Corrigendum to "Metabolic dysfunctions promoted by AIN-93G standard diet compared with three obesity-inducing diets in C57BL/6J mice" [Curr. Res. Physiol. (2022) 436-444]

[This corrects the article DOI: 10.1016/j.crphys.2022.11.001.].

Metabolic dysfunctions promoted by AIN-93G standard diet compared with three obesity-inducing diets in C57BL/6J mice

Researchers from different fields have studied the causes of obesity and associated comorbidities, proposing ways to prevent and treat this condition by using a common animal model of obesity to create a profound energy imbalance in young adult rodents. However, to confirm the harmful effects of consuming a high-fat and hypercaloric diet, it is common to include normolipidic and normocaloric control groups in the experimental protocols. This study compared the effect of three experimental diets described in the literature - namely, a high-fat diet, a high-fat and high-sucrose diet, and a high-fat and high-fructose diet - to induce obesity in C57BL/6 J mice with the standard AIN-93G diet as a control. We hypothesize that the AIN diet formulation is not a good control in this type of experiment because this diet promotes weight gain and metabolic dysfunctions similar to the hypercaloric diet. The metabolic data of animals fed the AIN-93G diet were similar to those of the high-calorie groups (development of steatosis and hyperlipidemia). However, it is important to emphasize that the group fed a high-fat diet had a higher percentage of total fat (p = 0.0002) and abdominal fat (p = 0.013) compared to the other groups. Also, the high-fat group responded poorly to glucose and insulin tolerance tests, showing a picture of insulin resistance. As expected, the intake of the AIN-93G diet promotes metabolic alterations in the animals like the high-fat formulations. Therefore, although this diet continues to be used as the gold standard for growth and maintenance, it warrants a reassessment of its composition to minimize the metabolic changes observed in this study, thus updating its fitness as a normocaloric model of a standard rodent diet.

Investigation of the antioxidant and hypoglycemiant properties of Alibertia edulis (L.C. Rich.) A.C. Rich. leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Alibertia edulis (L.C. Rich.) A.C. Rich is a vegetable species used in Brazilian folk medicine due to it is putative hypoglycemiant effect but has never been pharmacologically investigated. It is popularly used for the control of diabetes, especially in the state of Mato Grosso, Brazil. Following confirmation of the antioxidant activity of A. edulis by Aquino et al. (2017), the aim of this study was to evaluate the effects of leaves of A. edulis aqueous extract (AEAE) on some biochemical parameters in mice fed a high-fat fed.

MATERIAL AND METHODS

Leaves of A. edulis were air-dried in an oven at 40 °C for 10 days and ground into a fine powder by mechanical milling. The AEAE was prepared by decoction (1:10 w/v) at 97 °C for 15 min, and later filtered and lyophilized. Preliminary phytochemical analysis of the AEAE has been already indetified the presence of caffeic acid, quercetin 3-rhamnosyl-(1 → 6)-galactoside and iridois ioxide, ferulic acid and rutin in decocted leaves (Aquino et al., 2017). In one experiment, the acute oral toxicity AEAE was evaluated at 2,000 mg/kg of body weight. The animals were observed periodically for 14 days. In second experiment, the animals were divided into four groups (n = 5): Control, AEAE 200, AEAE 400 mg/kg and positive control (Metformin 100 mg/kg). In a third experiment, animals were divided into: Control RC (standard diet) (n = 24) and Control HFF (high-fat fed) (n = 24) groups for induction of glucose intolerance. After eight weeks, they were further subdivided into six groups (n = 8 each) RC or HFF with or without AEAE at doses of 200 and 400 mg/kg (2-wk) treatments to assess glucose tolerance. Plasma indicators of glucose tolerance and liver damage, skeletal muscle expression of antioxidant enzymes, and expression of the antioxidant proteins of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and phosphorylated IKK were determined.

RESULTS

The HF-fed animals developed glucose intolerance which the AEAE failed to revert. Meanwhile, the AEAE treatment did lower the glucose levels in the normolipidic cohorts by virtue of its antioxidant property. It was also observed that the treatment with the AEAE reduced food intake negatively interfering weight accretion. Beyond that, the treatment with AEAE interfered in the SOD and catalase expression and inhibited phosphorylation of IKK thus suggesting that the observed hypoglycemiant power may be related to its known antioxidant potential. No sings of toxicity or hemolysis were detectaed at indicating that, at the concentrations evaluated, the extract was not toxic to normal cells.

CONCLUSION

The AEAE showed a hypoglycemiant effect in the normolipidic mice that received the control diet, but not in those that were made glucose-intolerant by consuming a high-fat fed. The extract also exhibited substantial protection against hemolysis and oxidative stress. Moreover, no signs of toxicity were evident at 2000 mg/kg of body weight.

