-
1.
Lipid Metabolism Links Nutrient-Exercise Timing to Insulin Sensitivity in Men Classified as Overweight or Obese.
Edinburgh, RM, Bradley, HE, Abdullah, NF, Robinson, SL, Chrzanowski-Smith, OJ, Walhin, JP, Joanisse, S, Manolopoulos, KN, Philp, A, Hengist, A, et al
The Journal of clinical endocrinology and metabolism. 2020;105(3)
-
-
-
Free full text
-
Plain language summary
Following exercise, various metabolic changes occur which may be of benefit in fighting diseases such as type 2 diabetes and obesity. However, the degree of change may vary depending on whether the exercise has been performed pre or post meal consumption. This 6-week randomised crossover trial of 30 overweight or obese men aimed to determine the effect of exercising before or after breakfast on the use of fats and sugars by the body. The results showed that exercise before breakfast increased fat and sugar use in the body and also resulted in the alteration of eight genes associated with metabolism. Exercise before carbohydrate consumption also increased lipid use and improved insulin sensitivity, however body composition was similar regardless of when exercise was performed. It was concluded that exercising in the fasted state can optimise the body’s response without having to change intensity or effort. This study could be used by health care professionals to advise patients with obesity or overweight that exercising whilst in the fasted state could optimise their outcomes without having to increase exercise intensity or frequency.
Abstract
CONTEXT Pre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. OBJECTIVE To assess acute and chronic effects of exercise performed before versus after nutrient ingestion on whole-body and intramuscular lipid utilization and postprandial glucose metabolism. DESIGN (1) Acute, randomized, crossover design (Acute Study); (2) 6-week, randomized, controlled design (Training Study). SETTING General community. PARTICIPANTS Men with overweight/obesity (mean ± standard deviation, body mass index: 30.2 ± 3.5 kg⋅m-2 for Acute Study, 30.9 ± 4.5 kg⋅m-2 for Training Study). INTERVENTIONS Moderate-intensity cycling performed before versus after mixed-macronutrient breakfast (Acute Study) or carbohydrate (Training Study) ingestion. RESULTS Acute Study-exercise before versus after breakfast consumption increased net intramuscular lipid utilization in type I (net change: -3.44 ± 2.63% versus 1.44 ± 4.18% area lipid staining, P < 0.01) and type II fibers (-1.89 ± 2.48% versus 1.83 ± 1.92% area lipid staining, P < 0.05). Training Study-postprandial glycemia was not differentially affected by 6 weeks of exercise training performed before versus after carbohydrate intake (P > 0.05). However, postprandial insulinemia was reduced with exercise training performed before but not after carbohydrate ingestion (P = 0.03). This resulted in increased oral glucose insulin sensitivity (25 ± 38 vs -21 ± 32 mL⋅min-1⋅m-2; P = 0.01), associated with increased lipid utilization during exercise (r = 0.50, P = 0.02). Regular exercise before nutrient provision also augmented remodeling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (P < 0.05). CONCLUSIONS Experiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed before versus after nutrient intake (ie, in the fasted state) may exert beneficial effects on lipid utilization and reduce postprandial insulinemia.
-
2.
Metabolic impact of weight loss induced reduction of adipose ACE-2 - Potential implication in COVID-19 infections?
Li, L, Spranger, L, Soll, D, Beer, F, Brachs, M, Spranger, J, Mai, K
Metabolism: clinical and experimental. 2020;113:154401
-
-
-
Free full text
-
Plain language summary
Obesity is now recognised as a risk factor for increased severity of Covid-19 infections. ACE-2 is a protein that has many functions but also allows Covid-19 into cells and is particularly evident in body tissues, which store fat. It is therefore possible that Covid-19 will target fat-storing tissues in the body. This 12-month randomised control weight-loss intervention study of 143 obese individuals aimed to determine ACE-2 expression and whether it could be modified by weight loss. The results showed that ACE-2 was only present in fat storing tissue and not muscle tissue. Interestingly individuals with pre-diabetes or diabetes had the lowest levels of ACE-2. Weight loss resulted in reduced ACE-2 in fat storing tissue, which resulted in an improvement in markers for diabetes. It was concluded that reduction of ACE-2 in fat storing tissues as a result of weight loss can improve markers for diabetes and could impact the severity of Covid-19 infection. Healthcare professionals could use this study to understand how weight loss in patients with obesity could decrease their risk of severe Covid-19 infection.
