Hormesis provides a generalized quantitative estimate of biological plasticity

Kaempferol, a widely ingested dietary flavonoid and supplement, enhances biological performance via hormesis, especially for ageing-related processes

Kaempferol is a polyphenol in various fruits and vegetables. It is also commercially developed and sold to consumers as a supplement. It has been extensively assessed in clinical trials for clinical utility based upon its numerous experimentally based chemopreventive properties. Kaempferol has been evaluated at the levels of molecule, cell, and individual animal, showing a broad spectrum of biological effects. Kaempferol-induced hormetic concentration responses are common, being reported in many cell types and biological models for numerous endpoints. While the hormetic effects of kaempferol are biologically diverse, there has been a strong focus on age-related endpoints affecting numerous organ systems and endpoints, indicating that kaempferol is a senolytic agent, showing similar properties as quercetin and fisetin. This paper offers the first integrated evaluation of kaempferol-induced hormetic dose responses, their quantitative characteristics, mechanistic explanations, extrapolative strengths or limitations, and related experimental design, biomedical, therapeutic, ageing, and public health, including ageing related applications.

Effects of Solvent Dimethyl Sulfoxide Invites a Rethink of Its Application in Amyloid Beta Cytotoxicity

Dimethyl sulfoxide (DMSO) is commonly used as a solvent for preparing amyloid-beta (Aβ) peptides implicated in Alzheimer's disease. While considered relatively non-toxic at low concentrations, DMSO itself may exert biological effects that could confound experimental outcomes, especially for weakly cytotoxic substances like Aβ. Seven brain cell types (BV-2, N2a, SH-SY5Y, U87, neurons, astrocytes, microglia) were treated with varying DMSO concentrations or Aβ1-42 oligomers/protofibrils/fibrils prepared using DMSO. Cell viability was assessed by CCK-8 and LDH assays. Matched DMSO controls were prepared alongside Aβ treatments to delineate solvent effects. Low DMSO concentrations (0.0625-0.015625%) exhibited hormetic cytoprotective and growth-promoting effects, while higher concentrations (≥2%) were cytotoxic. Importantly, these hormetic solvent effects confounded the measurement of Aβ cytotoxicity. By accounting for matched DMSO controls, the study revealed that Aβ fibril toxicity may have been underestimated due to the cytoprotective solvent effects of low DMSO concentrations used in their preparation. In conclusion, DMSO exhibits complex hormetic dose-responses that can significantly influence experimental outcomes, especially for weakly cytotoxic agents like Aβ. Rigorous solvent controls are crucial to delineate genuine substance effects from potential solvent confounds and avoid erroneous interpretations.

Life at new extremes: Integrating stress physiology and the bio-exposome in the Anthropocene

Conventional physiological research has focused on elucidating the endogenous mechanisms that underly the adaptations of species to life in extreme habitats, such as polar regions or deserts. In this review article, we argue that even habitats that are not considered extremes are facing unpredictable, rapid, and strong modifications due to human activities that expose animals to novel extreme conditions. Thus, physiological research on these animals can offer insight on the role of physiological plasticity in driving their resilience and adaptation. To this end, we discuss how stress physiology (with a particular focus on oxidative stress) has a central role in mediating the interaction between the exposome (measure of all the environmental exposures of an individual in a lifetime) and cellular processes (bio-exposome) in the contexts of relevant extreme anthropogenic changes to the habitat conditions. We also provide concrete examples on the relationship between oxidative stress and the bio-exposome in free-living animals, and how this research can be relevant to human health. Finally, we propose future research directions integrating the bio-exposome and the One Health framework to achieve a holistic understanding of the proximate mechanisms underlying individual responses to extreme anthropogenic environmental changes.

Hormesis and hydra effects revealed by intraspecific overcompensation models and dose-response curves

Overcompensation, defined as recovery beyond a baseline state, arises from both hormetic and hydra effects, illustrating adaptive responses to stress. The overcompensation framework of a re-evaluated fishery resource management model was examined through nonlinear growth patterns based on logistic or Ricker models, emphasizing population size over carrying capacity. This complete overcompensation model's threshold conditions reveal an interplay between hydra and hormetic effects. Also, when dividing a population into distinct subgroups, such as susceptible and infected classes in disease transmission, the population size can be modelled as a function of the basic reproduction number ([Formula: see text]). A threshold condition of [Formula: see text] allows examination of how disease infectivity triggers hydra or hormetic effects and, also, development of a partial overcompensation model that elucidates the internal mechanisms of overcompensation. Analysis of data from 24 groups of U-shaped or inverted U-shaped dose-response curves validated the dose-response curves. The simplified modelling approach developed revealed the mechanisms underlying hydra and hormetic effects, highlighting the importance of strong growth or regenerative capabilities, overcompensatory responses (strong nonlinearity), mild external stimuli (weak stressors) and the baseline population size. Our new analytical techniques for overcompensation modelling can be adapted to many fields, including tumour treatment and toxicology.

Do the hormetic effects of chlorogenic acid mediate some of the beneficial effects of coffee?

The present paper provides the first documentation and assessment of the capacity of chlorogenic acid to induce hormetic dose-response relationships. The findings suggest that chlorogenic acid may induce anabolic (i.e., growth) and catabolic (i.e., protective) hormetic dose responses in several cell types via a range of complementary and cross-talking pathways, affecting a spectrum of endpoints of biomedical and therapeutic importance. This paper also addresses the issue of whether the widely recognized beneficial effects of coffee consumption, as reported in multiple epidemiological studies, may be related to the hormetic effects of chlorogenic acid and its metabolites and their interactions. The present analysis suggests that some beneficial effects of coffee consumption may be due to the effects of chlorogenic acid and/or its metabolites on the gastrointestinal tract via their capacity to impact gastrointestinal integrity, structure, and functionality. These effects collectively contribute to the attenuation of the gastrointestinal tract and concurrent systemic oxidative stress, positively affecting a range of organ-specific effects.

