A probiotic strain of Escherichia coli,Nissle 1917, given orally exerts local and systemic anti-inflammatory effects in lipopolysaccharide-induced sepsis in mice

Background and purpose:

Escherichia coli Nissle 1917 is a probiotic strain used in the treatment of intestinal immune diseases, including ulcerative colitis. The aim of the present study was to test if this probiotic bacterium can also show systemic immunomodulatory properties after oral administration.

Experimental approach:

The probiotic strain was administered to rats or mice for 2 weeks before its assay in two experimental models of altered immune response, the trinitrobenzenesulphonic acid (TNBS) model of rat colitis, localized in the colon, and the lipopolysaccharide (LPS) model of systemic septic shock in mice. Inflammatory status was evaluated both macroscopically and biochemically after 1 week in the TNBS model or after 24 h in the LPS shock model. In addition, splenocytes were obtained from mice and stimulated, ex vivo, with concanavalin A or LPS to activate T or B cells, respectively, and cytokine production (IL-2, IL-5 and IL-10) by T cells and IgG secretion by B cells measured.

Key results:

E. coli Nissle 1917 was anti-inflammatory in both models of altered immune response. This included a reduction in the pro-inflammatory cytokine tumour necrosis factor-α both in the intestine from colitic rats, and in plasma and lungs in mice treated with LPS. The systemic beneficial effect was associated with inhibited production of the T cell cytokines and by down-regulation of IgG release from splenocyte-derived B cells.

Conclusions and implications:

The anti-inflammatory effects of E. coli Nissle 1917 given orally were not restricted to the gastrointestinal tract.     

Anti-atherogenic effect of statins: role of nitric oxide,peroxynitrite and haem oxygenase-1

Background and purpose:

The pleiotropic effects of HMG-CoA inhibitors (statins), which include anti-inflammation, antioxidation and immunomodulation, are not yet fully understood. The present study was designed to elucidate the role of nitric oxide (NO), peroxynitrite (ONOO⁻) and haem oxygenase-1 (HO-1) in the anti-atherogenic effect of statins.

Experimental approach:

Normal and atherosclerotic New Zealand rabbits were treated with atorvastatin or simvastatin in the presence or absence of inhibitors and promoters of endothelial nitric oxide synthase (eNOS) and HO-1. NO and ONOO⁻ released from isolated aortae by calcium ionophore were measured with nanosensors placed 6 ± 2 nm from aortic endothelium. Expression of eNOS and HO-1 protein, HO activity, plasma malondialdehyde (MDA) and vessel wall thickness were also measured.

Key results:

Hypercholesterolaemia decreased eNOS expression by 31 ± 3%, decreased NO (230 ± 16 vs. 433 ± 17 nmol·L⁻¹ control) and increased cytotoxic ONOO⁻ (299 ± 15 vs. 187 ± 11 nmol·L⁻¹ control). The concentration ratio of [NO]/[ONOO⁻] decreased from 2.3 ± 0.1 (normal) to 0.7 ± 0.1 indicating an increase of nitroxidative stress in atherosclerotic endothelium. Expression of HO-1 protein increased by 20 ± 8% in atherosclerosis and further increased (about 30%) after treatment with statins. Statins partially restored the [NO]/[ONOO⁻] balance (1.5 ± 0.1 for atorvastatin and 1.4 ± 0.1 simvastatin), decreased MDA and wall thickening. Promoters of eNOS and HO-1 (L-arginine and haemin) ameliorated the [NO]/[ONOO⁻] ratio while their inhibitors (L-NAME or tin-protoporphyrin) showed no improvement in these ratio.

Conclusions and implications:

Atherosclerosis induced an endothelial [NO]/[ONOO⁻] balance indicative of endothelial dysfunction. Statins showed anti-atherosclerotic effects mediated by HO-1/eNOS, restoring the [NO]/[ONOO⁻] imbalance and reducing lipid peroxidation.     

SB265610 is an allosteric,inverse agonist at the human CXCR2 receptor

Background and purpose:

In several previous studies, the C-X-C chemokine receptor (CXCR)2 antagonist 1-(2-bromo-phenyl)-3-(7-cyano-3H-benzotriazol-4-yl)-urea (SB265610) has been described as binding competitively with the endogenous agonist. This is in contrast to many other chemokine receptor antagonists, where the mechanism of antagonism has been described as allosteric.

Experimental approach:

To determine whether it displays a unique mechanism among the chemokine receptor antagonists, the mode of action of SB265610 was investigated at the CXCR2 receptor using radioligand and [³⁵S]-GTPγS binding approaches in addition to chemotaxis of human neutrophils.

Key results:

In equilibrium saturation binding studies, SB265610 depressed the maximal binding of [¹²⁵I]-interleukin-8 ([¹²⁵I]-IL-8) without affecting the K_d. In contrast, IL-8 was unable to prevent binding of [³H]-SB265610. Kinetic binding experiments demonstrated that this was not an artefact of irreversible or slowly reversible binding. In functional experiments, SB265610 caused a rightward shift of the concentration-response curves to IL-8 and growth-related oncogene α, but also a reduction in maximal response elicited by each agonist. Fitting these data to an operational allosteric ternary complex model suggested that, once bound, SB265610 completely blocks receptor activation. SB265610 also inhibited basal [³⁵S]-GTPγS binding in this preparation.

