The Prognostic Value of Endotoxemia and Intestinal Barrier Biomarker ZO-1 in Bacteremic Sepsis

Gut barrier dysfunction, endotoxemia and inflammatory response in STEMI patients and effect of primary PCI

BACKGROUND

Gut-derived bacterial and endotoxin translocation induce systemic inflammation, which exerts a pivotal pathogenetic role in all phases of atherosclerosis.

OBJECTIVES

To investigate prospectively the gut barrier function, endotoxin translocation and inflammatory response in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary artery intervention (PPCI).

METHODS

Twenty-seven patients with STEMI that underwent successful PPCI were subjected to peripheral blood sampling at 3-time points; before PPCI (day0), 24 h (day1) and 96 h (day4) after PPCI and were compared with 20 chronic coronary syndrome (CCS) patients and 11 healthy controls. Serum ZO-1, I-FABP and endotoxin concentrations were determined by ELISA. Concentrations of cytokines IL-1β, -6, -8, -10 and TNF-α were determined by flow cytometry.

RESULTS

Patients with STEMI before PPCI (day0) had increased serum ZO-1 and endotoxin, both at significantly higher levels compared to CCS patients. STEMI induced also significant increases of the cytokines IL-6, -8 and -10. After PPCI, a significant improvement of gut barrier integrity (ZO-1) and endotoxemia was observed from the first day. At day4 post PPCI, systemic endotoxin and cytokines IL-6, -8 and -10 levels were reduced to control levels. Serum ZO-1 levels were positively correlated with systemic IL-10 concentrations (r = 0.471).

CONCLUSION

STEMI is associated with gut barrier dysfunction, systemic endotoxemia and inflammatory response, which improve rapidly following successful PPCI.

Lactobacillus rhamnosus NKU FL1-8 Isolated from Infant Feces Ameliorates the Alcoholic Liver Damage by Regulating the Gut Microbiota and Intestinal Barrier in C57BL/6J Mice

Alcoholic liver damage is caused by long-term or heavy drinking, and it may further progress into alcoholic liver diseases (ALD). Probiotic supplements have been suggested for the prevention or improvement of liver damage. This study was designed to consider the ameliorative effects of Lactobacillus rhamnosus NKU FL1-8 isolated from infant feces against alcoholic liver damage. The mice were gavaged with a 50% ethanol solution and treated with 109 CFU of L. rhamnosus NKU FL1-8 suspension. The factors for liver function, oxidative stress, inflammation, gut microbiota composition, and intestinal barrier integrity were measured. The results showed that L. rhamnosus NKU FL1-8 could decrease the levels of aspartate aminotransferase (AST) to 61% and alanine aminotransferase (ALT) to 50% compared with ethanol given by gavage. It could inhibit the expression level of malondialdehyde (MDA), increase superoxide dismutase (SOD), glutathione (GSH) to relieve oxidative stress, and down-regulate the cytokines to decrease hepatic inflammation. After treatment, the level of triglycerides was reduced, and the expression levels of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and the peroxisome proliferators-activated receptor-α (PPAR-α) pathway were up-regulated. Additionally, the 16S rRNA sequencing analysis showed that L. rhamnosus NKU FL1-8 increased the relative abundance of Lactobacillus, Ruminococcaceae, etc. At the same time, L. rhamnosus NKU FL1-8 could significantly reduce lipopolysaccharides (LPS) and enhance intestinal tight junction proteins. These results demonstrated that L. rhamnosus NKU FL1-8 could reduce the level of oxidative stress, fat accumulation, and liver inflammation caused by alcohol in the host. The underlying mechanism could be that L. rhamnosus NKU FL1-8 inhibits LPS by regulating the gut microbiota and repairing the intestinal barrier. Thereby, these findings support L. rhamnosus NKU FL1-8 as a potential functional food for the relief of ALD.

Transient receptor potential vanilloid 4 channel inhibition attenuates lung ischemia-reperfusion injury in a porcine lung transplant model

OBJECTIVE

Transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel important in many physiological and pathophysiological processes, including pulmonary disease. Using a murine model, we previously demonstrated that TRPV4 mediates lung ischemia-reperfusion injury, the major cause of primary graft dysfunction after transplant. The current study tests the hypothesis that treatment with a TRPV4 inhibitor will attenuate lung ischemia-reperfusion injury in a clinically relevant porcine lung transplant model.