Subchronic Effects of Tetrachloroethylene on Two Freshwater Copepod Species: Implications for Groundwater Risk Assessment

Aliphatic chlorinated hydrocarbons, notably tetrachloroethylene (also known as perchloroethylene [PCE]), are persistent, mobile, and toxic (PMT) and/or very persistent, mobile, and toxic (vPMT) groundwater pollutants, often exceeding safe drinking water thresholds. The present study delves into the groundwater risk assessment of PCE with a novel focus on the sensitivity of stygobitic species-organisms uniquely adapted to groundwater environments. Through a comparative analysis of the subchronic effects of PCE on the locomotion behavior of two copepod species, the stygobitic Moraria sp. and the nonstygobitic Bryocamptus zschokkei, we highlighted the inadequacy of the current European predicted-no-effect concentration of PCE for groundwater ecosystems. Our findings indicate significant behavioral impairments in both species at a concentration (32 ng/L PCE) well below the threshold deemed safe, suggesting that the current European guidelines for groundwater risk assessment may not adequately protect the unique biodiversity of groundwater habitats. Importantly, B. zschokkei demonstrated sensitivity to PCE comparable to or greater than that of the target stygobitic species, suggesting its utility as a substitute species in groundwater risk assessment. The present study adds to the limited research on the ecotoxicological sensitivity of groundwater species to PMT/vPMT chemicals and highlights the need for refined groundwater risk-assessment methodologies that consider the susceptibilities of stygobitic species. Environ Toxicol Chem 2024;43:2515-2527. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Moringa induces its beneficial effect via hormesis

Moringa oleifera, a traditional Indian herb, is widely known for its capacity to induce antioxidant, anti-inflammatory and other chemoprotective effects in a broad range of biomedical models. These perspectives have led to an extensive number of studies using various moringa extracts to evaluate its capacity to protect biological systems from oxidative stress and to explore whether it could be used to slow the onset of numerous age-related conditions and diseases. Moringa extracts have also been applied to prevent damage to plants from oxidative and saline stresses, following hormetic dose–response patterns. The present paper provides the first integrated and mechanistically based assessment showing that moringa extracts commonly induce hormetic dose responses and that many, perhaps most, of the beneficial effects of moringa are due to its capacity to act as an hormetic agent.

The extremely low-frequency electromagnetic field (50 Hz) can establish a new "set-point" for the activity of the locus coeruleus-noradrenergic (LC-NA) system in rat

Exposure of organisms to extremely low-frequency electromagnetic field (ELF-EMF; 50 Hz) has been increasing in recent decades, which is connected with dynamic technological development. ELF-EMF is considered a stress factor and its effects on organisms are still being investigated. We aimed to determine its impact on the locus coeruleus-noradrenergic (LC-NA) system enabling adaptation to stressful conditions. For this purpose, we exposed rats to 50 Hz ELF-EMF of 1 and 7 mT, 1 h/day for 7 days. The procedure was repeated three times to examine the organism's adaptive capabilities. Subsequently, the concentration of adrenaline, noradrenaline and its metabolite MHPG as well as the expression of the β2-adrenergic receptor was assessed. After the end of each exposure, part of the animals were subjected to a behavioural test to assess the influence of repeated ELF-EMF exposure on stress response to subsequent stress factors. Our research proved that mechanisms underlying the effects of ELF-EMF on stress response include the LC-NA system. ELF-EMF of 1 mT induced adaptive changes in the NA-LC system. However, exposure to 7 mT caused increased activity of the stress system which resulted in sensitization to subsequent, heterotypic (different from the one previously acting) stress factor. As ELF-EMF of 7 mT caused a profound decrease in β2-AR level would strongly inhibit the potential for neuroplastic processes in the hippocampus. Moreover, rats exposed to ELF-EMF of 7 mT showed moderately increased anxiety-related behaviour. Disturbances in NA-LC transmission may underlie the development of some neurodegenerative and psychiatric diseases which indicates the possible involvement of ELF-EMF in the pathogenesis of these disorders.

Synergistic Protection of Vitamin B Complex and Alpha-Lipoic Acid Against Hepatic Ischemia-Reperfusion Injury: Boosting Antioxidant Defenses in Rats

This study aimed to investigate the protective effects of vitamin B complex and alpha-lipoic acid (ALA) pre-treatments on hepatic ischemia-reperfusion injury (IRI) in rats, focusing on their potential to enhance antioxidant defense mechanisms and reduce post-ischemic liver damage. Thirty male Wistar albino rats were divided into four groups: sham group (n = 10), IRI group (n = 10), vitamin B group (n = 10), vitamin B + ALA group (n = 10). In the IRI, vitamin B, and vitamin B + ALA groups, the rats underwent 45 min of hepatic ischemia followed by 60 min of reperfusion. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, and lactate dehydrogenase (LDH) were measured. Additionally, serum total antioxidant status (TAS) and total oxidant status (TOS) were assessed, and the oxidative stress index (OSI) was calculated. Liver tissue samples were collected for morphological evaluation. In the vitamin B and vitamin B + ALA groups, ALT, AST, urea, creatinine and LDH levels were better compared with the IRI group but the difference was statistically significant for only LDH levels in the vitamin B group and ALT, urea, and LDH levels in the vitamin B + ALA group (p < 0.05). The lowest TOS and OSI levels were reported in the vitamin B and vitamin B + ALA groups and these groups had statistically significantly higher TAS compared with the sham and IRI groups (p < 0.05). Our findings suggest that a vitamin B complex alone or a vitamin B complex + ALA combination reduces post-ischemic hepatic injury by enhancing the anti-oxidative status. The low dose of ALA may be a co-factor in these results and studies with larger doses of ALA are required to determine its effects on IRI of the liver.

The chemoprotective hormetic effects of rosmarinic acid

Rosmarinic acid is a polyphenol found in numerous fruits and vegetables, consumed in supplement form, and tested in numerous clinical trials for therapeutic applications due to its putative chemopreventive properties. Rosmarinic acid has been extensively studied at the cellular, whole animal, and molecular mechanism levels, presenting a complex array of multi-system biological effects. Rosmarinic acid-induced hormetic dose responses are widespread, occurring in numerous biological models and cell types for a broad range of endpoints. Consequently, this article provides the first assessment of rosmarinic acid-induced hormetic concentration/dose responses, their quantitative features, mechanistic foundations, extrapolative strengths/limitations, and their biomedical, clinical, and public health implications.

Caffeic Acid: Numerous Chemoprotective Effects are Mediated via Hormesis

Caffeic acid is a common phenolic acid found in coffee and numerous fruits and vegetables. Known for its antioxidant properties, it is widely used as a dietary supplement as part of a polyphenol mixture or as an extract in the form of a capsule or powder. It is also available in liquid form as a homeopathic supplement. Caffeic acid phenethyl ester (CAPE) is an active component of propolis produced by honey bees. Propolis extract is used as a supplement and is available in various forms. The present paper is a comprehensive review of the biomedical literature, showing that caffeic acid effects are hormetic and occur in numerous biological models and cell types for a broad range of endpoints including many aging-related processes. Hormesis is a biphasic dose/concentration response displaying a low concentration/dose stimulation and a high concentration/dose inhibition. Complex alternative search strategies for caffeic acid were used since publications rarely used the terms hormesis or hormetic. Evaluation of the data provides the first assessment of caffeic acid-induced hormetic concentration/dose responses and their quantitative features. Their mechanistic foundations, extrapolative strengths/limitations, and their biomedical, clinical, and public health implications are discussed. Suggestions for future research are presented.

