Sumatriptan attenuates fear-learning despair induced by social isolation stress in mice: Mediating role of hypothalamic-pituitary-adrenal axis

OBJECTIVES

Research has demonstrated that chronic stress experienced early in life can lead to impairments in memory and learning. These deficits are attributed to an imbalance in the interaction between glucocorticoids, the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and glucocorticoid receptors in brain regions responsible for mediating memory, such as the hippocampus. This imbalance can result in detrimental conditions like neuroinflammation. The aim of this study was to assess the impact of sumatriptan, a selective agonist for 5-HT 1B/1D receptors, on fear learning capabilities in a chronic social isolation stress model in mice, with a particular focus on the role of the HPA axis.

METHODS

Mice were assigned to two opposing conditions, including social condition (SC) and isolated condition (IC) for a duration of five weeks. All mice underwent passive avoidance test, with their subsequent freezing behavior serving as an indicator of fear retrieval. Mice in the IC group were administered either a vehicle, sumatriptan, GR-127935 (a selective antagonist for 5-HT 1B/1D receptors), or a combination of sumatriptan and GR-127935 during the testing sessions. At the end, all mice were sacrificed and samples of their serum and hippocampus were collected for further analysis.

RESULTS

Isolation was found to significantly reduce freezing behavior (p<0.001). An increase in the freezing response among IC mice was observed following the administration of varying doses of sumatriptan, as indicated by a one-way ANOVA analysis (p<0.001). However, the mitigating effects of sumatriptan were reversed upon the administration of GR-127935. An ELISA assay conducted before and after the passive avoidance test revealed no significant change in serum corticosterone levels among SC mice. In contrast, a significant increase was observed among IC mice, suggesting hyper-responsiveness of the HPA axis in isolated animals. This hyper-responsiveness was ameliorated following the administration of sumatriptan. Furthermore, both the sumatriptan and SC groups exhibited a similar trend, showing a significant increase in the expression of hippocampal glucocorticoid receptors following the stress of the passive avoidance test. Lastly, the elevated production of inflammatory cytokines (TNF-α, IL-1β) observed following social isolation was attenuated in the sumatriptan group.

CONCLUSION

Sumatriptan improved fear learning probably through modulation of HPA axis and hippocampus neuroinflammation.

Evaluation of colonic anastomosis healing using hybrid nanosheets containing molybdenum disulfide (MOS2) scaffold of human placental amniotic membrane and polycaprolactone (PCL) in rat animal model

Anastomosis is a standard technique following different conditions such as obstruction, tumor, and trauma. Obstruction, adhesion, or anastomosis leakage can be some of its complications. To improve healing and prevent postoperative complications, we design a hybrid scaffold containing acellular human amniotic membranes and polycaprolactone-molybdenum disulfide nanosheets for colon anastomosis. The animal model of colocolonic anastomosis was performed on two groups of rats: control and scaffold. The hybrid scaffold was warped around the anastomosis site in the scaffold group. Samples from the anastomosis site were resected on the third and seventh postoperative days for histopathological and molecular assessments. Histopathologic score and burst pressure had shown significant improvement in the scaffold group. No mortality and anastomosis leakage was reported in the scaffold group. In addition, inflammatory markers were significantly decreased, while anti-inflammatory cytokines were increased in the scaffold group. The result indicates that our hybrid scaffold is a proper choice for colorectal anastomosis repair by declining postoperative complications and accelerating healing.

The efficacy of intrathecal methyl-prednisolone for acute spinal cord injury: A pilot study

Study design

Randomized clinical trial.

Objectives

To evaluate the safety and effectiveness of intrathecal methyl-prednisolone compared to intravenous methyl-prednisolone in acute spinal cord injuries.

Setting

Imam Reza Hospital, Tabriz University of Medical Sciences.

Methods

Patients meeting our inclusion and exclusion criteria were enrolled in the study and divided randomly into two treatment arms: intrathecal and intravenous. Standard spinal cord injury care (including surgery) was given to each patient based on our institutional policy. Patients were then assessed for neurological status (based on ASIA scores, Frankel scores) and complications for six months and compared to baseline status after injury. To better understand the biological bases of methyl-prednisolone on spinal cord injuries, we measured two biomarkers for oxidative stress (serum malondialdehyde and total antioxidant capacity) in these patients at arrival and day three after injury.

