Pain after upper limb surgery under peripheral nerve block is associated with gut microbiome composition and diversity.

Gut microbiota play a role in certain pain states. Hence, these microbiota also influence somatic pain. We aimed to determine if there was an association between gut microbiota (composition and diversity) and postoperative pain. Patients (n = 20) undergoing surgical fixation of distal radius fracture under axillary brachial plexus block were studied. Gut microbiota diversity and abundance were analysed for association with: (i) a verbal pain rating scale of < 4/10 throughout the first 24 h after surgery (ii) a level of pain deemed "acceptable" by the patient during the first 24 h following surgery (iii) a maximum self-reported pain score during the first 24 h postoperatively and (iv) analgesic consumption during the first postoperative week. Analgesic consumption was inversely correlated with the Shannon index of alpha diversity. There were also significant differences, at the genus level (including Lachnospira), with respect to pain being "not acceptable" at 24 h postoperatively. Porphyromonas was more abundant in the group reporting an acceptable pain level at 24 h. An inverse correlation was noted between abundance of Collinsella and maximum self-reported pain score with movement. We have demonstrated for the first time that postoperative pain is associated with gut microbiota composition and diversity. Further work on the relationship between the gut microbiome and somatic pain may offer new therapeutic targets.

Metagenomic analysis of mother-infant gut microbiome reveals global distinct and shared microbial signatures.

Emerging evidence indicates maternal microbiota as one major reservoir for pioneering microbes in infants. However, the global distinct and identical features of mother-infant gut microbiota at various taxonomic resolutions and metabolic functions across cohorts and potential of infant microbial prediction based on their paired mother's gut microbiota remain unclear. Here, we analyzed 376 mother-infant dyads (468 mother and 1024 infant samples) of eight studies from six countries and observed higher diversity at species and strain levels in maternal gut microbiota but not their metabolic functions. A number of 290 species were shared in at least one mother-infant dyad, with 26 species (five at strain level) observed across cohorts. The profile of mother-infant shared species and strains was further influenced by delivery mode and feeding regimen. The mother-sourced species in infants exhibited similar strain heterogeneity but more metabolic functions compared to other-sourced species, suggesting the comparable stability and fitness of shared and non-shared species and the potential role of shared species in the early gut microbial community, respectively. Predictive models showed moderate performance accuracy for shared species and strains occurrences in infants. These generalized mother-infant shared species and strains may be considered as the primary targets for future work toward infant microbiome development and probiotics exploration.

The effect of seaweed enriched bread on carbohydrate digestion and the release of glucose from food.

Two seaweeds; Ascophyllum nodosum and Fucus vesiculosus, were incorporated into bread at 0.5 and 2% and their effect on blood glucose in vivo and carbohydrate digestion in vitro were studied. In the five way randomised placebo controlled double blind pilot trial (n = 10) each volunteer consumed 100 g of available carbohydrate (from bread) and their blood glucose was measured over two hours. The breads were tested in a human digestion model and compared against control bread and control bread with the equivalent amount of seaweed. In the pilot human study the enriched breads did not cause any significant reductions in iAUC of blood glucose with average reductions of 0.1 ± 44.4%, 8.2 ± 19.3%, 1.0 ± 54.3% and 2.7 ± 31.9% for 0.5% F.vesiculosus, 0.5% A.nodosum, 2% F.vesiculosus, and 2% A.nodosum respectively. However, seaweed added alongside the control bread in vitro significantly reduced the level of carbohydrate digestion compared to the control bread. F.vesiculosus or A.nodosum can reduce carbohydrate digestion, however baking into bread reduces the effect.

Enduring Behavioral Effects Induced by Birth by Caesarean Section in the Mouse.

Birth by Caesarean (C)-section impacts early gut microbiota colonization and is associated with an increased risk of developing immune and metabolic disorders. Moreover, alterations of the microbiome have been shown to affect neurodevelopmental trajectories. However, the long-term effects of C-section on neurobehavioral processes remain unknown. Here, we demonstrated that birth by C-section results in marked but transient changes in microbiome composition in the mouse, in particular, the abundance of Bifidobacterium spp. was depleted in early life. Mice born by C-section had enduring social, cognitive, and anxiety deficits in early life and adulthood. Interestingly, we found that these specific behavioral alterations induced by the mode of birth were also partially corrected by co-housing with vaginally born mice. Finally, we showed that supplementation from birth with a Bifidobacterium breve strain, or with a dietary prebiotic mixture that stimulates the growth of bifidobacteria, reverses selective behavioral alterations in C-section mice. Taken together, our data link the gut microbiota to behavioral alterations in C-section-born mice and suggest the possibility of developing adjunctive microbiota-targeted therapies that may help to avert long-term negative consequences on behavior associated with C-section birth mode.

