Anti-inflammatory properties of lipoxin A4 protect against diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury

Lipoxins in the Nervous System: Brighter Prospects for Neuroprotection

Lipoxins (LXs) are generated from arachidonic acid and are involved in the resolution of inflammation and confer protection in a variety of pathological processes. In the nervous system, LXs exert an array of protective effects against neurological diseases, including ischemic or hemorrhagic stroke, neonatal hypoxia-ischemia encephalopathy, brain and spinal cord injury, Alzheimer's disease, multiple sclerosis, and neuropathic pain. Lipoxin administration is a potential therapeutic strategy in neurological diseases due to its notable efficiency and unique superiority regarding safety. Here, we provide an overview of LXs in terms of their synthesis, signaling pathways and neuroprotective evidence. Overall, we believe that, along with advances in lipoxin-related drug design, LXs will bring brighter prospects for neuroprotection.

Effects of Upregulation of TNFAIP3 on Diabetic Neuropathic Pain in Mice

Globally, diabetes has assumed epidemic proportions with the neuropathic complications attributed to the malady emerging as a substantial burden on patients and society. DNP has greatly affected the daily life of patients, the effect of traditional treatment methods is not ideal, and it is easy to produce drug resistance. This work is aimed at scrutinizing the effect of upregulating the expression of TNFAIP3 on diabetic neuralgia in mice. This work entailed ascertaining the effects of TNFAIP3 on a murine DNP system. This inspired us to observe the analgesic effect via high expression of lentivirus-mediated TNFAIP3 by intrathecal injection in the animal model to explore its regulatory impacts, symptom relief, and mechanistic role in pain. The results displayed an attenuation of hind paw pain hypersensitivity by LV-TNFAIP3 in the animals. The spinal cord and dorsal root ganglion of mice with neuropathic pain displayed an evident dip in TNFAIP3. Inhibition of the ERK/NF-κB signaling pathway employing LV-TNFAIP3 conspicuously suppressed this pathway while the diabetic pain hypersensitivity was quelled. This effect was also seen with insulin treatment evidently. In conclusion, according to the above analyses, the interaction between DNP and extracellular signal-regulated kinase signal transduction pathway is one of the key factors of pathogenesis.

Molecular biochemical aspects of salt (sodium chloride) in inflammation and immune response with reference to hypertension and type 2 diabetes mellitus

Obesity, insulin resistance, type 2 diabetes mellitus (T2DM) and hypertension (HTN) are common that are associated with low-grade systemic inflammation. Diet, genetic factors, inflammation, and immunocytes and their cytokines play a role in their pathobiology. But the exact role of sodium, potassium, magnesium and other minerals, trace elements and vitamins in the pathogenesis of HTN and T2DM is not known. Recent studies showed that sodium and potassium can modulate oxidative stress, inflammation, alter the autonomic nervous system and induce dysfunction of the innate and adaptive immune responses in addition to their action on renin-angiotensin-aldosterone system. These actions of sodium, potassium and magnesium and other minerals, trace elements and vitamins are likely to be secondary to their action on pro-inflammatory cytokines IL-6, TNF-α and IL-17 and metabolism of essential fatty acids that may account for their involvement in the pathobiology of insulin resistance, T2DM, HTN and autoimmune diseases.

Specialized pro-resolving lipid mediators in cardiovascular disease, diagnosis, and therapy

Persistent inflammation is the key aggravator in many cardiovascular diseases, including atherosclerosis, aneurysm, injury/reperfusion, thrombosis, and neointimal hyperplasia following surgical or percutaneous interventions. Resolution is an active process orchestrated by specialized pro-resolving lipid mediators (SPMs) which tamp down acute inflammatory signals, promote healing and facilitate a return to homeostasis. SPMs are endogenously derived from poly-unsaturated fatty acids, and their biologic activity is mediated via specific G-protein coupled receptor binding. The potency of SPM in regulating the inflammatory response has encouraged investigation into their therapeutic and diagnostic use in cardiovascular pathologies. Herein we describe the translational groundwork which has established the synthesis and interactions of SPM in cardiovascular and hematologic cells, the therapeutic effects of SPM in animal models of cardiovascular disease, and some early technologies that harness and attempt to optimize SPM delivery and "resolution pharmacology". Further studies are required to precisely determine the mechanisms of resolution in the cardiovascular system and to determine the clinical settings in which SPM can be utilized to optimize patient outcomes.