Abstract
BACKGROUND & AIMS Angiotensin converting enzyme (ACE)-2 is a modulator of adipose tissue metabolism. However, human data of adipose ACE-2 is rarely available. Considering that, ACE-2 is believed to be the receptor responsible for cell entry of SARS-CoV-2, a better understanding of its regulation is desirable. We therefore characterized the modulation of subcutaneous adipose ACE-2 mRNA expression during weight loss and the impact of ACE-2 expression on weight loss induced short- and long-term improvements of glucose metabolism. METHODS 143 subjects (age > 18; BMI ≥ 27 kg/m2) were analyzed before and after a standardized 12-week dietary weight reduction program. Afterwards subjects were randomized to a 12-month lifestyle intervention or a control group (Maintain-Adults trial). Insulin sensitivity (IS) was estimated by HOMA-IR (as an estimate of liver IS) and ISIClamp (as an estimate of skeletal muscle IS). ACE-2 mRNA expression (ACE-2AT) was measured in subcutaneous adipose tissue before and after weight loss. RESULTS ACE-2AT was not affected by obesity, but was reduced in insulin resistant subjects. Weight loss resulted in a decline of ACE-2AT (29.0 (20.0-47.9) vs. 21.0 (13.0-31.0); p = 1.6 ∗ 10-7). A smaller reduction of ACE-2 AT (ΔACE-2AT) was associated with a larger improvement of ISIClamp (p = 0.013) during weight reduction over 3 months, but not with the extend of weight loss. The degree of changes in insulin resistance were preserved until month 12 and was also predicted by the weight loss induced degree of ΔACE-2AT (p = 0.011). CONCLUSIONS Our data indicate that subcutaneous adipose ACE-2 expression correlates with insulin sensitivity. Weight loss induced decline of subcutaneous adipose ACE-2 expression might affect short- and long-term improvement of myocellular insulin sensitivity, which might be also relevant in the context of ACE-2 downregulation by SARS-CoV-2. TRIAL REGISTRATION ClinicalTrials.gov number: NCT00850629, https://clinicaltrials.gov/ct2/show/NCT00850629, date of registration: February 25, 2009.
-
3.
Effect of inorganic nitrate on exercise capacity, mitochondria respiration, and vascular function in heart failure with reduced ejection fraction.
Woessner, MN, Neil, C, Saner, NJ, Goodman, CA, McIlvenna, LC, Ortiz de Zevallos, J, Garnham, A, Levinger, I, Allen, JD
Journal of applied physiology (Bethesda, Md. : 1985). 2020;128(5):1355-1364
-
-
-
Free full text
Plain language summary
Patients with chronic heart failure (CHF) are characterised by reduced aerobic capacity (V ̇O2peak) and early fatigue. Improving V ̇O2peak is an important clinical goal in CHF as it is correlated with reduced mortality rate and increased quality of life. The main aim of this study was to test the hypothesis that chronic oral inorganic nitrate supplementation will improve V ̇O2peak during treadmill exercise in patients with heart failure with reduced ejection fraction (HFrEF). This study is a randomised, placebo-controlled, double-blind, crossover study. Nineteen participants were recruited, and 16 individuals with diagnosed HFrEF completed the study. Participants were randomised to consume either nitrate-rich beetroot juice (210 mL, 16 mmol nitrate) or a nitrate-depleted placebo for 5 days. Results show that in patients with HFrEF, chronic oral inorganic nitrate supplementation had no significant effect on aerobic exercise capacity, vascular function, peripheral and central blood pressures, or muscle respiration. Authors conclude that future studies should characterise the diversity and abundance of the oral microbiome in HFrEF to elucidate approaches that could lead to a potential benefit of oral nitrate supplementation.
