine the skeletal muscle index. Sarcopenia was defined by the presence of the psoas area less than the median of the cohort. Acute toxicity was defined as within 3 months of radiotherapy based on Common Terminology Criteria for Adverse Events. ROC curve, logistic regression, and Kaplan Meier estimates were used when appropriate.

Results

Sarcopenia was associated with increased acute grade ≥3 toxicity from chemoradiation by ROC analysis using a cut off of 841.5 mm²/m² (P=0.003, AUC 0.709, sensitivity 60.9%, specificity 78.8%) and logistic regression (P=0.002). Patients with TPA <841.5 mm²/m² were 5.78 times more likely to develop grade 3 or higher toxicity (P=0.004). Sarcopenia did not predict a difference in overall survival (P=0.217) and was not significant for pathologic complete response or favorable pathologic response (TRG 0/1).

Conclusions

In our cohort of patients, sarcopenia was associated with a significant increase in acute grade ≥3 toxicity with chemoradiation, suggesting a potential role for neoadjuvant patient selection strategies. There was no difference in pathologic response or overall survival.

Frailty and sarcopenia: The potential role of an aged immune system

Frailty is a common negative consequence of ageing. Sarcopenia, the syndrome of loss of muscle mass, quality and strength, is more common in older adults and has been considered a precursor syndrome or the physical manifestation of frailty. The pathophysiology of both syndromes is incompletely described with multiple causes, inter-relationships and complex pathways proposed. Age-associated changes to the immune system (both immunesenescence, the decline in immune function with ageing, and inflammageing, a state of chronic inflammation) have been suggested as contributors to sarcopenia and frailty but a direct causative role remains to be established. Frailty, sarcopenia and immunesenescence are commonly described in older adults but are not ubiquitous to ageing. There is evidence that all three conditions are reversible and all three appear to share common inflammatory drivers. It is unclear whether frailty, sarcopenia and immunesenescence are separate entities that co-occur due to coincidental or potentially confounding factors, or whether they are more intimately linked by the same underlying cellular mechanisms. This review explores these possibilities focusing on innate immunity, and in particular associations with neutrophil dysfunction, inflammation and known mechanisms described to date. Furthermore, we consider whether the age-related decline in immune cell function (such as neutrophil migration), increased inflammation and the dysregulation of the phosphoinositide 3-kinase (PI3K)-Akt pathway in neutrophils could contribute pathogenically to sarcopenia and frailty.

Changes of peripheral lymphocyte subsets and cytokine environment during aging and deteriorating gastrointestinal tract health status

Human immune senescence accompanies with the physical and physiological frailty. The functional change and shift of NK, NKT and T cell subsets by aging have been widely studied. However, it remains largely unclear how the aging and disease conditions affect the distribution of lymphocytes. In the present study, 233 subjects with age range from 20 to 87 year old, including healthy people, people with chronic gastrointestinal tract disease or cancers were investigated. We found that the proportion of NK cells, CD8⁺ T cells and NKT cells remained relatively unchanged with aging. However, NKG2D and CD16 expression level on NK cells decreased with aging indicating impaired NK cell function. Surprisingly, the proportion of NK, NKT and T cells all declined with deteriorating health status from health to chronic gastrointestinal tract disease and cancer. Furthermore, cytokine and chemokine profiles changed with aging, but did not vary with different health status. Our results highlight new evidence for a continuum of change during immunologic aging and show unique data for variations of NK cells, CD8⁺ T cells, NKT cells, and cytokine microenvironment with human aging and health status transformation.

Radiographic sarcopenia predicts postoperative infectious complications in patients undergoing pancreaticoduodenectomy

BACKGROUND

Recently, skeletal muscle depletion (sarcopenia) has been reported to influence postoperative outcomes after certain procedures. This study investigated the impact of sarcopenia on postoperative outcomes following pancreaticoduodenectomy (PD).

METHODS

We performed a retrospective study of consecutive patients (n = 219) who underwent PD at our institution between January 2007 and May 2013. Sarcopenia was evaluated using preoperative computed tomography. We evaluated postoperative outcomes and the influence of sarcopenia on short-term outcomes, especially infectious complications. Subsequently, multivariate analysis was used to assess the impact of prognostic factors (including sarcopenia) on postoperative infections.

RESULTS

The mortality, major complication, and infectious complication rates for all patients were 1.4%, 16.4%, and 47.0%, respectively. Fifty-five patients met the criteria for sarcopenia. Sarcopenia was significantly associated with a higher incidence of in-hospital mortality (P = 0.004) and infectious complications (P < 0.001). In multivariate analyses, sarcopenia (odds ratio = 3.43; P < 0.001), preoperative biliary drainage (odds ratio = 2.20; P = 0.014), blood loss (odds ratio = 1.92; P = 0.048), and soft pancreatic texture (odds ratio = 3.71; P < 0.001) were independent predictors of postoperative infections.

CONCLUSIONS

Sarcopenia is an independent preoperative predictor of infectious complications after PD. Clinical assessment combined with sarcopenia may be helpful for understanding the risk of postoperative outcomes and determining perioperative management strategies.