Results

The present study showed no significant difference between the treatment arms in neurological status (sensory scores or motor scores) or complications. However, the within-group analysis showed improvement in neurological status in each treatment arm within six months. Serum malondialdehyde and total antioxidant capacity were analyzed, and no significant difference between the groups was seen.

Conclusion

This is the first known clinical trial investigating the effect of intrathecal MP in acute SCI patients. Our finding did not show any significant differences in complication rates and neurological outcomes between the two study arms. Further studies should be conducted to define the positive and negative effects of this somehow novel technique in different populations as well.

Albendazole ameliorates inflammatory response in a rat model of acute mesenteric ischemia reperfusion injury

BACKGROUND

Acute mesenteric ischemia is known as a life threatening condition. Re-establishment of blood flow in this condition can lead to mesenteric ischemia reperfusion (MIR) injury which is accompanied by inflammatory response. Still, clear blueprint of inflammatory mechanism underlying MIR injury has not been provided. Interestingly, Albendazole has exhibited notable effects on inflammation and cytokine production. In this study, we aimed to evaluate outcomes of MIR injury following pretreatment with Albendazole with respect to assessment of mesenteric inflammation and ischemia threshold.

METHODS

Male rats were randomly divided into sham operated, vehicle treated, Albendazole 100 mg/kg and Albendazole 200 mg/kg groups. MIR injury was induced by occlusion of superior mesenteric artery for 30 min followed by 120 min of reperfusion. Samples were utilized for assessment of epithelial survival and villous height. Immunohistochemistry study revealed intestinal expression of TNF-α and HIF-1-α. Gene expression of NF-κB/TLR4/TNF-α/IL-6 was measured using RTPCR. Also protein levels of inflammatory cytokines in serum and intestine were assessed by ELISA method.

RESULTS

Histopathological study demonstrated that pretreatment with Albendazole could ameliorate decline in villous height and epithelial survival following MIR injury. Also, systemic inflammation was suppressed after administration of Albendazole. Analysis of possible participating inflammatory pathway could demonstrate that intestinal expression of NF-κB/TLR4/TNF-α/IL-6 is significantly attenuated in treated groups. Eventually, IHC study illustrated concordant decline in mesenteric expression of HIF-1-α/TNF-α.

CONCLUSION

Single dose pretreatment with Albendazole could ameliorate inflammatory response and enhance ischemia threshold following induction of MIR injury. More studies would clarify existing causality in this phenomenon.

Ac-SDKP peptide improves functional recovery following spinal cord injury in a preclinical model

Damage to the spinal cord triggers a local complex inflammatory reaction that results in irreversible impairments or complete loss of motor function. The evidence suggested that inhibiting the pro-inflammatory macrophage/microglia (M1 subsets) and stimulating the anti-inflammatory macrophage/microglia (M2 subsets) are potential strategies for the treatment of neuroinflammation-related diseases. We evaluated the potentially protective effect of Ac-SDKP as an endogenous tetrapeptide on rat spinal cord injury (SCI). Wistar rats were subjected to a weight-drop contusion model and were treated with Ac-SDKP (0.8 mg/kg) given subcutaneously once a day for 7 days starting at two clinically relevant times, at 2 h or 6 h post-injury. The effect of Ac-SDKP was assessed by motor functional analysis, real-time PCR (CD86 and CD206 mRNA), western blot (caspase-3), ELISA (TNF-a, IL-10), and histological analysis (toluidine blue staining). Ac-SDKP improved locomotor recovery and rescue motor neuron loss after SCI. Moreover, a decreased in TNF-a level as well as caspase 3 protein levels occurred in the lesion epicenter of the spinal cord following treatment. In addition, CD206 mRNA expression level increased significantly in Ac-SDKP treated rats compared with SCI. Together these data suggest that Ac-SDKP might be a novel immunomodulatory drug. It may be beneficial for the treatment of SCI with regards to increasing CD206 gene expression and suppress inflammatory cytokine to improve motor function and reducing histopathological lesion.