Liraglutide protects against diabetes mellitus complicated with focal cerebral ischemic injury by activating mitochondrial ATP-sensitive potassium channels

Cerebral infarction is a common disease that threatens the health of humankind worldwide. Diabetes is one of the important causes of cerebral ischemic (CI) injury. CI complicated with diabetes has a worse prognosis and lacks effective treatment. Our preliminary study demonstrated that liraglutide mitigates CI injuries in diabetic rats. However, the essential mechanism underlying this effect remained to be fully investigated. Recent research has shown that damaged mitochondrial ATP-sensitive potassium channels (mitoKATP) play a critical role in diabetes-aggravated CI injury. Therefore, we hypothesized that liraglutide may confer therapeutic effects against CI with diabetes by activating mitoKATP channels. In this study, liraglutide, but not insulin, significantly improved ischemia-induced neurological deficits and decreased infarct volumes following CI in diabetic rats, down-regulated the expression of myeloperoxidase and up-regulated the expression of superoxide dismutase and two subunits of the mitoKATP channel (SUR1 and Kir6.2). However, these effects were weakened by the mitoKATP antagonist 5-hydroxydecanoic acid. Our study demonstrated that the neuroprotective effects of liraglutide on CI injury with diabetes, which occurs by reducing oxidative stress and the inflammatory response, are associated with the activation of the mitoKATP channel.

Pro-resolving lipid mediators in vascular disease

Unresolved inflammation is central to the pathophysiology of commonly occurring vascular diseases such as atherosclerosis, aneurysm, and deep vein thrombosis - conditions that are responsible for considerable morbidity and mortality. Surgical or catheter-based procedures performed on affected blood vessels induce acute-on-chronic inflammatory responses. The resolution of vascular inflammation is an important driver of vessel wall remodeling and functional recovery in these clinical settings. Specialized pro-resolving lipid mediators (SPMs) derived from omega-3 polyunsaturated fatty acids orchestrate key cellular processes driving resolution and a return to homeostasis. The identification of their potent effects in classic animal models of sterile inflammation triggered interest in their vascular properties. Recent studies have demonstrated that SPMs are locally synthesized in vascular tissues, have direct effects on vascular cells and their interactions with leukocytes, and play a protective role in the injury response. Early translational work has established the potential for SPMs as vascular therapeutics, and as candidate biomarkers in vascular disease. Further investigations are needed to understand the molecular and cellular mechanisms of resolution in the vasculature, to improve tools for clinical measurement, and to better define the potential for "resolution therapeutics" in vascular patients.

Low dose aspirin increases 15-epi-lipoxin A4 levels in diabetic chronic kidney disease patients

BACKGROUND

Resolution of inflammation is regulated by endogenous lipid mediators, such as lipoxins and their epimers, including 15-epi-lipoxin A4 (15-epi-LXA4). However, there is no information on 15-epi-LXA4 and its in vivo regulation in chronic kidney disease (CKD) patients.

STUDY DESIGN

Open label randomized clinical trial.

SETTING AND PARTICIPANTS

50 participants with chronic kidney disease (CKD) stage 3 and 4 without prior cardiovascular disease (25 in the aspirin group and 25 in the standard group) followed for 46 months.

INTERVENTION

Aspirin (100mg/day) or standard treatment.

AIM

To analyze the effect of aspirin on plasma 15-epi-LXA4 levels and inflammatory markers in CKD patients.

RESULTS

Baseline plasma15-epi-LXA4 levels were lower in diabetic (1.22 ± 0.99ng/ml) than in non-diabetic CKD patients (2.05 ± 1.06ng/ml, p < 0.001) and inversely correlated with glycosylated hemoglobin levels (r = -0.303, p = 0.006). In multivariate analysis, diabetes was associated with lower 15-epi-LXA4 levels, adjusted for age, inflammatory markers and renal function (p = 0.005). In the whole study population, 15-epi-LXA4 levels tended to increase, but not significantly (p = 0.45), after twelve months on aspirin (from mean ± SD 1.84 ± 1.06 to 2.04 ± 0.75ng/ml) and decreased in the standard care group (1.60 ± 1.15 to 1.52 ± 0.68ng/ml, p = 0.04). The aspirin effect on 15-epi-LXA4 levels was more striking in diabetic patients, increasing from 0.94 ± 0.70 to 1.93 ± 0.74ng/ml, p = 0.017.

CONCLUSIONS

Diabetic patients with CKD have lower circulating 15-epi-LXA4 levels than non-diabetic CKD patients. Low dose aspirin for 12 months increased 15-epi-LXA4 levels in diabetic patients. Given its anti-inflammatory properties, this increase in 15-epi-LXA4 levels may contribute to the beneficial effects of low dose aspirin.

