Energy and metabolism

Research progresses on mitochondrial-targeted biomaterials for bone defect repair

In recent years, the regulation of the cell microenvironment has opened up new avenues for bone defect repair. Researchers have developed novel biomaterials to influence the behavior of osteoblasts and immune cells by regulating the microenvironment, aiming to achieve efficient bone repair. Mitochondria, as crucial organelles involved in energy conversion, biosynthesis and signal transduction, play a vital role in maintaining bone integrity. Dysfunction of mitochondria can have detrimental effects on the transformation of the immune microenvironment and the differentiation of stem cells, thereby hindering bone tissue regeneration. Consequently, targeted therapy strategies focusing on mitochondria have emerged. This approach offers a wide range of applications and reliable therapeutic effects, thereby providing a new treatment option for complex and refractory bone defect diseases. In recent studies, more biomaterials have been used to restore mitochondrial function and promote positive cell differentiation. The main directions are mitochondrial energy metabolism, mitochondrial biogenesis and mitochondrial quality control. In this review, we investigated the biomaterials used for mitochondria-targeted treatment of bone defect repair in recent years from the perspective of progress and strategies. We also summarized the micro-molecular mechanisms affected by them. Through discussions on energy metabolism, oxidative stress regulation and autophagy regulation, we emphasized the opportunities and challenges faced by mitochondria-targeted biomaterials, providing vital clues for developing a new generation of bone repair materials.

The role of ATP in sleep-wake regulation: In adenosine-dependent and -independent manner

ATP plays a crucial role as an energy currency in the body's various physiological functions, including the regulation of the sleep-wake cycle. Evidence from genetics and pharmacology demonstrates a strong association between ATP metabolism and sleep. With the advent of new technologies such as optogenetics, genetically encoded biosensors, and novel ATP detection methods, the dynamic changes in ATP levels between different sleep states have been further uncovered. The classic mechanism for regulating sleep by ATP involves its conversion to adenosine, which increases sleep pressure when accumulated extracellularly. However, emerging evidence suggests that ATP can directly bind to P2 receptors and influence sleep-wake regulation through both adenosine-dependent and independent pathways. The outcome depends on the brain region where ATP acts and the expression type of P2 receptors. This review summarizes the experimental evidence on the relationship between ATP levels and changes in sleep states and outlines the mechanisms by which ATP is involved in regulating the sleep-wake cycle through both adenosine-dependent and independent pathways. Hopefully, this review will provide a comprehensive understanding of the current research basis and progress in this field and promote further investigations into the specific mechanisms of ATP in regulating sleep.

Research progress of metabolomics in cervical cancer

INTRODUCTION

Cervical cancer threatens women's health seriously. In recent years, the incidence of cervical cancer is on the rise, and the age of onset tends to be younger. Prevention, early diagnosis and specific treatment have become the main means to change the prognosis of cervical cancer patients. Metabolomics research can directly reflect the changes of biochemical processes and microenvironment in the body, which can provide a comprehensive understanding of the changes of metabolites in the process of disease occurrence and development, and provide new ways for the prevention and diagnosis of diseases.

OBJECTIVES

The aim of this study is to review the metabolic changes in cervical cancer and the application of metabolomics in the diagnosis and treatment.

METHODS

PubMed, Web of Science, Embase and Scopus electronic databases were systematically searched for relevant studies published up to 2022.

RESULTS

With the emergence of metabolomics, metabolic regulation and cancer research are further becoming a focus of attention. By directly reflecting the changes in the microenvironment of the body, metabolomics research can provide a comprehensive understanding of the patterns of metabolites in the occurrence and development of diseases, thus providing new ideas for disease prevention and diagnosis.

CONCLUSION

With the continuous, in-depth research on metabolomics research technology, it will bring more benefits in the screening, diagnosis and treatment of cervical cancer with its advantages of holistic and dynamic nature.

