Development of Receptor for Advanced Glycation End Products (RAGE) ligands through target directed dynamic combinatorial chemistry: a novel class of possible antagonists.

RAGE is a transmembrane receptor of immunoglobulin family that can bind various endogenous and exogenous ligands, initiating the inflammatory downstream signaling pathways, including inflammaging. Therefore, RAGE represents an attractive drug target for age-related diseases. For the development of small-molecule RAGE antagonists, we employed protein-templated dynamic combinatorial chemistry (ptDCC) using RAGE's VC1 domain as a template, the first application of this approach in the context of RAGE. The affinities of DCC hits were validated using microscale thermophoresis. Subsequent screening against AGE2 (glyceraldehyde-modified AGE)-sRAGE (solubleRAGE) (AGE2-BSA/sRAGE) interaction using ELISA tests led to the identification of antagonists with micromolar potency. Our findings not only demonstrate the successful application of ptDCC on RAGE but also highlight its potential to address the pressing need for alternative strategies for the development of small-molecule RAGE antagonists, an area of research that has experienced a slowdown in recent years.

Hemolysis is associated with altered heparan sulfate of the endothelial glycocalyx and with local complement activation in thrombotic microangiopathies.

The complement system plays a key role in the pathophysiology of kidney thrombotic microangiopathies (TMA), as illustrated by atypical hemolytic uremic syndrome. But complement abnormalities are not the only drivers of TMA lesions. Among other potential pathophysiological actors, we hypothesized that alteration of heparan sulfate (HS) in the endothelial glycocalyx could be important. To evaluate this, we analyzed clinical and histological features of kidney biopsies from a monocentric, retrospective cohort of 72 patients with TMA, particularly for HS integrity and markers of local complement activation. The role of heme (a major product of hemolysis) as an HS-degrading agent in vitro, and the impact of altering endothelial cell (ECs) HS on their ability to locally activate complement were studied. Compared with a positive control, glomerular HS staining was lower in 57 (79%) patients with TMA, moderately reduced in 20 (28%), and strongly reduced in 37 (51%) of these 57 cases. Strongly reduced HS density was significantly associated with both hemolysis at the time of biopsy and local complement activation (C3 and/or C5b-9 deposits). Using primary endothelial cells (HUVECs, Glomerular ECs), we observed decreased HS expression after short-term exposure to heme, and that artificial HS degradation by exposure to heparinase was associated with local complement activation. Further, prolonged exposure to heme modulated expression of several key genes of glycocalyx metabolism involved in coagulation regulation (C5-EPI, HS6ST1, HS3ST1). Thus, our study highlights the impact of hemolysis on the integrity of endothelial HS, both in patients and in endothelial cell models. Hence, acute alteration of HS may be a mechanism of heme-induced complement activation.

Relevance of inflammatory and complement activation biomarkers profiling in antiphospholipid syndrome patients outside acute thrombosis.

OBJECTIVES: To evaluate whether inflammatory and complement biomarkers are associated with specific characteristics of antiphospholipid syndrome (APS). METHODS: Serum levels of interleukin (IL)-1ß (IL-1ß), IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, interferon-α (IFN)-α, IFN-γ, vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), E-selectin, and vascular cell adhesion molecule (VCAM)-1, and plasma levels of soluble C5b-9 (sC5b-9), C3a, C4a, Bb fragment were measured in unselected APS patients. Twenty-five healthy blood donors were included as controls. RESULTS: Between January 2020 and April 2021, 98 APS patients were included outside acute thrombosis (median time from the last APS manifestation: 60 (23;132) months). Levels of IL6, VCAM-1, sC5b-9, C3a, C4a, and Bb were significantly increased in APS patients compared to controls. A cluster analysis allowed to divide patients into two clusters: "inflammatory" (higher levels of IL-6 and VCAM-1) and "complement". In APS, elevated IL-6 was associated with hypertension, diabetes, BMI, and hypertriglyceridaemia. 85% of our APS patients had elevated levels of at least one complement biomarker. Elevated Bb (34%) was associated with aPL positivities, especially with triple aPL positivity (50% vs. 18%, p<0.001). 7/8 patients with history of catastrophic APS had elevated levels of complement biomarkers. CONCLUSIONS: Our findings suggested that APS patients outside acute thrombosis might be divided into two clusters: "inflammatory" and "complement". Elevated IL-6 was associated with cardiovascular risk factors and metabolic parameters, whereas Bb fragments, a marker of alternative pathway complement activation, was strongly associated with aPL profile at highest risk of severe disease.

