Omega-3 polyunsaturated fatty acids inhibit the increase in cytokines and chemotactic factors induced in vitro by lymph fluid from an intestinal ischemia-reperfusion injury model

Intestinal ischemic reperfusion injury: Recommended rats model and comprehensive review for protective strategies

Intestinal ischemic reperfusion injury (IIRI) is a life-threatening condition with high morbidity and mortality in the clinic. IIRI was induced by intestinal ischemic diseases such as, small bowel transplantation, aortic aneurysm surgery, and strangulated hernias. Although related mechanisms have not been fully elucidated, during the last decade, researches have demonstrated that many factors are crucial in the pathological process, including oxidative stress (OS), epithelial barrier function disorder, and so on. Rats model, as the most applied animal IIRI model, provides specific targets for researches and therapeutic strategies. Moreover, various treatment strategies such as, anti-oxidative stress, anti-apoptosis, and anti-inflammation, have shown promising effects in alleviating IIRI. However, current researches cannot solve the clinical problems of IIRI, and specific treatment strategies are still needed to be exploited. This review focuses on a recommended experimental IIRI rat model and understanding of the involved mechanisms such as, OS, gut bacteria translocation, apoptosis, and necroptosis, aim at providing novel ideas for therapeutic strategies of IIRI.

Nutritional Neuroscience as Mainstream of Psychiatry: The Evidence- Based Treatment Guidelines for Using Omega-3 Fatty Acids as a New Treatment for Psychiatric Disorders in Children and Adolescents

Omega-3 polyunsaturated fatty acids (or omega-3 PUFAs, n-3 PUFAs) are essential nutrients throughout the life span. Recent studies have shown the importance of n-3 PUFAs supplementation during prenatal and perinatal period as a potential protective factor of neurodevelopmental disorders. N-3 PUFAs have been reported to be lower in youth with attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD) and major depressive disorder (MDD). N-3 PUFAs supplementation has shown potential effects in the improvement of clinical symptoms in youth with ADHD, ASD, and MDD, especially those with high inflammation or a low baseline n-3 index. Moreover, it has been suggested that n-3 PUFAs had positive effects on lethargy and hyperactivity symptoms in ASD. For clinical application, the following dosage and duration are recommended in youth according to available randomized controlled trials and systemic literature review: (1) ADHD: a combination of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) ≥ 750 mg/d, and a higher dose of EPA (1,200 mg/d) for those with inflammation or allergic diseases for duration of 16−24 weeks; (2) MDD: a combination of a EPA + DHA of 1,000−2,000 mg/d, with EPA:DHA ratio of 2 to 1, for 12−16 weeks; (3) ASD: a combination of EPA + DHA of 1,300−1,500 mg/d for 16−24 weeks as add-on therapy to target lethargy and hyperactivity symptoms. The current review also suggested that n-3 index and inflammation may be potential treatment response markers for youth, especially in ADHD and MDD, receiving n-3 PUFA.

Dynamic metabolomic analysis of intestinal ischemia-reperfusion injury in rats

Intestinal ischemia-reperfusion injury (IIR) is a life-threatening abdominal emergency. Compared to traditional steady-state works, we profiled the blood of rats over 72 hr (15 time points) and examined dynamic changes in molecular pathways during IIR. Using a series of methods designed for dynamic datasets analysis (batch effects corrections, metabolomics data reduction, and different features selection), we identified 39 significant different metabolites and discovered the trends of these molecules. Four main patterns were uncovered by a longitudinal pattern recognition method. Furthermore, pathway networks were explored to uncover the possible mechanisms of IIR. We found that IIR is a complex physiological process involved in multiple pathways, such as biosynthesis of amino acids, 2-oxocarboxylic acid metabolism, arginine-related metabolism, and glutathione metabolism. Among which, metabolites related with phenylalanine tyrosine and tryptophan metabolism reached a peak during the early stage of reperfusion, while molecules in biosynthesis of unsaturated fatty acids metabolism declined. Our work provides a feasible scheme to understand dynamic molecule variation and will provide new explications about the effect of intestinal ischemia reperfusion from a dynamic perspective.

Association between serum n-3 polyunsaturated fatty acids and quadriceps weakness immediately after total knee arthroplasty

Objectives

Quadriceps weakness (QW) following total knee arthroplasty (TKA) can be elicited by tourniquet-induced ischaemia reperfusion (IR), which causes a vigorous acute inflammatory response. Dietary n-3 polyunsaturated fatty acids (PUFA) are important determinants of organ and tissue protection from IR. This study aimed to examine the association between serum n-3 PUFA levels and QW, knee pain, and knee swelling immediately after TKA.

