Low-Grade Inflammation and Ultra-Processed Foods Consumption: A Review

Low-grade inflammation alters the homeostasis of the organism and favors the onset of many chronic diseases. The global growth in the prevalence of noncommunicable diseases in recent years has been accompanied by an increase in the consumption of ultra-processed foods (UPF). Known to be hyperpalatable, economic and ready-to-eat, increased consumption of UPF has already been recognized as a risk factor for several chronic diseases. Different research groups have tried to investigate whether UPF consumption could promote low-grade inflammation and thus favor the development of noncommunicable diseases. Current evidence highlights the adverse health effects of UPF characteristics, not only due to the nutrients provided by a diet rich in UPF, but also due to the non-nutritive components present in UPF and the effect they may have on gut health. This review aims to summarize the available evidence on the possible relationship between excessive UPF consumption and modulation of low-grade inflammation, as potential promoters of chronic disease.

Dysbiosis versus diabesity: pathological signaling and promising therapeutic strategies

A healthy life depends on the inseparable relationship between a host and the gut microbiota. A healthy gut microbiota regulates intestinal integrity, whereas an unbalanced gut microbiota contributes to junctional remodeling and leads to dysbiosis. Bacterial infiltration and dysbiosis are reported to activate a series of pathological cascades that trigger metabolic abnormalities, including diabesity. Conversely, recent studies revealed that the incidence of dysbiosis itself is fuelled by diabesity. In this review, we highlight the molecular aspects of multifaceted pathological signaling between dysbiosis and diabetes that could pave the way for new drug discovery. Moreover, to reinstate the gut microbiota and restrict the epidemic of dysbiosis and diabesity, we also scrutinize a promising therapeutic strategy that can challenge the pathological interlink. Teaser: Dysbiosis and diabesity are closely related and can influence each other. Dysbiosis can worsen diabesity, whereas diabesity can affect the gut microbiota. Thus, to prevent and treat diabesity, it is important to understand this complex interplay.

[Research progress on the relationship between gut microbiota dysbiosis and osteoarthritis]

Objective

To introduce the research progress on the relationship between gut microbiota dysbiosis and osteoarthritis (OA), focus on the possible mechanism of gut microbiota dysbiosis promoting OA, and propose a new therapeutic direction.

Methods

The domestic and foreign research literature on the relationship between gut microbiota dysbiosis and OA was reviewed. The role of the former in the occurrence and development of OA and the new ideas for the treatment of OA were summarized.

Results

The gut microbiota dysbiosis promotes the development of OA mainly in three aspects. First, the gut microbiota dysbiosis destroys intestinal permeability and causes low-grade inflammation, which aggravate OA. Secondly, the gut microbiota dysbiosis promotes the development of OA through metabolic syndrome. Thirdly, the gut microbiota dysbiosis is involved in the development of OA by regulating the metabolism and transport of trace elements. Studies have shown that improving gut microbiota dysbiosis by taking probiotics and transplanting fecal microbiota can reduce systemic inflammation and regulate metabolic balance, thus treating OA.

Conclusion

Gut microbiota dysbiosis is closely related to the development of OA, and improving gut microbiota dysbiosis can be an important idea for OA treatment.

Role of inflammation in pediatric irritable bowel syndrome

BACKGROUND

IBS affects a large number of children throughout the world and is thought to be the result of disturbed neuroimmune function along with the brain-gut axis. Although the underlying pathophysiologic mechanisms are not clear, the role of low-grade inflammation and mucosal immune activation in IBS symptom generation has become evident also in subsets of pediatric patients. Animal models provided meaningful insight in the causal relationship between abnormal mucosal immune activation and changes in gastrointestinal (GI) sensory-motor function. Likewise, the development of long-standing GI symptoms fulfilling the current criteria for functional GI disorders after infection gastroenteritis and in patients with IBD or celiac disease in remission further supports this hypothesis. Immune activation, its impact on gut sensory-motor function, and potential implications for symptom generation emerged in both children and adults with IBS.

PURPOSE

The aim of this review is to summarize the main evidence on the presence of low-grade inflammation and immune activation in children with IBS, its possible role in symptom generation, and its potential implication for new therapeutic strategies.