Biomarkers of disease in human nails: a comprehensive review.

Diagnostic, monitoring, response, predictive, risk, and prognostic biomarkers of disease are all widely studied, for the most part in biological fluids or tissues, but there is steadily growing interest in alternative matrices such as nails. Here we comprehensively review studies dealing with molecular or elemental biomarkers of disease, as opposed to semiological, pharmacological, toxicological, or biomonitoring studies. Nails have a long history of use in medicine as indicators of pathological processes and have also been used extensively as a matrix for monitoring exposure to environmental pollution. Nail clippings are simple to collect noninvasively as well as to transport and store, and the matrix itself is relatively stable. Nails incorporate, and are influenced by, circulating molecules and elements over their several months of growth, and it is widely held that markers of biological processes will remain in the nail, even when their levels in blood have declined. Nails thus offer the possibility to not only look back into a subject's metabolic history but also to study biomarkers of processes that operate over a longer time scale such as the post-translational modification of proteins. Reports on ungual biomarkers of metabolic and endocrine diseases, cancer, and psychological and neurological disorders will be presented, and an overview of the sampling and analytical techniques provided.

The relationship between social deprivation and a frailty index of cumulative deficits in French middle-aged caregivers.

BACKGROUND: The Institut Pasteur de Lille, in the north of France, has implemented a large, multidisciplinary health check, which aims to identify frailty in middle-aged caregivers. We aimed to construct an adapted frailty index of cumulative deficit (FI-CD) and study the associated factors, in particular socioeconomic factors. METHODS: The cross-sectional study included caregivers aged 45 to 65. A 34-item FI-CD including deficits adapted to a middle-aged population (related to cognition and autonomy, dietetics, physical activity, comorbidities, functional signs, lab values and paraclinical examinations) was constructed in accordance with standard procedures. It was calculated as a ratio of deficits present out of the total number of possible deficits, giving a continuous score between 0 and 1. Scores > 0.25 and >  0.4 were classified as frailty and severe frailty, respectively. Univariate and multivariate associations were studied using linear regressions. RESULTS: One hundred and seventeen caregivers were included; among them, 111 were analyzed due to missing values. The mean FI-CD was 0.22 ± 0.08. Forty (36%) individuals were classified as frailty and three (2.7%) as severe frailty. In multivariate analysis, FI-CD was significantly associated with age (beta [95% confidence interval] = 0.005 [0.002; 0.009] per 1-year increase, p = 0.005) and social deprivation (beta = 0.054 [0.007; 0.102], p = 0.025). A significant interaction was observed between and age and social deprivation (p = 0.036). The adjusted relationship between FI-CD and age was beta = 0.010 [0.002; 0.019], p = 0.017 in precarious caregivers, and beta = 0.003 [- 0.001; 0.007], p = 0.19 in non-precarious caregivers. CONCLUSIONS: The study suggested that the 34-item FI-CD could have clinical utility in the management of middle-aged caregivers. Social deprivation appeared as an important factor associated with frailty, highlighting the importance of early care and social support for precarious caregivers.

Circulating biomarkers of nitric oxide bioactivity and impaired muscle vasoreactivity to exercise in adults with uncomplicated type 1 diabetes.