Advanced Regenerative Medicine Strategies for Treatment of Perianal Fistula in Crohn's Disease

Regenerative medicine is an emerging therapeutic method that aims to reconstruct tissues and organs. This advanced therapeutic approach has demonstrated great potential in addressing the limitations of medical and surgical procedures for treating perineal fistula in patients with Crohn's disease. Recent developments in stem cell technology have led to a massive good manufacturing practices (GMPs) production of various stem cells, including mesenchymal and embryonic cells, along with induction of pluripotent stem cells to repair damaged tissues in the fistula. The recent advances in separation and purification of exosomes, as biologic nanovesicles carrying anti-inflammatory and regenerative agents, have made them powerful tools to treat this inflammatory disease. Further, tremendous advances in nanotechnology, biomaterials, and scaffold fabrication methods enable tissue engineering methods to synthesize tissue-like structures to assist surgical techniques. This review focuses on advanced regenerative-based methods including stem cell therapy, exosome therapy, and tissue engineering used in the treatment of perianal fistula. Relevant in vitro and in vivo studies and the latest innovations in implementation of regenerative medicine for this disease are also separately reviewed. Additionally, current challenges regarding implementation of g stem cells, exosomes, and tissue engineering methods for bridging the gaps between laboratory findings and clinic application will be discussed.

Therapeutic Effects of Azithromycin on Spinal Cord Injury in Male Wistar Rats: A Role for Inflammatory Pathways

BACKGROUND

 Inflammatory responses, including macrophages/microglia imbalance, are associated with spinal cord injury (SCI) complications. Accumulating evidence also suggests an anti-inflammatory property of azithromycin (AZM).

MATERIAL AND METHODS

 Male Wistar rats were subjected to T9 vertebra laminectomy. SCI was induced by spinal cord compression at this level with an aneurysmal clip for 60 seconds. They were divided into three groups: the sham-operated group and two SCI treatment (normal saline as a vehicle control vs. AZM at 180 mg/kg/d intraperitoneally for 3 days postsurgery; first dose: 30 minutes after surgery) groups. Locomotor scaling and behavioral tests for neuropathic pain were evaluated and compared through a 28-day period. At the end of the study, tissue samples were taken to assess neuroinflammatory changes and neural demyelination using ELISA and histopathologic examinations, respectively. In addition, the proportion of M1/M2 macrophage polarization was assessed by using flow cytometry.

RESULTS

 Post-SCI AZM treatment (180 mg/kg/d for 3 days) significantly improved locomotion (p < 0.01) and decreased sensitivity to mechanical (p < 0.01) and thermal allodynia (p < 0.001). Moreover, there was a significant tumor necrosis factor-α (TNF-α) decline (p < 0.01) and interleukin-10 (IL-10) elevation (p < 0.01) in the spinal cord tissue of the AZM-treated group compared with the control groups 28 days post-SCI. AZM significantly improved neuroinflammation as evidenced by reduction of the M1 expression, elevation of M2 macrophages, and reduction of the M1/M2 ratio in both the dorsal root ganglion and the spinal cord tissue after SCI compared with controls (p < 0.01).

CONCLUSION

 AZM treatment can be considered a therapeutic agent for SCI, as it could reduce neuroinflammation and SCI sensory/locomotor complications.

Melatonin improves learning and memory of mice with chronic social isolation stress via an interaction between microglia polarization and BDNF/TrkB/CREB signaling pathway

Chronic social isolation stress (SIS) could impair learning and memory-related behaviors. Herein, we investigated the efficacy of Melatonin in treatment of memory despair and also its possible underlying mechanism of action in an animal model of SIS. For this purpose, mice were allocated to two opposing conditions, including social condition (SC) and isolated condition (IC), for five weeks. The study consisted of three groups, including saline-treated SC, saline-treated IC, Melatonin-treated IC (10 mg/kg/day for five successive days). At the end of the isolation period, mice underwent three neurobehavioral tests: passive avoidance (PA), Morris water maze (MWM), and Y maze (YM) tests. Hippocampus samples were obtained and the expressions of BDNF, TrkB, phosphorylated TrkB (pTrkB), CREB, phosphorylated CREB (pCREB), as well as M1 and M2 microglia were assessed. Interpreting the behavioral tests, we found that isolated mice showed lower freezing response in the PA test, lower number of novel arm visits in the YM, and higher escape latency and less time spent in the target quadrant in the MWM, when compared to SC rodents (P values < 0.001). The isolated group had higher M1/M2 relative ratio (P < 0.001), as well as lower concentrations of BDNF mRNA (p < 0.001) and protein (P < 0.001), TrkB protein (P = 0.035), CREB mRNA (P < 0.001) and protein (P = 0.012), pTrkB (P < 0.001), and pCREB (P = 0.035). However, Melatonin relatively reversed the behavioral, cellular, and molecular effects of SIS. Taken together, melatonin therapy could alleviate memory impairment through switching microglial polarization from M1 to M2 phenotype along with altered expression and function in the BDNF/TrkB/CREB signaling pathway.

