Early metabolite changes after melatonin treatment in neonatal rats with hypoxic-ischemic brain injury studied by <i>in-vivo</i> ¹H MR spectroscopy

<div><p>Melatonin is a promising neuroprotective agent after perinatal hypoxic-ischemic (HI) brain injury. We used <i>in-vivo</i> ¹H magnetic resonance spectroscopy to investigate effects of melatonin treatment on brain metabolism after HI. Postnatal day 7 Sprague-Dawley rats with unilateral HI brain injury were treated with either melatonin 10 mg/kg dissolved in phosphate-buffered saline (PBS) with 5% dimethyl sulfoxide (DMSO) or vehicle (5% DMSO and/or PBS) directly and at 6 hours after HI. ¹H MR spectra from the thalamus in the ipsilateral and contralateral hemisphere were acquired 1 day after HI. Our results showed that injured animals had a distinct metabolic profile in the ipsilateral thalamus compared to sham with low concentrations of total creatine, choline, <i>N</i>-acetyl aspartate (NAA), and high concentrations of lipids. A majority of the melatonin-treated animals had a metabolic profile characterized by higher total creatine, choline, NAA and lower lipid levels than other HI animals. When comparing absolute concentrations, melatonin treatment resulted in higher glutamine levels and lower lipid concentrations compared to DMSO treatment as well as higher macromolecule levels compared to PBS treatment day 1 after HI. DMSO treated animals had lower concentrations of glucose, creatine, phosphocholine and macromolecules compared to sham animals. In conclusion, the neuroprotective effects of melatonin were reflected in a more favorable metabolic profile including reduced lipid levels that likely represents reduced cell injury. Neuroprotective effects may also be related to the influence of melatonin on glutamate/glutamine metabolism. The modulatory effects of the solvent DMSO on cerebral energy metabolism might have masked additional beneficial effects of melatonin.</p></div

Metabolic profiles of the ipsilateral thalamus of HI animals after 2 treatment injections.

<p>(a) The metabolic profiles of the HI animals treated with either melatonin (10 mg/kg) dissolved in PBS with 5% DMSO (MEL), PBS with 5% DMSO (DMSO) or only PBS (PBS) are displayed in the PCA score plot. The shaded area marks the animals treated with melatonin with higher levels of energy metabolites, neurotransmitters and macromolecules as shown in (b). (b) The corresponding loading plot shows the metabolic alterations related to the separation along PC 1. Glx, glutamine+glutamate; GPC glycerophosphocholine; HI, hypoxia-ischemia; NAA, N-acetyl aspartate; NAAG, N-acetyl aspartyl glutamate; MM, macromolecules; Lip, lipids; PC, principle component; PCA, principle component analysis; PCh, phosphocholine; PCr, phosphocreatine; ppm, parts per million.</p

¹H spectrum of the ipsilateral thalamus.

<p>Acquired ¹H spectrum of the ipsilateral thalamus of an animal exposed to HI. Cr, creatine; DMSO, dimethyl sulfoxide; Gln, glutamine; Glu, glutamate; GPC, glycerophosphocholine; GSH, glutathione; Ins, myo-inositol; NAA, N-acetyl aspartate; PCh, phosphocoline; PCr, phosphocreatine; Tau, taurine.</p

Metabolite concentrations in the contralateral thalamus within 1 day after HI.

<p>Concentrations of (a) energy metabolites, (b) neurotransmitters, (c) anti-oxidants and osmolytes, (d) metabolites representing cell injury/viability and (e) lipids and macromolecules in HI animals exposed to PBS, DMSO or melatonin (MEL) treatment and sham animals (here presented as one group). Results are presented as mean ± SEM. * significant differences between groups. GPC glycerophosphocholine; HI, hypoxia-ischemia; Lip, lipids; MM, macromolecules; NAA, N-acetyl aspartate; ppm, parts per million; sham, sham-operated.</p

Metabolic profiles of the ipsilateral thalamus of HI and sham animals 1 day after HI.

