Activation of α-7 nicotinic acetylcholine receptor reduces ischemic stroke injury through reduction of pro-inflammatory macrophages and oxidative stress

Activation of α-7 nicotinic acetylcholine receptor (α-7 nAchR) has a neuro-protective effect on ischemic and hemorrhagic stroke. However, the underlying mechanism is not completely understood. We hypothesized that α-7 nAchR agonist protects brain injury after ischemic stroke through reduction of pro-inflammatory macrophages (M1) and oxidative stress. C57BL/6 mice were treated with PHA568487 (PHA, α-7 nAchR agonist), methyllycaconitine (MLA, nAchR antagonist), or saline immediately and 24 hours after permanent occlusion of the distal middle cerebral artery (pMCAO). Behavior test, lesion volume, CD68⁺, M1 (CD11b⁺/Iba1⁺) and M2 (CD206/Iba1⁺) microglia/macrophages, and phosphorylated p65 component of NF-kB in microglia/macrophages were quantified using histological stained sections. The expression of M1 and M2 marker genes, anti-oxidant genes and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase were quantified using real-time RT-PCR. Compared to the saline-treated mice, PHA mice had fewer behavior deficits 3 and 7 days after pMCAO, and smaller lesion volume, fewer CD68⁺ and M1 macrophages, and more M2 macrophages 3 and 14 days after pMCAO, whereas MLA's effects were mostly the opposite in several analyses. PHA increased anti-oxidant genes and NADPH oxidase expression associated with decreased phosphorylation of NF-kB p65 in microglia/macrophages. Thus, reduction of inflammatory response and oxidative stress play roles in α-7 nAchR neuro-protective effect.

Amniotic membrane grafts for the prevention of esophageal stricture after circumferential endoscopic submucosal dissection

Background and Aims

The prevention of esophageal strictures following circumferential mucosal resection remains a major clinical challenge. Human amniotic membrane (AM) is an easily available material, which is widely used in ophthalmology due to its wound healing, anti-inflammatory and anti-fibrotic properties. We studied the effect of AM grafts in the prevention of esophageal stricture after endoscopic submucosal dissection (ESD) in a swine model.

Animals and Methods

In this prospective, randomized controlled trial, 20 swine underwent a 5 cm-long circumferential ESD of the lower esophagus. In the AM Group (n = 10), amniotic membrane grafts were placed on esophageal stents; a subgroup of 5 swine (AM 1 group) was sacrificed on day 14, whereas the other 5 animals (AM 2 group) were kept alive. The esophageal stent (ES) group (n = 5) had ES placement alone after ESD. Another 5 animals served as a control group with only ESD.

Results

The prevalence of symptomatic strictures at day 14 was significantly reduced in the AM group and ES groups vs. the control group (33%, 40% and 100%, respectively, p = 0.03); mean esophageal diameter was 5.8±3.6 mm, 6.8±3.3 mm, and 2.6±1.7 mm for AM, ES, and control groups, respectively. Median (range) esophageal fibrosis thickness was 0.87 mm (0.78–1.72), 1.19 mm (0.28–1.95), and 1.65 mm (0.7–1.79) for AM 1, ES, and control groups, respectively. All animals had developed esophageal strictures by day 35.

Conclusions

The anti-fibrotic effect of AM on esophageal wound healing after ESD delayed the development of esophageal stricture in our model. However, this benefit was of limited duration in the conditions of our study.

Esophageal circumferential en bloc endoscopic submucosal dissection: assessment of a new technique

BACKGROUND

Endoscopic esophageal piecemeal mucosectomy for high-grade dysplasia on Barrett's esophagus leads to suboptimal histologic evaluation, as well as recurrence on remaining mucosa. Circumferential en bloc mucosal resection would significantly improve the management of dysplastic Barrett's esophagus. Our aim was to describe a new method of esophageal circumferential endoscopic en bloc submucosal dissection (CESD) in a swine model.