Virulence Factors of the Gut Microbiome Are Associated with BMI and Metabolic Blood Parameters in Children with Obesity

The development of metabolic diseases is linked to the gut microbiota. A cross-sectional study involving 45 children (6 to 12 years old) was conducted to investigate the relationship between gut microbiota and childhood obesity. Anthropometric and metabolic measurements, food-frequency questionnaires (FFQs), and feces samples were obtained. Using the body mass index (BMI) z-score, we categorized each participant as normal weight (NW), or overweight and obese (OWOB). We determined 2 dietary profiles: one with complex carbohydrates and proteins (pattern 1), and the other with saturated fat and simple carbohydrates (pattern 2). The microbial taxonomic diversity and metabolic capacity were determined using shotgun metagenomics. We found differences between both BMI groups diversity. Taxa contributing to this difference, included Eubacterium sp., Faecalibacterium prausnitzii, Dialister, Monoglobus pectinilyticus, Bifidobacterium pseudocatenulatum, Intestinibacter bartlettii, Bacteroides intestinalis, Bacteroides uniformis, and Methanobrevibacter smithii. Metabolic capacity differences found between NW and OWOB, included the amino acid biosynthesis pathway, the cofactor, carrier, and vitamin biosynthesis pathway, the nucleoside and nucleotide biosynthesis and degradation pathways, the carbohydrate-sugar degradation pathway, and the amine and polyamine biosynthesis pathway. We found significant associations between taxa such as Ruminococcus, Mitsuokella multacida, Klebsiella variicola, and Citrobacter spp., metabolic pathways with the anthropometric, metabolic, and dietary data. We also found the microbiome's lipooligosaccharide (LOS) category as differentially abundant between BMI groups. Metabolic variations emerge during childhood as a result of complex nutritional and microbial interactions, which should be explained in order to prevent metabolic illnesses in adolescence and maturity. IMPORTANCE The alteration of gut microbiome composition has been commonly observed in diseases involving inflammation, such as obesity and metabolic impairment. Inflammatory host response in the gut can be a consequence of dietary driven dysbiosis. This response is conducive to blooms of particular bacterial species, adequate to survive in an inflammatory environment by means of genetical capability of utilizing alternative nutrients. Understanding the genomic and metabolic contribution of microbiota to inflammation, including virulence factor prevalence and functional potential, will contribute to identifying modifiable early life exposures and preventive strategies associated with obesity risk in childhood.

The influence of apical periodontitis on circulatory inflammatory mediators in peripheral blood: A prospective case-control study

AIM

To explore the influence of apical periodontitis (AP) on inflammatory markers in blood of otherwise healthy individuals and to depict the inflammatory profile of the healing after dental extraction.

METHODOLOGY

This is a prospective case-control intervention study, during which, individuals with a diagnosis of AP of one affected tooth were included, along with a control group matched for age and gender. A broad panel of blood inflammatory mediators was examined longitudinally in all subjects during six visits. In the case of the AP subjects, the tooth with AP was extracted at the third visit. Results were analysed by linear regression analyses and linear mixed-model analyses.

RESULTS

A total of 53 subjects were included in the study, 27 with AP and 26 without. Fifteen females and 12 males were included in the AP group, and 14 females and 12 males in the control group. At baseline, granulocyte colony-stimulating factor (p < .001), interleukin (IL)-1β (p = .03) and IL-4 (p = .01) were significantly lower in AP subjects than in controls. Comparison of the differences between baseline and the last visit, i.e. 3 months after the tooth extraction, showed a significant reduction in IL-10 (p = .03) and IL-12p70 (p = .01).

CONCLUSIONS

The immunologic profile of chronic AP in one tooth and its healing profile reveals a systemic low-grade inflammation through compensatory immunosuppression. A larger lesion or multiple lesions could disrupt the balance that the system is trying to maintain, resulting in loss of homeostasis.

Glucagon induces the hepatic expression of inflammatory markers in vitro and in vivo

Glucagon exerts multiple hepatic actions, including stimulation of glycogenolysis/gluconeogenesis. The liver plays a crucial role in chronic inflammation by synthesizing proinflammatory molecules, which are thought to contribute to insulin resistance and hyperglycaemia. Whether glucagon affects hepatic expression of proinflammatory cytokines and acute-phase reactants is unknown. Herein, we report a positive relationship between fasting glucagon levels and circulating interleukin (IL)-1β (r = 0.252, p = .042), IL-6 (r = 0.230, p = .026), fibrinogen (r = 0.193, p = .031), complement component 3 (r = 0.227, p = .024) and high sensitivity C-reactive protein (r = 0.230, p = .012) in individuals without diabetes. In CD1 mice, 4-week continuous treatment with glucagon induced a significant increase in circulating IL-1β (p = .02), and IL-6 (p = .001), which was countered by the contingent administration of the glucagon receptor antagonist, GRA-II. Consistent with these results, we detected a significant increase in the hepatic activation of inflammatory pathways, such as expression of NLRP3 (p < .02), and the phosphorylation of nuclear factor kappaB (NF-κB; p < .02) and STAT3 (p < .01). In HepG2 cells, we found that glucagon dose-dependently stimulated the expression of IL-1β (p < .002), IL-6 (p < .002), fibrinogen (p < .01), complement component 3 (p < .01) and C-reactive protein (p < .01), stimulated the activation of NLRP3 inflammasome (p < .01) and caspase-1 (p < .05), induced the phosphorylation of TRAF2 (p < .01), NF-κB (p < .01) and STAT3 (p < .01). Preincubating cells with GRA-II inhibited the ability of glucagon to induce an inflammatory response. Using HepaRG cells, we confirmed the dose-dependent ability of glucagon to stimulate the expression of NLRP3, the phosphorylation of NF-κB and STAT3, in the absence of GRA-II. These results suggest that glucagon has proinflammatory effects that may participate in the pathogenesis of hyperglycaemia and unfavourable cardiometabolic risk profile.