Effects of a polysaccharide-rich extract derived from Irish-sourced Laminaria digitata on the composition and metabolic activity of the human gut microbiota using an in vitro colonic model.

BACKGROUND: Brown seaweeds are known to be a rich source of fiber with the presence of several non-digestible polysaccharides including laminarin, fucoidan and alginate. These individual polysaccharides have previously been shown to favorably alter the gut microbiota composition and activity albeit the effect of the collective brown seaweed fiber component on the microbiota remains to be determined. METHODS: This study investigated the effect of a crude polysaccharide-rich extract obtained from Laminaria digitata (CE) and a depolymerized CE extract (DE) on the gut microbiota composition and metabolism using an in vitro fecal batch culture model though metagenomic compositional analysis using 16S rRNA FLX amplicon pyrosequencing and short-chain fatty acid (SCFA) analysis using GC-FID. RESULTS: Selective culture analysis showed no significant changes in cultured lactobacilli or bifidobacteria between the CE or DE and the cellulose-negative control at any time point measured (0, 5, 10, 24, 36, 48 h). Following metagenomic analysis, the CE and DE significantly altered the relative abundance of several families including Lachnospiraceae and genera including Streptococcus, Ruminococcus and Parabacteroides of human fecal bacterial populations in comparison to cellulose after 24 h. The concentrations of acetic acid, propionic acid, butyric acid and total SCFA were significantly higher for both the CE and DE compared to cellulose after 10, 24, 36 and 48 h fermentation (p < 0.05). Furthermore, the acetate:propionate ratio was significantly reduced (p < 0.05) for both CD and DE following 24, 36 and 48 h fermentation. CONCLUSION: The microbiota-associated metabolic and compositional changes noted provide initial indication of putative beneficial health benefits of L. digitata in vitro; however, research is needed to clarify if L. digitata-derived fiber can favorably alter the gut microbiota and confer health benefits in vivo.

Prebiotics from Seaweeds: An Ocean of Opportunity?

Seaweeds are an underexploited and potentially sustainable crop which offer a rich source of bioactive compounds, including novel complex polysaccharides, polyphenols, fatty acids, and carotenoids. The purported efficacies of these phytochemicals have led to potential functional food and nutraceutical applications which aim to protect against cardiometabolic and inflammatory risk factors associated with non-communicable diseases, such as obesity, type 2 diabetes, metabolic syndrome, cardiovascular disease, inflammatory bowel disease, and some cancers. Concurrent understanding that perturbations of gut microbial composition and metabolic function manifest throughout health and disease has led to dietary strategies, such as prebiotics, which exploit the diet-host-microbe paradigm to modulate the gut microbiota, such that host health is maintained or improved. The prebiotic definition was recently updated to "a substrate that is selectively utilised by host microorganisms conferring a health benefit", which, given that previous discussion regarding seaweed prebiotics has focused upon saccharolytic fermentation, an opportunity is presented to explore how non-complex polysaccharide components from seaweeds may be metabolised by host microbial populations to benefit host health. Thus, this review provides an innovative approach to consider how the gut microbiota may utilise seaweed phytochemicals, such as polyphenols, polyunsaturated fatty acids, and carotenoids, and provides an updated discussion regarding the catabolism of seaweed-derived complex polysaccharides with potential prebiotic activity. Additional in vitro screening studies and in vivo animal studies are needed to identify potential prebiotics from seaweeds, alongside untargeted metabolomics to decipher microbial-derived metabolites from seaweeds. Furthermore, controlled human intervention studies with health-related end points to elucidate prebiotic efficacy are required.

Risks and benefits of consuming edible seaweeds.

Recent interest in seaweeds as a source of macronutrients, micronutrients, and bioactive components has highlighted prospective applications within the functional food and nutraceutical industries, with impetus toward the alleviation of risk factors associated with noncommunicable diseases such as obesity, type 2 diabetes, and cardiovascular disease. This narrative review summarizes the nutritional composition of edible seaweeds; evaluates the evidence regarding the health benefits of whole seaweeds, extracted bioactive components, and seaweed-based food products in humans; and assesses the potential adverse effects of edible seaweeds, including those related to ingestion of excess iodine and arsenic. If the potential functional food and nutraceutical applications of seaweeds are to be realized, more evidence from human intervention studies is needed to evaluate the nutritional benefits of seaweeds and the efficacy of their purported bioactive components. Mechanistic evidence, in particular, is imperative to substantiate health claims.

Inhibitory activity of extracts of Hebridean brown seaweeds on lipase activity.