Oocyte maturation, blastocyst and embryonic development are mediated and enhanced via hormesis

The present paper provides the first integrative assessment of the capacity of dietary, endogenous and other agents to induce hormetic dose responses in oocytes, their supportive cells such as granulosa cells, blastocyst formation and early stage embryo development with the goal of improving fertility and reproductive success. The analysis showed that numerous agents enhance oocyte maturation and blastocyst/embryonic development in an hormetic fashion. These findings indicate that numerous agents improve oocyte-related biological functioning under normal conditions as well as enhancing its capacity to prevent damage from numerous chemical toxins and related stressor agents, including heat and age-related processes in pre-post conditioning and concurrent exposures. The present assessment suggests that hormetic-based lifestyles and dietary interventions may offer the potential to enhance healthy reproductive performance with applications to animal husbandry and human biology. The present findings also significantly extend the generality of the hormesis dose response concept to multiple fundamental biological processes (i.e., oocyte maturation, fertilization and blastocyst/embryo development).

Enhancing the human health and lifespan: a targeted strategy emphasizing statins

There has been substantial research interest in finding activities/agents that slow the onset and reduce the severity of numerous age-related diseases/conditions. This assessment indicates that the most studied agent intended to promote health in human population investigations for a broad spectrum of diseases are the statins, with large-scale epidemiological studies addressing numerous health endpoints. The key findings are that statin treatment consistently reduces the occurrence and attenuates the course of numerous non-communicable and contagious pathologies and numerous types of cancer with high mortality rates by about 20-50%. That one agent could affect such a broad based and consistently positive trends in epidemiological studies is unexpected and impressive, along with consistent cell and animal model research. Underlying mechanisms have been proposed that significantly contribute to the spectrum of salutary effects of statins, especially the capacity to activate Nrf2 showing hormetic dose responses in multiple organs and cell types, due to its bioavailability and broad tissue distribution. The widespread use of statins, which has the capacity to enhance human health span, should be considered for experimental exploration as a novel public health strategy that includes practical approaches for reduction of the most common adverse effects of this class of drugs including myalgia/myopathy and transaminitis.

Current advances and future trends of hormesis in disease

Hormesis, an adaptive response, occurs when exposure to low doses of a stressor potentially induces a stimulatory effect, while higher doses may inhibit it. This phenomenon is widely observed across various organisms and stressors, significantly advancing our understanding and inspiring further exploration of the beneficial effects of toxins at doses both below and beyond traditional thresholds. This has profound implications for promoting biological regulation at the cellular level and enhancing adaptability throughout the biosphere. Therefore, conducting bibliometric analysis in this field is crucial for accurately analyzing and summarizing its current research status. The results of the bibliometric analysis reveal a steady increase in the number of publications in this field over the years. The United States emerges as the leading country in both publication and citation numbers, with the journal Dose-Response publishing the highest number of papers in this area. Calabrese E.J. is a prominent person with significant contributions and influence among authors. Through keyword co-occurrence and trend analysis, current hotspots in this field are identified, primarily focusing on the relationship between hormesis, oxidative stress, and aging. Analysis of highly cited references predicts that future research trends may center around the relationship between hormesis and stress at different doses, as well as exploring the mechanisms and applications of hormesis. In conclusion, this review aims to visually represent hormesis-related research through bibliometric methods, uncovering emerging patterns and areas of focus within the field. It provides a summary of the current research status and forecasts trends in hormesis-related research.

RUTIN, a widely consumed flavonoid, that commonly induces hormetic effects

Rutin is a flavonoid present in numerous fruits and vegetables and therefore widely consumed by humans. It is also a popular dietary supplement of 250-500 mg/day. There is considerable consumer interest in rutin due to numerous reports in the biomedical literature of its multi-system chemo-preventive properties. The present paper provides the first assessment of rutin-induced hormetic concentration/dose responses, their quantitative features and mechanistic basis, along with their biological, biomedical, clinical, and public health implications. The findings indicate that rutin-induced hormetic dose responses are widespread, being reported in numerous biological models and cell types for a wide range of endpoints. Of critical importance is that the optimal hormetic findings shown in in vitro systems are currently not achievable for human populations due to low gastrointestinal tract bioavailability. These findings have the potential to strengthen future experimental studies with rutin, particularly concerning study design parameters.

Taurine induces hormesis in multiple biological models: May have transformative implications for overall societal health

This paper represents the first integrative assessment and documentation of taurine-induced hormetic effects in the biological and biomedical areas, their dose response features, mechanistic frameworks, and possible public health, therapeutic and commercial applications. Taurine-induced hormetic effects are documented in a wide range of experimental models, cell types and for numerous biological endpoints, with most of these experimental findings being reported within the past five years. It is suggested that the concept of hormesis may have a transformative effect on taurine research and its public health and therapeutic applications.

Flavonoids commonly induce hormetic responses

The present paper provides a new perspective of previously published findings by Siwak (Food Chem 141:1227-1241, 2013) which showed that 15 structurally diverse flavonoids reduced toxicity (i.e., enhanced cell viability) from hypochlorite using the MTT assay within a pre-conditioning experimental protocol, with each agent showing a similar biphasic concentration response relationship. We use this Commentary to point out that each of the concentration response relationships are consistent with the hormetic dose response. The paper of Siwak (Food Chem 141:1227-1241, 2013) is unique in that it provides a comparison of a relatively large number of agents using the identical experimental protocol.

Glyphosate hormesis induced by treatment via seed stimulates the growth and biomass accumulation in soybean seedlings

Glyphosate hormesis, identified as a potential means to enhance crop yields, encounters practical constraints because it is typically assessed through foliar applications. The expression and extend of hormesis in this approach are influenced by unpredictable environmental conditions, highlighting the need to explore alternative glyphosate application methods, such as seed treatment. This study aimed to assess glyphosate hormesis on growth rates and biomass accumulation in seedlings soybean cultivars. Two dose-response experiments [doses from 0 to 2880 g acid equivalent (ae) ha-1], one via foliar and one via seed, were conducted on three soybean cultivars [one non-glyphosate-resistant (NGR) and two glyphosate-resistant (GR, one RR and one RR2)]. In a subsequent experiment, three safe glyphosate doses (0, 90 and 180 g ae ha-1) applied via seed were evaluated on four soybean cultivars (two RR and two RR2). For foliar applications, the range of glyphosate doses increasing growth rates and dry biomass by 12-28 % were 5.6-45 g ae ha-1 for the NGR cultivar, of 45-720 g ae ha-1 for RR and of 11.25-180 g ae ha-1 for RR2. In the seed treatment, biomass increases of 16-60 % occurred at 45-180 g ae ha-1 for the NGR and RR cultivars, and 90-360 g ae ha-1 for RR2. Glyphosate doses of 90 and 180 g ae ha-1, applied via seeds, provided greater growth and biomass accumulation for the RR and RR2 soybean cultivars. Both foliar and seed applications of glyphosate increased growth and biomass accumulation in soybean cultivars, with seed treatments showing greater and more consistent enhancements. These findings propose practical and viable alternative for harnessing glyphosate hormesis to facilitate the early development of soybeans and potentially enhance crop yield.