Low-Grade Inflammation and Role of Anti-Inflammatory Diet in Childhood Obesity

At present, pediatric obesity is a significant public health concern. We have seen a surge of disorders that are obesity-related, e.g., insulin resistance (IR), type 2 diabetes mellitus (T2DM), high blood pressure, heart disease, stroke, cancer, non-alcoholic fatty liver disease (NAFLD), autoimmune disorders and many more. The mechanisms linking these diseases to excess body weight are related to low-grade inflammation (LGI). Although there is a limited number of studies assessing this immune process in childhood obesity, they indicate its significant importance for the health of future generations. There is a need for more research into the prevention and treatment of low-grade inflammation in childhood. The aim of this review is to present and discuss the process of "cold" inflammation, and its impact on health and anti-inflammation nutrition. A diet rich in anti-inflammatory nutrients may be the key to maintaining health, as well as recovery.

Low-Grade Inflammation in Gestational Diabetes Mellitus and Its Correlation with Maternal Insulin Resistance and Fetal Growth Indices

Introduction

Chronic low-grade inflammation (LGI) plays a role in the pathogenesis of gestational diabetes mellitus (GDM). LGI, on the one hand, promotes insulin resistance and at the same time, affects fetal development. The study aimed to use clinically feasible means to evaluate the association between maternal LGI and maternal insulin resistance and fetal growth indices by ultrasound in the third trimester.

Methods

A crossectional and descriptive study on 248 first-time diagnosed GDM in Vietnam.

Results

Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte (PLR) indices were significantly higher in GDM than in normal glucose-tolerant pregnancies (p = 0.048 and 0.016, respectively). GDM with LGI witnessed significantly higher systolic blood pressure, BMI, HbA1c, and significantly lower quantitative Insulin Sensitivity Check Index (QUICKI) than those without LGI. After adjusting for maternal BMI, fasting plasma glucose (FPG), age, and parity, C-reactive protein (CRP) was positively correlated with HOMA2-IR (B=0.13, p<0.01) and Mathews index (B=0.29, p<0.01). Regarding fetal characteristics, LGI was associated with fetal growth indices in the third trimester of GDM. NLR was negatively correlated with estimated fetal weight (EFW) (B=-64.4, p<0.05) after adjusting for maternal BMI and FPG. After adjusting for maternal BMI, FPG, age, and parity, PLR was negatively correlated with biparietal diameter (B=-0.02, p<0.01) and abdominal circumference (AC) (B=-0.16, p<0.05), and EFW (B=-1.1, p<0.01), and head circumference (HC) (B=-0.06, p<0.01); CRP was negatively correlated with AC (B=-0.16, p<0.001), EFW (B=-85.3, p<0.001), and HC (B=-5.0, p<0.001).

Conclusion

In the third trimester, LGI was associated with maternal glucose and insulin resistance in GDM. Moreover, LGI was associated with fetal characteristics in ultrasonic images. There were negative correlations between LGI and fetal developmental characteristics.

The association between physical activity, low-grade inflammation, and labour market attachment among people with multimorbidity: A cross-sectional study from the Lolland-Falster Health Study, Denmark

Aim

Evidence suggests low-grade inflammation (LGI) to be associated with multimorbidity. Furthermore, there are links between inflammation markers, physical activity (PA), and labour market participation. The aims of this study were to examine the association between PA and LGI in people with multimorbidity and if this association was moderated by self-reported labour market attachment.

Methods

Cross-sectional data were collected in the Lolland-Falster Health Study (LOFUS) from 2016-2020. We included 1,106 participants with multimorbidity and valid accelerometer data. PA was measured as the average counts per minute (CPM) per day during wake time and split in time spent in moderate to vigorous intensity (MVPA) and light intensity (LPA). Degree of inflammation was determined by high sensitive C-reactive protein (hsCRP) level. Associations were investigated using multiple logistic regression analyses, stratified by labour market attachment.

Results

The odds of having LGI was higher with lower amount of daily LPA. The highest odds of LGI was observed for CPM < 200 per day (odds ratio (OR) 2.55; 95% confidence interval (CI) 1.46-4.43), MVPA < 15 minutes per day (OR 2.97; 95 % CI 1.56-5.62), and LPA < 90 (OR 2.89; 95 % CI 1.43-5.81) with the reference groups being CPM ≥ 400 per day, MVPA ≥ 30, and LPA ≥ 180 min per day, respectively. We could not preclude an interaction between LPA and labour market attachment (p = 0.109).

