Acute Administration of n-3 Rich Triglyceride Emulsions Provides Cardioprotection in Murine Models after Ischemia-Reperfusion

Dietary n-3 fatty acids (FAs) may reduce cardiovascular disease risk. We questioned whether acute administration of n-3 rich triglyceride (TG) emulsions could preserve cardiac function and decrease injury after ischemia/reperfusion (I/R) insult. We used two different experimental models: in vivo, C57BL/6 mice were exposed to acute occlusion of the left anterior descending coronary artery (LAD), and ex-vivo, C57BL/6 murine hearts were perfused using Langendorff technique (LT). In the LAD model, mice treated with n-3 TG emulsion (1.5g/kg body weight), immediately after ischemia and 1h later during reperfusion, significantly reduced infarct size and maintained cardiac function (p<0.05). In the LT model, administration of n-3 TG emulsion (300mgTG/100ml) during reperfusion significantly improved functional recovery (p<0.05). In both models, lactate dehydrogenase (LDH) levels, as a marker of injury, were significantly reduced by n-3 TG emulsion. To investigate the mechanisms by which n-3 FAs protects hearts from I/R injury, we investigated changes in key pathways linked to cardioprotection. In the ex-vivo model, we showed that n-3 FAs increased phosphorylation of AKT and GSK3β proteins (p<0.05). Acute n-3 TG emulsion treatment also increased Bcl-2 protein level and reduced an autophagy marker, Beclin-1 (p<0.05). Additionally, cardioprotection by n-3 TG emulsion was linked to changes in PPARγ protein expression (p<0.05). Rosiglitazone and p-AKT inhibitor counteracted the positive effect of n-3 TG; GSK3β inhibitor plus n-3 TG significantly inhibited LDH release. We conclude that acute n-3 TG injection during reperfusion provides cardioprotection. This may prove to be a novel acute adjunctive reperfusion therapy after treating patients with myocardial infarction

Alzheimer’s-associated upregulation of mitochondria-associated ER membranes after traumatic brain injury

23 p.-5 fig.-3 tab.-1 graph. abst.Traumatic brain injury (TBI) can lead to neurodegenerative diseases such as Alzheimer’s disease (AD) through mechanisms that remain incompletely characterized. Similar to AD, TBI models present with cellular metabolic alterations and modulated cleavage of amyloid precursor protein (APP). Specifically, AD and TBI tissues display increases in amyloid-β as well as its precursor, the APP C-terminal fragment of 99 a.a. (C99). Our recent data in cell models of AD indicate that C99, due to its affinity for cholesterol, induces the formation of transient lipid raft domains in the ER known as mitochondria-associated endoplasmic reticulum (ER) membranes (“MAM” domains). The formation of these domains recruits and activates specific lipid metabolic enzymes that regulate cellular cholesterol trafficking and sphingolipid turnover. Increased C99 levels in AD cell models promote MAM formation and significantly modulate cellular lipid homeostasis. Here, these phenotypes were recapitulated in the controlled cortical impact (CCI) model of TBI in adult mice. Specifically, the injured cortex and hippocampus displayed significant increases in C99 and MAM activity, as measured by phospholipid synthesis, sphingomyelinase activity and cholesterol turnover. In addition, our cell type-specific lipidomics analyses revealed significant changes in microglial lipid composition that are consistent with the observed alterations in MAM-resident enzymes. Altogether, we propose that alterations in the regulation of MAM and relevant lipid metabolic pathways could contribute to the epidemiological connection between TBI and AD.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the U.S. National Institutes of Health (T32-DK007647 to RRA; R21NS125395 to LS; S10-OD016214 and P30-CA013330 to FPM; R01-EB029523 to WM; R01-NS095803 to SGK; R01-NS088197 to RJD; R01-AG056387 to EA-G) and the U.S. Department of Defense (National Defense Science and Engineering Graduate Fellowship, FA9550-11-C-0028, to RRA).Peer reviewe

DHA but Not EPA Emulsions Preserve Neurological and Mitochondrial Function after Brain Hypoxia-Ischemia in Neonatal Mice