Glyphosate hormesis effects on the vegetative and reproductive development of glyphosate-susceptible and -resistant Conyza sumatrensis biotypes

Low glyphosate doses that produce hormesis may alter the susceptibility to herbicides of weeds or enhance their propagation and dispersal. The objective of this work was to evaluate the hormetic effects of glyphosate on the vegetative, phenological and reproductive development in resistant (R) and susceptible (S) Conyza sumatrensis biotypes. The glyphosate resistance level of biotype R was 11.2-fold compared to the S biotype. Glyphosate doses <11.25 g ae ha-1 induced temporary and permanent hormetic effects for the number of leaves, plant height and dry mass accumulation up to 28 d after application in both R and S biotypes. The S biotype required 15-19% fewer thermal units at 1.4 and 2.8 g ae ha-1 glyphosate than untreated plants to reach the bolting stage. Also, this biotype had less thermal units associated with the appearance (1225 vs 1408 units) and opening (1520 vs 1765 units) of the first capitulum than the R biotype. In addition, glyphosate affected reproductive traits of both biotypes compared to their controls, increasing the number of capitulum's and seeds per plant up to 37 and 41% (at 2.8 and 0.7 g ae h-1, respectively) in the S biotype, and by 48 and 114% (both at 5.6 g ae ha-1) in the R biotype. Depending on environmental parameters, glyphosate may or may not cause hormetic effects on the vegetative and phenological development of C. sumatrenis biotypes; however, this herbicide increases the speed and fecundity of reproduction, regardless of the glyphosate susceptibility level, which can alter the population dynamics and glyphosate susceptibility of future generations.

Unraveling the parahormetic mechanism underlying the health-protecting effects of grapeseed procyanidins

Proanthocyanidins (PACs), the predominant constituents within Grape Seed Extract (GSE), are intricate compounds composed of interconnected flavan-3-ol units. Renowned for their health-affirming properties, PACs offer a shield against a spectrum of inflammation associated diseases, such as diabetes, obesity, degenerations and possibly cancer. While monomeric and dimeric PACs undergo some absorption within the gastrointestinal tract, their larger oligomeric and polymeric counterparts are not bioavailable. However, higher molecular weight PACs engage with the colonic microbiota, fostering the production of bioavailable metabolites that undergo metabolic processes, culminating in the emergence of bioactive agents capable of modulating physiological processes. Within this investigation, a GSE enriched with polymeric PACs was employed to explore in detail their impact. Through comprehensive analysis, the present study unequivocally verified the gastrointestinal-mediated transformation of medium to high molecular weight polymeric PACs, thereby establishing the bioaccessibility of a principal catabolite termed 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (VL). Notably, our findings, encompassing cell biology, chemistry and proteomics, converge to the proposal of the notion of the capacity of VL to activate, upon oxidation to the corresponding quinone, the nuclear factor E2-related factor 2 (Nrf2) pathway-an intricate process that incites cellular defenses and mitigates stress-induced responses, such as a challenge brought by TNFα. This mechanistic paradigm seamlessly aligns with the concept of para-hormesis, ultimately orchestrating the resilience to stress and the preservation of cellular redox equilibrium and homeostasis as benchmarks of health.

Testing the hormesis hypothesis on motor behavior under stress

While much research has focused on the deleterious effects of stress on goal-directed behavior in recent decades, current views increasingly discuss growth under stress, often assuming dose-dependent effects of stress in a curvilinear association. This is based on the concept of hormesis, which postulates a strengthening effect of stress at low-to-moderate doses. Leveraging this approach, hormetic curves indicate under which stress dose an individual is able to maintain or even increase goal-directed behavior. The present study aimed to test the hormetic effect of low-to-moderate stress on tactical movement performance in the context of police operational scenarios in virtual reality. In teams of three to four, 37 riot police officers had to search a building for a potentially aggressive perpetrator in three scenarios with escalating stress potential (i.e., increasing weapon violence and number of civilians). Tactical movement performance as behavioral response was quantified by the sample entropy of each officer's velocity derived from positional data. To account for inter-individuality in response to the scenarios, we assessed self-reported stress, anxiety, mental effort, and vagally mediated heart rate variability. Specifically, we tested the quadratic associations between tactical movement performance and stress parameters, respectively. Random-intercept-random-slope regressions revealed neither significant linear nor quadratic associations between any of the stress parameters and performance. While we did not find evidence for hormesis in the present study, it stimulates theoretical discussions about the definition of "baseline" functioning and how the understanding of hormesis can move from psychological to behavioral adaptations to stressors.

Hormesis determines lifespan

This paper addresses how long lifespan can be extended via multiple interventions, such as dietary supplements [e.g., curcumin, resveratrol, sulforaphane, complex phytochemical mixtures (e.g., Moringa, Rhodiola)], pharmaceutical agents (e.g., metformin), caloric restriction, intermittent fasting, exercise and other activities. This evaluation was framed within the context of hormesis, a biphasic dose response with specific quantitative features describing the limits of biological/phenotypic plasticity for integrative biological endpoints (e.g., cell proliferation, memory, fecundity, growth, tissue repair, stem cell population expansion/differentiation, longevity). Evaluation of several hundred lifespan extending agents using yeast, nematode (Caenorhabditis elegans), multiple insect and other invertebrate and vertebrate models (e.g., fish, rodents), revealed they responded in a manner [average (mean/median) and maximum lifespans] consistent with the quantitative features [i.e., 30-60% greater at maximum (Hormesis Rule)] of the hormetic dose response. These lifespan extension features were independent of biological model, inducing agent, endpoints measured and mechanism. These findings indicate that hormesis describes the capacity to extend life via numerous agents and activities and that the magnitude of lifespan extension is modest, in the percentage, not fold, range. These findings have important implications for human aging, genetic diseases/environmental stresses and lifespan extension, as well as public health practices and long-term societal resource planning.

NQO1 Mediates Lenvatinib Resistance by Regulating ROS-induced Apoptosis in Hepatocellular Carcinoma

OBJECTIVE

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated death worldwide. As a first-line drug for advanced HCC treatment, lenvatinib faces a significant hurdle due to the development of both intrinsic and acquired resistance among patients, and the underlying mechanism remains largely unknown. The present study aims to identify the pivotal gene responsible for lenvatinib resistance in HCC, explore the potential molecular mechanism, and propose combinatorial therapeutic targets for HCC management.

METHODS

Cell viability and colony formation assays were conducted to evaluate the sensitivity of cells to lenvatinib and dicoumarol. RNA-Seq was used to determine the differences in transcriptome between parental cells and lenvatinib-resistant (LR) cells. The upregulated genes were analyzed by GO and KEGG analyses. Then, qPCR and Western blotting were employed to determine the relative gene expression levels. Afterwards, the intracellular reactive oxygen species (ROS) and apoptosis were detected by flow cytometry.