Clinical Phenotype of Depression Affects Interleukin-6 Synthesis

Major depressive disorder (MDD) is not a single disease, but a number of various ailments that form one entity. Psychomotor retardation, anhedonia, sleep disorders, an increased suicide risk, and anxiety are the main symptoms that often define the clinical diagnosis of depression. Interleukin-6 (IL-6), as one of the proinflammatory cytokines, seems to be overexpressed during certain mental disorders, including MDD. Overexpression of IL-6 in depression is thought to be a factor associated with bad prognosis and worse disease course. IL-6 may directly affect brain functioning and production of neurotransmitters; moreover, its concentration is correlated with certain clinical symptoms within the wide range of depressive symptomatology. Furthermore, there is a strong correlation between IL-6 synthesis and psychosomatic functioning of the patient. This article discusses potential sources and significance of IL-6 in the pathogenesis of depression.

Parallel Profiles of Inflammatory and Effector Memory T Cells in Visceral Fat and Liver of Obesity-Associated Cancer Patients

In the midst of a worsening obesity epidemic, the incidence of obesity-associated morbidities, including cancer, diabetes, cardiac and liver disease is increasing. Insights into mechanisms underlying pathological obesity-associated inflammation are lacking. Both the omentum, the principal component of visceral fat, and liver of obese individuals are sites of excessive inflammation, but to date the T cell profiles of both compartments have not been assessed or compared in a patient cohort with obesity-associated disease. We have previously identified that omentum is enriched with inflammatory cytokines, chemokines and T cells. Here, we compared the inflammatory profile of T cells in the omentum and liver of patients with the obesity-associated malignancy oesophageal adenocarcinoma (OAC). Furthermore, we assessed the secreted cytokine profile in OAC patient serum, omentum and liver to assess systemic and local inflammation. We observed parallel T cell cytokine profiles and phenotypes in the omentum and liver of OAC patients, in particular CD69(+) and inflammatory effector memory T cells. This study reflects similar processes of inflammation and T cell activation in the omentum and liver, and may suggest common targets to modulate pathological inflammation at these sites.

Preventing aging with stem cell rejuvenation: Feasible or infeasible?

Characterized by dysfunction of tissues, organs, organ systems and the whole organism, aging results from the reduced function of effective stem cell populations. Recent advances in aging research have demonstrated that old tissue stem cells can be rejuvenated for the purpose of maintaining the old-organ function by youthful re-calibration of the environment where stem cells reside. Biochemical cues regulating tissue stem cell function include molecular signaling pathways that interact between stem cells themselves and their niches. Historically, plasma fractions have been shown to contain factors capable of controlling age phenotypes; subsequently, signaling pathways involved in the aging process have been identified. Consequently, modulation of signaling pathways such as Notch/Delta, Wnt, transforming growth factor-β, JAK/STAT, mammalian target of rapamycin and p38 mitogen-activated protein kinase has demonstrated potential to rejuvenate stem cell function leading to organismic rejuvenation. Several synthetic agents and natural sources, such as phytochemicals and flavonoids, have been proposed to rejuvenate old stem cells by targeting these pathways. However, several concerns still remain to achieve effective organismic rejuvenation in clinical settings, such as possible carcinogenic actions; thus, further research is still required.

IL-15 Activates the Jak3/STAT3 Signaling Pathway to Mediate Glucose Uptake in Skeletal Muscle Cells

Myokines are specialized cytokines that are secreted from skeletal muscle (SKM) in response to metabolic stimuli, such as exercise. Interleukin-15 (IL-15) is a myokine with potential to reduce obesity and increase lean mass through induction of metabolic processes. It has been previously shown that IL-15 acts to increase glucose uptake in SKM cells. However, the downstream signals orchestrating the link between IL-15 signaling and glucose uptake have not been fully explored. Here we employed the mouse SKM C2C12 cell line to examine potential downstream targets of IL-15-induced alterations in glucose uptake. Following differentiation, C2C12 cells were treated overnight with 100 ng/ml of IL-15. Activation of factors associated with glucose metabolism (Akt and AMPK) and known downstream targets of IL-15 (Jak1, Jak3, STAT3, and STAT5) were assessed with IL-15 stimulation. IL-15 stimulated glucose uptake and GLUT4 translocation to the plasma membrane. IL-15 treatment had no effect on phospho-Akt, phospho-Akt substrates, phospho-AMPK, phospho-Jak1, or phospho-STAT5. However, with IL-15, phospho-Jak3 and phospho-STAT3 levels were increased along with increased interaction of Jak3 and STAT3. Additionally, IL-15 induced a translocation of phospho-STAT3 from the cytoplasm to the nucleus. We have evidence that a mediator of glucose uptake, HIF1α, expression was dependent on IL-15 induced STAT3 activation. Finally, upon inhibition of STAT3 the positive effects of IL-15 on glucose uptake and GLUT4 translocation were abolished. Taken together, we provide evidence for a novel signaling pathway for IL-15 acting through Jak3/STAT3 to regulate glucose metabolism.