METHODS

A porcine left-lung transplant model was used. Animals were randomized to 2 treatment groups (n = 5/group): vehicle or GSK2193874 (selective TRPV4 inhibitor). Donor lungs underwent 30 minutes of warm ischemia and 24 hours of cold preservation before left lung allotransplantation and 4 hours of reperfusion. Vehicle or GSK2193874 (1 mg/kg) was administered to the recipient as a systemic infusion after recipient lung explant. Lung function, injury, and inflammatory biomarkers were compared.

RESULTS

After transplant, left lung oxygenation was significantly improved in the TRPV4 inhibitor group after 3 and 4 hours of reperfusion. Lung histology scores and edema were significantly improved, and neutrophil infiltration was significantly reduced in the TRPV4 inhibitor group. TRPV4 inhibitor-treated recipients had significantly reduced expression of interleukin-8, high mobility group box 1, P-selectin, and tight junction proteins (occludin, claudin-5, and zonula occludens-1) in bronchoalveolar lavage fluid as well as reduced angiopoietin-2 in plasma, all indicative of preservation of endothelial barrier function.

CONCLUSIONS

Treatment of lung transplant recipients with TRPV4 inhibitor significantly improves lung function and attenuates ischemia-reperfusion injury. Thus, selective TRPV4 inhibition may be a promising therapeutic strategy to prevent primary graft dysfunction after transplant.

Ghrelin/GHSR Axis Induced M2 Macrophage and Alleviated Intestinal Barrier Dysfunction in a Sepsis Rat Model by Inactivating E2F1/NF-κB Signaling

Sepsis is an inflammatory reaction disorder state that is induced by infection. The activation and regulation of the immune system play an essential role in the development of sepsis. Our previous studies have shown that ghrelin ameliorates intestinal dysfunction in sepsis. Very little is known about the mechanism of ghrelin and its receptor (GHSR) on the intestinal barrier and the immune function of macrophage regulation. Our research is to investigate the regulatory effect and molecular mechanism of the ghrelin/GHSR axis on intestinal dysfunction and macrophage polarization in septic rats. A rat model of sepsis was established by cecal ligation and puncture (CLP) operation. Then, the sepsis rats were treated with a ghrelin receptor agonist (TZP-101) or ghrelin inhibitor (obestatin). The results suggested that TZP-101 further enhanced ghrelin and GHSR expressions in the colon and spleen of septic rats and obestatin showed the opposite results. Ghrelin/GHSR axis ameliorated colonic structural destruction and intestinal epithelial tight junction injury in septic rats. In addition, the ghrelin/GHSR axis promoted M2-type polarization of macrophages, which was characterized by the decreases of IL-1β, IL-6, and TNF-α, as well as the increase of IL-10. Mechanistically, the ghrelin/GHSR axis promoted E2F2 expression and suppressed the activation of the NF-κB signaling pathway in septic rats. Collectively, targeting ghrelin/GHSR during sepsis may represent a novel therapeutic approach for the treatment of intestinal barrier injury.

Sinisan ameliorates colonic injury induced by water immersion restraint stress by enhancing intestinal barrier function and the gut microbiota structure

CONTEXT

Sinisan (SNS) has been used to treat psychosomatic diseases of the digestive system. But little is known about how SNS affects water immersion restraint stress (WIRS).

OBJECTIVE

To study the effects of SNS on colonic tissue injury in the WIRS model.

MATERIALS AND METHODS

Forty-eight Kunming (KM) mice were randomized into 6 groups (n = 8): The control and WIRS groups receiving deionized water; the SNS low-dose (SL, 3.12 g/kg/d), SNS middle-dose (SM, 6.24 g/kg/d), SNS high-dose (SH, 12.48 g/kg/d), and diazepam (DZ, 5 mg/kg/d) groups; each with two daily administrations for 5 consecutive days. The 5 treatment groups were subjected to WIRS for 24 h on day 6. The effects of SNS on colon tissue injury caused by WIRS were assessed by changes in colon histology, inflammatory cytokines, brain-gut peptides, and tight junction (TJ) proteins levels. 16S rRNA gene sequencing was used to detect the regulation of the gut microbiota.