Background and Purpose Treatment with triglyceride emulsions of docosahexaenoic acid (tri-DHA) protected neonatal mice against hypoxia-ischemia (HI) brain injury. The mechanism of this neuroprotection remains unclear. We hypothesized that administration of tri-DHA enriches HI-brains with DHA/DHA metabolites. This reduces Ca2+-induced mitochondrial membrane permeabilization and attenuates brain injury. Methods: 10-day-old C57BL/6J mice following HI-brain injury received tri-DHA, tri-EPA or vehicle. At 4–5 hours of reperfusion, mitochondrial fatty acid composition and Ca2+ buffering capacity were analyzed. At 24 hours and at 8–9 weeks of recovery, oxidative injury, neurofunctional and neuropathological outcomes were evaluated. In vitro, hyperoxia-induced mitochondrial generation of reactive oxygen species (ROS) and Ca2+ buffering capacity were measured in the presence or absence of DHA or EPA. Results: Only post-treatment with tri-DHA reduced oxidative damage and improved short- and long-term neurological outcomes. This was associated with increased content of DHA in brain mitochondria and DHA-derived bioactive metabolites in cerebral tissue. After tri-DHA administration HI mitochondria were resistant to Ca2+-induced membrane permeabilization. In vitro, hyperoxia increased mitochondrial ROS production and reduced Ca2+ buffering capacity; DHA, but not EPA, significantly attenuated these effects of hyperoxia. Conclusions: Post-treatment with tri-DHA resulted in significant accumulation of DHA and DHA derived bioactive metabolites in the HI-brain. This was associated with improved mitochondrial tolerance to Ca2+-induced permeabilization, reduced oxidative brain injury and permanent neuroprotection. Interaction of DHA with mitochondria alters ROS release and improves Ca2+ buffering capacity. This may account for neuroprotective action of post-HI administration of tri-DHA

Nutrigenomics

The whole complex of molecular processes of human organism results from endogenous physiological execution of the information encoded in the genome but is also influenced by exogenous factors which include those originating from nutrition as major agents. Nutrient molecules assimilation within human body continuously allows homeostatic reconstitution of its qualitative and quantitative composition but also takes part in physiological changes of body growth and adaptation to particular situations. Nevertheless, in addition to replace material and energetic losses, nutritional intake also provides bioactive molecules which are selectively able to modulate specific metabolic pathways, noticeably affecting risk of cardiovascular and neoplastic diseases, which are the major cause of mortality in developed countries. Numerous bioactive nutrients are being progressively identified and their chemopreventive effects are being described at clinical and molecular mechanism level. All “omics” technologies (such as transcriptomics, proteomics and metabolomics) allow systematic analyses to study dietary bioactive molecules effect on the totality of molecular processes. Since each nutrient might also have specific effects on individually different genomes, nutrigenomic and nutrigenetic analysis data can be distinguished by two different observational views: 1) effects of whole diet and of specific nutrients on genes, proteins, metabolic pathways and metabolites; 2) effects of specific individual genomes on biological activity of nutritional intake and of specific nutrients. Nutrigenomic knowledge on physiologic status and disease risk will provide both developments of better diagnostic procedures and of new therapeutic strategies specifically targeted on nutritionally relevant processes

Perspectives of choroidal neovascularization therapy.

Vision loss secondary to Choroidal Neovascularization (CNV) is becoming a major disease condition in the developed world. CNV is typically secondary to age-related macular degeneration (AMD) and these conditions are major, and also substantially increasing, causes of blindness among aged people. Several therapeutic options are currently available to treat CNV with variable efficacy on disease progress. Among existing treatments there are laser photocoagulation, photodynamic therapies, local corticosteroids and, more recently, the use of anti-angiogenic factors. Although by these treatments very effective results are obtained and their further improvement is still possible, it is also reasonable and necessary to look for more successful and definitive alternatives. The research in this direction is already very active and it can be expected that applications of the more recent molecular technologies will bring important advances also for CNV. These will likely regard the use of gene therapy and of new target specific factors. Gene therapy methodologies are rapidly becoming closer to current clinical use and, since the eye is a particularly favorable organ for drug delivery, their ocular use is probably going to be among the first successful applications of these techniques. In addition to its specific technology, gene therapy requires the knowledge of specific genes to be modulated to adequately affect pathogenesis and progression of the disease for which it has to be applied. This will also be true for the use of novel target specific drugs such as antibodies and other molecules able to affect cellular factors and pathways also related to disease development. For this reason, a major direction of future CNV therapies will be the identification of specific gene, gene products, metabolic pathways and metabolites related to the disease. This information, in addition to be suitable for gene and target specific therapies, will also allow the development of new procedures to improve diagnosis and/or prognostic evaluation of the disease

Induction of alkaline phosphatase activity by exposure of human cell lines to a low frequency (LF) electric field from apparatuses used in clinical therapies.

Low-frequency (LF) electric fields (EFs) are currently used in clinical therapies of several bone diseases to increase bone regenerative processes. To identify possible molecular mechanisms involved in these processes, we evaluated the effects on cell cultures of 1 h exposures to the signal generated by an apparatus of current clinical use (frequency 60 kHz, frequency of the modulating signal 12.5 Hz, 50% duty cycle, peak-to-peak voltage 24.5 V). Two different human cell lines, bone SaOS-2 and liver HepG2, were used. Exposures significantly increased alkaline phosphatase (ALP) enzymatic activity in both cell lines. The increase was about 35% in SaOS-2 cells and about 80% in HepG2 cells and occurred in the first 4 h after exposure and decreased to almost no change by 24 h. Since ALP represents a typical marker of bone regeneration, these results represent a first molecular evidence of biological effects from 60 kHz EF exposures. The finding of similar effects in cells derived from two different tissues more likely indicates the effective operation of the mechanism in living organisms