AIMS/HYPOTHESIS: Early compromised endothelial function challenges the ability of individuals with type 1 diabetes to perform normal physical exercise. The exact mechanisms underlying this vascular limitation remain unknown, but may involve either formation or metabolism of nitric oxide (NO), a major vasodilator, whose activity is known to be compromised by oxidative stress. METHODS: Muscle microvascular reactivity (near-infrared spectroscopy) to an incremental exhaustive bout of exercise was assessed in 22 adults with uncomplicated type 1 diabetes (HbA1c 64.5 ± 15.7 mmol/mol; 8.0 ± 1.4%) and in 21 healthy individuals (18-40 years of age). NO-related substrates/metabolites were also measured in the blood along with other vasoactive compounds and oxidative stress markers; measurements were taken at rest, at peak exercise and after 15 min of recovery. Demographic characteristics, body composition, smoking status and diet were comparable in both groups. RESULTS: Maximal oxygen uptake was impaired in individuals with type 1 diabetes compared with in healthy participants (35.6 ± 7.7 vs 39.6 ± 6.8 ml min-1 kg-1, p < 0.01) despite comparable levels of habitual physical activity (moderate to vigorous physical activity by accelerometery, 234.9 ± 160.0 vs 280.1 ± 114.9 min/week). Compared with non-diabetic participants, individuals with type 1 diabetes also displayed a blunted exercise-induced vasoreactivity (muscle blood volume at peak exercise as reflected by ∆ total haemoglobin, 2.03 ± 5.82 vs 5.33 ± 5.54 µmol/l; interaction 'exercise' × 'group', p < 0.05); this was accompanied by lower K+ concentration (p < 0.05), reduced plasma L-arginine (p < 0.05)-in particular when HbA1c was high (mean estimation: -4.0, p < 0.05)-and lower plasma urate levels (p < 0.01). Nonetheless, exhaustive exercise did not worsen lipid peroxidation or other oxidative stress biomarkers, and erythrocytic enzymatic antioxidant resources were mobilised to a comparable extent in both groups. Nitrite and total nitrosation products, which are potential alternative NO sources, were similarly unaltered. Graphical abstract CONCLUSIONS/INTERPRETATION: Participants with uncomplicated type 1 diabetes displayed reduced availability of L-arginine, the essential substrate for enzymatic nitric oxide synthesis, as well as lower levels of the major plasma antioxidant, urate. Lower urate levels may reflect a defect in the activity of xanthine oxidase, an enzyme capable of producing NO from nitrite under hypoxic conditions. Thus, both canonical and non-canonical NO production may be reduced. However, neither of these changes exacerbated exercise-induced oxidative stress. TRIAL REGISTRATION: clinicaltrials.gov NCT02051504.

Metabolic transit of dietary advanced glycation end-products - the case of NƐ-carboxymethyllysine.

The Maillard reaction, also called glycation, is one of the major chemical reactions responsible for most yellow-to-brown colors and aromas in cooked foods. This reaction between reducing sugars and amino functions on proteins affects not only the flavor of food, but also leads to the formation of an heterogenous group of structurally-modified amino acids. Some of these, known as "advanced glycation end products" (AGEs), have been found in both foods and human biological fluids, tissues and organs. Except for those that are formed over long periods in vivo at 37 °C, AGEs in the body originate from the digestion and absorption of dietary sources. A high or chronic exposure to dietary AGEs (dAGEs) is suspected as potentially detrimental to human health and studies in the field of food safety have begun to focus their attention on the metabolic transit of dAGEs. This review presents some important findings in this field, with a focus on NƐ-carboxymethyllysine, and presents the evidence for and against an association between intake of dAGEs and their presence in the body. New and promising avenues of research are described, and some future directions outlined.

Protein recycling and limb muscle recovery after critical illness in slow- and fast-twitch limb muscle.

