Adipose tissue inflammation in obesity and the influence of marine long chain polyunsaturated omega-3 fatty acids

Obesity is an excess of adipose tissue and is linked with increased inflammation that enhances risk of type-2 diabetes and cardiovascular disease. Despite this knowledge, a comprehensive overview of the inflammatory state of subcutaneous white adipose tissue (scWAT), which is the main pool for excess dietary lipid storage and plays a major role in whole body endocrine processes, is not reported for humans, particularly in those in which metabolic syndrome is yet to manifest. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been widely examined for their anti-inflammatory effects including modulating gene expression and secretion of systemic inflammatory markers. The research described in this thesis explores scWAT fatty acid (FA) and lipid metabolite composition, the whole tissue transcriptome, protein expression, enzyme activity, and tissue morphology in metabolically healthy obese individuals in comparison to normal weight individuals to provide a comprehensive overview of the inflammatory and metabolic state of the tissue in this condition. Furthermore, it explores the anti-inflammatory potential of a 12-week fish oil (FO) intervention on these tissue parameters. Metabolically healthy obesity (MHO) was associated with an altered FA composition and lipid metabolite profile of scWAT. There was a lower proportion of saturated fatty acids, a higher proportion of monounsaturated fatty acids (MUFA), a higher proportion of arachidonic acid (AA) and concentrations of respective oxylipins and COX-2 protein, lower concentrations of DHA oxylipins, and an alteration of the endocannabinoid system (ECS). MHO was further associated with an altered transcriptome suggestive of enhanced inflammation, immune response, tissue remodelling and expansion, altered lipid and carbohydrate metabolism, and lipid mobilization. This was concordant with tissue morphology which showed evidence of adipocyte hypertrophy and the presence of macrophages arranged in crown like structures. Chronic supplementation with EPA+DHA increased concentrations of sWAT omega-3 FAs and derived oxylipins and decreased AA oxylipins, with an effect on the ECS predominantly in normal weight individuals. EPA+DHA modulated the scWAT transcriptome suggesting promotion of tissue remodelling and down regulation of cell differentiation and the chronic inflammatory response, but to a lesser extent in MHO than in normal weight individuals. This lesser effect in MHO may be explained by several processes observed to be altered in MHO at study entry including mobilization and metabolism of EPA and DHA, in addition to greater proportions of omega-6 PUFA which persisted after 12-week FO intervention. The ratio of omega-6:omega-3 FA is of importance and therefore, greater concentrations of EPA and DHA may be required in these individuals to alter this ratio and subsequent oxylipin synthesis and transcriptome modulation. These data suggest MHO is associated with enhanced sWAT inflammation in the context of tissue expansion, remodelling, and alteration to lipid metabolism and signalling. Furthermore, the data suggest that sWAT from metabolically healthy obese individuals without metabolic syndrome maintains some degree of normal function in that it is not fibrotic and is sensitive to dietary lipid manipulation. EPA+DHA modulated synthesis of EPA, DHA and AA derived oxylipins and the transcriptome but resistance to these effects, particularly on the ECS, was exhibited in MHO

Maternal high fat diet in mice alters immune regulation and lung function in the offspring

PUFA modulate immune function and have been associated with the risk of childhood atopy and asthma. We investigated the effect of maternal fat intake in mice on PUFA status, elongase and desaturase gene expression, inflammatory markers and lung function in the offspring. C57BL/6J mice (n 32) were fed either standard chow (C, 20·4 % energy as fat) or a high-fat diet (HFD, 39·9 % energy as fat) for 4 weeks prior to conception and during gestation and lactation. At 21 d of age, offspring were weaned onto either the HFD or C, generating four experimental groups: C/C, C/HF, HF/C and HF/HF. Plasma and liver fatty acid composition were measured by GC and gene expression by quantitative PCR. Lung resistance to methacholine was assessed. Arachidonic acid concentrations in offspring plasma and liver phospholipids were increased by HFD; this effect was greater in the post-natal HFD group. DHA concentration in offspring liver phospholipids was increased in response to HFD and was higher in the post-natal HFD group. Post-natal HFD increased hepatic fatty acid desaturase (FADS) 2 and elongation of very long-chain fatty acid 5 expression in male offspring, whereas maternal HFD elevated expression of FADS1 and FADS2 in female offspring compared with males. Post-natal HFD increased expression of IL-6 and C-C motif chemokine ligand 2 (CCL2) in perivascular adipose tissue. The HFD lowered lung resistance to methacholine. Excessive maternal fat intake during development modifies hepatic PUFA status in offspring through regulation of gene expression of enzymes that are involved in PUFA biosynthesis and modifies the development of the offspring lungs leading to respiratory dysfunction.</p