Methods

A total of 32 patients who underwent unilateral TKA participated in this prospective study. On Postoperative Day 1, serum n-3 PUFA (eicosapentaenoic acid and docosahexaenoic acid) levels were measured. Preoperatively and on Postoperative Day 4, quadriceps strength, knee pain during quadriceps testing, and knee circumference were measured. QW, knee pain, and knee swelling were defined as changes in quadriceps strength, knee pain during quadriceps testing, and knee circumference, respectively, between the preoperative to the postoperative measurement.

Results

Mean serum n-3 PUFA levels were 192 μg/mL (standard deviation, 58 μg/mL) on Postoperative Day 1. All measured variables changed significantly between the preoperative and the postoperative measurement time-points (P <0.01). Quadriceps strength decreased from 1.2 to 0.4 Nm/kg (QW = −65%). Knee pain during quadriceps testing increased from 1.1 to 6.0 (knee pain = 4.0). Knee circumference increased from 40 to 44 cm (knee swelling = 10%). Multivariate analysis showed that lower serum n-3 PUFA levels were independently associated with an increased QW after adjusting for the Kellgren-Lawrence grade and the tourniquet time (P = 0.04). No significant relationship was observed between serum n-3 PUFA levels and knee pain or knee swelling.

Conclusion

Higher serum n-3 PUFA are independently associated with a lower increase in the QW immediately after TKA.

Xuezhikang improves the outcomes of cardiopulmonary resuscitation in rats by suppressing the inflammation response through TLR4/NF-κB pathway

BACKGROUND/AIMS

Xuezhikang (XZK), a red yeast rice extract with lipid-lowering effect, contains a family of naturally statins, such as lovastatin. In recent years, its effect beyond the regulation of lipids has also been received increasing attention. Therefore, the purpose of this study was to explore the protective effects and possible molecular mechanisms of XZK on brain injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR), and to investigate whether it has a dose-dependent effect and the difference with lovastatin.

METHODS

Rats were treated with low-dose XZK (XZK-L, 20 mg/kg/d), high-dose XZK (XZK-H, 200 mg/kg/d) and lovastatin by gavage once daily for 2 weeks before CA. The levels of TNF-α, IL-6 and IL-1β were evaluated at 1, 4, and 72 h post-CA/CPR. The survival rate, neurological deficit score (NDS), and expression of TLR4, phosphorylated NF-κB and TNF-α in hippocampal tissues were evaluated at 72 h post-CA/CPR.

RESULTS

CA/CPR induced a significant increase in serum TNF-α, IL-6 and IL-1β, as well as increased expressions of TLR4, phosphorylated NF-κB and TNF-α in the hippocampus. Both low-dose and high-dose XZK treatment inhibited the expression of these inflammatory cytokines. In addition, it reduced the number of defibrillations and shortened the duration of CPR required for return of spontaneous circulation (ROSC). XZK treatment also improved neurological function and 72-hour survival rate in rats. However, high-dose XZK was superior to lovastatin in the suppression of IL-1β mRNA level and TNF-α protein level in hippocampal tissue after CPR. There were no significant differences observed among high-dose XZK, low-dose XZK and lovastatin groups in other respects.

CONCLUSION

These results indicated that XZK had a protective effect against brain injury post-CA/CPR. The mechanisms underlying the protective effects of XZK may be related to the suppressing of CA/CPR-induced inflammatory response through the inhibiting TLR4/NF-κB signaling pathway.

Docosahexaenoic acid, but not eicosapentaenoic acid, improves septic shock-induced arterial dysfunction in rats

Introduction

Long chain n-3 fatty acid supplementation may modulate septic shock-induced host response to pathogen-induced sepsis. The composition of lipid emulsions for parenteral nutrition however remains a real challenge in intensive care, depending on their fatty acid content. Because they have not been assessed yet, we aimed at determining the respective effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during septic shock-induced vascular dysfunction.

Methods

In a peritonitis-induced septic shock model, rats were infused with EPA, DHA, an EPA/DHA mixture or 5% dextrose (D5) during 22 hours. From H18, rats were resuscitated and monitored during 4 hours. At H22, plasma, aorta and mesenteric resistance arteries were collected to perform ex vivo experiments.

Results

We have shown that septic rats needed an active resuscitation with fluid challenge and norepinephrine treatment, while SHAM rats did not. In septic rats, norepinephrine requirements were significantly decreased in DHA and EPA/DHA groups (10.6±12.0 and 3.7±8.0 μg/kg/min respectively versus 17.4±19.3 μg/kg/min in D5 group, p<0.05) and DHA infusion significantly improved contractile response to phenylephrine through nitric oxide pathway inhibition. DHA moreover significantly reduced vascular oxidative stress and nitric oxide production, phosphorylated IκB expression and vasodilative prostaglandin production. DHA also significantly decreased polyunsaturated fatty acid pro-inflammatory mediators and significantly increased several anti-inflammatory metabolites.