Moderate intake of BCAA-rich protein improves glucose homeostasis in high-fat-fed mice

Notwithstanding the fact that dietary branched-chain amino acids (BCAAs) have been considered to be a cause of insulin resistance (IR), evidence indicates that BCAA-rich whey proteins (WPs) do not lead to IR in animals consuming high-fat (HF) diets and may instead improve glucose homeostasis. To address the role of BCAA-rich WP as dietary protein in IR and inflammatory response, we fed C57BL/6J mice either high-fat (HF) or low-fat (LF) diets formulated with moderate protein levels (13% w/w) of either WP or hydrolyzed WP (WPH) and compared them with casein (CAS) as a reference. The muscle and plasma free amino acid profiles, inflammatory parameters and glycemic homeostasis were examined. While the LF/CAS diet promoted the rise in triglycerides and inflammatory parameters, the HF/CAS induced typical IR responses and impaired biochemical parameters. No differences in plasma BCAAs were detected, but the HF/WPH diet led to a twofold increase in gastrocnemius muscle free amino acids, including BCAAs. In general, ingestion of WPH was effective at averting or attenuating the damage caused by both the LF and HF diets. No high concentrations of BCAAs in the plasma or signs of IR were found in those mice fed an HF diet along with the hydrolyzed whey proteins. It is concluded that consumption of BCAA-rich whey proteins, especially WPH, does not result in the development of IR.

The Step of Incorporation of Bacillus coagulans GBI-30 6086 Into "requeijão cremoso" Processed Cheese Does Not Affect Metabolic Homeostasis of Rats

Dairy product consumption is a common habit in Brazil. These products present a good matrix for probiotic incorporation. Thus, in this study the feasibility of producing a probiotic “requeijão cremoso” incorporated with Bacillus coagulans GBI-30 6086 in three different steps and its metabolic effect in an animal model for 2 weeks has been evaluated. Wistar adult health rats were randomized into one to five groups (n = 8 for each group): Control (C); “requeijão cremoso” without probiotic (RC); probiotic inoculated in the milk before pasteurization at 65°C/30 min (RPP); “requeijão cremoso” inoculated before the fusion step and consequently exposed to 90°C/5 min (RPF); and “requeijão cremoso” inoculated after fusion step, i.e., once the product temperature reached 50°C (RPAF). At the end of treatment, analysis of molecular markers of proteins of stress and antioxidant system, HSP 25, 60, 70 and 90, SOD and catalase were performed in the animals’ muscles by Western Blot technique. The HSP25, HSP90 and catalase levels of C, RPP, RPF, and RPAF were similar, indicating that the homeostasis remained unchanged. The incorporation of B. coagulans GBI-30 6086 in the “requeijão cremoso” was shown to be stable and the microorganism remained viable in all steps tested. The incorporation of the probiotic strain in the fusion stage facilitated the technological process, since it allowed a better homogenization of the product and did not affect the maintenance of the metabolic homeostasis of rats.

Novel process of hydration, followed by incubation and thermal processing, for high isoflavone bioconversion in soybeans

The potentially bioavailable aglyconic isoflavone content of soybeans was increased by a process based on the controlled hydration of whole beans, followed by an incubation step and cooking. For developing the process, the effects of three operation variables: temperature, intermittent soaking and incubation time on the isoflavone profile of the processed soybeans were assessed. By hydrating the whole beans under controlled conditions (54 °C; 15 rpm for a rotating soaking basket) and holding the beans for an appropriate incubation time, it was possible to substantially increase the total aglycone content from (μmol·10-2·g-1) ~5 in the raw, to ~95 in the processed soybean. A conventional thermal treatment (1 kg⋅cm-2, 5 min), necessary to attain the nutritional and sensory characteristics, produced additional hydrolysis of glucosides, accounting for extra 14% of total aglycone yield. The entire process avoided the need to grind the bean and permitted an overall 21.8-fold increase (per-mole basis) conversion of all forms of isoflavone glucosides to aglycones, particularly to the (S)-equol precursor, daidzein, and with minimal back-diffusion or leaching to the outside medium.

The Expression of and Preoperative Correlation between Heat-Shock Protein 70, EuroSCORE, and Lactate in Patients undergoing CABG with Cardiopulmonary Bypass

Objetive

Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) improved symptoms and increased survival and quality of life in patients with coronary artery disease. However, it should be the main cause of a complex organic systemic inflammatory response that greatly contributes to several postoperative adverse effects.

Methods

We aimed to evaluate heat-shock protein 70 (HSP 70) expression as a morbimortality predictor in patients with preserved ventricular function undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) and to determine their association with the lactate as a marker of tissue hypoperfusion and the EuroSCORE risk score. This is a prospective, observational study including 46 patients and occurring between May and July 2016. Patients without ventricular dysfunction undergoing myocardial revascularization with extracorporeal circulation were included. They were divided into (1) complicated and (2) uncomplicated postoperative evolution groups. EuroSCORE, lactate levels, and HSP 70 expression and their correlations were determined.

Results

Statistical analysis showed that the group with complicated evolution had higher EuroSCORE values than the other group. HSP 70 protein levels were significantly increased in the group with uncomplicated evolution and showed similar results. According to our results, HSP family proteins may be independent predictors of uncomplicated evolution in patients without ventricular dysfunction undergoing CABG with CPB.