RESULTS

SNS pretreatment significantly reduced TNF-α (0.75- to 0.81-fold), IL-6 (0.77-fold), and IFN-γ (0.69-fold) levels; and increased TJ proteins levels, such as ZO-1 (4.06- to 5.27-fold), claudin-1 (3.33- to 5.14-fold), and occludin (6.46- to 11.82-fold). However, there was no significant difference between the levels of substance P (SP) and vasoactive intestinal peptide (VIP) in the control and WIRS groups. SNS regulated the composition of gut microbiota in WIRS mice.

CONCLUSION

The positive effects of SNS on WIRS could provide a theoretical basis to treat stress-related gastrointestinal disorders.

Serum Zonula Occludens-1 and Claudin-5 Levels in Patients with Insomnia Disorder: A Pilot Study

Purpose

This research aimed to investigate serum Zonula occludens-1 (ZO-1) and Claudin-5 (CLDN5) levels to show whether or not their eventual changes in patients with insomnia disorder could have etiopathogenetic importance. There was no research investigating serum ZO-1 and CLDN5 concentrations in insomnia disorder.

Patients and Methods

This study included 60 insomnia disorder patients and 45 normal controls. None of the patients received drugs for insomnia. The patients completed Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI), and Polysomnography (PSG) to score the insomnia disorder symptoms. Venous blood samples were collected, and serum ZO-1 and claudin-5 levels were analyzed by enzyme-linked immunosorbent assay (ELISA).

Results

Serum ZO-1 level was significantly higher without a significant difference between age, sex, and body mass index, whereas the difference in serum claudin-5 level between the two groups was not statistically significant. In addition, ZO-1 levels were positively correlated with ISI and PSQI and negatively with N1 and N1_perc. We also demonstrated a positive correlation between the levels of CLDN5 and HAMA, and a negative correlation with total sleep time (TST), N1 and N1_perc.

Conclusion

Our findings suggest an association between these intestinal and brain endothelial permeability markers and insomnia disorders. However, these remain modest and preliminary and need more extensive studies, including long-term follow-up populations and involving gut microbes, to further validate and explore the mechanisms involved.

Melatonin Attenuates Sepsis-Induced Acute Lung Injury via Inhibiting Excessive Mitophagy

Background

Epidemiological studies have indicated that lung injury is a frequent complication of sepsis. Mitophagy is vital to multiple pathological processes and diseases; however, its influence on sepsis-induced acute lung injury remains elusive. Melatonin has multiple antioxidant action and anti-inflammatory effects, including regulating mitophagy and inflammatory cytokine expression. Whereas, little is known about the affection of melatonin and mitophagy on CLP-induced ALI.

Methods

The in vivo effect of melatonin on OPTN-mediated mitophagy was studied by CLP-induced ALI in a mouse model using C57BL/6 followed by treatment with vehicle and melatonin (30 mg/kg/d, intraperitoneal injection). ALI was assayed by lung wet /dry ratio, hematoxylin and eosin staining, and immunohistochemical staining. Signaling pathway changes were subsequently determined by Western blotting and immunofluorescence staining. The effects of melatonin on STAT3 activation and TNF-α production were detected by Western blotting, PCR, and immunohistochemical staining.

Results

Our results indicated that OPTN, mitophagy adaptors were significantly repressed in CLP-induced ALI, accompanied by overactivation of mitophagy and inflammation. At the same time, we found that melatonin treatment alleviated ALI caused by CLP, and the effect was highly correlated with OPTN-related mitophagy. Furthermore, we demonstrated that OPTN-related mitophagy, which was normalized by melatonin, blocked STAT3 involved epithelial barrier and inflammation in vivo.

Conclusion

Overall, our results confirm that mitophagy is adjusted by melatonin in the CLP-induced ALI. Moreover, manipulation of mitophagy through melatonin could be a possible treatment to reduce sepsis-associated lung injury.

Prediction of short-term mortality in elderly patients with sepsis using immunoglobulin G2: An observational study

Background

Sepsis is a global healthcare issue and continues to cause high mortality especially in elderly patients. The humoral immune system plays an important role in protecting from microbial contamination. The goal of this study is to investigate the immune status and prognostic evaluation of elderly patients with sepsis.