Abstract
Chronic underperfusion of the skeletal muscle tissues is a contributor to a decrease in exercise capacity in patients with heart failure with reduced ejection fraction (HFrEF). This underperfusion is due, at least in part, to impaired nitric oxide (NO) bioavailability. Oral inorganic nitrate supplementation increases NO bioavailability and may be used to improve exercise capacity, vascular function, and mitochondrial respiration. Sixteen patients with HFrEF (fifteen men, 63 ± 4 yr, body mass index: 31.8 ± 2.1 kg/m2) participated in a randomized, double-blind, crossover design study. Following consumption of either nitrate-rich beetroot juice (16 mmol nitrate/day) or a nitrate-depleted placebo for 5 days, participants completed separate visits for assessment of exercise capacity, endothelial function, and muscle mitochondrial respiration. Participants then had a 2-wk washout before completion of the same protocol with the other intervention. Statistical significance was set a priori at P < 0.05, and between-treatment differences were analyzed via paired t test analysis. Following nitrate supplementation, both plasma nitrate and nitrite increased (933%, P < 0.001 and 94%, P < 0.05, respectively). No differences were observed for peak oxygen consumption (nitrate: 18.5 ± 1.4 mL·kg-1·min-1, placebo: 19.3 ± 1.4 mL·kg-1·min-1; P = 0.13) or time to exhaustion (nitrate: 1,165 ± 92 s, placebo: 1,207 ± 96 s; P = 0.16) following supplementation. There were no differences between interventions for measures of vascular function, mitochondrial respiratory function, or protein expression (all P > 0.05). Inorganic nitrate supplementation did not improve exercise capacity and skeletal muscle mitochondrial respiratory function in HFrEF. Future studies should explore alternative interventions to improve peripheral muscle tissue function in HFrEF.NEW & NOTEWORTHY This is the largest study to date to examine the effects of inorganic nitrate supplementation in patients with heart failure with reduced ejection fraction (HFrEF) and the first to include measures of vascular function and mitochondrial respiration. Although daily supplementation increased plasma nitrite, our data indicate that supplementation with inorganic nitrate as a standalone treatment is ineffective at improving exercise capacity, vascular function, or mitochondrial respiration in patients with HFrEF.
-
4.
The mitochondria-targeted antioxidant MitoQ, attenuates exercise-induced mitochondrial DNA damage.
Williamson, J, Hughes, CM, Cobley, JN, Davison, GW
Redox biology. 2020;36:101673
-
-
-
Free full text
Plain language summary
Mitochondria have an established role in the life cycle of a cell, contributing to cellular networks aligned to metabolism, biosynthetic pathways, and apoptotic cell death. Exercise increases the univalent reduction of ground state molecular dioxygen to superoxide in skeletal muscle. The aim of this study was to determine whether (1) a bout of high-intensity intermittent exercise (HIIE) damaged mitochondrial (mt)DNA; and (2) Mitoquinone (MitoQ) [orally available mitochondrial-targeted coenzyme Q10] could prevent mtDNA damage. This study is a double-blind, randomized, placebo-controlled design. Twenty-four (n = 24) healthy, recreationally active males volunteered to take part in the study. The participants were allocated to two groups: MitoQ (n = 12) and placebo (n = 12), and subsequently took part in a two-phased supplementation trial. Results showed that: - exercise increased DNA damage in nucleus and mitochondria. In fact, HIIE damages mtDNA both systemically in lymphocytes and locally in muscle tissue, occurring in parallel with nuclear DNA damage. - chronic MitoQ supplementation offers a prophylactic effect. - MitoQ decreases exercise-induced DNA damage. Authors conclude that the notion that a protective effect of a mitochondria-targeted antioxidant is only unmasked by exercise, reinforces the value of interrogating multiple physiological states when appraising the efficacy of an antioxidant.
Abstract
High-intensity exercise damages mitochondrial DNA (mtDNA) in skeletal muscle. Whether MitoQ - a redox active mitochondrial targeted quinone - can reduce exercise-induced mtDNA damage is unknown. In a double-blind, randomized, placebo-controlled design, twenty-four healthy male participants consisting of two groups (placebo; n = 12, MitoQ; n = 12) performed an exercise trial of 4 x 4-min bouts at 90-95% of heart rate max. Participants completed an acute (20 mg MitoQ or placebo 1-h pre-exercise) and chronic (21 days of supplementation) phase. Blood and skeletal muscle were sampled immediately pre- and post-exercise and analysed for nuclear and mtDNA damage, lipid hydroperoxides, lipid soluble antioxidants, and the ascorbyl free radical. Exercise significantly increased nuclear and mtDNA damage across lymphocytes and muscle (P < 0.05), which was accompanied with changes in lipid hydroperoxides, ascorbyl free radical, and α-tocopherol (P < 0.05). Acute MitoQ treatment failed to impact any biomarker likely due to insufficient initial bioavailability. However, chronic MitoQ treatment attenuated nuclear (P < 0.05) and mtDNA damage in lymphocytes and muscle tissue (P < 0.05). Our work is the first to show a protective effect of chronic MitoQ supplementation on the mitochondrial and nuclear genomes in lymphocytes and human muscle tissue following exercise, which is important for genome stability.