The effect of three Hebridean brown seaweeds on lipase activity was assessed using a turbidimetric lipase activity assay and an in vitro simulation of the upper digestive tract. The preparations of Ascophyllum nodosum, Fucus vesiculosus, and Pelvetia canaliculata were tested; whole seaweed homogenate, sodium carbonate extract, and ethanol extracts (pellet and supernatant were tested separately). All extracts showed significant inhibition of lipase, suggesting multiple bioactive agents, potentially including alginates, fucoidans, and polyphenols. Whole homogenate extract of F. vesiculosus was the most potent inhibitor of Lipase (IC50 = 0.119 mg mL-1), followed by ethanol supernatant (IC50 = 0.159 mg mL-1) while ethanol pellet and sodium carbonate extract showed relatively weaker inhibition (IC50 = 0.360 mg mL-1 and IC50 = 0.969 mg mL-1 respectively). For A. nodosum and P. canaliculata, strongest inhibition occurred with ethanol pellet (IC50 = 0.238 and 0.228 mg mL-1, respectively). These inhibitory effects were validated in a model gut system. The data presented herein suggests the use of seaweed as a potential weight management tool is deserving of further investigation.

The effect of consuming Palmaria palmata-enriched bread on inflammatory markers, antioxidant status, lipid profile and thyroid function in a randomised placebo-controlled intervention trial in healthy adults.

PURPOSE: Palmaria palmata (P. Palmata) is reported to contain anti-inflammatory and antioxidant compounds albeit no study has investigated these effects in humans. METHODS: A randomised parallel placebo-controlled human intervention study was carried out to investigate the effect of consuming P. Palmata (5 g/day) incorporated into a bread on serum markers of inflammation [C-reactive protein (CRP); cytokine analysis] with secondary analysis investigating changes in lipids (cholesterol, triglycerides), thyroid function [thyroid-stimulating hormone (TSH)] and antioxidant status ferric reducing antioxidant power. ANCOVA with baseline values as covariates, controlling for age, BMI, sex and smoking status, was used to compare differences between treatment groups over time . In vitro studies investigated the inflammatory activity of P. Palmata extracts (hot water, cold water and ethanol extract), protein extracts and associated protein hydrolysates using a Caco-2 inflammation cell model. RESULTS: Consumption of P. Palmata-enriched bread significantly increased serum CRP (+16.1 %, P = 0.011), triglycerides (+31.9 %, P = 0.001) and TSH (+17.2 %, P = 0.017) when compared to the control group. In vitro evaluation of P. palmata extracts and protein hydrolysates identified a significant induction of IL-8 secretion by Caco-2 cells, and the hot water P. palmata extract was shown to increase adipocyte glycerol release (P < 0.05). CONCLUSION: Evidence from this human study suggests that P. palmata stimulates inflammation, increases serum triglycerides and alters thyroid function; however, these changes are not likely to impact health as changes remained within the normal clinical range. The data from the in vitro study provided indications that IL-8 may contribute to the apparent immunostimulation noted in the human study.

Effect of 6 weeks of sprint training on growth hormone responses to sprinting.

This study examined the effect of 6 weeks of prescribed sprint training on the human growth hormone (hGH) response to cycle ergometer sprinting. Sixteen male subjects were randomly assigned to a training (n=8) or a control (n=8) group. Each subject completed two main trials, consisting of two all-out 30-s cycle-ergometer sprints separated by 60 min of passive recovery, once before, and once after a 6-week training period. The training group completed three supervised sprint-training sessions per week in addition to their normal activity, whilst control subjects continued with their normal activity. In the training group, peak and mean power increased post-training by 6% (P<0.05) and 5% (P<0.05), respectively. Post-exercise blood pH did not change following training, but the highest post-exercise blood lactate concentrations were greater [highest measured value: 13.3 (1.0) vs 15.0 (1.1) mmol l(-1)], with lower blood lactate concentrations for the remainder of the recovery period (P<0.05). Post-exercise plasma ammonia concentrations were lower after training [mean highest measured value: 184.1 (9.8) vs 139.0 (11.7) micromol l(-1), P<0.05]. Resting serum hGH concentrations did not change following training, but the peak values measured post-exercise decreased by over 40% in the training group [10.3 (3.1) vs 5.8 (2.5) microg l(-1), P<0.05], and mean integrated serum hGH concentrations were 55% lower after training [567 (158) vs 256 (121) min microg l(-1), P<0.05]. The hGH response to the second sprint was attenuated similarly before and after training. This study showed that 6 weeks of combined speed- and speed-endurance training blunted the human growth hormone response to sprint exercise, despite an improvement in sprint performance.