Higher total energy costs strain the elderly, especially low-income, across 31 developed countries

Addressing the total energy cost burden of elderly people is essential for designing equitable and effective energy policies, especially in responding to energy crisis in an aging society. It is due to the double impact of energy price hikes on households-through direct impact on fuel bills and indirect impact on the prices of goods and services consumed. However, while examining the household energy cost burden of the elderly, their indirect energy consumption and associated cost burden remain poorly understood. This study quantifies and compares the direct and indirect energy footprints and associated total energy cost burdens for different age groups across 31 developed countries. It reveals that the elderly have larger per capita energy footprints, resulting from higher levels of both direct and indirect energy consumption compared with the younger age groups. More importantly, the elderly, especially the low-income elderly, have a higher total energy cost burden rate. As the share of elderly in the total population rapidly grows in these countries, the larger per capita energy footprint and associated cost burden rate of elderly people would make these aging countries more vulnerable in times of energy crises. It is therefore crucial to develop policies that aim to reduce energy consumption and costs, improve energy efficiency, and support low-income elderly populations. Such policies are necessary to reduce the vulnerability of these aging countries to the energy crisis.

Energy Crisis Links to Autophagy and Ferroptosis in Alzheimer's Disease: Current Evidence and Future Avenues

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases worldwide. The occult nature of the onset and the uncertainty of the etiology largely impede the development of therapeutic strategies for AD. Previous studies revealed that the disorder of energy metabolism in the brains of AD patients appears far earlier than the typical pathological features of AD, suggesting a tight association between energy crisis and the onset of AD. Energy crisis in the brain is known to be induced by the reductions in glucose uptake and utilization, which may be ascribed to the diminished expressions of cerebral glucose transporters (GLUTs), insulin resistance, mitochondrial dysfunctions, and lactate dysmetabolism. Notably, the energy sensors such as peroxisome proliferators-activated receptor (PPAR), transcription factor EB (TFEB), and AMP-activated protein kinase (AMPK) were shown to be the critical regulators of autophagy, which play important roles in regulating beta-amyloid (Aβ) metabolism, tau phosphorylation, neuroinflammation, iron dynamics, as well as ferroptosis. In this study, we summarized the current knowledge on the molecular mechanisms involved in the energy dysmetabolism of AD and discussed the interplays existing between energy crisis, autophagy, and ferroptosis. In addition, we highlighted the potential network in which autophagy may serve as a bridge between energy crisis and ferroptosis in the progression of AD. A deeper understanding of the relationship between energy dysmetabolism and AD may provide new insight into developing strategies for treating AD; meanwhile, the energy crisis in the progression of AD should gain more attention.

Annonaceous Acetogenin Mimic AA005 Inhibits the Growth of TNBC MDA-MB-468 Cells by Altering Cell Energy Metabolism

Triple-negative breast cancer (TNBC) is a serious health issue for women worldwide and there is still no suitable treatment option. AA005, a structurally simplified mimic of natural Annonaceous acetogenins, presents outstanding properties with impressive cytotoxicity and cell-type selective actions. The present study was aimed at evaluating the potential of AA005 as a therapeutic agent for TNBC. AA005 potently inhibited the growth of TNBC cells at 50 nM level. Inspired by the finding of the phosphatase and tensin homologue (PTEN) tumor suppressor, the effect of AA005 on aerobic glycolysis was investigated in TNBC MDA-MB-468 cells. A short-term AA005 exposure markedly suppressed mitochondrial function in MDA-MB-468 cells, thus activating the aerobic glycolysis to lessen the risk of decreased ATP generation in mitochondria. Prolonging the incubation time of AA005 clearly weakened the aerobic glycolysis in the cells. This was in part attributed to the PI3K-AKT pathway inactivation and subsequent declined glucose uptake. As a consequence, the energy supply was completely cut from the two major energy-producing pathways. Further experiments showed that AA005 resulted in irreversible damage on cell activity including cell cycle and growth, inducing mitochondrial oxidative stress and ultimately leading to cell death. In addition, the in vivo therapeutic efficacy of AA005 was proved on 4T1 xenograft tumor mice model. Our data demonstrate that AA005 exhibited a great potential for future clinical applications in TNBC therapy.