High-fat high-sucrose diet leads to dynamic structural and inflammatory alterations in the rat vastus lateralis muscle

The influence of obesity on muscle integrity is not well understood. The purpose of this study was to quantify structural and molecular changes in the rat vastus lateralis (VL) muscle as a function of a 12-week obesity induction period and a subsequent adaptation period (additional 16-weeks). Male Sprague-Dawley rats consumed a high-fat, high-sucrose (DIO, n = 40) diet, or a chow control-diet (n = 14). At 12-weeks, DIO rats were grouped as prone (DIO-P, top 33% of weight change) or resistant (DIO-R, bottom 33%). Animals were euthanized at 12- or 28-weeks on the diet. At sacrifice, body composition was determined and VL muscles were collected. Intramuscular fat, fibrosis, and CD68+ cells were quantified histologically and relevant molecular markers were evaluated using RT-qPCR. At 12- and 28-weeks post-obesity induction, DIO-P rats had more mass and body fat than DIO-R and chow rats (p < 0.05). DIO-P and DIO-R rats had similar losses in muscle mass, which were greater than those in chow rats (p < 0.05). mRNA levels for MAFbx/atrogin-1 were reduced in DIO-P and DIO-R rats at 12- and 28-weeks compared to chow rats (p < 0.05), while expression of MuRF1 was similar to chow values. DIO-P rats demonstrated increased mRNA levels for pro-inflammatory mediators, inflammatory cells, and fibrosis compared to DIO-R and chow animals, despite having similar levels of intramuscular fat. The down-regulation of MAFbx/atrogin-1 may suggest onset of degenerative changes in VL muscle integrity of obese rats. DIO-R animals exhibited fewer inflammatory changes compared to DIO-P animals, suggesting a protective effect of obesity resistance on local inflammation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2069-2078, 2016.

Impact of Skeletal Muscle Mass, Muscle Quality, and Visceral Adiposity on Outcomes Following Resection of Intrahepatic Cholangiocarcinoma

BACKGROUND

Decrease in skeletal muscle mass and function, known as sarcopenia, is associated with poor prognosis. Visceral fat accumulation also is related to mortality. This study investigated the impact of preoperative skeletal muscle mass, muscle quality, and visceral adiposity on outcomes in patients undergoing resection of intrahepatic cholangiocarcinoma (ICC).

METHODS

A retrospective analysis was performed of 109 patients undergoing resections of ICC between January 2004 and April 2015. Skeletal muscle mass [skeletal muscle index (SMI)], skeletal muscle quality [muscle attenuation (MA)], and visceral adiposity [visceral to subcutaneous adipose tissue area ratio (VSR)] were measured on preoperative computed tomography images. The impacts of these parameters on outcomes after ICC resections were analyzed.

RESULTS

The overall survival rates were significantly lower in patients with low SMI (P = 0.002), low MA (P = 0.032), and high VSR (P = 0.026) compared with patients with high SMI, high MA, and low VSR, respectively. With multivariate analyses, in patients with stage I-III, low SMI (hazard ratio (HR) 3.29, P = 0.003) and low MA (HR 2.86, P = 0.010) were revealed as independent significant risk factors for mortality. In patients with stage IV, none of these parameters was identified as risk factors, with only the absence of adjuvant chemotherapy identified as an independent risk factor for mortality (HR 5.92, P = 0.001).

CONCLUSIONS

Although stage was the most important factor, low skeletal muscle mass and quality were closely related to mortality after resection of ICC in patients with stage I-III.

IL-15 Mediates Mitochondrial Activity through a PPARδ-Dependent-PPARα-Independent Mechanism in Skeletal Muscle Cells

Molecular mediators of metabolic processes, to increase energy expenditure, have become a focus for therapies of obesity. The discovery of cytokines secreted from the skeletal muscle (SKM), termed "myokines," has garnered attention due to their positive effects on metabolic processes. Interleukin-15 (IL-15) is a myokine that has numerous positive metabolic effects and is linked to the PPAR family of mitochondrial regulators. Here, we aimed to determine the importance of PPARα and/or PPARδ as targets of IL-15 signaling. C2C12 SKM cells were differentiated for 6 days and treated every other day with IL-15 (100 ng/mL), a PPARα inhibitor (GW-6471), a PPARδ inhibitor (GSK-3787), or both IL-15 and the inhibitors. IL-15 increased mitochondrial activity and induced PPARα, PPARδ, PGC1α, PGC1β, UCP2, and Nrf1 expression. There was no effect of inhibiting PPARα, in combination with IL-15, on the aforementioned mRNA levels except for PGC1β and Nrf1. However, with PPARδ inhibition, IL-15 failed to induce the expression levels of PGC1α, PGC1β, UCP2, and Nrf1. Further, inhibition of PPARδ abolished IL-15 induced increases in citrate synthase activity, ATP production, and overall mitochondrial activity. IL-15 had no effects on mitochondrial biogenesis. Our data indicates that PPARδ activity is required for the beneficial metabolic effects of IL-15 signaling in SKM.

Preoperative Sarcopenia Strongly Influences the Risk of Postoperative Pancreatic Fistula Formation After Pancreaticoduodenectomy

BACKGROUND

Postoperative pancreatic fistula (POPF) is a serious complication of pancreaticoduodenectomy (PD). Sarcopenia is a newly identified marker of frailty. We performed this study to assess whether preoperative sarcopenia has an impact on clinically relevant POPF formation.

METHODS

A total of 266 consecutive patients who underwent a PD between 2010 and 2014 were enrolled in this retrospective study. Skeletal muscle mass was measured using preoperative computed tomography images. The impact of preoperative sarcopenia on clinically relevant POPF formation was analyzed using univariate and multivariate analyses.