Methods

A single-center, prospective observational study has been conducted, with the endpoint being the 28-day mortality. Patients 65 years and older who met the diagnostic criteria of Sepsis-3 in the Emergency Department of Beijing Chao-Yang Hospital were divided into survivors and non-survivors groups. Levels of immunoglobulin (Ig) A, IgG, IgM and their subclasses as well as clinical indicators were collected upon enrollment, and the results were statistically analyzed.

Results

This study finally enrolled 106 elderly patients, including 68 survivors and 38 non-survivors. Compared with survivors, IgG2 level and IgG4 level were lower in non-survivors ( P < 0.05 ). IgG2 could be regarded as an independent predictor of the 28-day mortality in elderly septic patients. IgG2 had a higher predictive value than other immunoglobulins, lactate, procalcitonin, SOFA score and APACHE II score for mortality in elderly septic patients, and the ratio of IgG2 to IgG had a slightly larger area under the ROC curve compared to IgG2 only (AUC: 0.776 v.s. 0.741).

Conclusion

IgG subclasses play important roles in the prognosis of elderly septic patients, with IgG2 being the main component. IgG2 was found to outperform other immunoglobulins, lactate, procalcitonin, SOFA score and APACHE II score in terms of predicting the mortality. A complete immunological evaluation is helpful to guide the prognosis and treatment of patients with age-related infection.

Effects of Acute Cold Stress after Intermittent Cold Stimulation on Immune-Related Molecules, Intestinal Barrier Genes, and Heat Shock Proteins in Broiler Ileum

Cold stress will have a negative impact on animal welfare and health. In order to explore the effect of intermittent cold stimulation training on the cold resistance of broilers. Immune-related and intestinal barrier genes were detected before and after acute cold stress (ACS), aiming to find an optimal cold stimulation training method. A total of 240 1-day-old Ross broilers (Gallus) were divided into three groups (G1, G2, and G3), each with 5 replicates (16 chickens each replicate). The broilers of G1 were raised at normal temperature, while the broilers of G2 and G3 were treated with cold stimulation at 3 °C lower than the G1 for 3 h and 6 h from 15 to 35 d, respectively, at one-day intervals. At 50 d, the ambient temperature for all groups was reduced to 10 °C for six hours. The results demonstrated that before ACS, IL6, IL17, TLR21, and HSP40 mRNA levels in G3 were apparently down-regulated (p < 0.05), while IL8 and Claudin-1 mRNA levels were significantly up-regulated compared with G1 (p < 0.05). After ACS, IL2, IL6, and IL8 expression levels in G3 were lower than those in G2 (p < 0.05). Compared to G2, Claudin-1, HSP90 mRNA levels, HSP40, and HSP70 protein levels were increased in G3 (p < 0.05). The mRNA levels of TLR5, Mucin2, and Claudin-1 in G2 and IL6, IL8, and TLR4 in G3 were down-regulated after ACS, while IL2, IL6, and IL17 mRNA levels in G2 and HSP40 protein levels in G3 were up-regulated after ACS (p < 0.05). Comprehensive investigation shows that cold stimulation at 3 °C lower than the normal feeding temperature for six hours at one day intervals can enhanced immune function and maintain the stability of intestinal barrier function to lessen the adverse effects on ACS in broilers.

Micronutrient Improvement of Epithelial Barrier Function in Various Disease States: A Case for Adjuvant Therapy

The published literature makes a very strong case that a wide range of disease morbidity associates with and may in part be due to epithelial barrier leak. An equally large body of published literature substantiates that a diverse group of micronutrients can reduce barrier leak across a wide array of epithelial tissue types, stemming from both cell culture as well as animal and human tissue models. Conversely, micronutrient deficiencies can exacerbate both barrier leak and morbidity. Focusing on zinc, Vitamin A and Vitamin D, this review shows that at concentrations above RDA levels but well below toxicity limits, these micronutrients can induce cell- and tissue-specific molecular-level changes in tight junctional complexes (and by other mechanisms) that reduce barrier leak. An opportunity now exists in critical care—but also medical prophylactic and therapeutic care in general—to consider implementation of select micronutrients at elevated dosages as adjuvant therapeutics in a variety of disease management. This consideration is particularly pointed amidst the COVID-19 pandemic.