Antidotal effect of dihydroxyacetone against phosphine poisoning in mice

Phosphine (PH₃ ) is widely used as an insecticide and rodenticide. On the contrary, many cases of PH₃ poisoning have been reported worldwide. Unfortunately, there is no specific antidote against PH₃ toxicity. Disruption of mitochondrial function and energy metabolism is a well-known mechanism of PH₃ cytotoxicity. Dihydroxyacetone (DHA) is an adenosine triphosphate supplying agent which significantly improves mitochondrial function. The current study was designed to evaluate DHA's effect on inhalational PH₃ poisoning in an animal model. DHA was injected into BALB/c mice before and/or after the start of the PH₃ inhalation. The cytochrome c oxidase activity was assessed in the animals' brain, heart, and liver exposed to PH₃ (for 15, 30, and 60 min, with and without the antidote). The LC₅₀ of PH₃ was calculated to be 18.02 (15.42-20.55) ppm over 2 h of exposure. Pretreatment of DHA (1 or 2 g/kg) increased the LC₅₀ of PH₃ by about 1.6- or 3-fold, respectively. Posttreatment with DHA (2 g/kg) increased the LC₅₀ of PH₃ by about 1.4-fold. PH₃ inhibited the activity of cytochrome c oxidase in the assessed organs. It was found that DHA treatment restored mitochondrial cytochrome c oxidase activity. These findings suggested that DHA could be an effective antidote for PH₃ poisoning.

Reprogramming an energetic AKT-PAK5 axis boosts axon energy supply and facilitates neuron survival and regeneration after injury and ischemia

Mitochondria supply adenosine triphosphate (ATP) essential for neuronal survival and regeneration. Brain injury and ischemia trigger acute mitochondrial damage and a local energy crisis, leading to degeneration. Boosting local ATP supply in injured axons is thus critical to meet increased energy demand during nerve repair and regeneration in adult brains, where mitochondria remain largely stationary. Here, we elucidate an intrinsic energetic repair signaling axis that boosts axonal energy supply by reprogramming mitochondrial trafficking and anchoring in response to acute injury-ischemic stress in mature neurons and adult brains. P21-activated kinase 5 (PAK5) is a brain mitochondrial kinase with declined expression in mature neurons. PAK5 synthesis and signaling is spatiotemporally activated within axons in response to ischemic stress and axonal injury. PAK5 signaling remobilizes and replaces damaged mitochondria via the phosphorylation switch that turns off the axonal mitochondrial anchor syntaphilin. Injury-ischemic insults trigger AKT growth signaling that activates PAK5 and boosts local energy supply, thus protecting axon survival and facilitating regeneration in in vitro and in vivo models. Our study reveals an axonal mitochondrial signaling axis that responds to injury and ischemia by remobilizing damaged mitochondria for replacement, thereby maintaining local energy supply to support central nervous system (CNS) survival and regeneration.

Disturbed mitochondrial redox state and tissue energy charge in cholestasis

The liver is the primary organ affected by cholestasis. However, the brain, skeletal muscle, heart, and kidney are also severely influenced by cholestasis/cirrhosis. However, little is known about the molecular mechanisms of organ injury in cholestasis. The current study was designed to evaluate the mitochondrial glutathione redox state as a significant index in cell death. Moreover, tissue energy charge (EC) was calculated. Rats underwent bile duct ligation (BDL) and the brain, heart, liver, kidney, and skeletal muscle mitochondria were assessed at scheduled time intervals (3, 7, 14, and 28 days after BDL). A significant decrease in mitochondrial glutathione redox state and EC was detected in BDL animals. Moreover, disturbed mitochondrial indices were evident in different organs of BDL rats. These data could offer new insight into the mechanisms of organ injury and the source of oxidative stress during cholestasis and might provide novel therapeutic strategies against these complications.

Purine adducts as a presumable missing link for aristolochic acid nephropathy-related cellular energy crisis, potential anti-fibrotic prevention and treatment

Aristolochic acid nephropathy is a progressive exposome-induced disease characterized by tubular atrophy and fibrosis culminating in end-stage renal disease and malignancies. The molecular mechanisms of the energy crisis as a putative cause of fibrosis have not yet been elucidated. In light of the fact that aristolochic acid forms DNA and RNA adducts by covalent binding of aristolochic acid metabolites to exocyclic amino groups of (deoxy)adenosine and (deoxy)guanosine, we hypothesize here that similar aristolochic acid adducts may exist with other purine-containing molecules. We also provide new insights into the aristolochic acid-induced energy crisis and presumably a link between already known mechanisms. In addition, an overview of potential targets in fibrosis treatment is provided, which is followed by recommendations on possible preventive measures that could be taken to at least postpone or partially alleviate aristolochic acid nephropathy.