An impaired capacity of muscle to regenerate after critical illness results in long-term functional disability. We previously described in a long-term rat peritonitis model that gastrocnemius displays near-normal histology whereas soleus demonstrates a necrotizing phenotype. We thus investigated the link between the necrotizing phenotype of critical illness myopathy and proteasome activity in these two limb muscles. We studied male Wistar rats that underwent an intraperitoneal injection of the fungal cell wall constituent zymosan or n-saline as a sham-treated control. Rats (n = 74) were killed at 2, 7, and 14 days postintervention with gastrocnemius and soleus muscle removed and studied ex vivo. Zymosan-treated animals displayed an initial reduction of body weight but a persistent decrease in mass of both lower hindlimb muscles. Zymosan increased chymotrypsin- and trypsin-like proteasome activities in gastrocnemius at days 2 and 7 but in soleus at day 2 only. Activated caspases-3 and -9, polyubiquitin proteins, and 14-kDa fragments of myofibrillar actin (proteasome substrates) remained persistently increased from day 2 to day 14 in soleus but not in gastrocnemius. These results suggest that a relative proteasome deficiency in soleus is associated with a necrotizing phenotype during long-term critical illness. Rescuing proteasome clearance may offer a potential therapeutic option to prevent long-term functional disability in critically ill patients.

The LepRdb/db mice model for studying glycation in the context of diabetes.

BACKGROUND: Early (furosine) and advanced (carboxymethyllysine, CML) products of glycation (AGEs) have been reported as increased in plasma, tissues, and organs of diabetic people, indicating a direct link between glycation and type 2 diabetes (T2D). While murine models present some of the characteristics observed in diabetic humans, their pertinence as models of glycation, particularly for T2D, remains poorly described. The aim of this study was to characterize and compare glycation in several organs of two commonly studied murine models of T2D using stable isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS). METHODS: Defining parameters of type 2 diabetes including body weight, fasting glycaemia, and glucose intolerance were measured in three different C57BL6 mouse models of T2D-the genetic LepRdb/db (db/db) model and two diet-induced obesity (DIO) models-and their respective controls. Furosine, free, and protein-bound CML were quantified in kidneys, lungs, heart, and liver by LC-MS/MS. RESULTS: The obesity, hyperglycaemia, and glucose intolerance in db/db mice was accompanied by an increase of furosine and protein-bound CML levels in all organs relative to controls. The DIO models took several months to become obese, exhibited less severe hyperglycaemia and glucose intolerance, while glycation products were not significantly different between these groups (with the exception of furosine in liver and CML in lungs). CONCLUSIONS: The db/db model better reflected the characteristics of human T2D compared with the DIO models and exhibited greater formation and accumulation of both furosine and protein-bound CML in all of the organs tested here.

The receptor for advanced glycation end-products (RAGE) is an important pattern recognition receptor (PRR) for inflammaging.

The receptor for advanced glycation end-products (RAGE) was initially characterized and named for its ability to bind to advanced glycation end-products (AGEs) that form upon the irreversible and non-enzymatic interaction between nucleophiles, such as lysine, and carbonyl compounds, such as reducing sugars. The concentrations of AGEs are known to increase in conditions such as diabetes, as well as during ageing. However, it is now widely accepted that RAGE binds with numerous ligands, many of which can be defined as pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). The interaction between RAGE and its ligands mainly results in a pro-inflammatory response, and can lead to stress events often favouring mitochondrial dysfunction or cellular senescence. Thus, RAGE should be considered as a pattern recognition receptor (PRR), similar to those that regulate innate immunity. Innate immunity itself plays a central role in inflammaging, the chronic low-grade and sterile inflammation that increases with age and is a potentially important contributory factor in ageing. Consequently, and in addition to the age-related accumulation of PAMPs and DAMPs and increases in pro-inflammatory cytokines from senescent cells and damaged cells, PRRs are therefore important in inflammaging. We suggest here that, through its interconnection with immunity, senescence, mitochondrial dysfunction and inflammasome activation, RAGE is a key contributor to inflammaging and that the pro-longevity effects seen upon blocking RAGE, or upon its deletion, are thus the result of reduced inflammaging.

