Overall, RYGB produces greater and more predicted favourable changes in gut microbiota functional capacity than SG. An increase in Roseburia species was the only compositional change common to both types of surgery among those achieving diabetes remission.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder that displays pathological characteristics including senile plaques and neurofibrillary tangles. Metabolic defects are also present in AD-brain: for example, signs of deficient cerebral glucose uptake may occur decades before onset of cognitive dysfunction and tissue damage. There have been few systematic studies of the metabolite content of AD human brain, possibly due to scarcity of high-quality brain tissue and/or lack of reliable experimental methodologies. Here we sought to: 1) elucidate the molecular basis of metabolic defects in human AD-brain; and 2) identify endogenous metabolites that might guide new approaches for therapeutic intervention, diagnosis or monitoring of AD. Brains were obtained from nine cases with confirmed clinical/neuropathological AD and nine controls matched for age, sex and post-mortem delay. Metabolite levels were measured in post-mortem tissue from seven regions: three that undergo severe neuronal damage (hippocampus, entorhinal cortex and middle-temporal gyrus); three less severely affected (cingulate gyrus, sensory cortex and motor cortex); and one (cerebellum) that is relatively spared. We report a total of 55 metabolites that were altered in at least one AD-brain region, with different regions showing alterations in between 16 and 33 metabolites. Overall, we detected prominent global alterations in metabolites from several pathways involved in glucose clearance/utilization, the urea cycle, and amino-acid metabolism. The finding that potentially toxigenic molecular perturbations are widespread throughout all brain regions including the cerebellum is consistent with a global brain disease process rather than a localized effect of AD on regional brain metabolism.

Increased expression and labelling of collagen in IDCM samples indicates fibrosis may contribute to t-tubule remodelling in human heart failure.

Deoxycytidine kinase (dCK) catalyzes the rate-limiting step of the deoxynucleoside salvage pathway in mammalian cells and plays a key role in the activation of several pharmacologically important nucleoside analogs. Using a highly specific polyclonal antibody raised against a C-terminal peptide of the human dCK, we analyzed its subcellular localization by Western blots of biochemically fractionated nuclear and cytoplasmic fractions as well as by in situ immunochemistry. Native dCK was found to be located mainly in the cytoplasm in several cell types, and the enzyme was more concentrated in the perinuclear and cellular membrane area. In contrast, when dCK was overexpressed in the cells, it was mainly located in the nucleus. The results demonstrate that native dCK is a cytoplasmic enzyme. However, it has the ability to enter the nucleus under certain conditions, suggesting the existence of a cytoplasmic retention mechanism that may have an important function in the regulation of the deoxynucleoside salvage pathway.

Hypertension now affects about 600 million people worldwide and is a leading cause of death in the Western world. The spontaneously hypertensive rat (SHR), provides a useful model to investigate hypertensive heart failure (HF). The SHR model replicates the clinical progression of hypertension in humans, wherein early development of hypertension is followed by a long stable period of compensated cardiac hypertrophy that slowly progresses to HF. Although the hypertensive failing heart generally shows increased substrate preference towards glucose and impaired mitochondrial function, the cause-and-effect relationship between these characteristics is incompletely understood. To explore these pathogenic processes, we compared cardiac mitochondrial proteomes of 20-month-old SHR and Wistar-Kyoto controls by iTRAQ-labelling combined with multidimensional LC/MS/MS. Of 137 high-scoring proteins identified, 79 differed between groups. Changes were apparent in several metabolic pathways, chaperone and antioxidant systems, and multiple subunits of the oxidative phosphorylation complexes were increased (complexes I, III and IV) or decreased (complexes II and V) in SHR heart mitochondria. Respiration assays on skinned fibres and isolated mitochondria showed markedly lower respiratory capacity on succinate. Enzyme activity assays often also showed mismatches between increased protein expression and activities suggesting elevated protein expression may be compensatory in the face of pathological stress.

