Discordant gene expression in subcutaneous adipose and skeletal muscle tissues in response to exercise training

Exercise has different effects on different tissues in the body, the sum of which may determine the response to exercise and the health benefits. In the present study, we aimed to investigate whether physical training regulates transcriptional network communites common to both skeletal muscle (SM) and subcutaneous adipose tissue (SAT). Eight such shared transcriptional communities were found in both tissues. Eighteen young overweight adults voluntarily participated in 7 weeks of combined strength and endurance training (five training sessions per week). Biopsies were taken from SM and SAT before and after training. Five of the network communities were regulated by training in SM but showed no change in SAT. One community involved in insulin- AMPK signaling and glucose utilization was upregulated in SM but downregulated in SAT. This diverging exercise regulation was confirmed in two independent studies and was also associated with BMI and diabetes in an independent cohort. Thus, the current finding is consistent with the differential responses of different tissues and suggests that body composition may influence the observed individual whole-body metabolic response to exercise training and help explain the observed attenuated whole-body insulin sensitivity after exercise training, even if it has significant effects on the exercising muscle.

A HIF-1 signature dominates the attenuation in the human skeletal muscle transcriptional response to high-intensity interval training

High-intensity interval training (HIIT) generates profound metabolic adaptations in skeletal muscle. These responses mirror performance improvements but follow a non-linear pattern comprised of an initial fast phase followed by a gradual plateau effect. The complete time-dependent molecular sequelae that regulates this plateau effect remains unknown. We hypothesize that the plateau effect during HIIT is restricted to specific pathways with communal upstream transcriptional regulation. To investigate this, eleven healthy men performed nine sessions of HIIT (10x4 minutes of cycling at 91 % of HR_max) over a 3-week period. Before and 3h after the 1^st and 9^th exercise bout, skeletal muscle biopsies were obtained, and RNA sequencing performed. Almost 2,000 genes across 84 pathways were differentially expressed in response to a single HIIT session. The overall transcriptional response to acute exercise was strikingly similar at 3 weeks, 83 % (n=1650) of the genes regulated after the 1^st bout of exercise were similarly regulated by the 9^th bout, albeit with a smaller effect size, and the response attenuated to on average 70 % of the 1^st bout. The attenuation differed substantially between pathways and was very pronounced for glycolysis and cellular adhesion but more preserved for MAPK and VEGF-A signalling. The attenuation was driven by a combination of changes in steady-state expression and specific transcriptional regulation. Given that the exercise intensity was progressively increased, and that the attenuation was pathway specific, we suggest that moderation of muscular adaptation after a period of training stems from targeted regulation rather than a diminished exercise stimulus.

The acute effect of metabolic cofactor supplementation: a potential therapeutic strategy against non-alcoholic fatty liver disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) continues to increase dramatically, and there is no approved medication for its treatment. Recently, we predicted the underlying molecular mechanisms involved in the progression of NAFLD using network analysis and identified metabolic cofactors that might be beneficial as supplements to decrease human liver fat. Here, we first assessed the tolerability of the combined metabolic cofactors including l-serine, N-acetyl-l-cysteine (NAC), nicotinamide riboside (NR), and l-carnitine by performing a 7-day rat toxicology study. Second, we performed a human calibration study by supplementing combined metabolic cofactors and a control study to study the kinetics of these metabolites in the plasma of healthy subjects with and without supplementation. We measured clinical parameters and observed no immediate side effects. Next, we generated plasma metabolomics and inflammatory protein markers data to reveal the acute changes associated with the supplementation of the metabolic cofactors. We also integrated metabolomics data using personalized genome-scale metabolic modeling and observed that such supplementation significantly affects the global human lipid, amino acid, and antioxidant metabolism. Finally, we predicted blood concentrations of these compounds during daily long-term supplementation by generating an ordinary differential equation model and liver concentrations of serine by generating a pharmacokinetic model and finally adjusted the doses of individual metabolic cofactors for future human clinical trials.

TCSBN: a database of tissue and cancer specific biological networks

Biological networks provide new opportunities for understanding the cellular biology in both health and disease states. We generated tissue specific integrated networks (INs) for liver, muscle and adipose tissues by integrating metabolic, regulatory and protein-protein interaction networks. We also generated human co-expression networks (CNs) for 46 normal tissues and 17 cancers to explore the functional relationships between genes as well as their relationships with biological functions, and investigate the overlap between functional and physical interactions provided by CNs and INs, respectively. These networks can be employed in the analysis of omics data, provide detailed insight into disease mechanisms by identifying the key biological components and eventually can be used in the development of efficient treatment strategies. Moreover, comparative analysis of the networks may allow for the identification of tissue-specific targets that can be used in the development of drugs with the minimum toxic effect to other human tissues. These context-specific INs and CNs are presented in an interactive website http://inetmodels.com without any limitation.