RESULTS

PLC-LR and Hep3B-LR were established. There was a total of 116 significantly upregulated genes common to both LR cell lines. The GO and KEGG analyses indicated that these genes were involved in oxidoreductase and dehydrogenase activities, and reactive oxygen species pathways. Notably, NAD(P)H:quinone oxidoreductase 1 (NQO1) was highly expressed in LR cells, and was involved in the lenvatinib resistance. The high expression of NQO1 decreased the production of ROS induced by lenvatinib, and subsequently suppressed the apoptosis. The combination of lenvatinib and NQO1 inhibitor, dicoumarol, reversed the resistance of LR cells.

CONCLUSION

The high NQO1 expression in HCC cells impedes the lenvatinib-induced apoptosis by regulating the ROS levels, thereby promoting lenvatinib resistance in HCC cells.

Quercetin induces its chemoprotective effects via hormesis

Quercetin is a polyphenol present in numerous fruits and vegetables and therefore widely consumed by humans with average daily dietary intakes of 10-20 mg/day. It is also a popular dietary supplement of 250-1000 mg/day. However, despite the widespread consumer interest in quercetin, due to its possible chemopreventive properties, the extensively studied quercetin presents a highly diverse and complex array of biological effects. Consequently, the present paper provides the first assessment of quercetin-induced hormetic concentration/dose responses, their quantitative features and mechanistic foundations, and their biological, biomedical, clinical, and public health implications. The findings indicate that quercetin-induced hormetic dose responses are widespread, being independent of biological model, cell type, and endpoint. These findings have the potential to enlighten future experimental studies with quercetin especially with respect to study design parameters and may also affect the appraisal of possible public health benefits and risks associated with highly diverse consumer consumption practices.

Comet assay and hormesis

The paper provides the first assessment of the occurrence of hormetic dose responses using the Comet assay, a genotoxic assay. Using a priori evaluative criteria based on the Hormetic Database on peer-reviewed comet assay experimental findings, numerous examples of hormetic dose responses were obtained. These responses occurred in a large and diverse range of cell types and for agents from a broad range of chemical classes. Limited attempts were made to estimate the frequency of hormesis within comet assay experimental studies using a priori entry and evaluative criteria, with results suggesting a frequency in the 40% range. These findings are important as they show that a wide range of genotoxic chemicals display evidence that is strongly suggestive of hormetic dose responses. These findings have significant implications for study design issues, including the number of doses selected, dose range and spacing. Likewise, the widespread occurrence of hormetic dose responses in this genotoxic assay has important risk assessment implications.

Callosobruchus maculatus males and females respond differently to grandparental effects

In this study, we used the cowpea weevil Callosobruchus maculatus (Coleoptera: Chrysomelidae) and two essential oils (mint and rosemary) to investigate the effect of the parents (F0) exposure to a sublethal dose of essential oil on grand offspring (F2) encountering the same essential oil. Then we evaluated biological parameters, including immature development time, sex ratio, adult emergence, egg number, egg hatch, longevity, and mating behaviors in three generations (F0, F1, and F2). Results showed when F0 experienced essential oil in the embryonic stage, parental and grandparental effects were more severe than adulthood experiences. Also, grandparental effects increased or decreased reactions of F2 generation when faced with a similar essential oil, depending on grand offspring sex. For example, when grandparents experienced rosemary essential oil in the embryonic stage, they produced more tolerant female grand offspring with a better ability to cope with the same essential oil (increased adult longevity and egg number). However, male grandoffspring were more sensitive (had a higher mortality percentage and less copulation success). Grandparental effects of exposure to mint essential oil diminished female grand offspring longevity and improved male copulation behavior parameters such as increased copulation duration and decreased rejection by females. In all, grandparental effects were different in male and female grand offspring based on the essential oil type experienced by F0.

The challenges of defining hormesis in epidemiological studies: The case of radiation hormesis

In the current radiation protection system, preventive measures and occupational exposure limits for controlling occupational exposure to ionizing radiation are based on the linear no-threshold extrapolation model. However, currently an increasing body of evidence indicates that this paradigm predicts very poorly biological responses in the low-dose exposure region. In addition, several in vitro and in vivo studies demonstrated the presence of hormetic dose response curves correlated to ionizing radiation low exposure. In this regard, it is noteworthy that also the findings of different epidemiological studies, conducted in different categories of occupationally exposed workers (e.g., healthcare, nuclear industrial and aircrew workers), observed lower rates of mortality and/or morbidity from cancer and/or other diseases in exposed workers than in unexposed ones or in the general population, then suggesting the possible occurrence of hormesis. Nevertheless, these results should be considered with caution since the identification of hormetic response in epidemiological studies is rather challenging because of a number of major limitations. In this regard, some of the most remarkable shortcomings found in epidemiological studies performed in workers exposed to ionizing radiation are represented by lack or inadequate definition of exposure doses, use of surrogates of exposure, narrow dose ranges, lack of proper control groups and poor evaluation of confounding factors. Therefore, considering the valuable role and contribution that epidemiological studies might provide to the complex risk assessment and management process, there is a clear and urgent need to overcome the aforementioned limits in order to achieve an adequate, useful and more real-life risk assessment that should also include the key concept of hormesis. Thus, in the present conceptual article we also discuss and provide possible approaches to improve the capacity of epidemiological studies to identify/define the hormetic response and consequently improve the complex process of risk assessment of ionizing radiation at low exposure doses.

Polyamines and hormesis: Making sense of a dose response dichotomy

The diverse biological effects of polyamines (putrescine, spermidine and spermine) were reviewed in the context of hormesis in an integrative manner for the first time. The findings illustrate that each of these polyamines commonly induces hormetic dose responses in a wide range of biological models and types of cells for multiple endpoints in numerous plant species and animal models. Plant research emphasized preconditioning experimental studies in which the respective polyamines conferred some protection against the damaging effects of a broad range of environmental stressors such as drought, salinity, cold/heat, heavy metals and UV-damage in an hormetic manner. Polyamine-based animal hormesis studies emphasized biomedical endpoints such as longevity and neuroprotection. These findings have important biological and biomedical implications and should guide experimental designs of low dose investigations.

Glucosinolates in cancer prevention and treatment: experimental and clinical evidence

Glucosinolates are naturally occurring β-d-thioglucosides that mainly exist in the Brassicaceae family. The enzyme myrosinase hydrolyzes glucosinolates to form isothiocyanates, which are chemical protectors. Phenethyl isothiocyanate, sulforaphane, and benzyl isothiocyanate are potential isothiocyanate with efficient anti-cancer effects as a protective or treatment agent. Glucosinolate metabolites exert the cancer-preventive activity through different mechanisms, including induction of the Nrf2 transcription factor, inhibition of expression of tumor necrosis factor-α (TNFα) and interleukin-1β (IL-1β), induction of apoptosis through inhibiting phase I enzymes and inducting phase II enzymes, interruption of caspase pathways, STAT1/STAT2, inhibition of sulfotransferases. Moreover, glucosinolates and their metabolites are effective in cancer treatment by inhibiting angiogenesis, upregulating natural killers, increasing expression of p53, p21, caspase 3 and 9, and modulating NF-κB. Despite the mentioned cancer-preventing effects, some isothiocyanates can increase the risk of tumors. So, further studies are needed to obtain an accurate and effective dose for each glucosinolates to treat different types of tumors.