Conclusion

HSP 70 should be a good discriminator and protection marker for complications in cardiac surgery.

Heat Shock Proteins: Protection and Potential Biomarkers for Ischemic Injury of Cardiomyocytes After Surgery

The heat shock proteins are endogenous proteins with the ability to act as molecular chaperones. Methods that provide cell protection by way of some damage can positively influence the results of surgery. The present review summarizes current knowledge concerning the cardioprotective role of the heat shock proteins as occurs in heart damage, including relevant information about the stresses that regulate the expression of these proteins and their potential role as biomarkers of heart disease.

Dietary Nutrients and Bioactive Substances Modulate Heat Shock Protein (HSP) Expression: A Review

Interest in the heat shock proteins (HSPs), as a natural physiological toolkit of living organisms, has ranged from their chaperone function in nascent proteins to the remedial role following cell stress. As part of the defence system, HSPs guarantee cell tolerance against a variety of stressors, including exercise, oxidative stress, hyper and hypothermia, hyper and hypoxia and improper diets. For the past couple of decades, research on functional foods has revealed a number of substances likely to trigger cell protection through mechanisms that involve the induction of HSP expression. This review will summarize the occurrence of the most easily inducible HSPs and describe the effects of dietary proteins, peptides, amino acids, probiotics, high-fat diets and other food-derived substances reported to induce HSP response in animals and humans studies. Future research may clarify the mechanisms and explore the usefulness of this natural alternative of defense and the modulating mechanism of each substance.

Partial nutrient characterization of arugula (rocket - Eruca sativa L.) and the effect of heat treatment on its lipoxidase activity

Abstract The objective of this work was to determine some key nutrients in arugula (or rocket) and the effect of heat treatment on its lipoxidase activity. The protein, lipid, carbohydrate, fibre, ash, fatty acid composition, α-tocopherol and carotenoid contents were determined. Due to its importance in lipid degradation, the lipoxidase activity was measured in the raw and cooked leaves. The composition was (% fresh mass): 2.5 protein, 0.3 lipids, 4.1 carbohydrates, 1.3 fibre and 1.8 ash. The lipid phase contained 6.2 mg of α-tocopherol, 5.3 mg of lutein and 3.2 mg of β-carotene. Arugula was found to be rich in α-linolenic acid (48% of the oil). The heat treatment was not sufficient to totally inactivate the lipoxidase activity.

Biotransformed citrus extract as a source of anti-inflammatory polyphenols: Effects in macrophages and adipocytes

Chronic non-communicable diseases such as obesity are preceded by increased macrophage infiltration in adipose tissue and greater secretion of pro-inflammatory cytokines. We evaluated the anti-inflammatory potential of Biotransformed extract, and two control extracts: In Natura and Autoclaved. The assays were performed using a cellular model with RAW264.7, 3T3-L1 cells, and RAW264.7 and 3T3-L1 co-culture. The innovation of the study was the use of Biotransformed extract, a unique phenolic extract of a bioprocessed citrus residue. LPS stimulated RAW264.7 cells treated with the Biotransformed extract exhibited lower secretion of TNF-α and NO and lower protein expression of NFκB. In RAW264.7 and 3T3-L1 co-culture, treatment with 1.0mg/mL of the Biotransformed extract reduced secretion of TNF-α (30.7%) and IL-6 (43.4%). Still, the Biotransformed extract caused higher increase in adiponectin in relation to control extracts. When the co-culture received a LPS stimulus, the Autoclaved extract at 1.0mg/mL reduced IL-6 and TNF-α concentrations, and raised adiponectin. However, it was noteworthy that the Biotransformed extract was also able to significantly reduce IL-6 concentration while the Natural extract was not. The Biotransformed citrus extract evaluated in this study showed anti-inflammatory activity in macrophages and in co-culture, indicating that bioprocess of citrus residue can contribute to new product development with anti-inflammatory potential.

Bioactivity of food peptides: biological response of rats to bovine milk whey peptides following acute exercise

Background: Several physiologically beneficial effects of consuming a whey protein hydrolysate (WPH) have been attributed to the greater availability of bioactive peptides.

Aims: The aim was to investigate the effect of four branched-chain amino acid- (BCAA-)containing dipeptides, present in WPH, on immune modulation, stimulation of HSP expression, muscle protein synthesis, glycogen content, satiety signals and the impact of these peptides on the plasma free amino acid profiles.

Methods: The animals were divided in groups: control (rest, without gavage), vehicle (water), L-isoleucyl-L-leucine (lle-Leu), L-leucyl-L-isoleucine (Leu-lle), L-valyl-Lleucine (Val-Leu), L-leucyl-L-valine (Leu-Val) and WPH. All animals were submitted to acute exercise, except for control.

Results: lle-Leu stimulated immune response, hepatic and muscle glycogen and HSP60 expression, whereas Leu-Val enhanced HSP90 expression. All dipeptides reduced glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, no changes were observed on leptin. All peptides inhibited NF-kB expression. The plasma amino acid time-course showed peptide-specific and isomer-specific metabolic features, including increases of the BCAAs.