RESULTS

Of the 266 patients, 132 (49.6 %) were classified as having preoperative sarcopenia. The rate of clinically relevant POPF formation was significantly higher in the sarcopenia group (22.0 vs. 10.4 %; P = 0.011). A multivariate logistic regression analysis showed that sarcopenia (odds ratio, 2.869; P = 0.007) was an independent risk factor for the development of clinically relevant POPF, along with a soft pancreas and a parenchymal thickness at the pancreatic resection site of ≥8 mm.

CONCLUSIONS

Preoperative sarcopenia was identified as a strong and independent risk factor for clinically relevant POPF formation after PD. Perioperative rehabilitation and nutrition therapy may contribute to the prevention of POPF formation and a safer PD.

Impact of preoperative hand grip strength on morbidity following gastric cancer surgery

BACKGROUND

Sarcopenia is a decrease in both muscle mass and strength. It remains unclear whether sarcopenia is associated with morbidity after gastric cancer surgery. This study evaluated the impact of sarcopenia on the morbidity of gastric cancer surgery.

METHODS

A total of 293 gastric cancer patients who underwent curative surgery between May 2011 and June 2013 were retrospectively examined. Patients with performance status 3 or 4 were excluded. Preoperative lean body mass (LBM) was evaluated by bioelectrical impedance analysis and expressed as LBM index. Preoperative muscle function was measured by hand grip strength (HGS). The cutoff values were the gender-specific lowest 20 %. Grade 2 or higher morbidities, as retrospectively evaluated by the Clavien-Dindo classification, were obtained from the patient record. The risk factors for morbidity were examined by univariate and multivariate analyses.

RESULTS

Morbidity was observed in 39 patients (13.3 %), including 7 with pancreatic leakage, 12 with anastomotic leakage, and 4 with intraabdominal abscesses, but no mortality was observed. The univariate analysis showed that male gender, total gastrectomy, splenectomy, and a low HGS were significant risk factors for morbidity. A low LBM was not a significant risk factor. A low HGS, male gender, and total gastrectomy remained significant in the multivariate analysis.

CONCLUSIONS

A low hand grip strength was a significant risk factor for morbidity after gastric cancer surgery. The importance of the hand grip strength as a risk factor should be examined in future prospective studies.

Increased body mass index and adjusted mortality in ICU patients with sepsis or septic shock: a systematic review and meta-analysis

Background

At least 25 % of adults admitted to intensive care units (ICU) in the United States have an overweight, obese or morbidly obese body mass index (BMI). The effect of BMI on adjusted mortality in adults requiring ICU treatment for sepsis is unclear. We performed a systematic review of adjusted all-cause mortality for underweight, overweight, obese and morbidly obese BMIs relative to normal BMI for adults admitted to the ICU with sepsis, severe sepsis, and septic shock.

Method

PubMed, the Cochrane Library, and EMBASE electronic databases were searched through November 18, 2015, without language restrictions. We included studies that reported multivariate regression analyses for all-cause mortality using standard BMI categories for adults admitted to the ICU for sepsis, severe sepsis, and septic shock. Articles were selected by consensus among multiple reviewers. Electronic database searches yielded 10,312 articles, of which six were eligible. Data were extracted by one reviewer and then reviewed by three independent reviewers. For the meta-analyses performed, the adjusted odds ratios (aOR) of mortality were combined using a random-effects model. Risk of bias was assessed using the Newcastle-Ottawa quality assessment scale for cohort studies.

Results

Four retrospective (n = 6609 patients) and two prospective (n = 556) studies met inclusion criteria. Compared to normal BMI, across five studies each, overweight or obese BMIs reduced the adjusted odds ratio (95 % CI) of mortality [aOR] [0.83 (0.75, 0.91) p < 0.001 and 0.82 (0.67, 0.99) p = 0.04, respectively] with low or moderate heterogeneity (I² = 15.7 %, p = 0.31 and I² = 53.0 %, p = 0.07, respectively). Across three studies each, morbidly obese BMI and underweight BMI did not alter aOR [0.90 (0.59, 1.39), p = 0.64; I² = 43.3 %, p = 0.17; and 1.24 (0.79, 1.95), p = 0.35; I² = 15.6 %, p = 0.31 respectively]. Only one study clearly defined how and when height and weight measurements were calculated. Site of underlying infection and illness severity may have favored overweight and obese BMIs.

Conclusions

This is the first meta-analysis to show that overweight or obese BMIs reduce adjusted mortality in adults admitted to the ICU with sepsis, severe sepsis, or septic shock. More rigorous studies that address these limitations are needed to clarify the impact of BMI on sepsis ICU outcomes.

Trial registration

PROSPERO International prospective register of systematic reviews 10.15124/CRD42014010556. Registered on July 11, 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1360-z) contains supplementary material, which is available to authorized users.

Selection Criteria and Current Issues in Liver Transplantation for Hepatocellular Carcinoma

Liver transplantation (LT) is an ideal treatment for hepatocellular carcinoma (HCC) because it not only resects HCCs but it also replaces the underlying damaged liver with normal tissue. However, the selection criteria are still a matter of debate. After the introduction of the Milan criteria, some expanded criteria focusing on tumor size and number have been proposed. In addition, new expanded criteria considering tumor biology have been proposed using tumor markers and (18)F-fluorodeoxyglucose positron emission tomography. This review summarizes the selection criteria in LT for HCC and introduces current issues focusing on the treatment for hepatitis C virus infection and the significance of sarcopenia in this field.