Hormesis defines the limits of lifespan

This commentary provides a novel synthesis of how biological systems adapt to a broad spectrum of environmental and age-related stresses that are underlying causes of numerous degenerative diseases and debilitating effects of aging. It proposes that the most fundamental, evolutionary-based integrative strategy to sustain and protect health is based on the concept of hormesis. This concept integrates anti-oxidant, anti-inflammatory and cellular repair responses at all levels of biological organization (i.e., cell, organ and organism) within the framework of biphasic dose responses that describe the quantitative limits of biological plasticity in all cells and organisms from bacteria and plants to humans. A major feature of the hormetic concept is that low levels of biological, chemical, physical and psychological stress upregulate adaptive responses that not only precondition, repair and restore normal functions to damaged tissues/organs but modestly overcompensate, reducing ongoing background damage, thereby enhancing health beyond that in control groups, lacking the low level "beneficial" stress. Higher doses of such stress often become counterproductive and eventually harmful. Hormesis is active throughout the life-cycle and can be diminished by aging processes affecting the onset and severity of debilitating conditions/diseases, especially in elderly subjects. The most significant feature of the hormetic dose response is that the limits of biological plasticity for adaptive processes are less than twice that of control group responses, with most, at maximum, being 30-60 % greater than control group values. Yet, these modest increases can make the difference between health or disease and living or dying. The quantitative features of these adaptive hormetic dose responses are also independent of mechanism. These features of the hormetic dose response determine the capacity to which systems can adapt/be protected, the extent to which biological performance (e.g., memory, resistance to injury/disease, wound healing, hair growth or lifespan) can be enhanced/extended and the extent to which synergistic interactions may occur. Hormesis defines the quantitative rules within which adaptive processes operate and is central to evolution and biology and should become transformational for experimental concepts and study design strategies, public health practices and a vast range of therapeutic strategies and interventions.

Naringin commonly acts via hormesis

The present paper provides the first integrative assessment of the capacity of naringin and its metabolite, naringenin, to induce hormetic dose responses within a broad range of experimental biomedical models. The findings indicate that these agents commonly induced protective effects that are typically mediated via hormetic mechanisms leading to biphasic dose-response relationships. The maximum protective effects are generally modest, 30-60 % greater than control group values. The range of experimental findings with these agents has been reported for models with various neurodegenerative diseases, nucleus pulpous cells (NPCs) located within intravertebral discs, several types of stem cells (i.e., bone marrow, amniotic fluid, periodontal, endothelial) as well as cardiac cells. These agents also were effective within preconditioning protocols protecting against environmental toxins such as ultraviolet radiation (UV), cadmium, and paraquat. The mechanism(s) by which the hormetic responses mediates these biphasic dose responses is complex but commonly involves the activation of nuclear factor erythroid 2-related factor (Nrf2), an increasingly recognized regulator of cellular resistance to oxidants. Nrf2 appears to play a role in controlling the basal and induced expression of an array of antioxidant response element-dependent genes to regulate oxidant exposure's physiological and pathophysiological outcomes. Hence its importance in the assessment of toxicologic and adaptive potential is likely to be significant.

Plant hormesis: Revising of the concepts of biostimulation, elicitation and their application in a sustainable agricultural production

Current research in basic and applied knowledge of plant science has aimed to unravel the role of the interaction between environmental factors and the genome in the physiology of plants to confer the ability to overcome challenges in a climate change scenario. Evidence shows that factors causing environmental stress (stressors), whether of biological, chemical, or physical origin, induce eustressing or distressing effects in plants depending on the dose. The latter suggests the induction of the "hormesis" phenomenon. Sustainable crop production requires a better understanding of hormesis, its basic concepts, and the input variables to make its management feasible. This implies that acknowledging hormesis in plant research could allow specifying beneficial effects to effectively manage environmental stressors according to cultivation goals. Several factors have been useful in this regard, which at low doses show beneficial eustressing effects (biostimulant/elicitor), while at higher doses, they show distressing toxic effects. These insights highlight biostimulants/elicitors as tools to be included in integrated crop management strategies for reaching sustainability in plant science and agricultural studies. In addition, compelling evidence on the inheritance of elicited traits in plants unfolds the possibility of implementing stressors as a tool in plant breeding.

Hormesis, biological plasticity, and implications for clinical trial research

The present paper identifies a critical factor that leads to false negative results (i.e., failing to indicate efficacy when beneficial results did occur) in randomized human drug trials. The paper demonstrates that human performance can only be enhanced by a maximum of 30-60% as described by the hormetic dose response which defines the limits of biological plasticity. However, human epidemiological/clinical trials typically contain such extensive variability that often requires responses greater than 2-3 times control group responses to show statistical significance. Thus, many potentially beneficial agents may be missed because the clinical trial fails to recognize and take into consideration the limits of biological plasticity. The paper proposes that this hormesis-biological plasticity-clinical trial conundrum can be addressed successfully via the use of a weight-of-evidence methodology similar to that used by regulatory agencies such as EPA in environmental assessment of chemical toxicity.

Protective effects of alpha lipoic acid (ALA) are mediated by hormetic mechanisms

The endogenous and dietary agent, alpha lipoic acid (ALA) is evaluated for its capacity to induce a broad spectrum of adaptive responses via hormetic dose responses and their underlying mechanisms. ALA was shown to induce hormetic effects in a wide range of experimental models within in vitro and in vivo experimental settings which included direct exposure and pre- and post-conditioning experimental protocols. The hormetic effects occur in a broad range of organ systems, including the brain, heart, kidney and other tissues, with possible public health and clinical/therapeutic applications linked to reducing the onset and progression of neurogenerative diseases and also in the preservation of sperm health and functionality during cryopreservation. This paper provides the first integrated assessment of ALA-induced hormetic dose responses. Underlying mechanisms that mediated the occurrence of ALA-induced hormetic effects involved the induction of low levels of ROS that activate key cell signaling antioxidant (e.g. Nrf2) pathways.

Rhodiola rosea and Salidroside commonly induce hormesis, with particular focus on longevity and neuroprotection

The biological effects of Rhodiola rosea extracts and one of its major constituents, Salidroside, were evaluated for their capacity to induce hormesis/hormetic effects. The findings indicate that the Rhodiola rosea extracts and Salidroside commonly induce hormetic dose responses within a broad range of biological models, cell types and across a broad range of endpoints, with particular emphasis on longevity and neuroprotective endpoints. This paper represents the first integrative documentation and assessment of Rhodiola rosea extracts and Salidroside induction of hormetic effects. These findings have important biomedical applications and should have an important impact with respect to critical study design, dose selection and other experimental features.