METHODS

After submucosal injection, circumferential incision was performed at each end of the esophageal segment to be removed. Mechanical submucosal dissection was performed from the proximal to the distal incision, using a mucosectomy cap over the endoscope. The removed mucosal ring was retrieved. Clinical, endoscopic, and histologic data were prospectively collected.

RESULTS

Esophageal CESD was conducted on 5 pigs. A median mucosal length of 6.5 cm (range, 4 to 8 cm) was removed in the lower third of the esophagus. The mean duration of the procedure was 36 minutes (range, 17 to 80 min). No procedure-related complication, including perforation, was observed. All animals exhibited a mild esophageal stricture at day 7, and a severe symptomatic stricture at day 14. Necropsy confirmed endoscopic findings with cicatricial fibrotic strictures. On histologic examination, an inflammatory cell infiltrate, diffuse fibrosis reaching the muscular layer, and incomplete reepithelialization were observed.

CONCLUSIONS

CESD enables expeditious resection and thorough examination of large segments of esophageal mucosa in safe procedural conditions, but esophageal strictures occur in the majority of the cases. Efficient methods for stricture prevention are needed for this technique to be developed in humans.

Oligoclonal expansions of mucosal T cells in Crohn's disease predominate in NKG2D-expressing CD4 T cells

Crohn's disease (CD) is an inflammatory pathology of the mucosal intestine that results from uncontrolled immune response towards commensal microbes. Clonal expansions of T cells have been found in patients with CD suggesting an antigen-specific stimulation of pathogenic T cells. Here we show, using T-cell receptor repertoire analysis by real-time PCR, that oligoclonal expansions are found in both CD8+ and CD4+ T cells in the blood and intestinal mucosa of CD patients. The majority of CD4+ T-cell-expanded clones are CD4+NKG2D+ T cells. These clonal expansions were found in both inflamed and neighboring healthy tissue and were persisting during the course of the disease. The presence of these CD4+NKG2D+ T-cell clones at the macroscopically normal edge of the surgical resection might be predictive of inflammation relapse post surgery.

Should an intrauterine insemination with donor semen be performed 1 or 2 days after the spontaneous LH rise? A prospective RCT

STUDY QUESTION

What is the impact on pregnancy rates when intrauterine insemination (IUI) is performed 1 or 2 days after the spontaneous LH rise?

SUMMARY ANSWER

IUI 1 day after the spontaneous LH rise results in significantly higher clinical pregnancy rates compared with IUI performed 2 days after the LH rise.

WHAT IS KNOWN ALREADY

IUI is scheduled within a limited time interval during which successful conception can be expected. Data about the optimal timing of IUI are based on inseminations following ovarian stimulation. There is no available evidence regarding the correct timing of IUI in a natural menstrual cycle following the occurrence of a spontaneous LH rise.

STUDY DESIGN, SIZE, DURATION

A prospective RCT, including patients undergoing IUI with donor sperm in a natural menstrual cycle. IUI cycles (n = 435) were randomized between October 2010 and April 2013, of which 23 were excluded owing to protocol deviation and 412 received the allocated intervention.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Serial serum LH concentrations were analysed in samples taken between 07:00 and 09:00 h to detect an LH rise from Day 11 of the cycle onwards. The subjects were randomized to receive insemination either 1 or 2 days after the observed LH rise. In the final analysis, there were 213 cycles in the group receiving IUI 1 day after the LH rise and 199 cycles in the group receiving IUI 2 days after the LH rise.