Kidney, heart and brain: three organs targeted by ageing and glycation.

Advanced glycation end-product (AGE) is the generic term for a heterogeneous group of derivatives arising from a non-enzymatic reaction between reducing sugars and proteins. In recent years, evidence has accumulated that incriminates AGEs in pathogenic processes associated with both chronic hyperglycaemia and age-related diseases. Regardless of their exogenous or endogenous origin, the accumulation of AGEs and their derivatives could promote accelerated ageing by leading to protein modifications and activating several inflammatory signalling pathways via AGE-specific receptors. However, it remains to be demonstrated whether preventing the accumulation of AGEs and their effects is an important therapeutic option for successful ageing. The present review gives an overview of the current knowledge on the pathogenic role of AGEs by focusing on three AGE target organs: kidney, heart and brain. For each of these organs we concentrate on an age-related disease, each of which is a major public health issue: chronic kidney disease, heart dysfunction and neurodegenerative diseases. Even though strong connections have been highlighted between glycation and age-related pathogenesis, causal links still need to be validated. In each case, we report evidence and uncertainties suggested by animal or epidemiological studies on the possible link between pathogenesis and glycation in a chronic hyperglycaemic state, in the absence of diabetes, and with exogenous AGEs alone. Finally, we present some promising anti-AGE strategies that are currently being studied.

No increase in small-solute transport in peritoneal dialysis patients treated without hypertonic glucose for fifty-four months.

BACKGROUND: Glucose is widely used as an osmotic agent in peritoneal dialysis (PD), but exerts untoward effects on the peritoneum. The potential protective effect of a reduced exposure to hypertonic glucose has never been investigated. METHODS: The cohort of PD patients attending our center which tackled the challenge of a restricted use of hypertonic glucose solutions has been prospectively followed since 1992. Small-solute transport was assessed using an equivalent of the glucose peritoneal equilibration test after 6 months, and then every year. Study was stopped on July 1st, 2008, before use of biocompatible solutions. Repeated measures in patients treated with PD for 54 months were analyzed by using (1) the slopes of the linear regression for D4/D0 ratios over time computed for each individual, and (2) a linear mixed model. RESULTS: In the study period, 44 patients were treated for a total of 2376 months, 2058 without hypertonic glucose. There was one episode of peritoneal infection every 18 patient-months. The mean of slopes of the linear regression for D4/D0 ratios was found to be significantly positive (Student's test, p < .001) and the results of the mixed model reflected a similar significant increase for D4/D0 ratios over time. These results reflected a significant decrease of small-solute transport. CONCLUSION: In this large series, minimizing the use of hypertonic glucose solutions was associated in patients on long term PD with an overall decrease of small-solute transport within 54 months, despite a high rate of peritoneal infection.

Implication of advanced glycation end products (Ages) and their receptor (Rage) on myocardial contractile and mitochondrial functions.

Advanced glycation end products (AGEs) play an important role for the development and/or progression of cardiovascular diseases, mainly through induction of oxidative stress and inflammation. AGEs are a heterogeneous group of molecules formed by non-enzymatic reaction of reducing sugars with amino acids of proteins, lipids and nucleic acids. AGEs are mainly formed endogenously, while recent studies suggest that diet constitutes an important exogenous source of AGEs. The presence and accumulation of AGEs in various cardiac cell types affect extracellular and intracellular structure and function. AGEs contribute to a variety of microvascular and macrovascular complications through the formation of cross-links between molecules in the basement membrane of the extracellular matrix and by engaging the receptor for advanced glycation end products (RAGE). Activation of RAGE by AGEs causes up regulation of the transcription factor nuclear factor-κB and its target genes. of the RAGE engagement stimulates oxidative stress, evokes inflammatory and fibrotic reactions, which all contribute to the development and progression of devastating cardiovascular disorders. This review discusses potential targets of glycation in cardiac cells, and underlying mechanisms that lead to heart failure with special interest on AGE-induced mitochondrial dysfunction in the myocardium.