-
5.
Exercise twice-a-day potentiates markers of mitochondrial biogenesis in men.
Andrade-Souza, VA, Ghiarone, T, Sansonio, A, Santos Silva, KA, Tomazini, F, Arcoverde, L, Fyfe, J, Perri, E, Saner, N, Kuang, J, et al
FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 2020;34(1):1602-1619
-
-
-
Plain language summary
Endurance exercise is a powerful stimulus affecting cytoplasmic and nuclear proteins, and genes encoding mitochondrial proteins, with a subsequent increase in mitochondrial biogenesis (ie, the generation of new mitochondrial components leading to increased mitochondrial content and respiratory function). The aim of this study was to investigate whether greater exercise-induced signalling with the “train-low” approach can be attributed to the cumulative effects of performing two exercise sessions in close proximity. This study enrolled eight healthy men whom each completed three experimental trials in a crossover, randomized, and incomplete balanced Latin Square counterbalanced measure design. Results show that the greater exercise-induced nuclear protein abundance and transcription of genes involved in mitochondrial biogenesis with the “train-low” approach might be attributed to performing two exercise sessions in close proximity. Furthermore, the twice-a-day approach was associated with a higher heart rate, ventilation, and oxygen uptake, and a lower plasma glucose concentration, during high-intensity interval exercise than both the once-daily and the control condition. Authors conclude that further studies comparing different “train-low” approached in well-trained athletes are required.
Abstract
Endurance exercise begun with reduced muscle glycogen stores seems to potentiate skeletal muscle protein abundance and gene expression. However, it is unknown whether this greater signaling responses is due to performing two exercise sessions in close proximity-as a first exercise session is necessary to reduce the muscle glycogen stores. In the present study, we manipulated the recovery duration between a first muscle glycogen-depleting exercise and a second exercise session, such that the second exercise session started with reduced muscle glycogen in both approaches but was performed either 2 or 15 hours after the first exercise session (so-called "twice-a-day" and "once-daily" approaches, respectively). We found that exercise twice-a-day increased the nuclear abundance of transcription factor EB (TFEB) and nuclear factor of activated T cells (NFAT) and potentiated the transcription of peroxisome proliferator-activated receptor-ɣ coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor-alpha (PPARα), and peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) genes, in comparison with the once-daily exercise. These results suggest that part of the elevated molecular signaling reported with previous "train-low" approaches might be attributed to performing two exercise sessions in close proximity. The twice-a-day approach might be an effective strategy to induce adaptations related to mitochondrial biogenesis and fat oxidation.
-
6.
The effect of different sources of fish and camelina sativa oil on immune cell and adipose tissue mRNA expression in subjects with abnormal fasting glucose metabolism: a randomized controlled trial.
de Mello, VD, Dahlman, I, Lankinen, M, Kurl, S, Pitkänen, L, Laaksonen, DE, Schwab, US, Erkkilä, AT
Nutrition & diabetes. 2019;9(1):1
-
-
-
Free full text
Plain language summary
Dietary fish oils, particularly omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in oily fish, nuts and seeds have long been researched and purported to have both anti-inflammatory and glucose-stabilising effects when consumed orally and it is widely believed that in reducing low-grade inflammation and stabilising blood glucose levels, the risk of suffering from type 2 diabetes, heart disease or a stroke is reduced. Lean fish on the other hand has been far less researched with regards to its protective effects. This study was a randomised controlled study designed to assess and compare the protective effects of fish oils and Camelina Sativa oil (CSO - a seed oil containing alpha-linolenic acid) on inflammatory-related genes in subjects with suggestive pre-diabetes. Subjects were allocated to a randomised group and instructed to consume a given amount of either fatty fish, lean fish, camelina oil, or no fish/oil (control group). The study was carried out on 72 participants over a 12-week period. Although no significant change could be seen on inflammatory gene expression for the group consuming fatty fish, there was a modest decrease in inflammatory gene markers in the group consuming lean fish and a significant decrease in the group consuming CSO. Implications from this study suggest that CSO exerts its protective effect by reducing inflammation, therefore possibly decreasing the risk of strokes and cardiovascular episodes. The authors suggest that consuming a variety of fish, especially lean fish 4 times/ week could also play a protective role in cardiovascular health and type 2 diabetes.