MAIN RESULTS AND THE ROLE OF CHANCE

Significantly higher clinical pregnancy rates per IUI cycle were observed in patients undergoing IUI 1 day after the LH rise when compared with patients undergoing IUI 2 days after the LH rise [19.7 (42/213) versus 11.1% (22/199), P = 0.02]. In view of the timing of sampling for LH, the inseminations were performed at 27 h (±2 h) and 51 h (±2 h) after detection of the LH rise. The risk ratio of achieving a clinical pregnancy if IUI was scheduled 1 day after the LH rise compared with 2 days was 1.78 [95% confidence interval (CI), 1.11-2.88]. This points towards a gain of one additional clinical pregnancy for every 12 cycles performed 1 day instead of 2 days after the LH rise. When analysing the results per patient, including only women who underwent their first treatment cycle of insemination, the outcome was in line with the per cycle analysis, demonstrating an 8% difference in pregnancy rate in favour of the early group (20.5 versus 12.2%), however, this difference was not significant.

LIMITATIONS, REASONS FOR CAUTION

Optimal monitoring for the occurrence of the LH rise involves several daily LH measurements, which is not always amenable to everyday clinical practice, however, daily sampling was sufficient to detect a significant difference in pregnancy rate. The strict inclusion of a highly selected population of patients who underwent IUI in a natural cycle may have been a limitation. IUI in a natural menstrual cycle confers lower success rates compared with IUI following ovarian stimulation and is not suitable for patients with ovulatory dysfunction. Furthermore, a similar study in a larger number of women is required to confirm the result in terms of pregnancy rate per patient.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first RCT to show that timing of IUI in a natural menstrual cycle is important and that IUI should be performed 1 day after the LH rise, rather than 2 days post-LH rise. Daily monitoring of the rise in LH, as performed in our study, can be adopted to achieve a higher pregnancy rate per IUI cycle.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was received for this study. All authors declare to have no conflict of interest with regard to this trial.

TRIAL REGISTRATION NUMBER

The trial was registered at clinicaltrials.gov (NCT01622023).

Abstract W P98: Activation of α7 Nicotinic Acetylcholine Receptor Reduces Pro-Inflammatory Macrophage and Improves Ischemic Stroke Recovery

Background and Purpose: Inflammation influences stroke recovery. Activation of α7 nicotinic acetylcholine receptor (α7 nAchR) attenuates inflammation. We hypothesize that α7 nAchR agonist treatment reduces pro-inflammatory macrophages (M1) and improves ischemic stroke recovery.

Methods: C57BL/6 mice underwent permanent distal middle cerebral artery occlusion (pMCAO). They were randomly assigned to 7 groups: injected intraperitoneally with 0.4 or 0.8 mg/Kg PHA568487 (PHA, α7 nAchR agonist), 4 or 6 mg/Kg methyllycaconitine (MLA, α7 nAchR antagonist), or saline immediately after pMCAO, or with 0.8 mg/Kg PHA or 6 mg/kg MLA immediately and 24 hours after pMCAO. Behavior was assessed by corner and adhesive removal tests at 3, 7, and 14 days after pMCAO (n=12). Atrophic volume (n=7) and the percentage of total (CD68 + ) and M1 (CD11b + /Iba1 + ) macrophages (n=6) among total cells in the peri-infarct region were quantified 14 days after pMCAO. The expression of M1 (CD11b and iNOS) and M2 marker (CD206) were quantified using real-time RT-PCR (n=4).

Results: Compared to the saline-treated mice, those treated with two doses of 0.8 mg/kg PHA performed better in both behavioral tests at 3 (adhesive: p=0.01, corner: p=0.02) and 7 (adhesive: p=0.005, corner: p=0.03) days, and in the adhesive removal test at 14 days (p=0.004) after pMCAO. They had smaller atrophic volume (16±7 mm 3 vs 26±5 mm 3 , p=0.008), and fewer total (9±2.5% vs 15.8±1.7%, p<0.001) and M1 (14±2.3% vs 20.6±4.2%, p=0.005) macrophages. Mice treated with two doses of 6 mg/kg MLA performed worse in the behavioral tests at all times (p<0.05), had larger atrophic volume (48±20 mm 3 , p=0.03), and more total (25±4.2%, p=0.0003) and M1 macrophages (28±4.5%, p=0.01). The expression of CD11b and iNOS decreased (p<0.05) in the PHA group, and increased (p=0.01) in the MLA group. CD206 expression increased (p=0.04) in the PHA group and did not change in the MLA group. One-dose treatment had no effect.

