D-β-Hydroxybutyrate and melatonin for treatment of porcine hemorrhagic shock and injury: a melatonin dose-ranging study

Total cucurbitacins from Herpetospermum pedunculosum pericarp do better than Hu-lu-su-pian (HLSP) in its safety and hepatoprotective efficacy

The pericarp of Herpetospermum pedunculosum (HPP) has traditionally been used for treating jaundice and hepatitis. However, the specific hepatoprotective components and their safety/efficacy profiles remain unclear. This study aimed to characterize the total cucurbitacins (TCs) extracted from HPP and evaluate their hepatoprotective potential. As a reference, Hu-lu-su-pian (HLSP), a known hepatoprotective drug containing cucurbitacins, was used for comparison of chemical composition, effects, and safety. Molecular networking based on UHPLC-MS/MS identified cucurbitacin B, isocucurbitacin B, and cucurbitacin E as the major components in TCs, comprising 70.3%, 26.1%, and 3.6% as determined by RP-HPLC, respectively. TCs treatment significantly reversed CCl4-induced metabolic changes associated with liver damage in a dose-dependent manner, impacting pathways including energy metabolism, oxidative stress and phenylalanine metabolism, and showed superior efficacy to HLSP. Safety evaluation also showed that TCs were safe, with higher LD50 and no observable adverse effect level (NOAEL) values than HLSP. The median lethal dose (LD50) and NOAEL values of TCs were 36.21 and 15 mg/kg body weight (BW), respectively, while the LD50 of HLSP was 14 mg/kg BW. In summary, TCs extracted from HPP demonstrated promising potential as a natural hepatoprotective agent, warranting further investigation into synergistic effects of individual cucurbitacin components.

Peptidomic Analysis Reveals Seasonal Neuropeptide and Peptide Hormone Changes in the Hypothalamus and Pituitary of a Hibernating Mammal

During the winter, hibernating mammals undergo extreme changes in physiology, which allow them to survive several months without access to food. These animals enter a state of torpor, which is characterized by decreased metabolism, near-freezing body temperatures, and a dramatically reduced heart rate. The neurochemical basis of this regulation is largely unknown. Based on prior evidence suggesting that the peptide-rich hypothalamus plays critical roles in hibernation, we hypothesized that changes in specific cell-cell signaling peptides (neuropeptides and peptide hormones) underlie physiological changes during torpor/arousal cycles. To test this hypothesis, we used a mass spectrometry-based peptidomics approach to examine seasonal changes of endogenous peptides that occur in the hypothalamus and pituitary of a model hibernating mammal, the thirteen-lined ground squirrel (Ictidomys tridecemlineatus). In the pituitary, we observed changes in several distinct peptide hormones as animals prepared for torpor in October, exited torpor in March, and progressed from spring (March) to fall (August). In the hypothalamus, we observed an overall increase in neuropeptides in October (pre-torpor), a decrease as the animal entered torpor, and an increase in a subset of neuropeptides during normothermic interbout arousals. Notable changes were observed for feeding regulatory peptides, opioid peptides, and several peptides without well-established functions. Overall, our study provides critical insight into changes in endogenous peptides in the hypothalamus and pituitary during mammalian hibernation that were not available from transcriptomic measurements. Understanding the molecular basis of the hibernation phenotype may pave the way for future efforts to employ hibernation-like strategies for organ preservation, combating obesity, and treatment of stroke.

Molecular Mechanisms of Lipid-Based Metabolic Adaptation Strategies in Response to Cold

Temperature changes and periods of detrimental cold occur frequently for many organisms in their natural habitats. Homeothermic animals have evolved metabolic adaptation strategies to increase mitochondrial-based energy expenditure and heat production, largely relying on fat as a fuel source. Alternatively, certain species are able to repress their metabolism during cold periods and enter a state of decreased physiological activity known as torpor. By contrast, poikilotherms, which are unable to maintain their internal temperature, predominantly increase membrane fluidity to diminish cold-related damage from low-temperature stress. However, alterations of molecular pathways and the regulation of lipid-metabolic reprogramming during cold exposure are poorly understood. Here, we review organismal responses that adjust fat metabolism during detrimental cold stress. Cold-related changes in membranes are detected by membrane-bound sensors, which signal to downstream transcriptional effectors, including nuclear hormone receptors of the PPAR (peroxisome proliferator-activated receptor) subfamily. PPARs control lipid metabolic processes, such as fatty acid desaturation, lipid catabolism and mitochondrial-based thermogenesis. Elucidating the underlying molecular mechanisms of cold adaptation may improve beneficial therapeutic cold treatments and could have important implications for medical applications of hypothermia in humans. This includes treatment strategies for hemorrhagic shock, stroke, obesity and cancer.