Abstract
BACKGROUND/OBJECTIVES Molecular mechanisms linking fish and vegetable oil intakes to their healthy metabolic effects may involve attenuation of inflammation. Our primary aim was to examine in a randomized controlled setting whether diets enriched in fatty fish (FF), lean fish (LF) or ALA-rich camelina sativa oil (CSO) differ in their effects on the mRNA expression response of selected inflammation-related genes in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue (SAT) in subjects with impaired fasting glucose. SUBJECTS/METHODS Samples from 72 participants randomized to one of the following 12-week intervention groups, FF (n = 19), LF (n = 19), CSO (n = 17) or a control group (n = 17), were available for the PBMC study. For SAT, 39 samples (n = 8, n = 10, n = 9, n = 12, respectively) were available. The mRNA expression was measured at baseline and 12 weeks by TaqMan® Low Density Array. RESULTS In PBMCs, LF decreased ICAM1 mRNA expression (P < 0.05), which was different (P = 0.06, Bonferroni correction) from the observed increase in the FF group (P < 0.05). Also, compared to the control group, LF decreased ICAM1 mRNA expression (P < 0.05). Moreover, the change in ICAM1 mRNA expression correlated positively with the intake of FF (P < 0.05) and negatively with the intake of LF (P < 0.05), independently of study group. A diet enriched in CSO, a rich source of alpha-linolenic acid (ALA), decreased PBMC IFNG mRNA expression (P < 0.01). The intake of CSO in the CSO group, but not the increase in plasma ALA proportions, correlated inversely with the IFNG mRNA expression in PBMCs (P = 0.08). In SAT, when compared with the control group, the effect of FF on decreasing IL1RN mRNA expression was significant (P < 0.03). CONCLUSION We propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed.
-
7.
Lysophosphatidylcholine acyltransferase 2-mediated lipid droplet production supports colorectal cancer chemoresistance.
Cotte, AK, Aires, V, Fredon, M, Limagne, E, Derangère, V, Thibaudin, M, Humblin, E, Scagliarini, A, de Barros, JP, Hillon, P, et al
Nature communications. 2018;9(1):322
-
-
-
Free full text
Plain language summary
Lipid droplet (LD) accumulation has been observed in an increasing number of cancer cell lines and is now a well-recognised hallmark of cancer. While the significance of LD accumulation remains unclear, recent studies have suggested it plays a role in tumour cell chemoresistance mechanisms. This study aims to fill in the gaps in the literature regarding LD formation and function under chemotherapy conditions in colorectal cancer cell models. For the first time, this study demonstrates a pertinent mechanism linking LD accumulation and resistance to conventional chemotherapies. The authors found that LD production is driven by the enzyme lysophosphatidylcholine acyltransferase 2 (LPCAT2), and that chemotherapy can trigger LD production, promoting chemoresistance. The authors conclude these findings could be useful for both prognostic factors as well as predictive factors for the patient’s responsiveness to conventional therapies.
Abstract
Lipid droplet (LD) accumulation is a now well-recognised hallmark of cancer. However, the significance of LD accumulation in colorectal cancer (CRC) biology is incompletely understood under chemotherapeutic conditions. Since drug resistance is a major obstacle to treatment success, we sought to determine the contribution of LD accumulation to chemotherapy resistance in CRC. Here we show that LD content of CRC cells positively correlates with the expression of lysophosphatidylcholine acyltransferase 2 (LPCAT2), an LD-localised enzyme supporting phosphatidylcholine synthesis. We also demonstrate that LD accumulation drives cell-death resistance to 5-fluorouracil and oxaliplatin treatments both in vitro and in vivo. Mechanistically, LD accumulation impairs caspase cascade activation and ER stress responses. Notably, droplet accumulation is associated with a reduction in immunogenic cell death and CD8+ T cell infiltration in mouse tumour grafts and metastatic tumours of CRC patients. Collectively our findings highlight LPCAT2-mediated LD accumulation as a druggable mechanism to restore CRC cell sensitivity.
-
8.
Hypothesis and data-driven dietary patterns and colorectal Cancer survival: findings from Newfoundland and Labrador colorectal Cancer cohort.