Oridonin interrupts cellular bioenergetics to suppress glioma cell growth by down-regulating PCK2

We aim to evaluate the tumor metabolic suppressive activity of Oridonin (extract of Rabdosia rubescens) in glioma and elucidate its potential mechanism. Effects of Oridonin on U251/U87 cells were determined by CCK8, RTCA, colony formation, flow cytometry, wound healing, and Transwell assay. Xenograft tumor model to evaluate the effect of Oridonin on glioma cells in vivo. Cellular bioenergetics were measured by Seahorse. RNA-seq was performed to screen potential biological pathways in Oridonin treated cells. Bioinformatics analysis of PCK2 in glioma was performed based on TCGA/CGGA. Endogenous PCK2 was knocked-down by lentivirus packaged shRNA. We found Oridonin significantly inhibited cell growth in U251/U87 in vitro and in vivo. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were decreased in Oridonin-treated U251/U87 cells. Oridonin treatment led to PCK2 down-regulation. Additionally, PCK2 was up-regulated in higher grade glioma and correlated with poor outcomes. Furthermore, PCK2 depletion significantly inhibited cell growth and decreased OCR/ECAR in U251/U87 which coincided with the effects of Oridonin. Therefore, we evaluated the potent anti-tumor property of Oridonin in glioma. Importantly, we demonstrated that PCK2 might be a novel target of Oridonin on glioma by inducing energy crisis and increasing oxidative stress.

The Role of Mitochondrial Impairment and Oxidative Stress in the Pathogenesis of Lithium-Induced Reproductive Toxicity in Male Mice

Lithium (Li+) is prescribed against a wide range of neurological disorders. Besides its excellent therapeutic properties, there are several adverse effects associated with Li+. The impact of Li+ on renal function and diabetes insipidus is the most common adverse effect of this drug. On the other hand, infertility and decreased libido is another complication associated with Li+. It has been found that sperm indices of functionality, as well as libido, is significantly reduced in Li+-treated men. These adverse effects might lead to drug incompliance and the cessation of drug therapy. Hence, the main aims of the current study were to illustrate the mechanisms of adverse effects of Li+ on the testis tissue, spermatogenesis process, and hormonal changes in two experimental models. In the in vitro experiments, Leydig cells (LCs) were isolated from healthy mice, cultured, and exposed to increasing concentrations of Li+ (0, 10, 50, and 100 ppm). In the in vivo section of the current study, mice were treated with Li+ (0, 10, 50, and 100 ppm, in drinking water) for five consecutive weeks. Testis and sperm samples were collected and assessed. A significant sign of cytotoxicity (LDH release and MTT assay), along with disrupted testosterone biosynthesis, impaired mitochondrial indices (ATP level and mitochondrial depolarization), and increased biomarkers of oxidative stress were detected in LCs exposed to Li+. On the other hand, a significant increase in serum and testis Li+ levels were detected in drug-treated mice. Moreover, ROS formation, LPO, protein carbonylation, and increased oxidized glutathione (GSSG) were detected in both testis tissue and sperm specimens of Li+-treated mice. Several sperm anomalies were also detected in Li+-treated animals. On the other hand, sperm mitochondrial indices (mitochondrial dehydrogenases activity and ATP levels) were significantly decreased in drug-treated groups where mitochondrial depolarization was increased dose-dependently. Altogether, these data mention oxidative stress and mitochondrial impairment as pivotal mechanisms involved in Li+-induced reproductive toxicity. Therefore, based on our previous publications in this area, therapeutic options, including compounds with high antioxidant properties that target these points might find a clinical value in ameliorating Li+-induced adverse effects on the male reproductive system.

