Very high intact-protein formula successfully provides protein intake according to nutritional recommendations in overweight critically ill patients: a double-blind randomized trial.

BACKGROUND: Optimal energy and protein provision through enteral nutrition is essential for critically ill patients. However, in clinical practice, the intake achieved is often far below the recommended targets. Because no polymeric formula with sufficient protein content is available, adequate protein intake can be achieved only by supplemental amino acids or semi-elemental formula administration. In the present study, we investigated whether protein intake can be increased with a new, very high intact-protein formula (VHPF) for enteral feeding. METHODS: In this randomized, controlled, double-blind, multicenter trial, 44 overweight (body mass index ≥ 25 kg/m2) intensive care unit patients received either a VHPF (8 g/100 kcal) or a commercially available standard high protein formula (SHPF) (5 g/100 kcal). Protein and energy intake, gastrointestinal tolerance (gastric residual volume, vomiting, diarrhea, and constipation), adverse events, and serious adverse events were recorded. Total serum amino acid levels were measured at baseline and day 5. RESULTS: The primary outcome, protein intake at day 5, was 1.49 g/kg body weight (95% CI 1.21-1.78) and 0.76 g/kg body weight (95% CI 0.49-1.03, P < 0.001) for VHPF and SHPF, respectively. Daily protein intake was statistically significantly higher in the VHPF group compared with the SHPF group from day 2 to day 10. Protein intake in the VHPF group as a percentage of target (1.5 g/kg ideal body weight) was 74.7% (IQR 53.2-87.6%) and 111.6% (IQR 51.7-130.7%) during days 1-3 and days 4-10, respectively. Serum amino acid concentrations were higher at day 5 in the VHPF group than in the SHPF group (P = 0.031). No differences were found in energy intake, measures of gastrointestinal tolerance, and safety. CONCLUSIONS: Enteral feeding with VHPF (8 g/100 kcal) resulted in higher protein intake and plasma amino acid concentrations than an isocaloric SHPF (5 g/100 kcal), without an increase in energy intake. This VHPF facilitates feeding according to nutritional guidelines and is suitable as a first-line nutritional treatment for critically ill overweight patients. TRIAL REGISTRATION: Netherlands Trial Register, NTR5643 . Registered on 2 February 2016.

The embryonic genes Dkk3, Hoxd8, Hoxd9 and Tbx1 identify muscle types in a diet-independent and fiber-type unrelated way.

BACKGROUND: The mouse skeletal muscle is composed of four distinct fiber types that differ in contractile function, number of mitochondria and metabolism. Every muscle type has a specific composition and distribution of the four fiber types. To find novel genes involved in specifying muscle types, we used microarray analysis to compare the gastrocnemius with the quadriceps from mice fed a low fat diet (LFD) or high fat diet (HFD) for 8 weeks. Additional qPCR analysis were performed in the gastrocnemius, quadriceps and soleus muscle from mice fed an LFD or HFD for 20 weeks. RESULTS: In mice fed the 8-week LFD 162 genes were differentially expressed in the gastrocnemius vs. the quadriceps. Genes with the strongest differences in expression were markers for oxidative fiber types (e.g. Tnni1) and genes which are known to be involved in embryogenesis (Dkk3, Hoxd8,Hoxd9 and Tbx1). Also Dkk2, Hoxa5, Hoxa10, Hoxc9, Hoxc10, Hoxc6 and Tbx15 were detectably, but not differentially expressed in adult muscle tissue. Expression of differentially expressed genes was not influenced by an 8-week or 20-week HFD. Comparing gastrocnemius, quadriceps and soleus, expression of Hoxd8 and Hoxd9 was not related with expression of markers for the four different fiber types. We found that the expression of both Hoxd8 and Hoxd9 was much higher in the gastrocnemius than in the quadriceps or soleus, whereas the expression of Dkk3 was high in quadriceps, but low in both gastrocnemius and soleus. Finally, expression of Tbx1 was high in quadriceps, intermediate in soleus and low in gastrocnemius. CONCLUSIONS: We found that genes from the Dkk family, Hox family and Tbx family are detectably expressed in adult mouse muscle. Interestingly, expression of Dkk3, Hoxd8, Hoxd9 and Tbx1 was highly different between gastrocnemius, quadriceps and soleus. In fact, every muscle type showed a unique combination of expression of these four genes which was not influenced by diet. Altogether, we conclude that genes important for embryogenesis identify mouse muscle types in a diet-independent and fiber type-unrelated manner.

Adipophilin protein expression in muscle--a possible protective role against insulin resistance.