Plasma Proteomics Analysis Reveals Dysregulation of Complement Proteins and Inflammation in Acquired Obesity-A Study on Rare BMI-Discordant Monozygotic Twin Pairs

PURPOSE

The purpose of this study is to elucidate the effect of excess body weight and liver fat on the plasma proteome without interference from genetic variation.

EXPERIMENTAL DESIGN

The effect of excess body weight is assessed in young, healthy monozygotic twins from pairs discordant for body mass index (intrapair difference (Δ) in BMI > 3 kg m^-2 , n = 26) with untargeted LC-MS proteomics quantification. The effect of liver fat is interrogated via subgroup analysis of the BMI-discordant twin cohort: liver fat discordant pairs (Δliver fat > 2%, n = 12) and liver fat concordant pairs (Δliver fat < 2%, n = 14), measured by magnetic resonance spectroscopy.

RESULTS

Seventy-five proteins are differentially expressed, with significant enrichment for complement and inflammatory response pathways in the heavier co-twins. The complement dysregulation is found in obesity in both the liver fat subgroups. The complement and inflammatory proteins are significantly associated with adiposity measures, insulin resistance and impaired lipids.

CONCLUSIONS AND CLINICAL RELEVANCE

The early pathophysiological mechanisms in obesity are incompletely understood. It is shown that aberrant complement regulation in plasma is present in very early stages of clinically healthy obese persons, independently of liver fat and in the absence of genetic variation that typically confounds human studies.

Characterization of different fat depots in NAFLD using inflammation-associated proteome, lipidome and metabolome

Non-alcoholic fatty liver disease (NAFLD) is recognized as a liver manifestation of metabolic syndrome, accompanied with excessive fat accumulation in the liver and other vital organs. Ectopic fat accumulation was previously associated with negative effects at the systemic and local level in the human body. Thus, we aimed to identify and assess the predictive capability of novel potential metabolic biomarkers for ectopic fat depots in non-diabetic men with NAFLD, using the inflammation-associated proteome, lipidome and metabolome. Myocardial and hepatic triglycerides were measured with magnetic spectroscopy while function of left ventricle, pericardial and epicardial fat, subcutaneous and visceral adipose tissue were measured with magnetic resonance imaging. Measured ectopic fat depots were profiled and predicted using a Random Forest algorithm, and by estimating the Area Under the Receiver Operating Characteristic curves. We have identified distinct metabolic signatures of fat depots in the liver (TAG50:1, glutamate, diSM18:0 and CE20:3), pericardium (N-palmitoyl-sphinganine, HGF, diSM18:0, glutamate, and TNFSF14), epicardium (sphingomyelin, CE20:3, PC38:3 and TNFSF14), and myocardium (CE20:3, LAPTGF-β1, glutamate and glucose). Our analyses highlighted non-invasive biomarkers that accurately predict ectopic fat depots, and reflect their distinct metabolic signatures in subjects with NAFLD.

Transfusion of frozen thawed blood stored at -20 degrees C to -25 degrees C

OBJECTIVE

To determine the clinical efficacy of transfusion of frozen-thawed (FT) red cells using a 5-bag system for freezing (at -20 degrees C to -25 degrees C), storage and reconstitution.

DESIGN

A prospective, controlled, non-randomised clinical trial was undertaken with two groups of orthopaedic surgical patients. Nine patients received FT homologous blood and a control group of 10 patients received homologous blood stored in liquid form at 4 degrees C. Five transfusion-dependent patients with medical conditions were also studied.

OUTCOME

Thirty-three FT units were transfused without incident to 14 patients. In addition to clinical assessment, haematological and biochemical parameters were monitored after transfusion. There were no clinical side effects and laboratory data were consistent with those after recent surgery or for pre-existing medical conditions and subsequent blood transfusion. On the practical side certain technical difficulties were encountered which improved with experience.

CONCLUSIONS

One of the major advantages of the system is the 35-day shelf-life at 4 degrees C after reconstitution. This system has potential for pre-deposit autologous collection, especially where large volume replacement may be required.

Thrombotic thrombocytopenic purpura in four siblings

A family is described in which four members of a sibship of seven suffered from a hematologic and systemic disorder whcih has been fatal in three and has been proved at autopsy to have been fatal in three and has been proved at autopsy to have been thrombotic purpura. The fourth member has probably suffered the same disorder. The clinical laboratory and genetic features of the family are discussed at length. No cause of the disorder has been determined.