Conclusion

PA recommendations should be developed with attention to people with chronic diseases, who may experience barriers to reach PA at high intensities. People with no labour market attachment may benefit from primary and secondary prevention of multimorbidity.

From Low-Grade Inflammation in Osteoarthritis to Neuropsychiatric Sequelae: A Narrative Review

Nowadays, osteoarthritis (OA), a common, multifactorial musculoskeletal disease, is considered to have a low-grade inflammatory pathogenetic component. Lately, neuropsychiatric sequelae of the disease have gained recognition. However, a link between the peripheral inflammatory process of OA and the development of neuropsychiatric pathology is not completely understood. In this review, we provide a narrative that explores the development of neuropsychiatric disease in the presence of chronic peripheral low-grade inflammation with a focus on its signaling to the brain. We describe the development of a pro-inflammatory environment in the OA-affected joint. We discuss inflammation-signaling pathways that link the affected joint to the central nervous system, mainly using primary sensory afferents and blood circulation via circumventricular organs and cerebral endothelium. The review describes molecular and cellular changes in the brain, recognized in the presence of chronic peripheral inflammation. In addition, changes in the volume of gray matter and alterations of connectivity important for the assessment of the efficacy of treatment in OA are discussed in the given review. Finally, the narrative considers the importance of the use of neuropsychiatric diagnostic tools for a disease with an inflammatory component in the clinical setting.

Vitamin D Supplementation Has No Impact on Cardiorespiratory Fitness, but Improves Inflammatory Status in Vitamin D Deficient Young Men Engaged in Resistance Training

Data on the effect of vitamin D (Vit-D) supplementation on cardiorespiratory fitness (VO2max) are conflicting. A possible source of discrepancies in the literature is the heterogeneity in baseline Vit-D status among participants in previous studies. The main objectives of the present study were to assess the impact of Vit-D supplementation on VO2max and inflammatory status in Vit-D deficient young healthy men. Participants (n = 39, baseline serum Vit-D level < 50 nmol/L) were quasi-randomly assigned to one of the two groups, which, in a double-blind manner, supplemented their diet daily with either Vit-D (8000 IU; VD) or placebo (PLC) and concomitantly performed a 12-week supervised resistance training program. During the 12-week intervention, serum Vit-D concentrations increased 3.9-fold (p < 0.001) in the VD group while no changes occurred in the PLC group. Baseline VO2max did not differ in the two groups and remained unchanged during the intervention. Serum interleukin-10/tumour necrosis factor alpha ratio increased significantly (30%, p = 0.007; effect size 0.399) in VD but not in PLC group. In conclusion, 12-week Vit-D supplementation increases serum 25(OH)D levels and improves inflammatory status, but has no impact on VO2max in Vit-D deficient young men engaged in resistance training.

Quercetin improves high-fat diet-induced obesity by modulating gut microbiota and metabolites in C57BL/6J mice

High-fat diet-induced obesity is characterized by low-grade inflammation, which has been linked to gut microbiota dysbiosis. We hypothesized that quercetin supplementation would alter gut microbiota and reduce inflammation in obese mice. Male C57BL/6J mice, 4 weeks of age, were divided into 3 groups, including a low-fat diet group, a high-fat diet (HFD) group, and a high-fat diet plus quercetin (HFD+Q) group. The mice in HFD+Q group were given 50 mg per kg BW quercetin by gavage for 20 weeks. The body weight, fat accumulation, gut barrier function, glucose tolerance, and adipose tissue inflammation were determined in mice. 16 s rRNA amplicon sequence and non-targeted metabolomics analysis were used to explore the alteration of gut microbiota and metabolites. We found that quercetin significantly alleviated HFD-induced obesity, improved glucose tolerance, recovered gut barrier function, and reduced adipose tissue inflammation. Moreover, quercetin ameliorated HFD-induced gut microbiota disorder by regulating the abundance of gut microbiota, such as Adlercreutzia, Allobaculum, Coprococcus_1, Lactococcus, and Akkermansia. Quercetin influenced the production of metabolites that were linked to alterations in obesity-related inflammation and oxidative stress, such as Glycerophospho-N-palmitoyl ethanolamine, sanguisorbic acid dilactone, O-Phospho-L-serine, and P-benzoquinone. Our results demonstrate that the anti-obesity effects of quercetin may be mediated through regulation in gut microbiota and metabolites.

Dietary Capsaicin: A Spicy Way to Improve Cardio-Metabolic Health?