Conclusion: The data indicate that lle-Leu was effective to attenuate immune-suppression exercise-induced, promoted glycogen content and stimulated anti-stress effect (HSP). Furthermore, Leu-Val increased HSP90, p-4EBP1, p-mTOR and p-AMPK expression. The data suggest the involvement of these peptides in various beneficial functions of WPH consumption.

Modulatory effects of arginine, glutamine and branched-chain amino acids on heat shock proteins, immunity and antioxidant response in exercised rats

Heat shock proteins (HSPs) are endogenous proteins whose function is to maintain the cell's tolerance to insult, including intense exercise.

Limonene reduces hyperalgesia induced by gp120 and cytokines by modulation of IL-1 β and protein expression in spinal cord of mice

AIMS

We have investigated the antihyperalgesic effects of limonene in mice that received intrathecal injection of gp120.

MAIN METHODS

Male Swiss mice received gp120, IL-1β or TNF-α intrathecally or sterile saline as a control. A mechanical sensitivity test was performed at 2 and 3h after the injection. Spinal cord and blood samples were isolated for protein quantification.

KEY FINDINGS

Intrathecal administration of gp120 increased mechanical sensitivity measured with an electronic Von Frey apparatus, at 2 and 3h after the injections. Limonene administered orally prior to gp120 administration significantly decreased this mechanical sensitivity at 3h after the gp120 injection. In addition, intrathecal injection of gp120 increased IL-1β and IL-10 in serum, and limonene prevented the ability of gp120 to increase these cytokines. Limonene also inhibited TNF-α and IL-1β-induced mechanical hyperalgesia. Western blot assay demonstrated limonene was capable of increasing SOD expression in the cytoplasm of cells from spinal cord at 4h after intrathecal IL-1β injection.

SIGNIFICANCE

These results demonstrate that gp120 causes mechanical hyperalgesia and a peripheral increase in IL-1β and IL-10, and that prior administration of limonene inhibits these changes. Also limonene modulates the activation of SOD expression in the spinal cord after spinal IL-1β application. The ability of limonene to inhibit the mechanical hyperalgesia induced by gp120, TNF-α and IL-1β emphasizes the anti-inflammatory action of limonene, specifically its ability to inhibit cytokine production and its consequences.

Assessment of antioxidant activity, lipid profile, general biochemical and immune system responses of Wistar rats fed with dairy dessert containing Lactobacillus acidophilus La-5

The viability and survival of Lactobacillus acidophilus La5 under in vitro simulated gastrointestinal in probiotic dairy dessert was assessed. In addition, the effects of regular consumption of the dessert (5g/day) on the lipid profile, immune system, and antioxidant/biochemical status of Wistar rats were also evaluated after 2weeks of treatment. Adequate counts of L. acidophilus La-5 were observed regards the viability and gastrointestinal conditions. The probiotic dairy dessert was efficient in reducing the LDL-cholesterol, triacylglycerol and increased the HDL-cholesterol in serum. Aspartate amino transferase, alanine aminotransferase, total protein, albumin, heat shock proteins, immune system responses, and blood-cells counts (monocyte, lymphocyte, neutrophil and leucocyte) were not affected (p>0.05) after 15days of treatment. Overall, the probiotic dairy dessert may be a viable alternative to enhance the blood lipid profile and could be used to improve the antioxidant defenses.

Green propolis modulates gut microbiota, reduces endotoxemia and expression of TLR4 pathway in mice fed a high-fat diet

Due to the various beneficial effects attributed to propolis, which include anti-inflammatory and anti-bacterial infection properties, the objective of the study was to evaluate the effect of propolis supplementation on the composition of the intestinal microbiota and its anti-inflammatory action. Forty male C57BL/6 mice were fed either a standard diet (control), a high-fat (HF) diet, or a high-fat diet supplemented with 0.2% crude propolis (HFP) for 2 or 5weeks prior to sacrifice. Blood samples were collected for the determination of lipopolysaccharide (LPS) and classical biochemical parameters. Expression of the TLR4 pathway in muscle, and DNA sequencing for the 16S rRNA of the gut microbiota were performed. The HF diet increased the proportion of the phylum Firmicutes and inflammatory biomarkers, while supplementation with propolis for five weeks rendered the microbiota profile nearly normal. Consistently with the above, the supplementation reduced levels of circulating LPS and down-regulated the TLR4 pathway and inflammatory cytokine expressions in muscle. Moreover, propolis improved such biochemical parameters as serum triacylglycerols and glucose levels. The data suggest that propolis supplementation reduces inflammatory response and endotoxemia by preventing dysbiosis in mice challenged with a high-fat diet.

Chia (Salvia hispanica L.) enhances HSP, PGC-1α expressions and improves glucose tolerance in diet-induced obese rats

OBJECTIVE

The aim of this study was to investigate the effects of chia seed and chia oil on heat shock protein (HSP) and related parameters in diet-induced obese rats.