Abnormal Mitochondrial cAMP/PKA Signaling Is Involved in Sepsis-Induced Mitochondrial and Myocardial Dysfunction.

Adrenergic receptors couple to Gs-proteins leading to transmembrane adenylyl cyclase activation and cytosolic cyclic adenosine monophosphate (cAMP) production. Cyclic AMP is also produced in the mitochondrial matrix, where it regulates respiration through protein kinase A (PKA)-dependent phosphorylation of respiratory chain complexes. We hypothesized that a blunted mitochondrial cAMP-PKA pathway would participate in sepsis-induced heart dysfunction. Adult male mice were subjected to intra-abdominal sepsis. Mitochondrial respiration of cardiac fibers and myocardial contractile performance were evaluated in response to 8Br-cAMP, PKA inhibition (H89), soluble adenylyl cyclase inhibition (KH7), and phosphodiesterase inhibition (IBMX; BAY60-7550). Adenosine diphosphate (ADP)-stimulated respiratory rates of cardiac fibers were reduced in septic mice. Compared with controls, stimulatory effects of 8Br-cAMP on respiration rates were enhanced in septic fibers, whereas inhibitory effects of H89 were reduced. Ser-58 phosphorylation of cytochrome c oxidase subunit IV-1 was reduced in septic hearts. In vitro, incubation of septic cardiac fibers with BAY60-7550 increased respiratory control ratio and improved cardiac MVO2 efficiency in isolated septic heart. In vivo, BAY60-7550 pre-treatment of septic mice have limited impact on myocardial function. Mitochondrial cAMP-PKA signaling is impaired in the septic myocardium. PDE2 phosphodiesterase inhibition by BAY60-7550 improves mitochondrial respiration and cardiac MVO2 efficiency in septic mice.

Registration on the renal transplantation waiting list and mortality on dialysis: an analysis of the French REIN registry using a multi-state model.

BACKGROUND: Access to the renal transplantation (RT) waiting list depends on factors related to lower mortality rates and often occurs after dialysis initiation. The aim of the study was to use a flexible regression model to determine if registration on the RT waiting list is associated with mortality on dialysis, independent of the comorbidities associated with such registration. METHODS: Data from the French REIN registry on 7138 incident hemodialysis (HD) patients were analyzed. A multi-state model including four states ('HD, not wait-listed', 'HD, wait-listed', 'death', and 'RT') was used to estimate the effect of being wait-listed on the probability of death. RESULTS: During the study, 1392 (19.5%) patients were wait-listed. Of the 2954 deaths observed in the entire cohort during follow-up, 2921 (98.9%) were observed in the not wait-listed group compared with only 33 (1.1%) in the wait-listed group. In the multivariable analysis, the adjusted hazard ratio for death associated with non-registration on the waiting list was 3.52 (95% CI, 1.70-7.30). The risk factors for death identified for not wait-listed patients were not found to be significant risk factors for wait-listed patients, with the exception of age. CONCLUSIONS: The use of a multi-state model allowed a flexible analysis of mortality on dialysis. Patients who were not wait-listed had a much higher risk of death, regardless of co-morbidities associated with being wait-listed, and did not share the same risk factors of death as wait-listed patients. Registration on the waiting list should therefore be taken into account in survival analysis of patients on dialysis.

Glugacon-like peptide-2: broad receptor expression, limited therapeutic effect on intestinal inflammation and novel role in liver regeneration.