Conclusions and implications:

Taken together, these data suggest that SB265610 behaves as an allosteric inverse agonist at the CXCR2 receptor, binding at a region distinct from the agonist binding site to prevent receptor activation, possibly by interfering with G protein coupling.     

The pivotal role of Bifida Ferment Lysate on reinforcing the skin barrier function and maintaining homeostasis of skin defenses in vitro

Background

The semiactive or inactive probiotics or their extracts used in dermatology have interesting properties to ameliorate signs of irritated skin and enhance the skin barrier. Bifidobacterium, as the most common probiotics, which has been found to be effective in reducing acne and improving the skin barrier function of atopic dermatitis. Bifida Ferment Lysate (BFL) can be obtained from Bifidobacterium by fermentation and extraction.

Purpose

In this study, we investigated the effect of a topically used BFL on the skin using in vitro evaluation methods.

Results

The results showed that upregulation of skin physical barrier gene (FLG, LOR, IVL, TGM1, and AQP3) and antimicrobial peptide gene (CAMP and hBD-2) in HaCaT cells by BFL might be responsible for skin barrier resistance. In addition, BFL had strong antioxidant properties representing a dose-dependent increasing of the scavenging capacity of DPPH, ABTS, hydroxyl, and superoxide radicals. BFL treatment also fundamentally inhibited the intracellular ROS and MDA production and improved the activities of antioxidant enzymes (CAT and GSH-Px) in H₂O₂-stimulated HaCaT cells. As a good immunomodulatory factor, BFL efficiently decreased the secretion of IL-8 and TNF-α cytokines, and COX-2 mRNA expression in LPS-induced THP-1 macrophages.

Conclusion

BFL can strengthen the skin barrier function and stimulate skin barrier resistance, to reinforce the skin against oxidative stress and inflammatory stimuli.     

Nocturnal blood pressure surge in seconds is associated with arterial stiffness independently of conventional nocturnal blood pressure variability in suspected obstructive sleep apnea patients

Nocturnal blood pressure (BP) surge in seconds (sec-surge), which is characterized as acute transient BP elevation over several tens of seconds is induced by obstructive sleep apnea (OSA) and OSA-related sympathetic hyperactivity. The authors assessed the relationship between sec-surge and arterial stiffness in 34 nocturnal hypertensive patients with suspected OSA (mean age 63.9 ± 12.6 years, 32.4% female). During the night, they had beat-by-beat (BbB) BP and cuff-oscillometric BP measurements, and brachial-ankle pulse wave velocity (baPWV) was assessed as an arterial stiffness index. Multiple linear regression analysis revealed that the upward duration (UD) of sec-surge was significantly associated with baPWV independently of nocturnal oscillometric systolic BP variability (β = .365, p = .046). This study suggests that the UD of sec-surge, which can only be measured using a BbB BP monitoring device, may be worth monitoring in addition to nocturnal BP level.     

Gait Asymmetry Variation in Kinematics,Kinetics, and Muscle Force along with the Severity Levels of Knee Osteoarthritis

Objective

Knee osteoarthritis (OA) patients exhibit greater gait asymmetry than healthy controls. However, gait asymmetry in kinematics, kinetics and muscle forces across patients with different severity levels of knee OA is still unknown. The study aimed to investigate the changes of gait asymmetry in lower limb kinematics, kinetics, and muscle force across patients with different severity levels of knee OA.

Methods

This is a cross-sectional study. From January 2020 to January 2021, 118 patients with symptomatic and radiographic medial knee OA were categorized into three groups using the Kellgren and Lawrence scale (mild: grade 1 and 2, n = 37; moderate: grade 3, n = 31; severe: grade 4, n = 50). During self-paced walking, marker trajectories and ground reaction forces data were recorded. Musculoskeletal simulations were used to determine gait kinematics, kinetics, and muscle force. One-way analysis of variance with Tukey's post-hoc test was used to evaluate group difference. Paired-sample t-test was used to compared the between-limb difference.

Results

In the Severe group, significantly greater asymmetry index in knee flexion/extension range of motion (45%) was observed with a greater value on the contralateral side (p < 0.01), compared to the Mild (15%) and Moderate (15%) groups. Significantly higher peak hip contact force (JCF) on the contralateral side was found in the Mild (more affected side: 3.80 ± 0.67 BW, contralateral side: 4.01 ± 0.58 BW), Moderate (more affected side: 3.67 ± 0.56 BW, contralateral side: 4.07 ± 0.81 BW), and Severe groups (more affected side: 3.66 ± 0.79 BW, contralateral side: 3.94 ± 0.64 BW) (p < 0.05). Significantly greater gluteus medius muscle force on the contralateral side was found in Mild (more affected side: 0.48 ± 0.09 BW, contralateral side: 0.52 ± 0.12 BW), Moderate (more affected side: 0.45 ± 0.10 BW, contralateral side: 0.51 ± 0.15 BW), and Severe groups (more affected side: 0.42 ± 0.15 BW, contralateral side: 0.47 ± 0.12 BW) (p < 0.05). The contralateral side showing significantly higher peak knee adduction moment and medial knee JCF was only observed in the Mild group (p < 0.05).

Conclusions

Gait asymmetry in kinematics and muscle forces increased from mild to severe knee OA. Asymmetrical gait pattern tends to transfer loads from the more affected side to the contralateral side. Peak hip JCF and gluteus medius muscle force can be used to detect this asymmetrical gait pattern in patients with knee OA, regardless of severity levels.