Inhibition of Mitochondrial Dynamics Preferentially Targets Pancreatic Cancer Cells with Enhanced Tumorigenic and Invasive Potential

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors, partly due to its intrinsic aggressiveness, metastatic potential, and chemoresistance of the contained cancer stem cells (CSCs). Pancreatic CSCs strongly rely on mitochondrial metabolism to maintain their stemness, therefore representing a putative target for their elimination. Since mitochondrial homeostasis depends on the tightly controlled balance between fusion and fission processes, namely mitochondrial dynamics, we aim to study this mechanism in the context of stemness. In human PDAC tissues, the mitochondrial fission gene DNM1L (DRP1) was overexpressed and positively correlated with the stemness signature. Moreover, we observe that primary human CSCs display smaller mitochondria and a higher DRP1/MFN2 expression ratio, indicating the activation of the mitochondrial fission. Interestingly, treatment with the DRP1 inhibitor mDivi-1 induced dose-dependent apoptosis, especially in CD133+ CSCs, due to the accumulation of dysfunctional mitochondria and the subsequent energy crisis in this subpopulation. Mechanistically, mDivi-1 inhibited stemness-related features, such as self-renewal, tumorigenicity, and invasiveness and chemosensitized the cells to the cytotoxic effects of Gemcitabine. In summary, mitochondrial fission is an essential process for pancreatic CSCs and represents an attractive target for designing novel multimodal treatments that will more efficiently eliminate cells with high tumorigenic potential.

Comprehensive Profile of Acute Mitochondrial Dysfunction in a Preclinical Model of Severe Penetrating TBI

Mitochondria constitute a central role in brain energy metabolism, and play a pivotal role in the development of secondary pathophysiology and subsequent neuronal cell death following traumatic brain injury (TBI). Under normal circumstances, the brain consumes glucose as the preferred energy source for adenosine triphosphate (ATP) production over ketones. To understand the comprehensive picture of substrate-specific mitochondrial bioenergetics responses following TBI, adult male rats were subjected to either 10% unilateral penetrating ballistic-like brain injury (PBBI) or sham craniectomy (n = 5 animals per group). At 24 h post-injury, mitochondria were isolated from pooled brain regions (frontal cortex and striatum) of the ipsilateral hemisphere. Mitochondrial bioenergetics parameters were measured ex vivo in the presence of four sets of metabolic substrates: pyruvate+malate (PM), glutamate+malate (GM), succinate (Succ), and β-hydroxybutyrate+malate (BHBM). Additionally, mitochondrial matrix dehydrogenase activities [i.e., pyruvate dehydrogenase complex (PDHC), alpha-ketoglutarate dehydrogenase complex (α-KGDHC), and glutamate dehydrogenase (GDH)] and mitochondrial membrane-bound dehydrogenase activities [i.e., electron transport chain (ETC) Complex I, II, and IV] were compared between PBBI and sham groups. Furthermore, mitochondrial coenzyme contents, including NAD_(t) and FAD_(t), were quantitatively measured in both groups. Collectively, PBBI led to an overall significant decline in the ATP synthesis rates (43-50%; ^* p < 0.05 vs. sham) when measured using each of the four sets of substrates. The PDHC and GDH activities were significantly reduced in the PBBI group (42-53%; ^* p < 0.05 vs. sham), whereas no significant differences were noted in α-KGDHC activity between groups. Both Complex I and Complex IV activities were significantly reduced following PBBI (47-81%; ^* p < 0.05 vs. sham), whereas, Complex II activity was comparable between groups. The NAD_(t) and FAD_(t) contents were significantly decreased in the PBBI group (27-35%; ^* p < 0.05 vs. sham). The decreased ATP synthesis rates may be due to the significant reductions in brain mitochondrial dehydrogenase activities and coenzyme contents observed acutely following PBBI. These results provide a basis for the use of "alternative biofuels" for achieving higher ATP production following severe penetrating brain trauma.

Ammonia-induced mitochondrial impairment is intensified by manganese co-exposure: relevance to the management of subclinical hepatic encephalopathy and cirrhosis-associated brain injury

Aim of the study

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome ensuing from liver failure. The liver is the major site of ammonia detoxification in the human body. Hence, acute and chronic liver dysfunction can lead to hyperammonemia. Manganese (Mn) is a trace element incorporated in several physiological processes in the human body. Mn is excreted through bile. It has been found that cirrhosis is associated with hyperammonemia as well as body Mn accumulation. The brain is the primary target organ for both ammonia and Mn toxicity. On the other hand, brain mitochondria impairment is involved in the mechanism of Mn and ammonia neurotoxicity.