METHODS

Animals were divided in six groups: control, high-fat and high-fructose diet (HFF), and HFF with chia seed or chia oil in short (6-wk) and long (12-wk) treatments. Plasma indicators of glucose tolerance and liver damage, skeletal muscle expression of antioxidant enzymes, and proteins controlling oxidative energy metabolism were determined. The limit of significance was set at P < 0.05.

RESULTS

The HFF diet induced glucose intolerance, insulin resistance, oxidative stress, and altered parameters related to obesity complications. The consumption of chia seed or chia oil did not reduce body weight gain or abdominal fat accumulation. However, chia seed and chia oil in both treatments improved glucose and insulin tolerance. Chia oil in both treatments induced expression of HSP70 and HSP25 in skeletal muscle. Short treatment with chia seed increased expression of HSP70, but not HSP25. Chia oil in both treatments restored superoxide dismutase and glutathione peroxidase expression. Extended treatment with chia seed and short treatment with chia oil restored peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression.

CONCLUSION

Chia oil restored the antioxidant system and induced the expression of a higher number of proteins than chia seed. The present study demonstrated new properties and molecular mechanisms associated with the beneficial effects of chia seed and chia oil consumption in diet-induced obese rats.

Influence of the composition of unripe genipap (Genipa americana L.) fruit on the formation of blue pigment

The physical and chemical characteristics of unripe genipap fruits and the proximate and amino acid compositions of the endocarp and mesocarp of the unripe fruits were determined, placing special emphasis on the possible role of the protein-amino acid fraction on the formation of the typical blue pigment of the matrix. The two parts of the fruit analyzed have low energy (49.88 kcal/100 g for mesocarp and 43.48 kcal/100 g for endocarp) and high fiber content (7.88 % for mesocarp and 16.76 % for endocarp). The endocarp showed protein content (3.19 %) five times higher than the mesocarp (0.62 %), which may explain in part the greater amounts of blue pigment formed in the endocarp when compared to the mesocarp. Furthermore, the pH found in mesocarp (4.49) and endocarp (5.21) is within the optimum range for the formation of the blue pigment. A significant color change (ΔE (*)  = 26.45) was observed in endocarp during its exposure to the air for 2 h. Free aspartic and glutamic acids and cystine were the predominant amino acids in the mesocarp, while glutamic and aspartic acids and leucine were predominant in the endocarp. According to the results, the formation of blue pigment does not cause any change in the amino acid composition.

Dietary supplement usage and motivation in Brazilian road runners

Background

The consumption of dietary supplements is highest among athletes and it can represent potential a health risk for consumers.

Objective

The aim of this study was to determine the prevalence of consumption of dietary supplements by road runners.

Methods

We interviewed 817 volunteers from four road races in the Brazilian running calendar. The sample consisted of 671 male and 146 female runners with a mean age of 37.9 ± 12.4 years.

Results

Of the sample, 28.33% reported having used some type of dietary supplement. The main motivation for this consumption is to increase in stamina and improve performance. The probability of consuming dietary supplements increased 4.67 times when the runners were guided by coaches. The consumption of supplements was strongly correlated (r = 0.97) with weekly running distance, and also highly correlated (r = 0.86) with the number of years the sport had been practiced. The longer the runner had practiced the sport, the higher the training volume and the greater the intake of supplements. The five most frequently cited reasons for consumption were: energy enhancement (29.5%), performance improvement (17.1%), increased level of endurance (10.3%), nutrient replacement (11.1%), and avoidance of fatigue (10.3%). About 30% of the consumers declared more than one reason for taking dietary supplements. The most consumed supplements were: carbohydrates (52.17%), vitamins (28.70%), and proteins (13.48%).

Conclusions

Supplement consumption by road runners in Brazil appeared to be guided by the energy boosting properties of the supplement, the influence of coaches, and the experience of the user. The amount of supplement intake seemed to be lower among road runners than for athletes of other sports. We recommend that coaches and nutritionists emphasise that a balanced diet can meet the needs of physically active people.

Intake of heat-expanded amaranth grain reverses endothelial dysfunction in hypercholesterolemic rabbits

Feeding amaranth grain to hypercholesterolemic rabbits showed the property of recovering the lost endothelial function even without removing the hypercholesterolemia-inducing diet. Results suggest an underlying protective effect.