A New Insight into Toxicity of Colchicine Analogues by Molecular Docking Analysis Based on Intestinal Tight Junction Protein ZO-1

Colchicine (COL) is a well-known plant alkaloid long used for medical purposes due to the selective anti-inflammatory effect on acute gouty arthritis. It is also a kind of mitosis toxin with strong inhibitory effects of cell division and is therefore being applied to the treatment of various cancers. However, this product shows a variety of adverse effects that are significantly correlated with the dosage and have attracted much attention. For the first time, the present work obtained a new insight into the gastrointestinal toxicity of colchicine analogues by molecular docking analysis, which was based on the 3D structure of intestinal tight junction protein ZO-1 and the ligand library containing dozens of small-molecule compounds with the basic skeleton of COL and its metabolites. The binding energy and mode of protein–ligand interaction were investigated to better understand the structure–toxicity relationships of COL analogues and the mechanism of action as well. Cluster analysis clearly demonstrated the strong correlation between the binding energy and toxicity of ligand molecules. The interaction mode further revealed that the hydrogen bonding (via the C-7 amide or C-9 carbonyl group) and hydrophobic effect (at ring A or C) were both responsible for ZO-1-related gastrointestinal toxicity of COL analogues, while metabolic transformation via phase I and/or phase II reaction would significantly attenuate the gastrointestinal toxicity of colchicine, indicating an effective detoxication pathway through metabolism.

Histone deacetylase inhibitor attenuates intestinal mucosal injury in fatally scalded rats

Background

Severe burns, trauma and shock can cause intestinal epithelial barrier dysfunction, which can lead to intestinal endotoxemia and even sepsis and multi-organ dysfunction. Many studies have shown that histone deacetylase inhibitors (HDACIs) can improve cell tolerance to hypoxia and inflammation, thus protecting the functions of important organs in the body, and at the same time, inhibiting the degradation of tight junction (TJ) proteins, protecting the intercellular barrier, and reducing tissue edema and organ damage. However, the mechanism is unclear.

Methods

Eighty male Sprague-Dawley rats (weighing 280-300 g) with a 50% total body surface area full-thickness dermal burn were randomly assigned to 4 groups (20 rats/group): sham control (SC group), scald + normal saline (SN group), scald + 2-methyl-2pentenoic acid (2M2P group), and scald + valproic acid (VPA group). After scalding, we measured the following parameters at various time intervals postburn injury: intestinal mucosal injury score, diamine oxidase (DAO) activity, intestinal protein expression of acetyl histone H3 at K9 (Ac-H3K9), hypoxia inducible factor 1α (HIF-1α), erythropoietin (EPO), zonula occludens-1 (ZO-1), endothelial nitric oxide synthase (eNOS) content, nitric oxide (NO) content, and intestinal mucosal blood flow (IMBF).

Results

Intestinal mucosa showed significant morphologic injury at 4 and 8 hours after scalding that was attenuated by VPA. DAO activity in the VPA group was significantly decreased compared with the other scald groups. At 4 and 8 hours after scalding, VPA enhanced Ac-H3K9 and ZO-1 expression and decreased HIF-1α and EPO expression in the intestine compared with the other scald groups. At 4 and 8 hours after scalding, eNOS and NO protein content and IMBF in the VPA group were markedly increased compared with the other scald groups.

Conclusions

HDACIs attenuated intestinal mucosal injury in fatally scalded rats. This may have involved VPA enhancing Ac-H3K9 and ZO-1 expression, inhibiting HIF-1α and EPO expression and inducing eNOS and NO increments.

Protective effect of sialyllactose on the intestinal epithelium in weaned pigs upon enterotoxigenic Escherichia coli challenge

Sialyllactose (SL), one of the most abundant oligosaccharides present in porcine breast milk, has been implicated in many biological functions, including the prebiotic and immune-modulating effects.