Impact of HIV-1 tropism on the emergence of non-AIDS events in HIV-infected patients receiving fully suppressive antiretroviral therapy

Objective:

The impact of HIV-1 tropism on the emergence of non-AIDS events was evaluated in a cohort of 116 antiretroviral therapy (ART) responder patients.

Methods:

The patients were followed for the emergence of hypertension, renal impairment, metabolic and bone disorders (defined as non-AIDS events) each 8 weeks at standard visits. A V3 plasma sequence genotype analysis was performed at the time of ART initiation and the geno2pheno algorithm with the results that defines the false-positive rate (FPR) was used to infer HIV tropism. The associations between the non-AIDS events and the FPR at baseline were evaluated using the χ² test for trend. A Cox-regression analysis using the counting process formulation of Andersen and Gill was performed to define whether the emergence of non-AIDS events was correlated to FPR.

Results:

The prevalence of at least one non-AIDS event resulted higher in patients with a FPR below 10% than in patients with a R5 virus (P = 0.033). Patients with a FPR below 5.0% most frequently developed non-AIDS events during ART (P = 0.01). A higher prevalence of patients with at least two AIDS events was found in the group of patients with a FPR below 5.0% with respect to the others (P < 0.001). At multivariate Cox-regression analysis, having an X4 virus and age were independently associated with a higher probability of non-AIDS event development.

Conclusion:

This study shows that an X4 virus, particularly a FPR less than 5%, is related to non-AIDS events development. Further studies are warranted to understand the mechanisms underlying this phenomenon.

Body composition of the host influences dendritic cell phenotype in patients treated for colorectal cancer

Dendritic cells (DCs) are antigen-presenting cells that can acquire tumour antigens and initiate cytotoxic T cell reactions. Obesity has been proposed as a cause for tumours escaping immune surveillance, but few studies investigate the impact of other body composition parameters. We examined the relationship of DC phenotype with computer tomography (CT)-defined parameters in patients with colorectal cancer (CRC). DCs were identified within peripheral blood mononuclear cells by flow cytometry as HLA-DR positive and negative for markers of other cell lineages in 21 patients. Analysis of CT scans was used to calculate lumbar skeletal muscle index (LSMI) and mean muscle attenuation (MA). Positive correlation between the LSMI and expression of CD40 in all DCs (r = 0.45; p = 0.04) was demonstrated. The MA was positively correlated with scavenger receptor CD36 [all DCs (r = 0.60; p = 0.01) and myeloid DCs (r = 0.63; p < 0.01)]. However, the MA was negatively correlated with CCR7 expression in all DCs (r = -0.46, p = 0.03.) and with CD83 [all DCs (r = -0.63; p = 0.01) and myeloid DCs (r = -0.75; p < 0.01)]. There were no relationships between the fat indexes and the DC phenotype. These results highlight a direct relationship between muscle depletion and changes in stimulatory, migratory and fatty acid-processing potential of DC in patients with CRC.

Sarcopenia is a risk factor for the recurrence of hepatocellular carcinoma after curative treatment

BACKGROUND AND AIM

Sarcopenia, initially proposed as decreased of muscle mass and strength, is associated with aging and malignant diseases. The aim of the present study was to determine whether there is a correlation between sarcopenia and the recurrence of hepatocellular carcinoma (HCC) after curative treatment.

METHODS

We conducted a retrospective analysis of consecutive naive patients with HCC who underwent curative resection or radiofrequency ablation. To eliminate the influence of cause or the severity of liver damage, subjects were limited to those with HCC with hepatitis C-related cirrhosis and Child-Pugh class A liver function. Patients were assessed using computed tomographic measurement of muscle mass at the level of the third lumbar (L3) vertebrae, the L3 skeletal muscle index (L3 SMI). Sarcopenia was defined by using previously published, sex-specific cut-off value.

RESULTS

Sarcopenia was present in 61 of 92 patients. Patients' median age was 71.5 years (range, 47-84), and the baseline characteristics of patients were comparable between patients with and without sarcopenia except for sex, serum albumin level, prothrombin time, diabetes mellitus and body mass index. Recurrence rates at 1, 3 and 5 years were 39.1%,77.1%,81.7% for patients with sarcopenia and 23.5%,59.5% and 75.7% for patients without sarcopenia, respectively (P = 0.03). Multivariate Cox analysis revealed that sarcopenia and preoperative α-fetoprotein of more than 40 ng/mL were significant independent factors for recurrence.

CONCLUSION

Sarcopenia is a risk factor for recurrence in patients with HCC who were treated with curative treatment.

Impact of postoperative changes in sarcopenic factors on outcomes after hepatectomy for hepatocellular carcinoma

BACKGROUND

We have reported that preoperative low skeletal muscle quality was an independent risk factor for poor outcomes after hepatectomy for hepatocellular carcinoma (HCC). However, postoperative changes of quality as well as quantity of skeletal muscle after hepatectomy for HCC and their impact on postoperative outcomes have not been fully investigated.

METHODS

We retrospectively analyzed 241 patients undergoing primary hepatectomy for HCC between January 2007 and September 2012. The quality and quantity of skeletal muscle were evaluated by intramuscular adipose tissue content (IMAC) and the psoas muscle mass index (PMI) using computed tomography imaging at the umbilical level, respectively. We evaluated postoperative changes in IMAC and PMI in patients according to preoperative sarcopenia, sex, and surgical procedure. We also investigated the impact of ΔIMAC and ΔPMI on HCC recurrence in patients with preoperative normal IMAC.