Conclusions

DHA infusion in septic rats improved hemodynamic dysfunction through decreased vascular oxidative stress and inflammation, while EPA infusion did not have beneficial effects.

Chronic Psychological Stress Was Not Ameliorated by Omega-3 Eicosapentaenoic Acid (EPA)

Background: Chronic psychological stress and mental health disorders are endemic in Western culture where population dietary insufficiencies of omega-3 fatty acids (n-3FA) from seafood have been observed. Objective: This study was designed to test for a causal relationship between one of the most active components of fish oil, eicosapentaenoic acid (EPA), and chronic psychological stress. Method: A randomized double-blind, placebo-controlled clinical trial with parallel-assignment to two groups was designed (Trial Id: ACTRN12610000404022). The interventions were four EPA-rich fish oil capsules per day, delivering 2.2 g/d EPA (and 0.44 g/d DHA), or identical placebo (low-phenolic olive oil capsules with 5% fish oil to aid blinding). The primary outcome was the between-group difference on the Perceived Stress Scale (PSS-10) after 12 weeks supplementation. An a priori power analysis determined that group sizes of 43 would provide 80% power to detect a significant between-group difference of 12.5%, at α = 0.05. Ninety community members (64 females, 26 males) reporting chronic work stress were recruited via public advertising in northern NSW, Australia. Results: At baseline the omega-3 index (EPA + DHA as % to total fatty acids in red blood cell membranes) was 5.2% in both groups (SD = 1.6% control group; 1.8% active group). After supplementation this remained stable at 5.3% (SD = 1.6%) for the control group but increased to 8.9% (SD = 1.5%) for the active group, demonstrating successful incorporation of EPA into cells. Intention-to-treat (ITT) analysis found no significant between-group differences in PSS outcome scores post-intervention (b = 1.21, p = 0.30) after adjusting for sex (b = 2.36, p = 0.079), baseline PSS (b = 0.42, p = 0.001) and baseline logEPA [b = 1.41, p = 0.185; F(3, 86) = 8.47, p < 0.01, n = 89, R-square = 0.243]. Discussion: Treatment increased cell membrane EPA but, contrary to the hypothesis, there was no effect on perceived stress. Limitations included an imbalance of gender in groups after randomization (68% of the males were in the placebo group). While we found no significant interaction between sex and group on the outcome after adjusting for baseline PSS, larger studies with groups stratified for gender may be required to further confirm these findings. Conclusion: This study demonstrated that 2. 2 g/day of EPA for 12 weeks did not reduce chronic psychological stress.

Relationship between Long Chain n-3 Polyunsaturated Fatty Acids and Autism Spectrum Disorder: Systematic Review and Meta-Analysis of Case-Control and Randomised Controlled Trials

Omega-3 long chain polyunsaturated fatty acid supplementation (n-3 LCPUFA) for treatment of Autism Spectrum Disorder (ASD) is popular. The results of previous systematic reviews and meta-analyses of n-3 LCPUFA supplementation on ASD outcomes were inconclusive. Two meta-analyses were conducted; meta-analysis 1 compared blood levels of LCPUFA and their ratios arachidonic acid (ARA) to docosahexaenoic acid (DHA), ARA to eicosapentaenoic acid (EPA), or total n-6 to total n-3 LCPUFA in ASD to those of typically developing individuals (with no neurodevelopmental disorders), and meta-analysis 2 compared the effects of n-3 LCPUFA supplementation to placebo on symptoms of ASD. Case-control studies and randomised controlled trials (RCTs) were identified searching electronic databases up to May, 2016. Mean differences were pooled and analysed using inverse variance models. Heterogeneity was assessed using I² statistic. Fifteen case-control studies (n = 1193) were reviewed. Compared with typically developed, ASD populations had lower DHA (−2.14 [95% CI −3.22 to −1.07]; p < 0.0001; I² = 97%), EPA (−0.72 [95% CI −1.25 to −0.18]; p = 0.008; I² = 88%), and ARA (−0.83 [95% CI, −1.48 to −0.17]; p = 0.01; I² = 96%) and higher total n-6 LCPUFA to n-3 LCPUFA ratio (0.42 [95% CI 0.06 to 0.78]; p = 0.02; I² = 74%). Four RCTs were included in meta-analysis 2 (n = 107). Compared with placebo, n-3 LCPUFA improved social interaction (−1.96 [95% CI −3.5 to −0.34]; p = 0.02; I² = 0) and repetitive and restricted interests and behaviours (−1.08 [95% CI −2.17 to −0.01]; p = 0.05; I² = 0). Populations with ASD have lower n-3 LCPUFA status and n-3 LCPUFA supplementation can potentially improve some ASD symptoms. Further research with large sample size and adequate study duration is warranted to confirm the efficacy of n-3 LCPUFA.