The fatty acid composition of human follicular fluid is altered by a six-week dietary intervention that includes marine omega-3 fatty acids

The fatty acid composition of human follicular fluid is important for oocyte development and for pregnancy following in vitro fertilization (IVF). This study investigated whether a dietary intervention that included an increase in marine omega‐3 fatty acids, olive oil and vitamin D alters the fatty acid composition of human follicular fluid. The association of lifestyle factors with follicular fluid fatty acid composition was also investigated. Fifty‐five couples awaiting IVF were randomized to receive the 6‐week treatment intervention of olive oil for cooking, an olive oil‐based spread, and a daily supplement drink enriched with vitamin D and the marine omega‐3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and 56 couples were randomized to receive placebo equivalents. Dietary questionnaires were completed, and samples of blood were taken before and after the intervention. Follicular fluid was collected at oocyte retrieval and the fatty acid profile assessed using gas chromatography. In the control group, individual fatty acids in red blood cells and follicular fluid were significantly correlated. Furthermore, a healthier diet was associated with a lower percentage of follicular fluid arachidonic acid. The follicular fluid of women in the treatment group contained significantly higher amounts of EPA and DHA compared to the control group, while the omega‐6 fatty acids linoleic, γ‐linolenic, dihomo‐γ‐linolenic, and arachidonic were lower. This is the first report of a dietary intervention altering the fatty acid composition of follicular fluid in humans. Further research is required to determine whether this intervention improves oocyte quality.<br/

Omega-3 fatty acids supplementation affects tryptophan metabolism during a 12-week endurance training in amateur runners – a randomized controlled trial

The effects of long-term omega-3 fatty acid (n-3 PUFAs) supplementation during endurance training on tryptophan (Trp) metabolism and mental state of healthy individuals have not been evaluated so far. Concentrations of plasma Trp, its metabolites and IL-6 were assessed in 26 male runners before and after a 12-week training combined with supplementation of n-3 PUFAs (O-3 + TRAIN group) or medium chain triglycerides (MCTs; TRAIN group). Mood and stress tests were also performed. The effects of the same supplementation protocol were evaluated also in 14 inactive subjects (O-3 + SEDEN group). Concentrations of 3-hydroxykynurenine (3-HK) and picolinic acid (PA) significantly increased only in the O-3 + TRAIN group (p = 0.01; η_p^2 = 0.22 and p = 0.01; η_(p )^2= 0.26). Favorable, but not statistically significant changes in the kynurenic acid (KYNA) (p = 0.06; η_(p )^2= 0.14), xanthurenic acid (XA) (p = 0.07; η_(p )^2= 0.13) and 3-hydroxyanthranilic acid (3-HAA) (p = 0.06; η_(p )^2= 0.15) and ratio of neurotoxic to neuroprotective metabolites was seen also only in the O-3 + TRAIN group. No changes in results of mental state tests and IL-6 concentrations were observed in either group. Supplementation with n-3 PUFAs during endurance training has beneficial effects on Trp's neuroprotective metabolites.<br/

Preoperative immunonutrition in patients undergoing liver resection: a prospective randomized trial