RESULTS

On multivariate analysis, indocyanine green retention test at 15 min ≥ 15% (odds ratio [OR] = 3.156; P = 0.041) and high ΔIMAC at 6 months after hepatectomy (OR = 3.713; P = 0.024) were the risk factors for HCC recurrence in patients with preoperative normal IMAC.

CONCLUSION

Postoperative depletion of skeletal muscle quality is closely involved with HCC recurrence after hepatectomy for HCC.

Effect of tamoxifen on fatty degeneration and atrophy of rotator cuff muscles in chronic rotator cuff tear: An animal model study

Fatty degeneration of the rotator cuff muscles is an irreversible change resulting from chronic rotator cuff tear and is associated with poor clinical outcomes following rotator cuff repair. We evaluated the effect of Tamoxifen, a competitive estrogen receptor inhibitor, on fatty degeneration using a mouse model for chronic rotator cuff tear. Sixteen adult mice were divided into two diet groups (Tamoxifen vs. Regular) and subjected to surgical creation of a large rotator cuff tear and suprascapular nerve transection in their left shoulder with the right shoulder serving as a control. The rotator cuff muscles were harvested at 16 weeks and subjected to histology and RT-PCR for adipogenic and myogenic markers. Histology showed substantially decreased atrophy and endomysial inflammation in Tamoxifen group, but no significant differences in the amount of intramuscular adipocytes and lipid droplets compared to the Regular group. With RT-PCR, the operated shoulders showed significant upregulation of myogenin and PPAR-γ, and downregulation of myostatin compared to the nonsurgical shoulder. No significant differences of gene expression were found between the two diet groups. Our study demonstrated that tamoxifen diet leads to decreased muscle atrophy and inflammatory changes following chronic rotator cuff tear, but has no apparent effect on adipogenesis.

Obesity-associated cancer: an immunological perspective

Epidemiological studies have established an association between obesity, insulin resistance, type 2 diabetes and a number of cancer types. Research has focused predominantly on altered endocrine factors, growth factors and signalling pathways, with little known in man about the immune involvement in the relevant pathophysiological processes. Moreover, in an era of exciting new breakthroughs in cancer immunotherapy, there is also a need to study the safety and efficacy of immunotherapeutics in the complex setting of inflammatory-driven obesity-associated cancer. This review addresses key immune cell subsets underpinning obesity-associated inflammation and describes how such immune compartments might be targeted to prevent and treat obesity-associated cancer. We propose that the modulation, metabolism, migration and abundance of pro- and anti-inflammatory cells and tumour-specific T cells might be therapeutically altered to both restore immune balance, alleviating pathological inflammation, and to improve anti-tumour immune responses in obesity-associated cancer.

Impact of the preoperative quantity and quality of skeletal muscle on outcomes after resection of extrahepatic biliary malignancies

BACKGROUND

Skeletal muscle depletion, referred to as sarcopenia, predicts mortality after major surgery. This study investigated the impact of preoperative skeletal muscle quantity and quality on outcomes in patients undergoing resection of extrahepatic biliary cancer.

METHODS

We performed a retrospective analysis of 207 patients undergoing resection for biliary cancer between 2004 and 2013. The quantity and quality of skeletal muscle, indicated by the psoas muscle mass index (PMI) and intramuscular adipose tissue content (IMAC), were measured on preoperative images of computed tomography. Overall survival (OS) and recurrence-free survival (RFS) rates were compared by PMI and IMAC, and prognostic factors after operation were assessed.

RESULTS

The OS and RFS rates were less in patients with low PMI (low muscle quantity) than in those with normal PMI (P < .001 and P < .001; 5-year OS, 15.7 vs 53.5%). The OS and RFS rates were also less in patients with high IMAC (low muscle quality) than in those with normal IMAC (P < .001 and P < .001; 5-year OS, 23.8 vs 55.9%). Low PMI and high IMAC were independent factors predictive of poor OS (hazard ratio [HR], 2.921 [95% CI, 1.920-4.470; P < .001] and HR, 1.725 [95% CI, 1.159-2.590; P = .007]) and RFS (HR, 2.141 [95% CI, 1.464-3.129, P < .001] and HR, 1.492 [95% CI, 1.032-2.166, P = .034]).

CONCLUSION

Preoperative sarcopenia, indicating a low quantity and quality of skeletal muscle, is related closely to mortality after resection of biliary cancer.

Influence of BMI on short-term surgical outcome after colorectal cancer surgery: a study based on the Swedish national quality registry

PURPOSE

It is well known that an increased body mass index (BMI) is associated with cancer development. Results from studies on colorectal cancer (CRC) treatment outcome and BMI are however conflicting. Our hypothesis was that a high as well as a low BMI will have negative effects on short-term outcome after CRC surgery.

METHODS

Data from the Swedish Colorectal Cancer Registry from 2007 to 2012 was analyzed. A total of 24,587 patients operated on for CRC were included in the study and divided into one of five categories for BMI. Operative bleeding, operating time, surgical complications, and 30-day mortality were compared between groups.

RESULTS

Operative bleeding as well as operating time was significantly increased when comparing normal-weight patients to overweight (p < 0.001). 15.1% of normal-weight patients suffered from postoperative surgical complications. This was significantly increased with each BMI step but did not affect the 30-day mortality. However, underweight patients, on the other hand, had fewer complications (13.3%) but an increased 30-day mortality.