Adipophilin is a 50 kDa protein that belongs to the PAT family (perilipin, adipophilin, TIP47, S3-12 and OXPAT), which comprises proteins involved in the coating of lipid droplets. Little is known about the functional role of adipophilin in muscle. Using the C2C12 cell line as a model, we demonstrate that palmitic acid-treated cells highly express the adipophilin protein in a dose-dependent way. Next, we show that oleic acid is a more potent inducer of adipophilin protein levels than palmitic acid. Cells treated with oleic acid have a higher adipophilin protein expression and higher triglyceride levels but less impairment of insulin signaling than cells treated with palmitic acid. Additionally, we show that peroxisome proliferator-activated receptor (PPAR)alpha, PPARbeta/delta and PPARgamma agonists all increase the expression of the adipophilin protein in C2C12 cells. This effect was most pronounced for the PPARalpha agonist GW7647. Furthermore, the expression of adipophilin as a 37 kDa N-terminally truncated protein is higher in the gastrocnemius than in the quadriceps of C57BL/6J mice, especially after an 8-week high-fat diet. The expression of adipophilin was higher in the muscle of mice fed a 4-week high-fat diet based on olive oil or safflower oil than in mice fed a 4-week high-fat diet based on palm oil. After 2 weeks of intervention, plasma glucose, plasma insulin and the homeostasis model assessment of insulin resistance index were lower in mice fed a 4-week high-fat diet based on olive oil or safflower oil than in mice fed a 4-week high-fat diet based on palm oil. Taken together, the results obtained in the present study indicate that adipophilin protein expression in muscle is involved in maintaining insulin sensitivity.

An 8-week high-fat diet induces obesity and insulin resistance with small changes in the muscle transcriptome of C57BL/6J mice.

BACKGROUND: Skeletal muscle is responsible for most of the insulin-stimulated glucose uptake and metabolism. Therefore, it plays an important role in the development of insulin resistance, one of the characteristics of the metabolic syndrome (MS). As the prevalence of the MS is increasing, there is an urgent need for more effective intervention strategies. METHODS: C57BL/6J mice were fed an 8-week low-fat diet (10 kcal%; LFD) or high-fat diet (45 kcal%; HFD). Microarray analysis was performed by using two comparisons: (1) 8-week HFD transcriptome versus 8-week LFD transcriptome and (2) transcriptome of mice sacrificed at the start of the intervention versus 8-week LFD transcriptome and 8-week HFD transcriptome, respectively. RESULTS: Although an 8-week HFD induced obesity and impaired insulin sensitivity, HFD-responsive changes in the muscle transcriptome were relatively small (<1.3-fold). In fact, 8-weeks of aging induced more pronounced changes than an HFD. One comparison revealed the transcriptional downregulation of the mito- gen-activated protein kinase cascade, whereas both comparisons showed the upregulation of fatty acid oxidation, demonstrating that the two comparison strategies are confirmative as well as complementary. CONCLUSION: We suggest using complementary analysis strategies in the genome-wide search for gene expression changes induced by mild interventions, such as an HFD.

Short-term high fat-feeding results in morphological and metabolic adaptations in the skeletal muscle of C57BL/6J mice.

The prevalence of the metabolic syndrome (MS) is rapidly increasing all over the world. Consequently, there is an urgent need for more effective intervention strategies. Both animal and human studies indicate that lipid oversupply to skeletal muscle can result in insulin resistance, which is one of the characteristics of the MS. C57BL/6J mice were fed a low-fat (10 kcal%) palm oil diet or a high-fat (45 kcal%; HF) palm oil diet for 3 or 28 days. By combining transcriptomics with protein and lipid analyses we aimed to better understand the molecular events underlying the early onset of the MS. Short-term HF feeding led to altered expression levels of genes involved in a variety of biological processes including morphogenesis, energy metabolism, lipogenesis, and immune function. Protein analysis showed increased levels of the myosin heavy chain, slow fiber type protein, and the complexes I, II, III, IV, and V of the oxidative phosphorylation. Furthermore, we observed that the main mitochondrial membrane phospholipids, phosphatidylcholine and phosphatidylethanolamine, contained more saturated fatty acids. Altogether, these results point to a morphological as well as a metabolic adaptation by promoting a more oxidative fiber type. We hypothesize that after this early positive adaptation, a continued transcriptional downregulation of genes involved in oxidative phosphorylation will result in decreased oxidative capacity at a later stage. Together with increased saturation of phospholipids of the mitochondrial membrane this can result in decreased mitochondrial function, which is a hallmark observed in insulin resistance and Type 2 diabetes.