Introduction of a Handmade Vacuum-Assisted Sponge Drain for the Treatment of Anastomotic Leakage After Low Anterior Rectal Resection

Purpose

Anastomotic leakage, a known major postoperative complication, potentially leads to readmission, reoperation, and increased mortality rates in patients, such as rectal cancer patients following a low anterior resection (LAR). Currently, vacuum-assisted closure, as featured by B-Braun (B-Braun Medical B.V.), is already being used for the treatment of gastrointestinal leakages and fistulas. The main aim of this study was to introduce a novel method for creating a vacuum-assisted drain for the treatment of anastomotic leakage after LAR.

Methods

All 10 patients, who underwent LAR surgery from 2018 to 2019, were diagnosed with anastomotic leakage and had received neoadjuvant chemotherapy prior to surgery. Therefore, patients were treated with a handmade vacuum-assisted drain and were revisited every 5 to 7 days for further evaluations and drain replacement until leakage resolution. Physical features of cavity, time of diagnose, and duration of treatment were analyzed correspondingly. The handmade vacuum-assisted sponge drain was prepared for each patient in each session of follow-up.

Results

Eight out of 10 patients experienced complete closure of the defect. The mean delay time from the day of operation to the diagnosis of anastomotic leakage was 61.0±80.4 days while the mean time for leakage closure was 117.6±68.3 days. Eventually, 7 cases underwent ileostomy reversal with no complications during a 3-month follow-up.

Conclusion

In this study, we evaluated the healing process of anastomotic leakage after the usage of a handmade vacuum-assisted sponge drain in a case series method. In our trial, we provided an innovative cost-benefit method easily applicable in the operating room.

Inhibition of phosphodiesterase IV enzyme improves locomotor and sensory complications of spinal cord injury via altering microglial activity: Introduction of Roflumilast as an alternative therapy

Despite the great search for an effective approach to minimize secondary injury in spinal cord injury (SCI) setting, there have been limited advances. Roflumilast is a selective inhibitor of phosphodiesterase 4 with potent anti-inflammatory properties. Here, we sought to explore Roflumilast efficacy in the improvement of locomotor and sensory deficits of SCI. In an animal setting, 50 male rats were randomly assigned to five groups: an SCI group receiving Placebo, three SCI groups receiving Roflumilast at the doses of 0.25, 0.5, and 1 mg/kg prior to T9 vertebra laminectomy, and a sham-operated group. Locomotor, mechanical, and thermal activities were evaluated for 28 days. At the end of the study, spinal cord samples were taken to assess the relative ratio of microglial subtypes, including M1 and M2, histopathological changes, levels of pro-inflammatory (TNF-α and IL-1β) and anti-inflammatory (IL-10) biomarkers, and cAMP level. Repeated measure analysis revealed significant effect for time-treatment interaction on locomotion [F (24, 270) = 280.7, p < 0.001], thermal sensitivity [F (16, 180) = 4.35, p < 0.001], and mechanical sensitivity [F (16, 180) = 7.96, p < 0.001]. As expected, Roflumilast significantly increased the expression of spinal cAMP. H&E staining exhibited lesser histopathological disruptions in Roflumilast-treated rodents. We also observed a significant reduction in the M1/M2 ratio (p values < 0.001) as well as in pro-inflammatory biomarkers following the administration of Roflumilast to the injured rats. Furthermore, IL-10 level was increased in rodents receiving 1 mg/kg of the reagent. In conclusion, the increased spinal cAMP following Roflumilast therapy might attenuate neuroinflammation via altering microglial activity; therefore, it could be considered as an alternative therapeutic agent for SCI complications.