CONCLUSION

Longer operating times and increased perioperative bleeding may be explanatory factors behind increased postoperative complication rates for CRC patients with higher BMI. In underweight patients, advanced disease may be a reason for a higher 30-day mortality. To improve outcome, specific precautions are suggested when operating on under- as well as overweight CRC patients. We also suggest that the registry introduces a better marker than BMI for central visceral fat-the link between obesity and cancer development. Further studies are needed to analyze the findings in detail and to study long-term effects.

Comparison of rapamycin schedules in mice on high-fat diet

At a wide range of doses, rapamycin extends life span in mice. It was shown that intraperitoneal injections (i.p.) of rapamycin prevent weight gain in mice on high-fat diet (HFD). We further investigated the effect of rapamycin on weight gain in female C57BL/6 mice on HFD started at the age of 7.5 months. By the age of 16 and 23 months, mice on HFD weighed significantly more (52 vs 33 g; p = 0.0001 and 70 vs 38 g; p < 0.0001, respectively) than mice on low fat diet (LFD). The i.p. administration of 1.5 mg/kg rapamycin, 3 times a week every other week, completely prevented weight gain, whereas administration of rapamycin by oral gavash did not. Rapamycin given in the drinking water slightly decreased weight gain by the age of 23 months. In addition, metabolic parameters were evaluated at the age of 16 and 23 months, 6 and 13 days after last rapamycin administration, respectively. Plasma leptin levels strongly correlated with body weight, (P < 0.0001, r=0.86), suggesting that the difference in weight was due to fat tissue mass. Levels of insulin, glucose, triglycerides and IGF1 were not statistically different in all groups, indicating that these courses of rapamycin treatment did not impair metabolic parameters at least after rapamycin discontinuation. Despite rapamycin discontinuation, cardiac levels of phospho-S6 and pAKT(S473) were low in the i.p.-treated group. This continuous effect of rapamycin can be explained by prevention of obesity in the i.p. group. We conclude that intermittent i.p. administration of rapamycin prevents weight gain without causing gross metabolic abnormalities. Intermittent gavash administration minimally affected weight gain. Potential clinical applications are discussed.

Cellular Senescence in Type 2 Diabetes: A Therapeutic Opportunity

Cellular senescence is a fundamental aging mechanism that has been implicated in many age-related diseases and is a significant cause of tissue dysfunction. Accumulation of senescent cells occurs during aging and is also seen in the context of obesity and diabetes. Senescent cells may play a role in type 2 diabetes pathogenesis through direct impact on pancreatic β-cell function, senescence-associated secretory phenotype (SASP)-mediated tissue damage, and involvement in adipose tissue dysfunction. In turn, metabolic and signaling changes seen in diabetes, such as high circulating glucose, altered lipid metabolism, and growth hormone axis perturbations, can promote senescent cell formation. Thus, senescent cells might be part of a pathogenic loop in diabetes, as both a cause and consequence of metabolic changes and tissue damage. Therapeutic targeting of a basic aging mechanism such as cellular senescence may have a large impact on disease pathogenesis and could be more effective in preventing the progression of diabetes complications than currently available therapies that have limited impact on already existing tissue damage. Therefore, senescent cells and the SASP represent significant opportunities for advancement in the prevention and treatment of type 2 diabetes and its complications.

Vaccination in the elderly: what can be recommended?

The age-associated increased susceptibility to infectious disease would suggest that vaccination should be a route to promote healthy aging and keep our seniors autonomous and independent. While vaccination represents a cost-effective and efficient strategy at community level, the ability of the immune system to mount a protective immune response is still unpredictable at the level of the individual. Thus, at a similar age, some individuals, including the elderly, might still be 'good' responders while some other, even younger, would definitely fail to mount a protective response. In this review, the current burden of vaccine-preventable diseases in the aging and aged population will be detailed with the aim to identify the ideal vaccine candidates over the age of 50 years. This article will conclude with potential strategies to reduce, as best as possible, this burden and the imperative need to overcome barriers in extending current vaccine coverage towards to a lifelong vaccine schedule.

Preoperative intramuscular adipose tissue content is a novel prognostic predictor after hepatectomy for hepatocellular carcinoma

BACKGROUND

Sarcopenia has been shown to be an independent predictor of lower disease-free and overall survival in various kinds of diseases. The quality of skeletal muscle has recently attracted much attention as a new parameter of sarcopenia.

METHODS

We performed a retrospective analysis of 477 patients undergoing hepatectomy for hepatocellular carcinoma (HCC) between April 2005 and August 2014. The quality of skeletal muscle was evaluated by intramuscular adipose tissue content (IMAC) using preoperative computed tomography (CT) imaging. The impact of IMAC on outcomes after hepatectomy for HCC was analyzed.

RESULTS

Patients with high IMAC showed older age, higher body mass index, higher indocyanine green retention test at 15 min, and more operative blood loss. The overall and recurrence-free survival rates were significantly lower in patients with high IMAC than in patients with normal IMAC (P < 0.0001, P = 0.0012, respectively). Multivariate analysis showed that high IMAC was the significant risk factor for death (hazard ratio [HR] = 2.942; P < 0.0001) and for HCC recurrence (HR = 1.529; P = 0.0007) after hepatectomy.