Icariin promotes osteogenic differentiation by upregulating alpha-enolase expression

Osteogenic differentiation is a crucial biological process for maintaining bone remodelling. Aerobic glycolysis is the main source of energy for osteogenic differentiation. Alpha-enolase (Eno1), a glycolytic enzyme, is a therapeutic target for numerous diseases. Icariin, a principal active component of the traditional Chinese medicine Epimedium grandiflorum, can stimulate osteogenic differentiation. Here, we aimed to determine if icariin promotes osteogenic differentiation via Eno1. Icariin (1 μM) significantly promoted osteogenic differentiation of MC3T3-E1 cells. Icariin upregulated Eno1 protein and gene expressions during osteogenic differentiation. Moreover, ENOblock, a specific inhibitor of Eno1, markedly inhibited icariin-induced osteogenic differentiation. Futhermore, western blot assay showed that Eno1 might mediate osteogenic differentiation through the BMP/Smad4 signalling pathway. Collectively, Eno1 could be a promising drug target for icariin to regulate osteogenic differentiation.

Solving the conundrum of intra-specific variation in metabolic rate: A multidisciplinary conceptual and methodological toolkit: New technical developments are opening the door to an understanding of why metabolic rate varies among individual animals of a species: New technical developments are opening the door to an understanding of why metabolic rate varies among individual animals of a species

Researchers from diverse disciplines, including organismal and cellular physiology, sports science, human nutrition, evolution and ecology, have sought to understand the causes and consequences of the surprising variation in metabolic rate found among and within individual animals of the same species. Research in this area has been hampered by differences in approach, terminology and methodology, and the context in which measurements are made. Recent advances provide important opportunities to identify and address the key questions in the field. By bringing together researchers from different areas of biology and biomedicine, we describe and evaluate these developments and the insights they could yield, highlighting the need for more standardisation across disciplines. We conclude with a list of important questions that can now be addressed by developing a common conceptual and methodological toolkit for studies on metabolic variation in animals.

Brain’s Energy After Stroke: From a Cellular Perspective Toward Behavior

Stroke is a neurological condition that impacts activity performance and quality of life for survivors. While neurological impairments after the event explain the performance of patients in specific activities, the origin of such impairments has traditionally been explained as a consequence of structural and functional damage to the nervous system. However, there are important mechanisms related to energy efficiency (trade-off between biological functions and energy consumption) at different levels that can be related to these impairments and restrictions: first, at the neuronal level, where the availability of energy resources is the initial cause of the event, as well as determines the possibilities of spontaneous recovery. Second, at the level of neural networks, where the “small world” operation of the network is compromised after the stroke, implicating a high energetic cost and inefficiency in the information transfer, which is related to the neurological recovery and clinical status. Finally, at the behavioral level, the performance limitations are related to the highest cost of energy or augmented energy expenditure during the tasks to maintain the stability of the segment, system, body, and finally, the behavior of the patients. In other words, the postural homeostasis. In this way, we intend to provide a synthetic vision of the energy impact of stroke, from the particularities of the operation of the nervous system, its implications, as one of the determinant factors in the possibilities of neurological, functional, and behavioral recovery of our patients.

A quantitative genetics perspective on the body-mass scaling of metabolic rate

Widely observed allometric scaling (log-log slope<1) of metabolic rate (MR) with body mass (BM) in animals has been frequently explained using functional mechanisms, but rarely studied from the perspective of multivariate quantitative genetics. This is unfortunate, given that the additive genetic slope (bA) of the MR-BM relationship represents the orientation of the 'line of least genetic resistance' along which MR and BM may most likely evolve. Here, we calculated bA in eight species. Although most bA values were within the range of metabolic scaling exponents reported in the literature, uncertainty of each bA estimate was large (only one bA was significantly lower than 3/4 and none were significantly different from 2/3). Overall, the weighted average for bA (0.667±0.098 95% CI) is consistent with the frequent observation that metabolic scaling exponents are negatively allometric in animals (b<1). Although bA was significantly positively correlated with the phenotypic scaling exponent (bP) across the sampled species, bP was usually lower than bA, as reflected in a (non-significantly) lower weighted average for bP (0.596±0.100). This apparent discrepancy between bA and bP resulted from relatively shallow MR-BM scaling of the residuals [weighted average residual scaling exponent (be)=0.503±0.128], suggesting regression dilution (owing to measurement error and within-individual variance) causing a downward bias in bP. Our study shows how the quantification of the genetic scaling exponent informs us about potential constraints on the correlated evolution of MR and BM, and by doing so has the potential to bridge the gap between micro- and macro-evolutionary studies of scaling allometry.