Nrf2 and NF-қB interplay in tamoxifen-induced hepatic toxicity: A promising therapeutic approach of sildenafil and low-dose γ radiation

Tamoxifen-induced hepatotoxicity is an inevitable side effect during breast cancer treatment. Low-dose gamma irradiation (IRR) shows many beneficial effects by stimulating various biological processes. This study evaluates the possible effect of sildenafil and low-dose gamma radiation on liver damages as new treatment strategies. Group I (control), group II: (tamoxifen), group III: (tamoxifen + Sildenafil), group IV: (tamoxifen+ irradiation) and group V: (tamoxifen +Sildenafil + irradiation). Rats were sacrificed after 5 h from tamoxifen injection. Results showed that tamoxifen caused elevation in serum AST, ALT and ALP as well hepatic ROS, iNOS, MDA, Keap-1 and NF-Kb, in addition to diminution in hepatic Nrf2 and HO-1. Exposure to low-dose gamma radiation and sildenafil amended the alterations in the measured parameters in serum and tissue. Moreover, all results were confirmed by histopathological examination. In conclusion, sildenafil and low-dose gamma radiation can mitigate the toxicity induced by tamoxifen in liver tissues. Hence, this treatment could be further evaluated as a new approach for alleviating various liver disorders.

Hormesis-tempting stressors driven by evolutionary factors for mitigating negative impacts instigated over extended exposure to chemical elements

The adaptive responses to moderate environmental challenges by the biological systems have usually been credited to hormesis. Since the hormetic biphasic dose-response illustrates a prominent pattern towards biological responsiveness, the studies concerning such aspects will get much more significance in risk assessment practices and toxicological evaluation research. From this point of view, the past few epochs have witnessed the extending recognition of the notion concerning hormesis. The extraction of its basic foundations of evolutionary perspectives-along with the probable underlying molecular and cellular mechanisms followed by the practical implications to enhance the quality of life. To get better and more effective output in this regard, the present article has evaluated the various observations of previous investigations. The intent of integrating the novel inferences concerning the hormesis-tempting stressors driven by predominant evolutionary factors for mitigating the adverse impacts that were prompted over frequent and continuous exposure to the various chemical elements. Such inferences can offer extensive insight into the implications concerning the risk assessment of hormesis.

Nitric oxide and hormesis

This present paper provides an assessment of the occurrence of nitric oxide (NO)-induced hormetic-biphasic dose/concentration relationships in biomedical research. A substantial reporting of such NO-induced hormetic effects was identified with particular focus on wound healing, tumor promotion, and sperm biology, including mechanistic assessment and potential for translational applications. Numerous other NO-induced hormetic effects have been reported, but require more development prior to translational applications. The extensive documentation of NO-induced biphasic responses, across numerous organs (e.g., bone, cardiovascular, immune, intestine, and neuronal) and cell types, suggests that NO-induced biological activities are substantially mediated via hormetic processes. These observations are particularly important because broad areas of NO biology are constrained by the quantitative features of the hormetic response. This determines the amplitude and width of the low dose stimulation, affecting numerous biomedical implications, study design features (e.g., number of doses, dose spacing, sample sizes, statistical power), and the potential success of clinical trials.

Nitric oxide, hormesis and plant biology

The present paper provides the first integrative assessment of the occurrence of nitric oxide (NO) induced hormetic effects in plant biology. Hormetic dose responses were commonly reported for NO donors on numerous plant species of agricultural and other commercial value. The NO donors were also shown to protect plants from a wide range of chemical (i.e., multiple toxic metals) and physical stressors (i.e., heat, drought) in preconditioning (aka priming) experimental protocols showing hormetic dose responses. Practical approaches for the use of NO donors to enhance plant growth using optimized dose response frameworks were also assessed. Considerable mechanistic findings indicate that NO donors have the capacity to enhance a broad range of adaptive responses, including highly integrated antioxidant activities. The integration of the hormesis concept with NO donors is likely to become a valuable practical general strategy to enhance plant productivity across a wide range of valuable plant species facing environmental pollution and climate changes.

Stress Management in Plants: Examining Provisional and Unique Dose-Dependent Responses

The purpose of this review is to critically evaluate the effects of different stress factors on higher plants, with particular attention given to the typical and unique dose-dependent responses that are essential for plant growth and development. Specifically, this review highlights the impact of stress on genome instability, including DNA damage and the molecular, physiological, and biochemical mechanisms that generate these effects. We provide an overview of the current understanding of predictable and unique dose-dependent trends in plant survival when exposed to low or high doses of stress. Understanding both the negative and positive impacts of stress responses, including genome instability, can provide insights into how plants react to different levels of stress, yielding more accurate predictions of their behavior in the natural environment. Applying the acquired knowledge can lead to improved crop productivity and potential development of more resilient plant varieties, ensuring a sustainable food source for the rapidly growing global population.

Boron enhances adaptive responses and biological performance via hormetic mechanisms

Boron is shown in the present review to induce hormetic dose responses in a broad range of biological models, organ systems and endpoints. Of particular importance is that numerous hormetic findings have been reported with whole animal studies, with extensive dose response evaluations with the optimal dosing being similar across multiple organ systems. These findings appear to be underappreciated and suggest that boron may have clinically significant systemic effects beyond that of its putative and more subtle essentiality functions. The re-exploration of boron's bioactivity as seen through hormetic mechanisms may also underscore the value of this approach to the assessment of micronutrient effects in human health and disease.

Ochratoxin A induces locomotor impairment and oxidative imbalance in adult zebrafish

Ochratoxin A (OTA) is a mycotoxin produced by species of filamentous fungi widely found as a contaminant in food and with high toxic potential. Studies have shown that this toxin causes kidney and liver damage; however, data on the central nervous system effects of exposure to OTA are still scarce. Thus, this study aimed to investigate the effects of exposure to OTA on behavioral and neurochemical parameters in adult zebrafish. The animals were treated with different doses of OTA (1.38, 2.77, and 5.53 mg/kg) with intraperitoneal injections and submitted to behavioral evaluations in the open tank and social interaction tests. Subsequently, they were euthanized, and the brains were used to assess markers associated with oxidative status. In the open tank test, OTA altered distance traveled, absolute turn angle, mean speed, and freezing time. However, no significant effects were observed in the social interaction test. Moreover, OTA also increased glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR) levels and decreased non-protein thiols (NPSH) levels in the zebrafish brain. This study showed that OTA can affect behavior and neurochemical levels in zebrafish.

Hormesis mediates platelet-rich plasma and wound healing

Platelet-rich plasma (PRP) has become an accepted and general wound healing approach with an extremely wide range of applications. Despite considerable diversity in the composition of platelet-rich plasma products that are applied in specific wound healing usage, it is widely recognised that such diverse platelet-rich plasma complex mixtures routinely display hormetic-like biphasic concentrations that are independent of the tissue treated and endpoints measured. The present paper is the first to place the area of platelet-rich plasma-biomedical research and applications within an hormetic framework. The platelet-rich plasma area is also unique as it represents the application of the hormetic concept to the issue of complex biological mixtures.