BackgroundBypass of foregut secreted factors promoting insulin resistance is hypothesized to be one of the mechanisms by which resolution of type 2 diabetes (T2D) follows roux-en-y gastric bypass (GBP) surgery.AimTo identify insulin resistance-associated proteins and metabolites which decrease more after GBP than after sleeve gastrectomy (SG) prior to diabetes remission.MethodsFasting plasma from 15 subjects with T2D undergoing GBP or SG was analyzed by proteomic and metabolomic methods 3 days before and 3 days after surgery. Subjects were matched for age, BMI, metformin therapy and glycemic control. Insulin resistance was calculated using homeostasis model assessment (HOMA-IR). For proteomics, samples were depleted of abundant plasma proteins, digested with trypsin and labeled with iTRAQ isobaric tags prior to liquid chromatography-tandem mass spectrometry analysis. Metabolomic analysis was performed using gas chromatography-mass spectrometry. The effect of the respective bariatric surgery on identified proteins and metabolites was evaluated using two-way analysis of variance and appropriate post-hoc tests.ResultsHOMA-IR improved, albeit not significantly, in both groups after surgery. Proteomic analysis yielded seven proteins which decreased significantly after GBP only, including Fetuin-A and Retinol binding protein 4, both previously linked to insulin resistance. Significant decrease in Fetuin-A and Retinol binding protein 4 after GBP was confirmed using ELISA and immunoassay. Metabolomic analysis identified significant decrease of citrate, proline, histidine and decanoic acid specifically after GBP.ConclusionGreater early decrease was seen for Fetuin-A, Retinol binding protein 4, and several metabolites after GBP compared to SG, preceding significant weight loss. This may contribute to enhanced T2D remission observed following foregut bypass procedures.

Diabetes now affects more than 5% of the world's population and heart failure is the most common cause of death amongst diabetic patients. Accumulating evidence supports a view that myocardial mitochondrial structural and functional changes are central to the onset of diabetic heart failure, but the exact nature of these changes at the proteomic level remains unclear.Here we report on proteomic changes in diabetic rat heart mitochondria following 120 days of streptozotocin-diabetes using the recently developed iTRAQ™ labeling method, which permits quantification of proteins directly from complex mixtures, bypassing the limitations associated with gel-based methods such as 2-DE. Of 252 unique proteins identified, 144 were represented in at least three of six individual paired experiments. Relative amounts of 65 proteins differed significantly between the groups, confirming that the cardiac mitochondrial proteome is indeed impacted by diabetes. The most significant changes were increased protein levels of enzymes involved in mitochondrial oxidation of long-chain fatty acids, which was also confirmed by enzyme assays, and decreased levels of multiple enzymes involved in oxidative phosphorylation and catabolism of short-chain fatty acids and branched-chain amino acids. We also found significant changes in levels of several enzymes linked to oxidative stress.

Biologically active factors produced by the intestine and transported by the aqueous and protein fraction of mesenteric lymph are now thought to contribute significantly to the development of distant organ failure in hemorrhagic shock. Despite the likely relevance of the protein composition of mesenteric lymph conditioned by hemorrhagic shock, there is no detailed description of its proteome. The aim of this study was to provide the first comprehensive description of the proteome of hemorrhagic shock-conditioned mesenteric lymph. Mesenteric lymph was collected from 16 male Wistar rats randomized to group 1 (n = 8) sham control and group 2 (n = 8) with hemorrhagic shock. The lymph was subjected to proteomic analysis using iTRAQ and liquid chromatography-tandem mass spectrometry. Sixty of the 245 proteins had a significant increase in their relative abundance in the hemorrhagic shock group. A bioinformatics approach highlighted the importance of the key gene ontology pathways relating to response to injury and metabolic responses as changing most significantly in shock. Using an interactome, we identified several highly connected proteins: 14-3-3 Zeta, 14-3-3 epsilon, actin, aldolase A, calmodulin, cofilin 1, cystatin C, fatty acid-binding protein 4, profilin 1, prolyl 4-hydrolase, peptidylprolyl isomerase, and transgelin. This study provides the first detailed description of protein changes in hemorrhagic shock-conditioned mesenteric lymph, and using a bioinformatics approach, we identified several targets for possible further research.