Differential response of heat shock proteins to uphill and downhill exercise in heart, skeletal muscle, lung and kidney tissues

Running on a horizontal plane is known to increase the concentration of the stress biomarker heat-shock protein (HSP), but no comparison of the expression of HSP70 has yet been established between the uphill (predominantly concentric) and downhill (predominantly eccentric) muscle contractions exercise. The objective of the study was to investigate the relationships between eccentric and concentric contractions on the HSP70 response of the lung, kidney, gastrocnemius, soleus and heart. Twenty-four male Wistar weanling rats were divided into four groups: non-exercised and three different grades of treadmill exercise groups: horizontal, uphill (+7%) and downhill (-7% of inclination). At the optimal time-point of six hours after the exercise, serum uric acid, creatine kinase (CK) and lactate dehydrogenase (LDH) were determined by standard methods and HSP70 by the Western blot analysis. HSP70 responds differently to different types of running. For kidney, heart, soleus and gastrocnemius, the HSP70 expression increased, 230, 180, 150 and 120% respectively of the reference (horizontal). When the contraction was concentric (uphill) and compared to downhill the increase in response of HSP70 was greater in 80% for kidney, 75% for gastrocnemius, 60% for soleus and 280% for the heart. Uric acid was about 50% higher (0.64 ± 0.03 mg·dL(-1)) in the uphill group as compared to the horizontal or downhill groups. Similarly, the activities of serum CK and LDH were both 100% greater for both the uphill and downhill groups as compared to the horizontal group (2383 ± 253 and 647.00 ± 73 U/L, respectively). The responsiveness of HSP70 appeared to be quite different depending on the type of tissue, suggesting that the impact of exercise was not restricted to the muscles, but extended to the kidney tissue. The uphill exercise increases HSP70 beyond the eccentric type and the horizontal running was a lower HSP70 responsive stimulus. Key PointsExercise can induce increases in HSP70 in the lung, kidney and heart, and in the soleus and gastrocnemius muscles, probably due to systemic alterations such as hypoxia, increase in temperature and the production of free radicals.Predominantly concentric contractions (running uphill), seem to be the most efficient way of increasing the HSP70 concentrations in the different tissues, followed by eccentric contraction (downhill) and lastly the concentric-eccentric cycle (horizontal).The energy demand, already known to influence HSP70, appears not to be the only factor responsible for the response of these proteins, considering that for the kidney and the soleus muscle, downhill running was more efficient in raising the HSP70 response than horizontal running.Future research should explore the mechanisms by which the eccentric, concentric and eccentric-concentric contractions are capable of influencing the responses of the heat shock proteins, opening possibilities for increasing the levels of these proteins in desirable situations, such as to protect against excess free radicals or injuries.

Whey protein hydrolysate increases translocation of GLUT-4 to the plasma membrane independent of insulin in wistar rats

Whey protein (WP) and whey protein hydrolysate (WPH) have the recognized capacity to increase glycogen stores. The objective of this study was to verify if consuming WP and WPH could also increase the concentration of the glucose transporters GLUT-1 and GLUT-4 in the plasma membrane (PM) of the muscle cells of sedentary and exercised animals. Forty-eight Wistar rats were divided into 6 groups (n = 8 per group), were treated and fed with experimental diets for 9 days as follows: a) control casein (CAS); b) WP; c) WPH; d) CAS exercised; e) WP exercised; and f) WPH exercised. After the experimental period, the animals were sacrificed, muscle GLUT-1 and GLUT-4, p85, Akt and phosphorylated Akt were analyzed by western blotting, and the glycogen, blood amino acids, insulin levels and biochemical health indicators were analyzed using standard methods. Consumption of WPH significantly increased the concentrations of GLUT-4 in the PM and glycogen, whereas the GLUT-1 and insulin levels and the health indicators showed no alterations. The physical exercise associated with consumption of WPH had favorable effects on glucose transport into muscle. These results should encourage new studies dealing with the potential of both WP and WPH for the treatment or prevention of type II diabetes, a disease in which there is reduced translocation of GLUT-4 to the plasma membrane.

A dipeptide and an amino acid present in whey protein hydrolysate increase translocation of GLUT-4 to the plasma membrane in Wistar rats

Whey protein hydrolysate (WPH) is capable of increasing muscle glycogen reserves and of concentrating the glucose transporter in the plasma membrane (PM). The objective of this study was to determine which WPH components could modulate translocation of the glucose transporter GLUT-4 to the PM of animal skeletal muscle. Forty-nine animals were divided into 7 groups (n=7) and received by oral gavage 30% glucose plus 0.55 g/kg body mass of the following WPH components: (a) control; (b) WPH; (c) L-isoleucine; (d) L-leucine; (e) L-leucine plus L-isoleucine; (f) L-isoleucyl-L-leucine dipeptide; (g) L-leucyl-L-isoleucine dipeptide. After receiving these solutions, the animals were sacrificed and the GLUT-4 analysed by western blot. Additionally, glycogen, glycaemia, insulin and free amino acids were also determined by standard methods. Of the WPH components tested, the amino acid L-isoleucine and the peptide L-leucyl-L-isoleucine showed greater efficiency in translocating GLUT-4 to the PM and of increasing glucose capture by skeletal muscle.