Layered Double Hydroxide Modified with Deoxycholic and Hyaluronic Acids for Efficient Oral Insulin Absorption

Introduction

This study aimed to construct a layered double hydroxide (LDH) nanoparticle delivery system that was modified by deoxycholic acid (DCA) and hyaluronic acid (HA) to increase the bioavailability of oral insulin.

Methods

LDH-DCA-HA was synthesized by the hybridization of DCA and HA with LDH. Subsequently, insulin was loaded onto LDH-DCA-HA, resulting in the formation of INS@LDH-DCA-HA. The in vivo and in vitro mechanisms of insulin release, as well as the efficiency of insulin absorption, were analyzed before and after DCA-HA modification.

Results

MTT assay showed that there was satisfactory biocompatibility between LDH-DCA-HA and Caco-2 cells at a concentration below 1000 μg/mL. Flow cytometry analysis revealed that Caco-2 cells absorbed INS@LDH-DCA-HA more readily than insulin. Measurement of transepithelial electrical resistance indicated that INS@LDH-DCA-HA induced the reversible opening of tight cell junctions, thereby facilitating its absorption. This was confirmed via laser confocal microscopy analysis, revealing that a large amount of zonula occludens-1 tight junction (TJ) protein was utilized for the paracellular pathway of nanoparticles. We also measured the blood glucose levels of type I diabetic mice and found that oral INS@LDH-DCA-HA exerted a steady hypoglycemic effect lasting 12 h, with a small range of postprandial blood glucose fluctuation. Immunofluorescence analysis showed that the strong penetration ability of INS@LDH-DCA-HA allowed insulin to enter epithelial cells more readily than free insulin. Finally, immunohistochemical analysis of anti-SLC10A1 protein confirmed that the cholic acid transporter receptor protein played a key role in the functioning of INS@LDH-DCA-HA.

Conclusion

LDH nanoparticles modified by DCA and HA improved the absorption efficiency of insulin by opening the TJs of cells and interacting with the cholic acid transporter receptor protein.

Hyperoxia Provokes Time- and Dose-Dependent Gut Injury and Endotoxemia and Alters Gut Microbiome and Transcriptome in Mice

Background: Oxygen therapy usually exposes patients to hyperoxia, which induces injuries in the lung, the heart, and the brain. The gut and its microbiome play key roles in critical illnesses, but the impact of hyperoxia on the gut and its microbiome remains not very clear. We clarified the time- and dose-dependent effects of hyperoxia on the gut and investigated oxygen-induced gut dysbiosis and explored the underlying mechanism of gut injury by transcriptome analysis. Methods: The C57BL/6 mice were randomly divided into the control group and nine different oxygen groups exposed to hyperoxia with an inspired O2 fraction (FiO2) of 40, 60, and 80% for 24, 72, and 168 h (7 days), respectively. Intestinal histopathological and biochemical analyses were performed to explore the oxygen-induced gut injury and inflammatory response. Another experiment was performed to explore the impact of hyperoxia on the gut microbiome by exposing the mice to hyperoxia (FiO2 80%) for 7 days, with the 16S rRNA sequencing method. We prolonged the exposure (up to 14 days) of the mice to hyperoxia (FiO2 80%), and gut transcriptome analysis and western blotting were carried out to obtain differentially expressed genes (DEGs) and signaling pathways related to innate immunity and cell death. Results: Inhaled oxygen induced time- and dose-dependent gut histopathological impairment characterized by mucosal atrophy (e.g., villus shortening: 80% of FiO2 for 24 h: P = 0.008) and enterocyte death (e.g., apoptosis: 40% of FiO2 for 7 days: P = 0.01). Administered time- and dose-dependent oxygen led to intestinal barrier dysfunction (e.g., endotoxemia: 80% of FiO2 for 72 h: P = 0.002) and potentiated gut inflammation by increasing proinflammatory cytokines [e.g., tumor necrosis factor alpha (TNF-α): 40% of FiO2 for 24 h: P = 0.003)] and reducing anti-inflammatory cytokines [Interleukin 10 (IL-10): 80% of FiO2 for 72 h: P < 0.0001]. Hyperoxia induced gut dysbiosis with an expansion of oxygen-tolerant bacteria (e.g., Enterobacteriaceae). Gut transcriptome analysis identified 1,747 DEGs and 171 signaling pathways and immunoblotting verified TLR-4, NOD-like receptor, and apoptosis signaling pathways were activated in oxygen-induced gut injury. Conclusions: Acute hyperoxia rapidly provokes gut injury in a time- and dose-dependent manner and induces gut dysbiosis, and an innate immune response is involved in an oxygen-induced gut injury.