Sharma, I, Roebothan, B, Zhu, Y, Woodrow, J, Parfrey, PS, Mclaughlin, JR, Wang, PP
Nutrition journal. 2018;17(1):55
-
-
-
Free full text
Plain language summary
Diet and lifestyle play a role in the risk and outcome of chronic diseases including colorectal cancer (CRC). This prospective follow-up study looked at the association between different dietary patterns and the risk of death and cancer recurrence in people with CRC. Over 500 CRC patients diagnosed between 1999 and 2003 were followed-up until 2010. Participants completed a food frequency questionnaire based on their diet a year prior to diagnosis, and this was used to identify several dietary patterns. Diets that were high in processed meats (HR 1.82), meat and dairy products (HR 2.19), and total grains, sugar and soft drinks (HR 1.95) were associated with a higher risk of mortality, cancer recurrence or metastasis. Poor adherence to a Mediterranean-style diet increased the risk of overall mortality (HR 1.62). Prudent vegetable, high sugar pattern, Recommended Food Scores and Dietary Inflammatory Index had no significant association with either mortality or combined mortality, recurrence or metastasis. The authors concluded that the risk of mortality, recurrence and metastasis in patients with colorectal cancer varies with different dietary patterns.
Abstract
BACKGROUND Dietary patterns are commonly used in epidemiological research, yet there have been few studies assessing if and how research results may vary across dietary patterns. This study aimed to estimate the risk of mortality/recurrence/metastasis using different dietary patterns and comparison amongst the patterns. METHODS Dietary patterns were identified by Cluster Analysis (CA), Principal Component Analysis (PCA), Alternate Mediterranean Diet score (altMED), Recommended Food Score (RFS) and Dietary Inflammatory Index (DII) scores using a 169-item food frequency questionnaire. Five hundred thirty-two colorectal cancer patients diagnosed between 1999 and 2003 in Newfoundland were followed-up until 2010. Overall Mortality (OM) and combined Mortality, Recurrence or Metastasis (cMRM) were identified. Comparisons were made with adjusted Cox proportional Hazards Ratios (HRs), correlation coefficients and the distributions of individuals in defined clusters by quartiles of factor and index scores. RESULTS One hundred and seventy cases died from all causes and 29 had a cancer recurrence/metastasis during follow-up. Processed meats as classified by PCA (HR 1.82; 95% confidence interval (CI) 1.07-3.09), clusters characterized by meat and dairy products (HR 2.19; 95% CI 1.03-4.67) and total grains, sugar, soft drinks (HR 1.95; 95% CI 1.13-3.37) were associated with a higher risk of cMRM. Poor adherence to AltMED increased the risk of all-cause OM (HR 1.62; 95% CI 1.04-2.56). Prudent vegetable, high sugar pattern, RFS and DII had no significant association with both OM and cMRM. CONCLUSION Estimation of OM and cMRM varied across dietary patterns which is attributed to the differences in the foundation of each pattern.
-
9.
Disruption of maternal gut microbiota during gestation alters offspring microbiota and immunity.
Nyangahu, DD, Lennard, KS, Brown, BP, Darby, MG, Wendoh, JM, Havyarimana, E, Smith, P, Butcher, J, Stintzi, A, Mulder, N, et al
Microbiome. 2018;6(1):124
-
-
-
Free full text
Plain language summary
The gut microbiota is key for immune development, especially during a critical window in infancy, and it has been shown that maternal diet before, during and after pregnancy influences infant metabolism and gut microbiota. The aim of this study was to assess the effects of maternal antibiotics administration during gestation and nursing on offspring gut microbiota and immunity. Pregnant mice, dams, received oral vancomycin in drinking water 5 days prior to give birth (gestation group), 14 days after delivery (nursing group) or 5 days prior to delivery and throughout nursing (gestation plus nursing group), while control mice received no vancomycin. Adaptive immunity and gut microbiota in dams and pups were analysed at various times after delivery. This study showed that antibiotic alteration of maternal gut microbiota during both pregnancy and nursing results in changes in the adaptive immunity in offspring. The authors conclude these findings are important as they provide insight into the mechanism by which maternal exposures during pregnancy may impact infant health, therefore identifying potential targets for intervention.