Probiotic cheese attenuates exercise-induced immune suppression in Wistar rats

Intense physical activity results in a substantial volume of stress and hence a significant probability of immunosuppression in athletes, with milk proteins being, perhaps, the most recommended protein supplements. Consumption of a probiotic cheese can attenuate immune suppression induced by exhausting exercise in rats. A popular Brazilian fresh cheese (Minas Frescal cheese) containing Lactobacillus acidophilus LA14 and Bifidobacterium longum BL05 was fed for 2wk to adult Wistar rats, which then were brought to exhaustion on the treadmill. Two hours after exhaustion, the rats were killed and material was collected for the determination of serum uric acid, total and high-density lipoprotein cholesterol fraction, total protein, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, creatine kinase, and blood cell (monocyte, lymphocyte, neutrophil, and leukocyte) counts. Exercise was efficient in reducing lymphocyte counts, irrespective of the type of ingested cheese, but the decrease in the group fed the probiotic cheese was 22% compared with 48% in the animals fed regular cheese. Monocyte counts were unaltered in the rats fed probiotic cheese compared with a significant decrease in the rats fed the regular cheese. Most importantly, ingestion of the probiotic cheese resulted in a >100% increase in serum high-density lipoprotein cholesterol and a 50% decrease in triacylglycerols. We conclude that probiotic Minas Frescal cheese may be a viable alternative to enhance the immune system and could be used to prevent infections, particularly those related to the physical overexertion of athletes.

Whey protein hydrolysate enhances the exercise-induced heat shock protein (HSP70) response in rats

Whey protein has been suggested to be potential protective agent against various forms of stress. The heat shock protein HSP70 confers greater cellular tolerance against stressors. The present study evaluated the effects of whey protein intake on HSP70 expression. Forty-eight male Wistar rats were divided into sedentary and exercised groups, and each group was fed as a protein source casein (CAS), whey protein (WP) or whey protein hydrolysate (WPH) for 3weeks. Exercise on a treadmill was used as the source of stress in the animals from the exercised group. The results showed a larger increase in HSP70 expression in the soleus, gastrocnemius and lung of the WPH-fed rats than WP or casein-fed rats. HSP70 expression in the sedentary rats was very low, independent of the diet or tissue. Protein carbonyls were lower in the group that consumed WPH. These data suggest that the consumption of WPH enhances HSP70 expression.

Mineral inadequacy of oral diets offered to patients in a Brazilian hospital

INTRODUCTION

While enteral diets for hospitalized patients normally follow nutrient composition guidelines, more than 90% of hospitalized patients receive oral diets with unknown mineral composition.

OBJECTIVE

To evaluate the mineral contents and adequacy of three types of oral diets (regular, blend and soft) and complementary snacks offered to patients of a Brazilian hospital.

METHODS

The amount of minerals was determined in two non-consecutive days in duplicate samples of breakfast, collation, lunch, snack, dinner, supper and a complementary snack meal. Dietary Reference Intakes (DRIs) were used to determine the adequacy of the daily amounts served to patients.

RESULTS AND DISCUSSION

The regular diet met the RDA (Recommended Dietary Allowances) requirements only for Mn, P and Se, while the blend diet was deficient in Ca, K and Mg, and the soft diet met RDA requirements only for P and Zn. Iron was below the RDA requirement in all diets for women in fertile age, and Na was above the safe limit of intake (UL) in all the diets. The use of complementary snack was effective in meeting RDA requirements for Cu in the regular diet, and Mn and Se in the soft diet, but promoted overconsumption of Na.

CONCLUSIONS

Evident nutritional imbalances have been detected at a key interphase between nutrition and public health services, but a solution does not appear to be insurmountable. A permanent nutritional evaluation of hospital oral diets should be an integral part of routine health care in order to speed the recovery of the hospitalized patient and dispel eventual risks due to critical mineral imbalances.

Soapstone utensils may improve iron status in adult women. A preliminary study

Soapstone is among the first heat-resistant materials to have been used by man for the manufacture of culinary utensils, but its impact on human nutrition has merited little attention. Here, we present a preliminary evaluation of the impact of soapstone pans on the iron status in humans. Five nuns (37.6 +/- 6.31 y) replaced the soapstone for their traditional aluminum cookware, without any alteration of the diet itself. Comparison of the hematological data, determined before and 10 weeks after switching the pans, revealed that hemoglobin rose from 13.26 to 14.0 mg x dL(-1) (p = 0.0048), and hematocrit increased from 38.14 to 40.71% (p = 0.0002), while the transferrin saturation index went from 28.04 to 28.96% (p = 0.0147) and ferritin, from 31.5 to 34.74 microg x gL(-1) (p = 0.0681). By simply replacing the soapstone for the traditional aluminum cookware, substantially improved the iron status in all subjects in a relatively short period of time.