Material and methods

The current study was designed to evaluate the effect of Mn and ammonia and their combination on mitochondrial indices of functionality in isolated brain mitochondria. Isolated brain mitochondria were exposed to increasing concentrations of ammonia and Mn alone and/or in combination and several mitochondrial indices were assessed.

Results

The collapse of mitochondrial membrane potential, increased mitochondrial permeabilization, reactive oxygen species formation, and a significant decrease in mitochondrial dehydrogenase activity and ATP content were evident in Mn-exposed (0.005-1 mM) brain mitochondria. On the other hand, ammonia (0.005-0.5 mM) caused no significant changes in brain mitochondrial function. It was found that co-exposure of the brain mitochondria to Mn and ammonia causes more evident mitochondrial impairment in comparison with Mn and/or ammonia alone.

Conclusions

These data indicate additive toxicity of ammonia and Mn in isolated brain mitochondria exposed to these neurotoxins.

The ACBP1-RAP2.12 signalling hub: A new perspective on integrative signalling during hypoxia in plants

During their lifetime, plants are frequently exposed to a variety of stresses which negatively impact on growth and vitality. In order to respond specifically to a given stress situation, integration of multiple signal inputs is of utmost importance. Recently, we demonstrated that recognition and adaptation to low-oxygen stress requires integration of signals from energy metabolism, lipid metabolism and oxygen availability. Low oxygen which results in an energy crisis causes a shift in lipid intermediate ratios. Binding of C18:1-CoA by ACYL-COA BINDING PROTEIN 1 (ACBP1) at the plasma membrane concomitantly leads to release and nuclear accumulation of the ERFVII transcription factor RELATED TO APETALA 2.12 (RAP2.12) which is central to the activation of anaerobic metabolism during stress. Moreover, RAP2.12 protein stability is oxygen-dependently regulated and its oxidation results in degradation by the N-end rule pathway. Here, we illuminate the concept of multiple-signal integration under hypoxia and discuss signal inputs merging at the ACBP1-ERFVII signaling hub.

Challenging the Cinderella Hypothesis: A New Model for the Role of the Motor Unit Recruitment Pattern in the Pathogenesis of Myofascial Pain Syndrome in Postural Muscles

BACKGROUND

The energy crisis hypothesis, which is a widely accepted model for the pathogenesis of myofascial pain, has been corroborated by experimental observations. However, the nature of the insult leading to the energy crisis remains elusive. A commonly cited model for this insult is the Cinderella hypothesis, suggesting that hierarchical recruitment of motor units leads to a disproportional load on small units, thus driving them towards an energy crisis. New findings cast doubt on this model, showing that in postural muscles motor units are recruited in rotation, rather than in a hierarchical order, precluding the formation of the so-called Cinderella units.

OBJECTIVE

To explore the influence of common myofascial predisposing factors such as muscle load and muscle strength on the relaxation time of postural muscle motor units, assuming they are recruited in rotation.

METHODS

A stochastic model of a postural skeletal muscle was developed which integrates the energy crisis model and motor unit rotation patterns observed in postural muscles. Postulating that adequate relaxation time is essential for the energetic replenishment of motor units, we explored the influence of different parameters on the relaxation time of individual motor units under varying conditions of muscle loads and muscle strengths.

RESULTS

The motor unit relaxation/contraction time ratio decreases with elevated muscle loads and with decreased total muscle strength.

CONCLUSIONS

In a model of a postural muscle, in which motor units are recruited in rotation, common predisposing factors of myofascial pain, such as increased muscle load and decreased muscle force, lead to shortened motor unit relaxation periods.