Assessment of the Hormetic Effect of Arsenic on Growth and Physiology of Two Cultivars of Maize (Zea mays L.)

Although growth stimulation at low arsenic doses was observed in several plants, few studies have focused on this phenomenon in more detail. The effects of different concentrations of arsenic (0-50 mg kg-1 of soil: As0-As50) on the growth and selected physiological parameters of two maize cultivars (Zea mays L. cvs. Chapalu and MvNK 333) were tested. Cultivar MvNK 333 manifested a generally higher tolerance to As than cv. Chapalu, which may be related to the lower content of As in the tissues. The highest stimulatory effect of As was recorded at doses of As1 and As2 (cv. Chapalu), and at the As5 dose (MvNK 333), there was an increase in shoot elongation, biomass, and relative water content (RWC), as well as the content of photosynthetic pigments. The stimulatory effect of lower doses of As apparently represents an adaptation mechanism that is associated with water content regulation in the given conditions. The stomata of the studied cultivars were involved in this regulation in different ways. While cv. Chapalu exhibited increased numbers of stomata on both sides of leaves, cv. MvNK 333 instead responded to the given conditions with decreased stomata size. Although hormetic manifestations closely related to changes in stomatal number and size were observed, a typical stomatal hormetic response was not observed in the given range of As doses.

Phenomics in sport: Can emerging methodology drive advanced insights?

Methodologies in applied sport science have predominantly driven a reductionist grounding to component-specific mechanisms to drive athlete training and care. While linear mechanistic approaches provide useful insights, they have impeded progress in the development of more complex network physiology models that consider the temporal and spatial interactions of multiple factors within and across systems and subsystems. For this, a more sophisticated approach is needed and the development of such a methodological framework can be considered a Sport Grand Challenge. Specifically, a transdisciplinary phenomics-based scientific and modeling framework has merit. Phenomics is a relatively new area in human precision medicine, but it is also a developed area of research in the plant and evolutionary biology sciences. The convergence of innovative precision medicine, portable non-destructive measurement technologies, and advancements in modeling complex human behavior are central for the integration of phenomics into sport science. The approach enables application of concepts such as phenotypic fitness, plasticity, dose-response dynamics, critical windows, and multi-dimensional network models of behavior. In addition, profiles are grounded in indices of change, and models consider the athlete's performance or recovery trajectory as a function of their dynamic environment. This new framework is introduced across several example sport science domains for potential integration. Specific factors of emphasis are provided as potential candidate fitness variables and example profiles provide a generalizable modeling approach for precision training and care. Finally, considerations for the future are discussed, including scaling from individual athletes to teams and additional factors necessary for the successful implementation of phenomics.

Hormesis: wound healing and fibroblasts

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Hormesis: Wound healing and keratinocytes

Hormetic dose responses (i.e., a biphasic dose/concentration response characterized by a low dose stimulation and a high dose inhibition) are shown herein to be commonly reported in the dermal wound healing process, with the particular focus on cell viability, proliferation, and migration of human keratinocytes in in vitro studies. Hormetic responses are induced by a wide range of substances, including endogenous agents, numerous drug and nanoparticle preparations and especially plant derived extracts, including many well-known dietary supplements as well as physical stressor agents, such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings suggest that the concept of hormesis plays a fundamental role in wound healing, with important potential implications for agent screening and evaluation, as well as clinical strategies.

Hormesis and Epidermal Stem Cells

This paper provides an assessment of hormetic dose responses in epidermal stem cells (EpSCs) in animal models and humans, with emphasis on cell proliferation and differentiation and application to wound healing and aging processes. Hormetic dose responses were induced by several agents, including dietary supplements (eg, luteolin, quercetin), pharmaceuticals (eg, nitric oxide), endogenous agents (eg, growth/differentiation factor 5), and via diverse chemical means to sustain steaminess features to retard aging and disease onset. While hormetic dose responses have been extensively reported in a broad spectrum of stem cells, this area has only been explored to a limited extent in EpSCs, principally within the past 5 years. Nonetheless, these findings provide the first integrated assessment of hormesis and EpSC biology within the context of enhancing key functions such as cell proliferation and differentiation and resilience to inflammatory stresses. This paper assesses putative mechanisms of hormetic responses in EpSCs and potential therapeutic applications to prevent dermatological injury and disease.

Review of molecular and biochemical responses during stress induced stimulation and hormesis in insects

The biphasic hormetic response to stress, defined by low-dose stimulation and high-dose inhibition is frequently observed in insects. Various molecular and biochemical responses associated with hormesis in insects have been reported in many studies, but no synthesis of all these findings has been undertaken. We conducted a systematic literature review, analyzing papers demonstrating phenotypic stimulatory effect(s) following exposure to stress where molecular or biochemical response(s) were also examined. Responses observed included stimulation of reproduction, survival and longevity, growth and development, and tolerance to temperature, chemical, or starvation and desiccation, in response to stressors including pesticides, oxidative stress, temperature, crowding and starvation, and radiation. Phenotypic stimulation ranged from <25% increased above controls to >100%. Reproductive stimulation was frequently <25% increased above controls, while stimulated temperature tolerance was frequently >100% increased. Molecular and biochemical responses had obvious direct connections to phenotypic responses in many cases, although not in all instances. Increased expression of heat shock proteins occurred in association with stimulated temperature tolerance, and increased expression of detoxification genes with stimulated pesticide or chemical tolerance, but also stimulated reproduction. Changes in the expression or activity of antioxidants were frequently associated with stimulation of longevity and reproduction. Stress induced changes in vitellogenin and juvenile hormone and genes in the IIS/TOR signalling pathway - which are directly responsible for regulating growth, development, and reproduction - were also reported. Our analysis showed that coordination of expression of genes or proteins associated with protection from oxidative stress and DNA and protein damage is important in the hormetic responses of insects.

Machine Learning for Plant Stress Modeling: A Perspective towards Hormesis Management

Plant stress is one of the most significant factors affecting plant fitness and, consequently, food production. However, plant stress may also be profitable since it behaves hormetically; at low doses, it stimulates positive traits in crops, such as the synthesis of specialized metabolites and additional stress tolerance. The controlled exposure of crops to low doses of stressors is therefore called hormesis management, and it is a promising method to increase crop productivity and quality. Nevertheless, hormesis management has severe limitations derived from the complexity of plant physiological responses to stress. Many technological advances assist plant stress science in overcoming such limitations, which results in extensive datasets originating from the multiple layers of the plant defensive response. For that reason, artificial intelligence tools, particularly Machine Learning (ML) and Deep Learning (DL), have become crucial for processing and interpreting data to accurately model plant stress responses such as genomic variation, gene and protein expression, and metabolite biosynthesis. In this review, we discuss the most recent ML and DL applications in plant stress science, focusing on their potential for improving the development of hormesis management protocols.