The Multiple Functions of Melatonin: Applications in the Military Setting

The aim of this review is to provide the reader with a general overview on the rationale for the use of melatonin by military personnel. This is a technique that is being increasingly employed to manage growing psycho-physical loads. In this context, melatonin, a pleotropic and regulatory molecule, has a potential preventive and therapeutic role in maintaining the operational efficiency of military personnel. In battlefield conditions in particular, the time to treatment after an injury is often a major issue since the injured may not have immediate access to medical care. Any drug that would help to stabilize a wounded individual, especially if it can be immediately administered (e.g., per os) and has a very high safety profile over a large range of doses (as melatonin does) would be an important asset to reduce morbidity and mortality. Melatonin may also play a role in the oscillatory synchronization of the neuro-cardio-respiratory systems and, through its epigenetic action, poses the possibility of restoring the main oscillatory waves of the cardiovascular system, such as the Mayer wave and RSA (respiratory sinus arrhythmia), which, in physiological conditions, result in the oscillation of the heartbeat in synchrony with the breath. In the future, this could be a very promising field of investigation.

Hibernation-Based Approaches in the Treatment of Hemorrhagic Shock

Hemorrhagic shock is the leading cause of preventable death after trauma. Hibernation-based treatment approaches have been of increasing interest for various biomedical applications. Owing to apparent similarities in tissue perfusion and metabolic activity between severe blood loss and the hibernating state, hibernation-based approaches have also emerged for the treatment of hemorrhagic shock. Research has shown that hibernators are protected from shock-induced injury and inflammation. Utilizing the adaptive mechanisms that prevent injury in these animals may help alleviate the detrimental effects of hemorrhagic shock in non-hibernating species. This review describes hibernation-based preclinical and clinical approaches for the treatment of severe blood loss. Treatments include the delta opioid receptor agonist D-Ala-Leu-enkephalin (DADLE), the gasotransmitter hydrogen sulfide, combinations of adenosine, lidocaine, and magnesium (ALM) or D-beta-hydroxybutyrate and melatonin (BHB/M), and therapeutic hypothermia. While we focus on hemorrhagic shock, many of the described treatments may be used in other situations of hypoxia or ischemia/reperfusion injury.

Molecular interactions underpinning the phenotype of hibernation in mammals

Mammals maintain a constant warm body temperature, facilitating a wide variety of metabolic reactions. Mammals that hibernate have the ability to slow their metabolism, which in turn reduces their body temperature and leads to a state of hypothermic torpor. For this metabolic rate reduction to occur on a whole-body scale, molecular interactions that change the physiology of cells, tissues and organs are required, resulting in a major departure from normal mammalian homeostasis. The aim of this Review is to cover recent advances in the molecular biology of mammalian hibernation, including the role of small molecules, seasonal changes in gene expression, cold-inducible RNA-binding proteins, the somatosensory system and emerging information on hibernating primates. To underscore the importance of differential gene expression across the hibernation cycle, mRNA levels for 14,261 ground squirrel genes during periods of activity and torpor are made available for several tissues via an interactive transcriptome browser. This Review also addresses recent findings on molecular interactions responsible for multi-day survival of near-freezing body temperatures, single-digit heart rates and a slowed metabolism that greatly reduces oxygen consumption. A better understanding of how natural hibernators survive these physiological extremes is beginning to lead to innovations in human medicine.

Development and in vivo evaluation of a novel lyophilized formulation for the treatment of hemorrhagic shock

Hemorrhagic shock, caused by trauma, is a leading cause of preventable death. A combination treatment of d-β-hydroxybutyrate (BHB) and melatonin (MLT), in dimethyl sulfoxide - water, increased survival. A freeze-dried BHB-MLT formulation, with a short reconstitution time, has been developed. This intravenous formulation, prepared with an aqueous vehicle, completely eliminated dimethyl sulfoxide, thereby avoiding the potential problems associated with this solvent. The poor aqueous solubility of MLT necessitated the use of polyvinylpyrrolidine (PVP) as a complexing agent. Thus the prelyophilization solution contained BHB (2 M), MLT (21.5 mM) and PVP (40 mM). Using a combination of low-temperature X-ray diffractometry and thermal analysis, the lyophilization process parameters were optimized. Infra-red spectra revealed hydrogen bonding interaction between PVP and MLT, while BHB crystallized as BHB.0.25 H₂O in the final lyophile. The formulation improved survival in a rat model of hemorrhagic shock. Based on the increase in rate of survival and longer survival time compared to untreated animals, we conclude that this formulation can serve as a promising first line of treatment for hemorrhagic shock.