Sulfasalazine induces mitochondrial dysfunction and renal injury

Sulfasalazine is a commonly used drug for the treatment of rheumatoid arthritis and inflammatory bowel disease. There are several cases of renal injury encompass sulfasalazine administration in humans. The mechanism of sulfasalazine adverse effects toward kidneys is obscure. Oxidative stress and its consequences seem to play a role in the sulfasalazine-induced renal injury. The current investigation was designed to investigate the effect of sulfasalazine on kidney mitochondria. Rats received sulfasalazine (400 and 600 mg/kg/day, oral) for 14 consecutive days. Afterward, kidney mitochondria were isolated and assessed. Sulfasalazine-induced renal injury was biochemically evident by the increase in serum blood urea nitrogen (BUN), gamma-glutamyl transferase (γ-GT), and creatinine (Cr). Histopathological presentations of the kidney in sulfasalazine-treated animals revealed by interstitial inflammation, tubular atrophy, and tissue necrosis. Markers of oxidative stress including an increase in reactive oxygen species (ROS) and lipid peroxidation (LPO), a defect in tissue antioxidant capacity, and glutathione (GSH) depletion were also detected in the kidney of sulfasalazine-treated groups. Decreased mitochondrial succinate dehydrogenase activity (SDA), mitochondrial depolarization, mitochondrial GSH depletion, increase in mitochondrial ROS, LPO, and mitochondrial swelling were also evident in sulfasalazine-treated groups. Current data suggested that oxidative stress and mitochondrial injury might be involved in the mechanism of sulfasalazine-induced renal injury.

Concussion: pathophysiology and clinical translation

The majority of the 3.8 million estimated annual traumatic brain injuries (TBI) in the United States are mild TBIs, or concussions, and they occur primarily in adolescents and young adults. A concussion is a brain injury associated with rapid brain movement and characteristic clinical symptoms, with no associated objective biomarkers or overt pathologic brain changes, thereby making it difficult to diagnose by neuroimaging or other objective diagnostic tests. Most concussion symptoms are transient and resolve within 1-2 weeks. Concussions share similar acute pathophysiologic perturbations to more severe TBI: there is a rapid release of neurotransmitters, which causes ionic disequilibrium across neuronal membranes. Re-establishing ionic homeostasis consumes energy and leads to dynamic changes in cerebral glucose uptake. The magnitude and duration of these changes are related to injury severity, with milder injuries showing faster normalization. Cerebral sex differences add further variation to concussion manifestation. Relative to the male brain, the female brain has higher overall cerebral blood flow, and demonstrates regional differences in glucose metabolism, inflammatory responses, and connectivity. Understanding the pathophysiology and clinical translation of concussion can move research towards management paradigms that will minimize the risk for prolonged recovery and repeat injury.

Energetics of acclimation to NaCl by submerged, anoxic rice seedlings

BACKGROUND AND AIMS

Our aim was to elucidate how plant tissues under a severe energy crisis cope with imposition of high NaCl, which greatly increases ion fluxes and hence energy demands. The energy requirements for ion regulation during combined salinity and anoxia were assessed to gain insights into ion transport processes in the anoxia-tolerant coleoptile of rice.

METHODS

We studied the combined effects of anoxia plus 50 or 100 mm NaCl on tissue ions and growth of submerged rice (Oryza sativa) seedlings. Excised coleoptiles allowed measurements in aerated or anoxic conditions of ion net fluxes and O2 consumption or ethanol formation and by inference energy production.

KEY RESULTS

Over 80 h of anoxia, coleoptiles of submerged intact seedlings grew at 100 mm NaCl, but excised coleoptiles, with 50 mm exogenous glucose, survived only at 50 mm NaCl, possibly due to lower energy production with glucose than for intact coleoptiles with sucrose as substrate. Rates of net uptake of Na+ and Cl- by coleoptiles in anoxia were about half those in aerated solution. Ethanol formation in anoxia and O2 uptake in aerobic solution were each increased by 13-15 % at 50 mm NaCl, i.e. ATP formation was stimulated. For acclimation to 50 mm NaCl, the anoxic tissues used only 25 % of the energy that was expended by aerobic tissues. Following return of coleoptiles to aerated non-saline solution, rates of net K+ uptake recovered to those in continuously aerated solution, demonstrating there was little injury during anoxia with 50 mm NaCl.

CONCLUSION

Rice seedlings survive anoxia, without the coleoptile incurring significant injury, even with the additional energy demands imposed by NaCl (100 mm when intact, 50 mm when excised). Energy savings were achieved in saline anoxia by less coleoptile growth, reduced ion fluxes as compared to aerobic coleoptiles and apparent energy-economic ion transport systems.