Today's sedentary lifestyle with too much food and too little exercise has made metabolic syndrome a pandemic. Metabolic syndrome is a major risk factor for type-2 diabetes and cardiovascular disease. New knowledge of medical and nutraceutical intervention in the early stages of metabolic syndrome is central to prevent these deadly complications. People who eat chili pepper on a regular basis seem to stay healthier and live longer than those who do not. Animal experiments suggest a therapeutic potential for dietary capsaicin, the active principle in hot chili pepper, to reduce the risk of developing metabolic syndrome. This is an attractive theory since capsaicin has been a culinary staple for thousands of years, and is generally deemed safe when consumed in hedonically acceptable doses. The broad expression of the capsaicin receptor TRPV1 in metabolically active tissues lends experimental support to this theory. This review critically evaluates the available experimental and clinical evidence for and against dietary capsaicin being an effective dietary means to improve cardio-metabolic health. It comes to the conclusion that although a chili pepper-rich diet is associated with a reduced risk of dying due to cardiovascular disease, dietary capsaicin has no clear effect on blood glucose or lipid profiles. Therefore, the reduced mortality risk may reflect the beneficial action of digested capsaicin on gut microbiota.

Phenolic Compounds Known to Be Present in Lingonberry (Vaccinium vitis-idaea L.) Enhance Macrophage Polarization towards the Anti-Inflammatory M2 Phenotype

Macrophages are pleiotropic immune cells whose phenotype can polarize towards the pro-inflammatory M1 or anti-inflammatory M2 direction as a response to environmental changes. In obesity, the number of macrophages in adipose tissue is enhanced, and they shift towards the M1 phenotype. Activated M1 macrophages secrete pro-inflammatory cytokines and adipokines involved in the development of systemic low-grade inflammation, complicating obesity. Polyphenols are widely found in the vegetable kingdom and have anti-inflammatory properties. We and others have recently found that lingonberry (Vaccinium vitis-idaea L.) supplementation is able to prevent the development of low-grade inflammation and its metabolic consequences in experimentally induced obesity. In the present study, we investigated the effects of twelve phenolic compounds known to be present in lingonberry (resveratrol, piceid, quercetin, kaempferol, proanthocyanidins, delphinidin, cyanidin, benzoic acid, cinnamic acid, coumaric acid, caffeic acid, and ferulic acid) on macrophage polarization, which is a meaningful mechanism determining the low-grade inflammation in obesity. Mouse J774 and human U937 macrophages and commercially available phenolic compounds were used in the studies. Three of the twelve compounds investigated showed an effect on macrophage polarization. Resveratrol, kaempferol, and proanthocyanidins enhanced anti-inflammatory M2-type activation, evidenced as increased expression of Arg-1 and MRC-1 in murine macrophages and CCL-17 and MRC-1 in human macrophages. Resveratrol and kaempferol also inhibited pro-inflammatory M1-type activation, shown as decreased expression of IL-6, NO, and MCP-1 in murine macrophages and TNF-α and IL-6 in human macrophages. In the further mechanistic studies, the effects of the three active compounds were investigated on two transcription factors important in M2 activation, namely on PPARγ and STAT6. Resveratrol and kaempferol were found to enhance PPARγ expression, while proanthocyanidins increased the phosphorylation of STAT6. The results suggest proanthocyanidins, resveratrol, and kaempferol as active constituents that may be responsible for the positive anti-inflammatory effects of lingonberry supplementation in obesity models. These data also extend the previous knowledge on the anti-inflammatory effects of lingonberry and encourage further studies to support the use of lingonberry and lingonberry-based products as a part of a healthy diet.

A Marked Low-Grade Inflammation and a Significant Deterioration in Metabolic Status in First-Episode Schizophrenia: A Five-Year Follow-Up Study

The objective of this study was to evaluate how schizophrenia spectrum disorders and applied long-term (5.1 years) antipsychotic (AP) treatment affect the serum level of acylcarnitines (ACs), cytokines and metabolic biomarkers and to characterize the dynamics of inflammatory and metabolic changes in the early course of the disorder. A total of 112 adults participated in the study (54 patients with first-episode psychosis (FEP) and 58 control subjects). Biomolecule profiles were measured at the onset of first-episode psychosis and 0.6 years and 5.1 years after the initiation of APs. The results of the present study confirmed that specific metabolic-inflammatory imbalance characterizes AP-naïve patients. Short-term (0.6-years) AP treatment has a favourable effect on psychotic symptoms, as well as the recovery of metabolic flexibility and resolution of low-level inflammation. However, 5.1 years of AP treatment resulted in weight gain and increased serum levels of interleukin (IL)-2, IL-4, IL-6, IL-10, interferon-γ, hexoses, acetylcarnitine, short-chain ACs (C3, C4) and long-chain ACs (C16:2, C18:1, C18:2). In conclusion, despite the improvement in psychotic symptoms, 5.1 years of AP treatment was accompanied by a pronounced metabolic-inflammatory imbalance, which was confirmed by the presence of enhanced pro-inflammatory activity and increased obesity with changes in the metabolism of carbohydrates, lipids, and their metabolites.