<p>(a) The PCA score plot shows the metabolic profiles of all animals. The HI animals were separated from the sham animals with the corresponding loading plot of PC 1 (b) showing the metabolic alterations that caused this separation. The shaded area is drawn based on visual inspection and is meant to highlight the separation between the groups. Glx, glutamine+glutamate; GPC glycerophosphocholine; HI, hypoxia-ischemia; NAA, N-acetyl aspartate; NAAG, N-acetyl aspartyl glutamate; MM, macromolecules; Lip, lipids; PC, principle component; PCA, principle component analysis; PCh, phosphocholine; PCr, phosphocreatine; ppm, parts per million.</p

Ticagrelor in patients with diabetes and stable coronary artery disease with a history of previous percutaneous coronary intervention (THEMIS-PCI) : a phase 3, placebo-controlled, randomised trial

Background: Patients with stable coronary artery disease and diabetes with previous percutaneous coronary intervention (PCI), particularly those with previous stenting, are at high risk of ischaemic events. These patients are generally treated with aspirin. In this trial, we aimed to investigate if these patients would benefit from treatment with aspirin plus ticagrelor. Methods: The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS) was a phase 3 randomised, double-blinded, placebo-controlled trial, done in 1315 sites in 42 countries. Patients were eligible if 50 years or older, with type 2 diabetes, receiving anti-hyperglycaemic drugs for at least 6 months, with stable coronary artery disease, and one of three other mutually non-exclusive criteria: a history of previous PCI or of coronary artery bypass grafting, or documentation of angiographic stenosis of 50% or more in at least one coronary artery. Eligible patients were randomly assigned (1:1) to either ticagrelor or placebo, by use of an interactive voice-response or web-response system. The THEMIS-PCI trial comprised a prespecified subgroup of patients with previous PCI. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke (measured in the intention-to-treat population). Findings: Between Feb 17, 2014, and May 24, 2016, 11 154 patients (58% of the overall THEMIS trial) with a history of previous PCI were enrolled in the THEMIS-PCI trial. Median follow-up was 3·3 years (IQR 2·8–3·8). In the previous PCI group, fewer patients receiving ticagrelor had a primary efficacy outcome event than in the placebo group (404 [7·3%] of 5558 vs 480 [8·6%] of 5596; HR 0·85 [95% CI 0·74–0·97], p=0·013). The same effect was not observed in patients without PCI (p=0·76, p interaction=0·16). The proportion of patients with cardiovascular death was similar in both treatment groups (174 [3·1%] with ticagrelor vs 183 (3·3%) with placebo; HR 0·96 [95% CI 0·78–1·18], p=0·68), as well as all-cause death (282 [5·1%] vs 323 [5·8%]; 0·88 [0·75–1·03], p=0·11). TIMI major bleeding occurred in 111 (2·0%) of 5536 patients receiving ticagrelor and 62 (1·1%) of 5564 patients receiving placebo (HR 2·03 [95% CI 1·48–2·76], p<0·0001), and fatal bleeding in 6 (0·1%) of 5536 patients with ticagrelor and 6 (0·1%) of 5564 with placebo (1·13 [0·36–3·50], p=0·83). Intracranial haemorrhage occurred in 33 (0·6%) and 31 (0·6%) patients (1·21 [0·74–1·97], p=0·45). Ticagrelor improved net clinical benefit: 519/5558 (9·3%) versus 617/5596 (11·0%), HR=0·85, 95% CI 0·75–0·95, p=0·005, in contrast to patients without PCI where it did not, p interaction=0·012. Benefit was present irrespective of time from most recent PCI. Interpretation: In patients with diabetes, stable coronary artery disease, and previous PCI, ticagrelor added to aspirin reduced cardiovascular death, myocardial infarction, and stroke, although with increased major bleeding. In that large, easily identified population, ticagrelor provided a favourable net clinical benefit (more than in patients without history of PCI). This effect shows that long-term therapy with ticagrelor in addition to aspirin should be considered in patients with diabetes and a history of PCI who have tolerated antiplatelet therapy, have high ischaemic risk, and low bleeding risk