The glucagon-like peptide 2 (GLP-2) is an intestinotrophic hormone with growth promoting and anti-inflammatory actions. However, the full biological functions of GLP-2 and the localization of its receptor (GLP-2R) remain controversial. Among cell lines tested, the expression of GLP-2R transcript was detected in human colonic myofibroblasts (CCD-18Co) and in primary culture of rat enteric nervous system but not in intestinal epithelial cell lines, lymphocytes, monocytes, or endothelial cells. Surprisingly, GLP-2R was expressed in murine (GLUTag), but not human (NCI-H716) enteroendocrine cells. The screening of GLP-2R mRNA in mice organs revealed an increasing gradient of GLP-2R toward the distal gut. An unexpected expression was detected in the mesenteric fat, mesenteric lymph nodes, bladder, spleen, and liver, particularly in hepatocytes. In two mice models of trinitrobenzene sulfonic acid (TNBS)- and dextran sulfate sodium (DSS)-induced colitis, the colonic expression of GLP-2R mRNA was decreased by 60% compared with control mice. Also, GLP-2R mRNA was significantly downregulated in intestinal tissues of inflammatory bowel disease patients. Therapeutically, GLP-2 showed a weak restorative effect on intestinal inflammation during TNBS-induced colitis as assessed by macroscopic score and inflammatory markers. Finally, GLP-2 treatment accelerated mouse liver regeneration following partial hepatectomy as assessed by histological and molecular analyses. In conclusion, the limited therapeutic effect of GLP-2 on colonic inflammation dampens its utility in the management of severe inflammatory intestinal disorders. However, the role of GLP-2 in liver regeneration is a novelty that might introduce GLP-2 into the management of liver diseases and emphasizes on the importance of elucidating other extraintestinal functions of GLP-2.

Sepsis-like Energy Deficit Is Not Sufficient to Induce Early Muscle Fiber Atrophy and Mitochondrial Dysfunction in a Murine Sepsis Model.

Sepsis-induced myopathy is characterized by muscle fiber atrophy, mitochondrial dysfunction, and worsened outcomes. Whether whole-body energy deficit participates in the early alteration of skeletal muscle metabolism has never been investigated. Three groups were studied: "Sepsis" mice, fed ad libitum with a spontaneous decrease in caloric intake (n = 17), and "Sham" mice fed ad libitum (Sham fed (SF), n = 13) or subjected to pair-feeding (Sham pair fed (SPF), n = 12). Sepsis was induced by the intraperitoneal injection of cecal slurry in resuscitated C57BL6/J mice. The feeding of the SPF mice was restricted according to the food intake of the Sepsis mice. Energy balance was evaluated by indirect calorimetry over 24 h. The tibialis anterior cross-sectional area (TA CSA), mitochondrial function (high-resolution respirometry), and mitochondrial quality control pathways (RTqPCR and Western blot) were assessed 24 h after sepsis induction. The energy balance was positive in the SF group and negative in both the SPF and Sepsis groups. The TA CSA did not differ between the SF and SPF groups, but was reduced by 17% in the Sepsis group compared with the SPF group (p < 0.05). The complex-I-linked respiration in permeabilized soleus fibers was higher in the SPF group than the SF group (p < 0.05) and lower in the Sepsis group than the SPF group (p < 0.01). Pgc1α protein expression increased 3.9-fold in the SPF mice compared with the SF mice (p < 0.05) and remained unchanged in the Sepsis mice compared with the SPF mice; the Pgc1α mRNA expression decreased in the Sepsis compared with the SPF mice (p < 0.05). Thus, the sepsis-like energy deficit did not explain the early sepsis-induced muscle fiber atrophy and mitochondrial dysfunction, but led to specific metabolic adaptations not observed in sepsis.

Overestimation of the probability of death on peritoneal dialysis by the Kaplan-Meier method: advantages of a competing risks approach.