BACKGROUND Preoperative supplementation with immunonutrients, including arginine and n-3 fatty acids, has been shown in a number of systematic reviews to reduce infectious complications in patients who have undergone gastrointestinal surgery. Limited information, however, is available on the benefits of nutritional supplementation enriched with arginine and n-3 fatty acids in patients undergoing liver resection. AIM To evaluate the effects of preoperative nutritional supplementation enriched with arginine and n-3 fatty acids on inflammatory and immunologic markers and clinical outcome in patients undergoing liver resection. METHODS Thirty-four patients undergoing liver resection were randomized to either five days of preoperative Impact® [1020 kcal/d, immunonutrition (IMN) group], or standard care [no supplementation, standard care (STD) group]. Nutritional status was measured at study entry by subjective global assessment (SGA). Functional assessments (grip strength, fatigue and performance status) were carried out at study entry, on the day prior to surgery, and on postoperative day (POD) 7 and 30. Inflammatory and immune markers were measured at study entry, on the day prior to surgery, and POD 1, 3, 5, 7, 10 and 30. Postoperative complications were recorded prospectively until POD30. RESULTS A total of 32 patients (17 IMN and 15 STD) were analysed. All except four patients were SGA class A. The plasma ratio of (eicosapentaenoic acid plus docosahexaenoic acid) to arachidonic acid was higher in IMN patients on the day prior to surgery and POD 1, 3, 5 and 7 (P &lt; 0.05). Plasma interleukin (IL)-6 concentrations were elevated in the IMN group (P = 0.017 for POD7). No treatment effect was detected for functional measures, immune response (white cell count and total lymphocytes) or markers of inflammation (C-reactive protein, tumour necrosis factor-α, IL-8, IL-10). There were 10 patients with infectious complications in the IMN group and 4 in the STD group (P = 0.087). Median hospital stay was 9 (range 4–49) d in the IMN group and 8 (3-34) d in the STD group (P = 0.476). CONCLUSION In well-nourished patients undergoing elective liver resection, this study failed to show any benefit of preoperative immunonutrition

Relationships between age, frailty, length of care home residence and biomarkers of immunity and inflammation in older care home residents in the UK

Ageing entails changes to the immune system, collectively termed immunosenescence and inflammageing. The relationships among age, frailty and immune parameters in older people resident in care homes deserves better exploration. We assessed immune and inflammatory parameters in UK care home residents aged over 65 yr and how they relate to age, frailty index and length of care home residence. Linear regression was used to identify the independent contribution of age, frailty and length of care home residence to the various immune parameters as dependent variables. Participants had a mean age (+ SD) of 85.3 ± 7.5 yr, had been residing in the care home for a mean (+ SD) of 1.9 ± 2.2 yr at the time of study commencement, 33.2% were severely frail. Length of care home residence and frailty index were correlated, age and frailty index, and age and length of care home residence were not significantly correlated. All components of the full blood count, apart from total lymphocytes, were within the reference range; 31% of participants had blood lymphocyte numbers below the lower value of the reference range. Among the components of the full blood count, platelet numbers were positively associated with frailty index. Amongst plasma inflammatory markers, C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1ra), soluble E-selectin and interferon gamma-induced protein 10 (IP-10) were positively associated with frailty. Plasma soluble vascular cell adhesion molecule 1 (sVCAM-1), IP-10 and tumor necrosis factor receptor II (TNFRII) were positively associated with age. Plasma monocyte chemoattractant protein 1 was positively associated with length of care home residence. Frailty was an independent predictor of platelet numbers, plasma CRP, IL-1ra, IP-10 and sE-selectin. Age was an independent predictor of activated monocytes and plasma IP-10, TNFRII and sVCAM-1. Length of care home residence was an independent predictor of plasma MCP-1. This study concludes that there are independent links between increased frailty and inflammation and between increased age and inflammation amongst older people resident in care homes in the UK. Since inflammation is known to contribute to morbidity and mortality in older people, causes and consequences of inflammation in this population should be further explored. <br/

Combination of the probiotics Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis, BB-12 has limited effect on biomarkers of immunity and inflammation in older people resident in care homes: results from the Probiotics to Reduce Infections iN CarE home reSidentS (PRINCESS) randomised, controlled trial

Aging is associated with a decline in many components of the immune system (immunosenescence). Probiotics may improve the immune response in older people. The objective was to determine the effect of the combination of two probiotic organisms [Lacticaseibacillus (previously known as Lactobacillus) rhamnosus GG (LGG) and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12)] on a range of immune biomarkers measured in the blood of older people resident in care homes in the UK. In a randomized controlled trial, older people [aged 67–97 (mean 86) years] resident in care homes received the combination of LGG+BB-12 (1.3–1.6 × 109 CFU per day) or placebo for up to 12 months. Full blood count, blood immune cell phenotypes, plasma immune mediator concentrations, phagocytosis, and blood culture responses to immune stimulation were all measured. Response to seasonal influenza vaccination was measured in a subset of participants. Paired samples (i.e., before and after intervention) were available for 30 participants per group. LGG and BB-12 were more likely to be present in feces in the probiotic group and were present at higher numbers. There was no significant effect of the probiotics on components of the full blood count, blood immune cell phenotypes, plasma immune mediator concentrations, phagocytosis by neutrophils and monocytes, and blood culture responses to immune stimulation. There was an indication that the probiotics improved the response to seasonal influenza vaccination with significantly (p = 0.04) higher seroconversion to the A/Michigan/2015 vaccine strain in the probiotic group than in the placebo group (47 vs. 15%)