The efficiency of a mixed exercise program on quality of life and fatigue levels in patients with breast cancer

OBJECTIVE

Exercise is a nonpharmacological supportive therapy which has been specifically identified to reduce postoperative complications or adverse events of cancer or treatments. Although there are few studies combining resistance and aerobic exercise in cancer survivors, exercise programs are very rare in different places in the literature. This study aims to investigate the effects of mixed-type exercise in different venues on weight, body mass index, fatigue, and quality of life in cancer survivors.

METHODS

This is a descriptive, intervention study. Participants were included in the study, and the exercise process was between January and November 2019. The exercise group consisted of 32 patients who had just completed their breast cancer treatment and did not have distant metastases, and they applied a mixed exercise program including resistance at home and aerobic exercise in the fitness center for 12 weeks. The patients with breast cancer in the control group (30 patients) did not receive any exercise program.

RESULTS

Subjective feelings of fatigue and decrease in concentration, motivation, and physical activity significantly decreased after exercise (p<0.001, p<0.001, p=0.006, p=0.008, and p<0.001, respectively) in the study group. The results also showed that physical health, general health status, and emotional and social health status significantly increased with the exercise program (p<0.001, p<0.001, p=0.004, and p=0.003, respectively).

CONCLUSION

Our results show that a mixed (fitness center and home) 12-week exercise program provides an improvement in general health and reduces the side effects of the treatments and fatigue in patients with breast cancer. For a good prognostic process after medical treatment, exercise can be recommended in every accessible area.

Meta-analysis reveals that resting metabolic rate is not consistently related to fitness and performance in animals

Explaining variation in the fitness of organisms is a fundamental goal in evolutionary ecology. Maintenance energy metabolism is the minimum energy required to sustain biological processes at rest (resting metabolic rate: RMR) and is proposed to drive or constrain fitness of animals; however, this remains debated. Hypotheses have been proposed as to why fitness might increase with RMR (the 'increased intake' or 'performance' hypothesis), decrease with RMR (the 'compensation' or 'allocation' hypothesis), or vary among species and environmental contexts (the 'context dependent' hypothesis). Here, we conduct a systematic review and meta-analysis of the literature, finding 114 studies with 355 relationships between RMR and traits that may be related to fitness. We show that individuals with relatively high RMR generally have high fitness overall, which might be supported by an increased energy intake. However, fitness proxies are not interchangeable: the nature of the RMR-fitness relationship varied substantially depending on the specific trait in question, and we found no consistent relationship between RMR and those traits most closely linked with actual fitness (i.e., lifetime reproductive success). We hypothesise that maintaining high RMR is not costly when resources are unlimited, and we propose ideas for future studies to identify mechanisms underlying RMR-fitness relationships.

AMPK, metabolism, and vascular function

Adenosine monophosphate-activated protein kinase (AMPK) is a cellular energy sensor activated during energy stress that plays a key role in maintaining energy homeostasis. This ubiquitous signaling pathway has been implicated in multiple functions including mitochondrial biogenesis, redox regulation, cell growth and proliferation, cell autophagy and inflammation. The protective role of AMPK in cardiovascular function and the involvement of dysfunctional AMPK in the pathogenesis of cardiovascular disease have been highlighted in recent years. In this review, we summarize and discuss the role of AMPK in the regulation of blood flow in response to metabolic demand and the basis of the AMPK physiological anticontractile, antioxidant, anti-inflammatory, and antiatherogenic actions in the vascular system. Investigations by others and us have demonstrated the key role of vascular AMPK in the regulation of endothelial function, redox homeostasis, and inflammation, in addition to its protective role in the hypoxia and ischemia/reperfusion injury. The pathophysiological implications of AMPK involvement in vascular function with regard to the vascular complications of metabolic disease and the therapeutic potential of AMPK activators are also discussed.