Abstract
BACKGROUND Early life microbiota is an important determinant of immune and metabolic development and may have lasting consequences. The maternal gut microbiota during pregnancy or breastfeeding is important for defining infant gut microbiota. We hypothesized that maternal gut microbiota during pregnancy and breastfeeding is a critical determinant of infant immunity. To test this, pregnant BALB/c dams were fed vancomycin for 5 days prior to delivery (gestation; Mg), 14 days postpartum during nursing (Mn), or during gestation and nursing (Mgn), or no vancomycin (Mc). We analyzed adaptive immunity and gut microbiota in dams and pups at various times after delivery. RESULTS In addition to direct alterations to maternal gut microbial composition, pup gut microbiota displayed lower α-diversity and distinct community clusters according to timing of maternal vancomycin. Vancomycin was undetectable in maternal and offspring sera, therefore the observed changes in the microbiota of stomach contents (as a proxy for breastmilk) and pup gut signify an indirect mechanism through which maternal intestinal microbiota influences extra-intestinal and neonatal commensal colonization. These effects on microbiota influenced both maternal and offspring immunity. Maternal immunity was altered, as demonstrated by significantly higher levels of both total IgG and IgM in Mgn and Mn breastmilk when compared to Mc. In pups, lymphocyte numbers in the spleens of Pg and Pn were significantly increased compared to Pc. This increase in cellularity was in part attributable to elevated numbers of both CD4+ T cells and B cells, most notable Follicular B cells. CONCLUSION Our results indicate that perturbations to maternal gut microbiota dictate neonatal adaptive immunity.
-
10.
Vitamin D supplementation for the prevention of type 2 diabetes in overweight adults: study protocol for a randomized controlled trial.
de Courten, B, Mousa, A, Naderpoor, N, Teede, H, de Courten, MP, Scragg, R
Trials. 2015;16:335
-
-
-
Free full text
Plain language summary
With the rising rates of vitamin D deficiency, identifying cost-effective, preventative strategies are imperative. Vitamin D plays a well-known role in bone mineralisation, however its protective role against chronic diseases is not very well understood. The aim of this trial is to investigate whether vitamin D supplementation will increase insulin sensitivity and secretion, as well as to determine whether vitamin D deficiency underlies the inflammatory properties associated with obesity. 50 overweight adults between 18 and 60 years old were recruited and assigned to receive either 4,000 IU vitamin D daily or identical placebo capsules for 16 weeks. This study elucidates the potential role vitamin D supplementation could have on preventing diabetes and its associated co-morbidities. It also provides comprehensive insight into the potential mechanisms of action. The authors conclude that this trial can corroborate existing knowledge while expanding the understanding on the role of vitamin D in the inflammatory response and subsequent development of disease.
Abstract
BACKGROUND Despite Australia's sunny climate, low vitamin D levels are increasingly prevalent. Sun exposure is limited by long working hours, an increase in time spent indoors, and sun protection practices, and there is limited dietary vitamin D fortification. While the importance of vitamin D for bone mineralization is well known, its role as a protective agent against chronic diseases, such as type 2 diabetes and cardiovascular disease, is less understood. Observational and limited intervention studies suggest that vitamin D might improve insulin sensitivity and secretion, mainly via its anti-inflammatory properties, thereby decreasing the risk of development and progression of type 2 diabetes. The primary aim of this trial is to investigate whether improved plasma concentrations of 25-hydroxyvitamin D (25(OH)D), obtained through vitamin D supplementation, will increase insulin sensitivity and insulin secretion. A secondary aim is to determine whether these relationships are mediated by a reduction in underlying subclinical inflammation associated with obesity. METHODS/DESIGN Fifty overweight but otherwise healthy nondiabetic adults between 18 and 60 years old, with low vitamin D levels (25(OH)D < 50 nmol/l), will be randomly assigned to intervention or placebo. At baseline, participants will undergo a medical review and anthropometric measurements, including dual X-ray absorptiometry, an intravenous glucose tolerance test, muscle and fat biopsies, a hyperinsulinemic euglycemic clamp, and questionnaires assessing diet, physical activity, sun exposure, back and knee pain, and depression. The intervention group will receive a first dose of 100,000 IU followed by 4,000 IU vitamin D (cholecalciferol) daily, while the placebo group will receive apparently identical capsules, both for a period of 16 weeks. All measurements will be repeated at follow-up, with the primary outcome measure expressed as a change from baseline in insulin sensitivity and secretion for the intervention group compared with the placebo group. Secondary outcome measures will compare changes in anthropometry, cardiovascular risk factors, and inflammatory markers. DISCUSSION The trial will provide much needed clinical evidence on the impact of vitamin D supplementation on insulin resistance and secretion and its underlying mechanisms, which are relevant for the prevention and management of type 2 diabetes. TRIAL REGISTRATION Clinicaltrials.gov ID: NCT02112721 .