Conclusions: Activation of α7 nAchR reduces pro-inflammatory macrophages in the peri-infarct region, which is associated with reduction of atrophic volume and improvement of behavioral recovery.

De novo cerebrovascular malformation in the adult mouse after endothelial Alk1 deletion and angiogenic stimulation

BACKGROUND AND PURPOSE

In humans, activin receptor-like kinase 1 (Alk1) deficiency causes arteriovenous malformations (AVMs) in multiple organs, including the brain. Focal Alk1 pan-cellular deletion plus vascular endothelial growth factor stimulation induces brain AVMs in the adult mouse. We hypothesized that deletion of Alk1 in endothelial cell (EC) alone plus focal vascular endothelial growth factor stimulation is sufficient to induce brain AVM in the adult mouse.

METHODS

Focal angiogenesis was induced in the brain of 8-week-old Pdgfb-iCreER;Alk1(2f/2f) mice by injection of adeno-associated viral vectors expressing vascular endothelial growth factor. Two weeks later, EC-Alk1 deletion was induced by tamoxifen treatment. Vascular morphology was analyzed, and EC proliferation and dysplasia index (number of vessels with diameter>15 μm per 200 vessels) were quantified 10 days after tamoxifen administration.

RESULTS

Tangles of enlarged vessels resembling AVMs were present in the brain angiogenic region of tamoxifen-treated Pdgfb-iCreER;Alk1(2f/2f) mice. Induced brain AVMs were marked by increased dysplasia index (P<0.001) and EC proliferation clustered within the dysplastic vessels. AVMs were also detected around the ear tag-wound and in other organs.

CONCLUSIONS

Deletion of Alk1 in EC in adult mice leads to an increased local EC proliferation during brain angiogenesis and de novo brain AVM.

Endoscopy as a prognostic marker in inflammatory bowel disease

In patients suffering from reflux esophagitis, the severity of the lesions helps to predict the prognosis and adapt treatment. We herein review the data which suggest that endoscopy also has a prognostic value in inflammatory bowel disease. In the 1990s, the general opinion, based on a few studies, was that assessing endoscopic lesions was not critical for the management of inflammatory bowel disease. The more recent therapeutic strategies using less steroids but purine analogs and anti-TNF antibodies have led to a higher chance of mucosal healing (MH), and there is growing evidence that reaching healing of lesions is of good prognostic value both in ulcerative colitis and Crohn's disease. There is a lower risk of hospitalization and of surgery in patients with MH than in those without healing. There is also a (moderately) lower risk of relapse after stopping treatments in patients with MH than in those with persistent lesions. The risk of cancer (on a long-term basis) also seems be lower in patients with controlled inflammatory lesions than in subjects with persistent inflammation. There are still many unanswered questions, the major one being what is the best treatment choice when MH is not reached?

[Endogenous endophthalmitis as a complication in erysipelas]

BACKGROUND

Endogenous endophthalmitis is a devastating infection of the eye that leads to blindness in about two-thirds of patients. It results from the haematogenous spread of a microorganism from a focus of sepsis, mainly gastro-intestinal, genitourinary or cardiac.

PATIENTS AND METHODS

We describe the case of a diabetic subject presenting endogenous endophthalmitis following erysipelas of the leg due to Streptococcus agalactiae. The outcome was favourable thanks to prompt initiation of appropriate antibiotic treatment.

DISCUSSION

Endogenous endophthalmitis as a complication of a skin infection is a rare entity, with only about 30 reported cases in the literature. Awareness of this condition among dermatologists would allow prompt intervention, which is essential for sparing of the patient's eyesight.