Stunted children display ectopic small intestinal colonization by oral bacteria, which cause lipid malabsorption in experimental models

Environmental enteric dysfunction (EED) is an inflammatory syndrome postulated to contribute to stunted child growth and to be associated with intestinal dysbiosis and nutrient malabsorption. However, the small intestinal contributions to EED remain poorly understood. This study aimed to assess changes in the proximal and distal intestinal microbiota in the context of stunting and EED and to test for a causal role of these bacterial isolates in the underlying pathophysiology. We performed a cross-sectional study in two African countries recruiting roughly 1,000 children aged 2 to 5 years and assessed the microbiota in the stomach, duodenum, and feces. Upper gastrointestinal samples were obtained from stunted children and stratified according to stunting severity. Fecal samples were collected. We then investigated the role of clinical isolates in EED pathophysiology using tissue culture and animal models. We find that small intestinal bacterial overgrowth (SIBO) is extremely common (>80%) in stunted children. SIBO is frequently characterized by an overgrowth of oral bacteria, leading to increased permeability and inflammation and to replacement of classical small intestinal strains. These duodenal bacterial isolates decrease lipid absorption in both cultured enterocytes and mice, providing a mechanism by which they may exacerbate EED and stunting. Further, we find a specific fecal signature associated with the EED markers fecal calprotectin and alpha-antitrypsin. Our study shows a causal implication of ectopic colonization of oral bacterial isolated from the small intestine in nutrient malabsorption and gut leakiness in vitro. These findings have important therapeutic implications for modulating the microbiota through microbiota-targeted interventions.

The immune response as a therapeutic target in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a complex and heterogeneous disorder considered a liver-damaging manifestation of metabolic syndrome. Its prevalence has increased in the last decades due to modern-day lifestyle factors associated with overweight and obesity, making it a relevant public health problem worldwide. The clinical progression of NAFLD is associated with advanced forms of liver injury such as fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). As such, diverse pharmacological strategies have been implemented over the last few years, principally focused on metabolic pathways involved in NAFLD progression. However, a variable response rate has been observed in NAFLD patients, which is explained by the interindividual heterogeneity of susceptibility to liver damage. In this scenario, it is necessary to search for different therapeutic approaches. It is worth noting that chronic low-grade inflammation constitutes a central mechanism in the pathogenesis and progression of NAFLD, associated with abnormal composition of the intestinal microbiota, increased lymphocyte activation in the intestine and immune effector mechanisms in liver. This review aims to discuss the current knowledge about the role of the immune response in NAFLD development. We have focused mainly on the impact of altered gut-liver-microbiota axis communication on immune cell activation in the intestinal mucosa and the role of subsequent lymphocyte homing to the liver in NAFLD development. We further discuss novel clinical trials that addressed the control of the liver and intestinal immune response to complement current NAFLD therapies.

Ameliorating effects of electroacupuncture on the low-grade intestinal inflammation in rat model of diarrhea-predominant irritable bowel syndrome

BACKGROUND AND AIM

We aim to investigate the effects and mechanisms of electroacupuncture (EA) at ST25 and ST37 on the intestinal low-grade inflammation (LGI) in rat model of Diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

IBS-D model rats were established by acetic acid enema combined with restraint and tail clamping. Before EA intervention, they were divided into three groups: blank 1 group, blank 2 group, and IBS-D model group. Diarrhea symptoms and visceral pain sensitivity were evaluated. After constructed the model successfully, the remaining IBS-D model group rats were randomly divided into model group and EA group. Local intestinal inflammation (HE staining), changes of intestinal mucosa (occludin protein and microvascular diameter) were evaluated. Differences between two groups were compared using t-test or Mann-Whitney U-test. Differences among more than two groups were compared using one-way ANOVA or Kruskal-Wallis test.

RESULTS

After modeling, the results of HE staining in intestinal tract of IBS-D model rats showed LGI. Compared with the model group, 4 h fecal moisture content (diarrhea index) and the AWR score were decreased in the EA group. The results of HE in EA group showed that the infiltration of intestinal inflammatory cells were alleviated. Additionally, EA significantly upregulated the expression of occludin protein and partially dilated the intestinal microvascular diameter. Pearson correlation analysis showed that the symptoms of IBS-D rats were correlated with the changes of intestinal mucosa.

CONCLUSION

EA may treat intestinal LGI in IBS-D rats by upregulating the expression of occludin protein and dilating the intestinal microvascular diameter.