Understanding variation in metabolic rate

Metabolic rate reflects an organism's capacity for growth, maintenance and reproduction, and is likely to be a target of selection. Physiologists have long sought to understand the causes and consequences of within-individual to among-species variation in metabolic rates – how metabolic rates relate to performance and how they should evolve. Traditionally, this has been viewed from a mechanistic perspective, relying primarily on hypothesis-driven approaches. A more agnostic, but ultimately more powerful tool for understanding the dynamics of phenotypic variation is through use of the breeder's equation, because variation in metabolic rate is likely to be a consequence of underlying microevolutionary processes. Here we show that metabolic rates are often significantly heritable, and are therefore free to evolve under selection. We note, however, that ‘metabolic rate’ is not a single trait: in addition to the obvious differences between metabolic levels (e.g. basal, resting, free-living, maximal), metabolic rate changes through ontogeny and in response to a range of extrinsic factors, and is therefore subject to multivariate constraint and selection. We emphasize three key advantages of studying metabolic rate within a quantitative genetics framework: its formalism, and its predictive and comparative power. We make several recommendations when applying a quantitative genetics framework: (i) measuring selection based on actual fitness, rather than proxies for fitness; (ii) considering the genetic covariances between metabolic rates throughout ontogeny; and (iii) estimating genetic covariances between metabolic rates and other traits. A quantitative genetics framework provides the means for quantifying the evolutionary potential of metabolic rate and why variance in metabolic rates within populations might be maintained.

Role of nociceptin/orphanin FQ in thermoregulation

Nociceptin/Orphanin FQ (N/OFQ) is a 17-amino acid peptide that binds to the nociceptin receptor (NOP). N/OFQ and NOP receptors are expressed in numerous brain areas. The generation of specific agonists, antagonists and receptor-deficient mice or rats has enabled progress in elucidating the biological functions of N/OFQ. These tools have been employed to identify the biological significance of the N/OFQ system and how it interacts with other endogenous systems to regulate several body functions. The present review focuses on the role of N/OFQ in the regulation of body temperature and its relationship with energy balance. Critical evaluation of the literature data suggests that N/OFQ, acting through the NOP receptor, may cause hypothermia by influencing the complex thermoregulatory system that operates as a federation of independent thermoeffector loops to control body temperature at the hypothalamic level. Furthermore, N/OFQ counteracts hyperthermia elicited by cannabinoids or µ-opioid agonists. N/OFQ-induced hypothermia is prevented by ω-conotoxin GVIA, an N-type calcium channel blocker. Hypothermia induced by N/OFQ is considered within the framework of the complex action that this neuropeptide exerts on energy balance. Energy stores are regulated through the complex neural controls exerted on both food intake and energy expenditure. In laboratory rodents, N/OFQ stimulates consummatory behavior and decreases energy expenditure. Taken together, these studies support the idea that N/OFQ contributes to the regulation of energy balance by acting as an "anabolic" neuropeptide as it elicits effects similar to those produced in the hypothalamus by other neuropeptides such as orexins and neuropeptide Y.

Subcellular energy balance of Odontesthes bonariensis exposed to a glyphosate-based herbicide

Water pollution by agrochemicals is currently one of the most critical problems for the conservation of aquatic ecosystems. Glyphosate [N-(phosphonomethyl) glycine); PMG] is the main broad-spectrum post emergence herbicide used for the control of a wide range of pests in soybean crops. Adenylate energy charge (AEC) reflects the energy balance of the cells, a measure of the energy available from the adenylate pool: adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Background adenylates, phosphagens and the AEC index of two year old Odontesthes bonariensis were determined in some tissues by HPLC, and the impact on subcellular energy balance of sublethal glyphosate-based herbicide exposure was analyzed. The doses used were 0 (control tank), 1 or 10mg PMGL(-1), trials were carried out during 15 days. AEC values in brain, liver and muscle from control fish were 0.37 ± 0.02, 0.49 ± 0.05 and 0.56 ± 0.03, respectively (means ± SEM). While brain ATP concentrations were undetectable (hence low values of AEC), the muscle tissue showed the highest concentrations of the more energetic molecules: 0.18 μmole ATP g(-1) and 8 μmole phosphocreatine g(-1) (PCrg(-1)). In the brain, no significant changes were detected in exposed fish compared to controls. Instead, in both the liver and muscle of animals exposed to the highest concentration of the herbicide, significant changes in the AEC (reduction of 26% and 15%, p<0.05) with respect to the control group were determined. Chronic exposure (15 days) of Odontesthes bonariensis to 1 and 10mgL(-1) of formulated glyphosate did not affect brain AEC. However, the highest concentration of the herbicide produced a significant decrease in liver and muscle AEC manifesting adverse sublethal effects on the energy metabolism. These results suggest the usefulness of AEC as a biomarker of fish glyphosate exposure.