Circulating levels of tight junction proteins in multiple sclerosis: Association with inflammation and disease activity before and after disease modifying therapy

BACKGROUND

Tight junction proteins contribute to maintenance of epithelial and endothelial barriers such as the intestinal barrier and the blood brain barrier (BBB). Increased permeability of these barriers has been linked to disease activity in MS and there is currently a lack of easily accessible biomarkers predicting disease activity in MS.

AIM

To investigate whether levels of circulating tight junction proteins occludin and zonula occludens-1 (ZO-1) are associated with biomarkers of inflammation and disease activity; and to determine whether they could serve as clinical biomarkers.

METHODS

We prospectively included 72 newly diagnosed patients with relapsing remitting MS or clinically isolated syndrome with no prior disease modifying therapy (DMT) use and 50 healthy controls (HCs). Patients were followed with blood samples, 3 tesla MRI, and clinical evaluation for 12 months. Occludin, ZO-1, calprotectin and soluble urokinase-type plasminogen activator receptor (suPAR) were measured by ELISA; serum neurofilament light (NfL) and IL-6 by single-molecule array (SIMOA). The mRNA expression of IFNG, IL1R1, IL10, IL1B, ARG1 and TNF was measured by quantitative real time polymerase chain reaction (qPCR) in whole blood.

RESULTS

Plasma occludin levels were higher in MS patients compared with HCs. After 12 months on DMT, occludin levels were reduced by approximately 25% irrespective of 1st or 2nd line DMT (p<0.001). Furthermore, NfL and calprotectin levels were significantly reduced by 31% and 29%, respectively. Occludin and ZO-1 did not correlate with biomarkers of inflammation and did not predict disease activity at baseline or after 12 months.

CONCLUSIONS

Higher levels of occludin suggest an increased permeability of the BBB and/or the intestinal barrier in MS patients. The reduction of occludin after 12 months on DMTs might reflect repair of these barriers upon treatment. However, plasma levels of ZO-1 and occludin could not predict clinical or MRI disease activity as determined by regression and ROC-curve analysis. Our results do not indicate a clear clinically relevant role for circulating tight junction proteins as biomarkers of disease activity in MS and further investigations in larger cohorts are needed to clarify this issue.

Intestinal Barrier Biomarker ZO1 and Endotoxin Are Increased in Blood of Patients With COVID-19-associated Pneumonia

BACKGROUND/AIM

The present study was undertaken to investigate (i) whether hospitalized patients with COVID-19 pneumonia present intestinal barrier dysfunction with consequent translocation of endotoxin into the systemic circulation and (ii) whether intestinal barrier biomarkers have any prognostic role in terms of progression to severe respiratory failure.

PATIENTS AND METHODS

In this prospective study, 22 patients with COVID-19-associated pneumonia and 19 patients with non-COVID-19-related community-acquired pneumonia (CAP group) were studied while 12 healthy persons comprised the control group. Blood samples were collected on admission and analysed for serum levels of endotoxin and zonula occludens-1 (ZO1). Clinical courses regarding progression to severe respiratory failure (SRF) requiring mechanical ventilation were recorded.

RESULTS

Patients with COVID-19-associated pneumonia and patients with CAP presented significantly higher serum endotoxin and ZO1 concentrations on admission as compared to healthy controls. There was no difference in endotoxin levels between patients with COVID-19-related pneumonia and patients with CAP. In patients with COVID-19-related pneumonia, serum endotoxin concentrations were positively correlated with C-reactive protein and ferritin values. There were no significant differences in serum endotoxin and ZO1 concentrations between patients with severe and not severe COVID-19-related pneumonia, nor between patients who developed SRF and those who did not Conclusion: Patients with COVID-19-related pneumonia present intestinal barrier dysfunction leading to systemic endotoxemia. Admission values of endotoxin and ZO1 do not have any prognostic role for progression to SRF.