Regulatory Effect of Isomaltodextrin on a High-Fat Diet Mouse Model with LPS-Induced Low-Grade Chronic Inflammation

This study aimed to identify the effects of isomaltodextrin (IMD) on sustaining the gut integrity and microbiota composition in a high-fat diet (HFD) with a lipopolysaccharide (LPS)-induced low-grade inflammation mouse model. The homeostasis of the immune response is important to reduce the risk of developing metabolic syndromes. The results of this study showed that pre-treatment of IMD at 5% (w/v) suppressed the concentration of endotoxin and pro-inflammatory mediators TNF-α, MCP-1, and IL-6 while increasing the adiponectin level in the plasma. Subsequently, IMD supplementation maintained the structural integrity and intestinal permeability by upregulating the tight junction protein expressions, leading to reducing D-mannitol concentration in the blood. In addition, dysbiosis was observed in mice induced by HFD plus LPS, suggesting that unhealthy dietary factors elicit metabolic endotoxemia and associated dysbiosis to impair the barrier function. However, IMD supplementation was shown to restore the microbial diversity, promote the growth of Bacteroides-Prevotella, and upregulate the related d-glucarate and d-galactarate degradation pathways, together demonstrating the benefits of IMD as a prebiotic able to promote energy homeostasis. Our results also showed that the blood lipid profile and glucose level in the low-grade inflammation mouse model were modulated by IMD. Moreover, IMD supplementation effectively prevented the metabolic disorder and modulated immune responses in inflamed white adipose tissues by inhibiting the macrophage infiltration and restoring the adiponectin, PPAR-γ, and IRS-1 expression. These findings provide strong evidence for IMD to be a potential prebiotic that acts to sustain a healthy gut microbiota composition and barrier function. By protecting against an unhealthy diet-impaired metabolic balance and maintaining immune homeostasis, IMD may affect the development of metabolic disorders.

Mild elevation of C-reactive protein in a young patient with severe periodontitis: a case report with 2 years of follow-up

Periodontal inflammation is associated with systemic disease. Low-grade inflammation (LGI) is critical to the link between periodontal disease and several systemic disorders. C-reactive protein (CRP) is a common circulating biomarker for acute-phase immune responses, and it is closely related to LGI. The present case demonstrated excellent results using a comprehensive approach for periodontitis in a young woman with severe periodontitis and mild CRP elevation. A 21-year-old Japanese woman complained of tooth mobility and bleeding during tooth brushing. She was pre-obese (body mass index = 29.9), and she had a mildly elevated CRP level (5.2 mg/L). Of all periodontal sites, 34.5% had deep pockets (≥6 mm). The patient was diagnosed with stage III, grade C periodontitis and generalized aggressive periodontitis. Comprehensive periodontal treatments, including regenerative procedures for vertical bone loss and furcation involvement, were performed. Periodontal tissue inflammation was resolved, and periodontal regeneration was achieved. During the 2-year follow-up period, her teeth did not exhibit any signs of instability, attachment loss, or bone loss. Despite the weak nature of the evidence, this case suggests that CRP is valuable for assessing LGI, and it may potentially be considered during periodontal grading in the future.

The Role of Rumen Microbiota and Its Metabolites in Subacute Ruminal Acidosis (SARA)-Induced Inflammatory Diseases of Ruminants

Subacute ruminal acidosis (SARA) is a common metabolic disease in ruminants. In the early stage of SARA, ruminants do not exhibit obvious clinical symptoms. However, SARA often leads to local inflammatory diseases such as laminitis, mastitis, endometritis and hepatitis. The mechanism by which SARA leads to inflammatory diseases is largely unknown. The gut microbiota is the totality of bacteria, viruses and fungi inhabiting the gastrointestinal tract. Studies have found that the gut microbiota is not only crucial to gastrointestinal health but also involved in a variety of disease processes, including metabolic diseases, autoimmune diseases, tumors and inflammatory diseases. Studies have shown that intestinal bacteria and their metabolites can migrate to extraintestinal distal organs, such as the lung, liver and brain, through endogenous pathways, leading to related diseases. Combined with the literature, we believe that the dysbiosis of the rumen microbiota, the destruction of the rumen barrier and the dysbiosis of liver function in the pathogenesis of SARA lead to the entry of rumen bacteria and/or metabolites into the body through blood or lymphatic circulation and place the body in the “chronic low-grade” inflammatory state. Meanwhile, rumen bacteria and/or their metabolites can also migrate to the mammary gland, uterus and other organs, leading to the occurrence of related inflammatory diseases. The aim of this review is to describe the mechanism by which SARA causes inflammatory diseases to obtain a more comprehensive and profound understanding of SARA and its related inflammatory diseases. Meanwhile, it is also of great significance for the joint prevention and control of diseases.