CONCLUSIONS

Preoperative quality of skeletal muscle was closely correlated with postoperative mortality and HCC recurrence. IMAC could be incorporated into new selection criteria for hepatectomy for HCC.

Skeletal muscle depletion is an independent prognostic factor for hepatocellular carcinoma

BACKGROUND

Skeletal muscle depletion or sarcopenia has been identified as a poor prognostic factor for various diseases. The aim of this study is to determine whether muscle depletion is a prognostic factor for hepatocellular carcinoma (HCC).

METHODS

We evaluated 217 consecutive patients with primary HCC. The skeletal muscle cross-sectional area was measured by computed tomography at the third lumbar vertebra (L3), from which the total body fat-free mass (FFM) and L3 skeletal muscle index (L3 SMI) were obtained. The factors contributing to overall survival (OS) were analyzed by univariate and multivariate Cox proportional hazards model.

RESULTS

In univariate analysis, FFM (P = 0.0422), Child-Pugh classification (P = 0.0058), serum albumin level (P < 0.0001), serum AFP level (P < 0.0001), serum proteins induced by vitamin K absence or antagonist-II level (P < 0.0001), cancer stage (P < 0.0001), and curability of the initial treatment (P < 0.0001) were significantly associated with the prognosis of HCC. Multivariate analysis indicated that FFM (P = 0.0499), albumin level (P = 0.0398), and curability of the initial treatment (P = 0.0008) were independent prognostic factors. Sarcopenia was defined as an L3 SMI value of ≤29.0 cm(2)/m(2) for women and ≤36.0 cm(2)/m(2) for men, and 24 patients (11.1%) have sarcopenia. Sarcopenic patients showed a significantly lower OS than those without sarcopenia (P = 0.0043). Sarcopenic patients who were overweight (BMI >22) died earlier (P = 0.0129).

CONCLUSIONS

Skeletal muscle depletion is an independent prognostic factor. Intervention to prevent muscle wasting might be an effective strategy for improving the outcome of HCC.

Microbial shifts in the aging mouse gut

BACKGROUND

The changes that occur in the microbiome of aging individuals are unclear, especially in light of the imperfect correlation of frailty with age. Studies in older human subjects have reported subtle effects, but these results may be confounded by other variables that often change with age such as diet and place of residence. To test these associations in a more controlled model system, we examined the relationship between age, frailty, and the gut microbiome of female C57BL/6 J mice.

RESULTS

The frailty index, which is based on the evaluation of 31 clinical signs of deterioration in mice, showed a near-perfect correlation with age. We observed a statistically significant relationship between age and the taxonomic composition of the corresponding microbiome. Consistent with previous human studies, the Rikenellaceae family, which includes the Alistipes genus, was the most significantly overrepresented taxon within middle-aged and older mice. The functional profile of the mouse gut microbiome also varied with host age and frailty. Bacterial-encoded functions that were underrepresented in older mice included cobalamin (B12) and biotin (B7) biosynthesis, and bacterial SOS genes associated with DNA repair. Conversely, creatine degradation, associated with muscle wasting, was overrepresented within the gut microbiomes of the older mice, as were bacterial-encoded β-glucuronidases, which can influence drug-induced epithelial cell toxicity. Older mice also showed an overabundance of monosaccharide utilization genes relative to di-, oligo-, and polysaccharide utilization genes, which may have a substantial impact on gut homeostasis.

CONCLUSION

We have identified taxonomic and functional patterns that correlate with age and frailty in the mouse microbiome. Differences in functions related to host nutrition and drug pharmacology vary in an age-dependent manner, suggesting that the availability and timing of essential functions may differ significantly with age and frailty. Future work with larger cohorts of mice will aim to separate the effects of age and frailty, and other factors.

Impact of quality as well as quantity of skeletal muscle on outcomes after liver transplantation

Intramuscular fat accumulation has come to be associated with loss of muscle strength and function, one of the components of sarcopenia. However, the impact of preoperative quality of skeletal muscle on outcomes after living donor liver transplantation (LDLT) is unclear. The present study evaluated the intramuscular adipose tissue content (IMAC) and psoas muscle mass index (PMI) in 200 adult patients undergoing LDLT at our institution between January 2008 and October 2013. Correlations of IMAC with other factors, overall survival rates in patients classified according to IMAC or PMI, and risk factors for poor survival after LDLT were analyzed. IMAC was significantly correlated with age (r = 0.229, P = 0.03) and PMI (r = -0.236, P = 0.02) in males and with age (r = 0.349, P < 0.001) and branched-chain amino acid (BCAA)-to-tyrosine ratio (r = -0.250, P = 0.01) in females. The overall survival rates in patients with high IMAC or low PMI were significantly lower than those for patients with normal IMAC or PMI (P < 0.001, P < 0.001, respectively). Multivariate analysis showed that high IMAC [odds ratio (OR) = 3.898, 95% confidence interval (CI) = 2.025-7.757, P < 0.001] and low PMI (OR = 3.635, 95% CI = 1.896-7.174, P < 0.001) were independent risk factors for death after LDLT. In conclusion, high IMAC and low PMI were closely involved with posttransplant mortality. Preoperative quality and quantity of skeletal muscle could be incorporated into new selection criteria for LDLT. Perioperative nutritional therapy and rehabilitation could be important for good outcomes after LDLT.