BACKGROUND: In survival analysis, patients on peritoneal dialysis are confronted with three different outcomes: transfer to hemodialysis, renal transplantation, or death. The Kaplan-Meier method takes into account one event only, so whether it adequately considers these different risks is questionable. The more recent competing risks method has been shown to be more appropriate in analyzing such situations. METHODS: We compared the estimations obtained by the Kaplan-Meier method and the competing risks method (namely the Kalbfleisch and Prentice approach), in 383 consecutive incident peritoneal dialysis patients. By means of simulations, we then compared the Kaplan-Meier estimations obtained in two virtual centers where patients had exactly the same probability of death. The only difference between these two virtual centers was whether renal transplantation was available or not. RESULTS: At five years, 107 (27.9%) patients had died, 109 (28.4%) had been transferred to hemodialysis, 91 (23.8%) had been transplanted, and 37 (9.7%) were still alive on peritoneal dialysis; before five years, 39 (10.2%) patients were censored alive on peritoneal dialysis. The five-year probabilities estimated by the Kaplan-Meier and the competing risks methods were respectively: death: 50% versus 30%; transfer to hemodialysis: 59% versus 32%; renal transplantation: 39% versus 26%; event-free survival: 12% versus 12%. The sum of the Kaplan-Meier estimations exceeded 100%, implying that patients could experience more than one event, death and transplantation for example, which is impossible. In the simulations, the probability of death estimated by the Kaplan-Meier method increased as the probability of renal transplantation increased, although the probability of death actually remained constant. CONCLUSION: The competing risks method appears more appropriate than the Kaplan-Meier method for estimating the probability of events in peritoneal dialysis in the context of univariable survival analysis.

Interconnections between Inflammageing and Immunosenescence during Ageing.

Acute inflammation is a physiological response to injury or infection, with a cascade of steps that ultimately lead to the recruitment of immune cells to clear invading pathogens and heal wounds. However, chronic inflammation arising from the continued presence of the initial trigger, or the dysfunction of signalling and/or effector pathways, is harmful to health. While successful ageing in older adults, including centenarians, is associated with low levels of inflammation, elevated inflammation increases the risk of poor health and death. Hence inflammation has been described as one of seven pillars of ageing. Age-associated sterile, chronic, and low-grade inflammation is commonly termed inflammageing-it is not simply a consequence of increasing chronological age, but is also a marker of biological ageing, multimorbidity, and mortality risk. While inflammageing was initially thought to be caused by "continuous antigenic load and stress", reports from the last two decades describe a much more complex phenomenon also involving cellular senescence and the ageing of the immune system. In this review, we explore some of the main sources and consequences of inflammageing in the context of immunosenescence and highlight potential interventions. In particular, we assess the contribution of cellular senescence to age-associated inflammation, identify patterns of pro- and anti-inflammatory markers characteristic of inflammageing, describe alterations in the ageing immune system that lead to elevated inflammation, and finally assess the ways that diet, exercise, and pharmacological interventions can reduce inflammageing and thus, improve later life health.

Supercritical fluid chromatography for separation of chiral planar metallocenes.

Unsymmetrically disubstituted metallocene derivatives, characterized as the first sandwich structure, have found interest in asymmetrical synthesis and in medicinal chemistry as well. Besides, they present a particular case of chirality. Twenty original and six commercially available molecules presenting either i) a planar chirality or ii) an asymmetrical carbon containing group or iii) being symmetrically substituted were analyzed in supercritical fluid chromatography on eleven polysaccharide-based chiral stationary phases with carbon dioxide containing 30% of methanol or 2-propanol as a co-solvent mobile phase. A basic additive, either diethylamine, triethylamine or n-butylamine was also required at 1% to the co-solvent for elution. While some of the tested chiral stationary phases provided enantioseparation for the racemates, chlorinated cellulosic phases proved to be both highly retentive and highly enantioselective towards these particular species with the highest rate of success compared to their non-chlorinated counterparts. For instance, the resolution value was equal to 14.1 for one ferrocene derivative in one-hour analysis time on cellulose tris(3,5-dichlorophenylcarbamate) column with 30% 2-propanol/1% n-butylamine while a single peak was observed under the same conditions on cellulose tris(3,5-dimethylphenylcarbamate) column. Experimental parameters were arbitrarily set at 150 bar outlet pressure, 40 °C temperature and 3 mL/min flow-rate.