Immunosenescence in Childhood Cancer Survivors and in Elderly: A Comparison and Implication for Risk Stratification

The population of childhood cancer survivors (CCS) has grown rapidly in recent decades. Although cured of their original malignancy, these individuals are at increased risk of serious late effects, including age-associated complications. An impaired immune system has been linked to the emergence of these conditions in the elderly and CCS, likely due to senescent immune cell phenotypes accompanied by low-grade inflammation, which in the elderly is known as "inflammaging." Whether these observations in the elderly and CCS are underpinned by similar mechanisms is unclear. If so, existing knowledge on immunosenescent phenotypes and inflammaging might potentially serve to benefit CCS. We summarize recent findings on the immune changes in CCS and the elderly, and highlight the similarities and identify areas for future research. Improving our understanding of the underlying mechanisms and immunosenescent markers of accelerated immune aging might help us to identify individuals at increased risk of serious health complications.

Dietary Influences on Gut Microbiota with a Focus on Metabolic Syndrome

There is a clear correlation between gut microbiota, diet, and metabolic outcomes. A diet high in fiber has been shown to decrease inflammation, increase insulin sensitivity, and reduce dyslipidemias whereas a diet high in fat and sugar leads to dyslipidemia, insulin resistance, and low-grade inflammation. There is recent evidence suggesting that the human gut microbiota has a significant role in the development or the resolution of metabolic syndrome (MetS) and associated conditions. Leading a stressful, sedentary lifestyle with limited or no physical activity and consuming an unhealthy diet high in saturated fat, simple carbohydrates, and sodium and low in dietary fiber and in high-quality protein are some of the contributing factors. Unhealthy diets have been shown to induce alterations in the gut microbiota and contribute to the pathogenesis of MetS by altering microbiota composition and disrupting the intestinal barrier, which leads to low-grade systemic inflammation. In contrast, healthy diets can lead to changes in microbiota that increase gut barrier function and increase the production of anti-inflammatory biomarkers. This review aims at providing a more in-depth discussion of diet-induced dysbiosis of the gut microbiota and its effect on MetS. Here, we discuss the possible mechanisms involved in the development of the metabolic biomarkers that define MetS, with an emphasis on the role of sugar and dietary fiber in microbiome-mediated changes in low-grade systemic inflammation and metabolic dysfunction.

Post-COVID-19 syndrome, low-grade inflammation and inflammatory markers: a cross-sectional study

OBJECTIVE

Post-COVID syndrome (PCS) is a poorly known entity. An underlying chronic, low-grade inflammation (LGI) has been theorized as a pathophysiological mechanism. Available data on biomarkers in PCS show conflicting results. Our aim was to know whether subjects with PCS present higher levels of inflammatory markers, after a mild COVID-19.

METHODS

Analytical cross-sectional study. Cases of mild COVID-19 in a community setting were included. We collected epidemiological data (age, sex, BMI, smoking, comorbidities), variables of the acute COVID-19 (duration, symptoms), and data at 3 months after the acute phase (symptoms and laboratory test). Serum C-reactive protein (CRP), neutrophil and lymphocyte counts, neutrophil/lymphocyte ratio (NLR), lactate dehydrogenase, ferritin, fibrinogen, and D-dimer levels were analysed. LGI was defined as CRP >0.3 and <1.0 mg/dL. A subject was classified as PCS + if presented signs and symptoms >12 weeks after an infection consistent with COVID-19. Five composite indices (C1-C5) were developed, combining the upper ranges of biomarkers distributions. Multivariate analyses were performed.

RESULTS

We analysed 121 mild COVID-19 cases (mean age = 45.7 years, 56.2% women). Among the acute symptoms, women presented a higher frequency of fatigue (54.4% vs 30.2%; p = .008). PCS affected 35.8% of women and 20.8% of men (p = .07), and the most reported symptoms were fatigue (42.8%), anosmia (40%), ageusia (22.8%), dyspnea (17.1%) and myalgia (11.4%). Neutrophil count, NLR, CRP and fibrinogen showed the best correlations with PCS and were selected to develop the indices. In women PCS+, C1, C3 and C4 indices were more frequently met, while in men PCS+, C2, C5 and CRP were in the range of LGI. Anosmia, ageusia and fatigue were related to higher neutrophil counts, with sex differences. Fibrinogen levels were higher in persistent myalgia (510 ± 82 mg/dL vs 394 ± 87; p = .013). In multivariable analysis, a woman with a neutrophil count above the median, or with fibrinogen level or NLR in the highest tertile, had a 4-5-fold increased risk of prevalent PCS. A man with CRP in the range of LGI, or fibrinogen level or a neutrophil count in the highest tertile, had a 10-17-fold increased risk of prevalent PCS.

CONCLUSIONS

The data obtained in the present cross-sectional study seems to demonstrate a consistent association between PCS and upper ranges of the neutrophil count, NLR, fibrinogen, and CRP in the LGI range. Furthermore, composite indices appear useful in detecting relationships between slight elevations of biomarkers and PCS, and our study identifies relevant sex differences in symptoms and markers regarding the PCS.