Self-sampling to identify pathogens and inflammatory markers in patients with acute sore throat: feasibility study

Introduction: sore throat is a common reason for overuse of antibiotics. The value of inflammatory or biomarkers in throat swab or saliva samples in predicting benefit from antibiotics is unknown.Methods: we used the ‘person-based approach’ to develop an online tool to support self-swabbing and recruited adults and children with sore throats through participating general practices and social media. Participants took bacterial and viral swabs and a saliva sponge swab and passive drool sample. Bacterial swabs were cultured for streptococcus (Group A, B, C, F and G). The viral swab and saliva samples were tested using a routine respiratory panel PCR and Covid-19 PCR testing. We used remaining viral swab and saliva sample volume for biomarker analysis using a panel of 13 biomarkers.Results: we recruited 11 asymptomatic participants and 45 symptomatic participants. From 45 symptomatic participants, bacterial throat swab, viral throat swab, saliva sponge and saliva drool samples were returned by 41/45 (91.1%), 43/45 (95.6%), 43/45 (95.6%) and 43/45 (95.6%) participants respectively. Three saliva sponge and 6 saliva drool samples were of insufficient quantity. Two adult participants had positive bacterial swabs. Six participants had a virus detected from at least one sample (swab or saliva). All of the biomarkers assessed were detectable from all samples where there was sufficient volume for testing. For most biomarkers we found higher concentrations in the saliva samples. Due to low numbers, we were not able to compare biomarker concentrations in those who did and did not have a bacterial pathogen detected. We found no evidence of a difference between biomarker concentrations between the symptomatic and asymptomatic participants but the distributions were wide.Conclusions: we have demonstrated that it is feasible for patients with sore throat to self-swab and provide saliva samples for pathogen and biomarker analysis. Typical bacterial and viral pathogens were detected but at low prevalence rates. Further work is needed to determine if measuring biomarkers using oropharyngeal samples can help to differentiate between viral and bacterial pathogens in patients classified as medium or high risk using clinical scores, in order to better guide antibiotic prescribing and reduce inappropriate prescriptions

Age and frailty are independently associated with increased COVID-19 mortality and increased care needs in survivors: results of an international multi-centre study

Introduction: Increased mortality has been demonstrated in older adults with coronavirus disease 2019 (COVID-19), but the effect of frailty has been unclear. Methods: This multi-centre cohort study involved patients aged 18 years and older hospitalised with COVID-19, using routinely collected data. We used Cox regression analysis to assess the impact of age, frailty and delirium on the risk of inpatient mortality, adjusting for sex, illness severity, inflammation and co-morbidities. We used ordinal logistic regression analysis to assess the impact of age, Clinical Frailty Scale (CFS) and delirium on risk of increased care requirements on discharge, adjusting for the same variables. Results: Data from 5,711 patients from 55 hospitals in 12 countries were included (median age 74, interquartile range [IQR] 54–83; 55.2% male). The risk of death increased independently with increasing age (>80 versus 18–49: hazard ratio [HR] 3.57, confidence interval [CI] 2.54–5.02), frailty (CFS 8 versus 1–3: HR 3.03, CI 2.29–4.00) inflammation, renal disease, cardiovascular disease and cancer, but not delirium. Age, frailty (CFS 7 versus 1–3: odds ratio 7.00, CI 5.27–9.32), delirium, dementia and mental health diagnoses were all associated with increased risk of higher care needs on discharge. The likelihood of adverse outcomes increased across all grades of CFS from 4 to 9. Conclusion: Age and frailty are independently associated with adverse outcomes in COVID-19. Risk of increased care needs was also increased in survivors of COVID-19 with frailty or older age.</p