Pretreatment with Fish Oil-Based Lipid Emulsion Modulates Muscle Leukocyte Chemotaxis in Murine Model of Sublethal Lower Limb Ischemia

This study investigated the effects of a fish oil- (FO-) based lipid emulsion on muscle leukocyte chemotaxis and inflammatory responses in a murine model of limb ischemia-reperfusion (IR) injury. Mice were assigned randomly to 1 sham (sham) group, 2 ischemic groups, and 2 IR groups. The sham group did not undergo the ischemic procedure. The mice assigned to the ischemic or IR groups were pretreated intraperitoneally with either saline or FO-based lipid emulsion for 3 consecutive days. The IR procedure was induced by applying a 4.5 oz orthodontic rubber band to the left thigh above the greater trochanter for 120 min and then cutting the band to allow reperfusion. The ischemic groups were sacrificed immediately while the IR groups were sacrificed 24 h after reperfusion. Blood, IR-injured gastrocnemius, and lung tissues were collected for analysis. The results showed that FO pretreatment suppressed the local and systemic expression of several IR-induced proinflammatory mediators. Also, the FO-pretreated group had lower blood Ly6C^hiCCR2^hi monocyte percentage and muscle M1/M2 ratio than the saline group at 24 h after reperfusion. These findings suggest that FO pretreatment may have a protective role in limb IR injury by modulating the expression of proinflammatory mediators and regulating the polarization of macrophage.

Mesenchymal stromal cell therapy for the treatment of intestinal ischemia: Defining the optimal cell isolate for maximum therapeutic benefit

Intestinal ischemia is a devastating intraabdominal emergency that often necessitates surgical intervention. Mortality rates can be high, and patients who survive often have significant long-term morbidity. The implementation of traditional medical therapies to prevent or treat intestinal ischemia have been sparse over the last decade, and therefore, the use of novel therapies are becoming more prevalent. Cellular therapy using mesenchymal stromal cells is one such treatment modality that is attracting noteworthy attention in the scientific community. Several groups have seen benefit with cellular therapy, but the optimal cell line has not been identified. The purpose of this review is to: 1) Review the mechanism of intestinal ischemia and reperfusion injury, 2) Identify the mechanisms of how cellular therapy may be therapeutic for this disease, and 3) Compare various MSC tissue sources to maximize potential therapeutic efficacy in the treatment of intestinal I/R diseases.

The effect of n-3/n-6 polyunsaturated fatty acids on acute reflux esophagitis in rats

BACKGROUND

Polyunsaturated fatty acids (PUFAs) play various roles in inflammation. However, the effect of PUFAs in the development of reflux esophagitis (RE) is unclear. This study is to investigate the potential effect of n-3/n-6 PUFAs on acute RE in rats along with the underlying protective mechanisms.

METHODS

Forty Sprague Dawley rats were randomly divided into four groups (n = 10 in each group). RE model was established by pyloric clip and section ligation. Fish oil- and soybean oil-based fatty emulsion (n-3 and n-6 groups), or normal saline (control and sham operation groups) was injected intraperitoneally 2 h prior to surgery and 24 h postoperatively (2 mL/kg, respectively). The expressions of interleukin (IL)-1β, IL-8, IL-6 and myeloid differentiation primary response gene 88 (MyD88) in esophageal tissues were evaluated by Western blot and immunohistochemistry after 72 h. The malondialdehyde (MDA) and superoxide dismutase (SOD) expression in the esophageal tissues were determined to assess the oxidative stress.

RESULTS

The mildest macroscopic/microscopic esophagitis was found in the n-3 group (P < 0.05). The expression of IL-1β, IL-8, IL-6 and MyD88 were increased in all RE groups, while the lowest and highest expression were found in n-3 and n-6 group, respectively (P < 0.05). The MDA levels were increased in all groups (P < 0.05), in an ascending trend from n-3, n-6 groups to control group. The lowest and highest SOD levels were found in the control and n-3 group, respectively (P < 0.05).

CONCLUSION

n-3 PUFAs may reduce acute RE in rats, which may be due to inhibition of the MyD88-NF-kB pathway and limit oxidative damage.