A food supplement of hydrolyzed collagen improves compositional and biodynamic characteristics of vertebrae in ovariectomized rats

Collagen hydrolysates (CHs) are mixtures of peptides obtained by partial hydrolysis of gelatins that are receiving scientific attention as potential oral supplements for the recovery of osteoarticular tissues. The effect of supplementing the diets with a CH was assessed in 48 ovariectomized rats by analyzing the compositional and biomechanical characteristics of the bone. Six groups of rats (three ovariectomized, one sham-operated, and two intact) were fed a standard diet, supplemented with either CH or gelatin (Control), at two levels: a dose equivalent to five times the amount suggested for humans (10 g/day) or another 10 times greater. After 8 weeks, the femora and vertebrae were excised, the blood was collected, and serum alkaline phosphatase and osteocalcin were determined. Bone weight, total protein, and biomechanical strength were also determined. The vertebrae of the ovariectomized group that received the higher dosage of CH withstood a load four times greater and exhibited higher levels of protein and osteocalcin content than those receiving either gelatin or no supplement. CH supplementation at the higher level in the ovariectomized rat had an unequivocal contribution in the conservation or preservation of vertebral mass, protein content, and mechanical strength not seen when gelatin was used as a supplement. Similar treatment of the intact rat with the CH, however, appeared to have the opposite effect.

Comparing the impact of chronic energy restriction and vitamin E supplementation on the behavior of adult rats

The purpose of this work was to investigate the influence of energy restriction and vitamin E supplementation on memory, learning, anxiety and spontaneous locomotion in adult rats. Three-month-old male Wistar rats were grouped according to diet: Control (AIN 93-M; n=18), Supplemented (AIN 93-M + 1425 IU all-rac-alpha-tocopheryl acetate/kg diet; n=22) and Restricted (AIN 93-M with 30% reduction in carbohydrate energy; n=23). Sixteen weeks after, the passive avoidance (PA), elevated plus-maze (EPM) and open field (OF) tests were applied. In the EPM test, the behavioral profile of the supplemented group was characterized by a lower frequency of entries into the open arms (P < 0,026), whereas the restricted group showed a lower frequency of head dipping (P < 0,003). The ratio between the time span of the shocks and the number of attempts were larger for the supplemented than for the non-supplemented animals (P = 0,0474), thus suggesting a delay in learning in the PA test. Taken together, these results suggest that a long-term combination of carbohydrate energy restriction in rats should not cause negative behavioral alterations. Compared with vitamin E supplementation, the restricted diet performed equally or better in rats as an alternate antioxidant diet.

Carbohydrate-energy restriction may protect the rat brain against oxidative damage and improve physical performance

Chronic energy restriction, alpha-tocopherol supplementation and their interaction with exhaustive exercise were investigated. Eleven-week-old male Wistar rats (n 6x 10) were fed either a control (C), a 30 % carbohydrate-energy-restricted control (R) or an alpha-tocopherol-supplemented (S) diet for 5 months. The animals in each diet were divided into exercised (E) and non-exercised (NE) groups. Before killing, the exercised rats were required to run to exhaustion (39 (se 6), 69 (se 11) and 18 (se 2) min for the C, R and S groups, respectively). Lipid peroxidation (thiobarbituric acid-reactive substances; TBARS), protein damage (reactive carbonyls) and alpha-tocopherol were determined in gastrocnemius, liver, brain and/or plasma. There was no difference in lipid peroxidation between the R and C groups, but in liver and muscle peroxidation appeared significantly lower in the S than the other two diets. TBARS in the brain were similar in all groups. On the other hand, reactive carbonyls showed that both the R and S diets reduced protein damage in the brain, while exhaustive exercise increased it. For liver and muscle, however, reactive carbonyl levels were similar in all groups. alpha-Tocopherol supplementation increased the vitamin concentrations in liver, muscle and plasma, but exercise decreased them in plasma and brain. Carbohydrate-energy restriction increased (P=0.0025) resistance to exhaustive exercise considerably without depleting stores of alpha-tocopherol or exacerbating oxidative damage in monitored tissues. It is concluded that while exhaustive exercise promotes a tissue-specific oxidative damage detectable only in brain proteins, both experimental diets tended to ameliorate this condition.

Soapstone (steatite) cookware as a source of minerals

Steatite or soapstone, is a soft metamorphic rock composed mainly of talc, dolomite and actinolite, which is abundantly found and used for the manufacture of cookware in south-east Brazil. The study estimates its usage for cookware among dwellers of Ouro Preto, and assesses the possible toxicological or nutritional impact on food preparation. Pans made of steatite were purchased both in the crude (n = 6) and 'cured'forms (n = 6). Migration of Ca, Fe, Mg, Mn, Co, Al, Cr, Ni, Pb and Cd was determined for 20 sequential cooking trials, using 3 and 5% acetic acid as a food simulant. Analytical determinations were carried out by inductively coupled plasma atomic-emission spectrometry and the data treated by an individual model of random effects, simple linear regression and Pearson's correlation. About 81% of Ouro Preto's native population own soapstone cookware and, of these, 79% use the pans regularly. Mineral migration followed the general solubility of the crystalline components of the rock. Therefore, Ca, Mg, Fe and Mn were, in that order, the elements that exhibited highest migration, whereas the remaining were seen in negligible levels, except for Ni in the crude pans. The 5% solution favoured migration, whereas curing tended to restrict migration and extend durability of the pan. It is concluded that while cured soapstone pans do not offer mineral toxicity, they may contribute to the mineral nutrition of human beings.