Lipoxin A4 pretreatment mitigates skeletal muscle ischemia-reperfusion injury in rats

The aim of this study was to investigate the protective effects and underlying anti-oxidative molecular mechanism of lipoxin A4 (LA4) in rats with ischemia/reperfusion (I/R)-injured skeletal muscle. A rat model of I/R-injured skeletal muscle was obtained by subjecting rats to a 3-h ligation of the right femoral artery followed by 3 h of reperfusion. Treatment with LA4 significantly ameliorated histological damage scores in I/R-injured skeletal muscle. LA4 treatment resulted in remarkable decreases in the wet weight/dry weight ratio (W/D ratio), inflammatory response, oxidative stress, and cell apoptosis. In addition, treatment with LA4 was accompanied by a prominently enhanced nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and expression of heme oxygenase 1 (HO-1) in the I/R-injured skeletal muscle. However, these protective effects were reversed by zinc protoporphyrin-IX (ZnPP), a specific HO-1 inhibitor. Our study shows that LA4 may have the potential as a therapeutic agent for I/R-injured muscle tissue via activation of the Nrf2/HO-1 signaling pathway.

Effect of etomidate on the oxidative stress response and levels of inflammatory factors from ischemia-reperfusion injury after tibial fracture surgery

The effect of etomidate on the oxidative stress response and levels of inflammatory factors resulting from ischemia-reperfusion injury of the lower extremities during tibial fracture surgery were investigated. From December 2013 to June 2015, 60 tibial fracture patients with surgical indications for open reduction and internal fixation were selected. Patients were randomly divided into the observation group and the control group. All patients were stanched by tourniquet hemostasis. Patients in the observation group were anesthetized with etomidate (3–6 mg/kg·h) + remifentanil (0.1–0.25 µg/kg/min) administered with an injection pump to maintain intraoperative sedation and analgesia anesthesia. Patients in the control group received propofol (3–6 mg/kg·h) + remifentanil (0.1–0.25 µg/kg/min). Before surgery (T0), before surgery was completed and anesthesia was stopped (T1), 24 h after surgery (T3), 48 h after surgery (T4), and 1 week after surgery (T5), serum superoxide dismutase (SOD) activity was determined with a kit, and ELISA was used to measure the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6 in peripheral blood from both groups of patients. Surgery in both groups was completed smoothly. We found that serum SOD levels of patients in the observation group were significantly higher than those of the control group, while the levels of TNF-α, IL-1, and IL-6 released by neutrophils were significantly decreased after ischemia-reperfusion injury (P<0.05). Postoperative length of stay in hospital of the observation group was significantly shorter and the occurrence rate of anesthesia complications was significantly lower than in the control group (P<0.05). In conclusion, during surgery for lower limb fracture, the use of etomidate for maintaining sedation can effectively maintain serum SOD activity and inhibit the release of inflammatory factors after ischemia-reperfusion injury of the fracture, to reduce the occurrence rate of anesthesia complications after surgery.

Fermented Chinese formula Shuan-Tong-Ling attenuates ischemic stroke by inhibiting inflammation and apoptosis

The fermented Chinese formula Shuan-Tong-Ling is composed of radix puerariae (Gegen), salvia miltiorrhiza (Danshen), radix curcuma (Jianghuang), hawthorn (Shanzha), salvia chinensis (Shijianchuan), sinapis alba (Baijiezi), astragalus (Huangqi), panax japonicas (Zhujieshen), atractylodes macrocephala koidz (Baizhu), radix paeoniae alba (Baishao), bupleurum (Chaihu), chrysanthemum (Juhua), rhizoma cyperi (Xiangfu) and gastrodin (Tianma), whose aqueous extract was fermented with lactobacillus, bacillus aceticus and saccharomycetes. Shuan-Tong-Ling is a formula used to treat brain diseases including ischemic stroke, migraine, and vascular dementia. Shuan-Tong-Ling attenuated H₂O₂-induced oxidative stress in rat microvascular endothelial cells. However, the potential mechanism involved in these effects is poorly understood. Rats were intragastrically treated with 5.7 or 17.2 mL/kg Shuan-Tong-Ling for 7 days before middle cerebral artery occlusion was induced. The results indicated Shuan-Tong-Ling had a cerebral protective effect by reducing infarct volume and increasing neurological scores. Shuan-Tong-Ling also decreased tumor necrosis factor-α and interleukin-1β levels in the hippocampus on the ischemic side. In addition, Shuan-Tong-Ling upregulated the expression of SIRT1 and Bcl-2 and downregulated the expression of acetylated-protein 53 and Bax. Injection of 5 mg/kg silent information regulator 1 (SIRT1) inhibitor EX527 into the subarachnoid space once every 2 days, four times, reversed the above changes. These results demonstrate that Shuan-Tong-Ling might benefit cerebral ischemia/reperfusion injury by reducing inflammation and apoptosis through activation of the SIRT1 signaling pathway.