Hormesis and medicine

Glucocorticoid receptor signaling in the brain and its involvement in cognitive function

The hypothalamic-pituitary-adrenal axis regulates the secretion of glucocorticoids in response to environmental challenges. In the brain, a nuclear receptor transcription factor, the glucocorticoid receptor, is an important component of the hypothalamic-pituitary-adrenal axis's negative feedback loop and plays a key role in regulating cognitive equilibrium and neuroplasticity. The glucocorticoid receptor influences cognitive processes, including glutamate neurotransmission, calcium signaling, and the activation of brain-derived neurotrophic factor-mediated pathways, through a combination of genomic and non-genomic mechanisms. Protein interactions within the central nervous system can alter the expression and activity of the glucocorticoid receptor, thereby affecting the hypothalamic-pituitary-adrenal axis and stress-related cognitive functions. An appropriate level of glucocorticoid receptor expression can improve cognitive function, while excessive glucocorticoid receptors or long-term exposure to glucocorticoids may lead to cognitive impairment. Patients with cognitive impairment-associated diseases, such as Alzheimer's disease, aging, depression, Parkinson's disease, Huntington's disease, stroke, and addiction, often present with dysregulation of the hypothalamic-pituitary-adrenal axis and glucocorticoid receptor expression. This review provides a comprehensive overview of the functions of the glucocorticoid receptor in the hypothalamic-pituitary-adrenal axis and cognitive activities. It emphasizes that appropriate glucocorticoid receptor signaling facilitates learning and memory, while its dysregulation can lead to cognitive impairment. This provides clues about how glucocorticoid receptor signaling can be targeted to overcome cognitive disability-related disorders.

The effect of curcumin, catechin and resveratrol on viability, proliferation and cytotoxicity of human umbilical cord Wharton's jelly derived mesenchymal stem cells

INTRODUCTION

Mesenchymal stem cells possess the capability to proliferate and differentiate into diverse lineages. Their beneficial properties have been explored widely to treat various disorders. Phytochemicals like curcumin, catechin and resveratrol have been evaluated for their medicinal values and have promising potential in treating numerous diseases. In this study, we have elucidated the in vitro survival, proliferative and cytotoxic effects of these phytochemicals at selected range of concentrations on human umbilical cord derived Wharton's jelly mesenchymal stem cells (WJ-MSCs).

METHODS

The human WJ-MSCs were extracted using explant culture method and characterized as per International Society for Cellular Therapy (ISCT) guidelines. To analyse the effect of different phytochemicals, the WJ-MSCs were treated with various concentrations ranging from 0.1 to 1000 µM and the viability, proliferative and toxicity effects were assayed using (3-(4,5-dimethylthioazolyl-2,5-diphenyltetrozolium bromide) MTT.

RESULTS

Curcumin and catechin elicited no cytotoxic effect on WJ-MSCs after 48 hours of treatment between the concentrations ranging from 0.1 to 10 µM and the viability was maintained above 80 %. For both the phytochemicals, there was a significant decrease in the viability of WJ-MSCs after 50 µM. Resveratrol was well tolerated at higher doses till 100 µM with a viability above 90 % and cytotoxic effect was observed above 250 µM.

CONCLUSION

Curcumin, catechin and resveratrol, affect the viability and proliferation of WJ-MSCs differently at varying concentrations. This data will be useful in deciding the dose of phytochemicals when employed concomitantly with stem cells to increase their efficiency.

A hormetic response model for glutamine stress in cancer

Glutamine metabolism supports the development and progression of many cancers and is considered a therapeutic target. Attempts to inhibit glutamine metabolism have resulted in limited success and have not translated into clinical benefit. The outcomes of these clinical studies, along with preclinical investigations, suggest that cellular stress responses to glutamine deprivation or targeting may be modeled as a biphasic hormetic response. By recognizing the multifaceted aspects of glutamine metabolism inhibition within a more comprehensive biological framework, the adoption of this model may guide future fundamental and translational studies. To achieve clinical efficacy, we posit that as a field we will need to anticipate the hormetic effects of glutamine stress and consider how best to co-target cancer cell adaptive mechanisms.

Nanostructured lipid carriers as a strategy to enhance oral levosulpiride delivery: An in vitro and ex vivo assessment

Oral absorption is limited for many small-molecule drugs due to their poor aqueous solubility as well as, for some, poor membrane permeation. One such is levosulpiride (LSP), used to treat psychotic and other conditions. The present study aims to explore the effect of nanostructured lipid carriers (NLCs) for the delivery of LSP. The permeation of LSP in vitro and ex vivo as well as effects on the epithelium and mucosa was monitored. In vitro and ex vivo permeation studies exhibited an 8-fold and 1.6-fold increase in the Papp of LSP respectively, as compared to unformulated LSP applied as a suspension. Transepithelial electrical resistance (TEER) measured in real-time by impedance spectroscopy decreased during exposure yet recovered upon removal of the NLCs. Together with the increased passage of the paracellular markers [14C]-mannitol and FD4 applied together with blank NLCs, but not the transcellular marker [3H]-metoprolol, this indicates permeation of LSP via the paracellular pathway. The reversible effect on integrity was associated with altered cell morphology confirmed by occludin and f-actin localization with insignificant effect on metabolic activity. These results suggest that the NLCs and/or components thereof can mediate improved absorption of drugs by increasing the permeability of the intestinal epithelial membrane, further facilitated by increased drug solubilization.

Mitragynine and morphine produce dose-dependent bimodal action on food but not water intake in rats

Kratom (Mitragyna speciosa), containing the primary alkaloid mitragynine, has emerged as an alternative self-treatment for opioid use disorder. Mitragynine binds numerous receptor types, including opioid receptors, which are known to modulate food consumption. However, the ability of acute mitragynine to modulate food consumption remains unknown. The current study assessed the effects of acute mitragynine or morphine administration on unconditioned food and water intake in 16 Sprague-Dawley rats. Food and water intake changes were monitored in response to morphine, mitragynine (1.78-56 mg/kg ip), saline, or vehicle controls for 12 h, starting at the onset of the dark cycle. Naltrexone pretreatment was used to examine pharmacological specificity. Both morphine and mitragynine demonstrated a biphasic food intake dose-effect, with low doses (5.6 mg/kg) increasing and high doses (56 mg/kg) decreasing food intake. All morphine doses reduced water intake; however, only the highest dose of mitragynine (56 mg/kg) reduced water intake. Naltrexone attenuated both stimulatory and inhibitory effects of morphine on food intake, but only the stimulatory effect of mitragynine. In conclusion, low doses of mitragynine stimulate food intake via opioid-related pathways, while high doses likely recruit other targets.NEW & NOTEWORTHY This study reveals that morphine and the kratom alkaloid mitragynine produce dose-dependent effects on feeding in rats. Low doses stimulate food intake via opioid pathways, while high doses decrease consumption through nonopioid mechanisms. Morphine potently suppresses water intake at all doses, whereas only high doses of mitragynine reduce drinking. These findings provide novel insights into the complex opioid and nonopioid mechanisms underlying the effects of mitragynine on ingestive behaviors.

The Effects of Lead and Cross-Talk Between Lead and Pea Aphids on Defence Responses of Pea Seedlings

The main goal of this study was to investigate the effect of lead (Pb) at various concentrations, as an abiotic factor, and the cross-talk between Pb and pea aphid (Acyrthosiphon pisum (Harris)) (Hemiptera: Aphididae), as a biotic factor, on the defence responses of pea seedlings (Pisum sativum L. cv. Cysterski). The analysis of growth parameters for pea seedlings demonstrated that Pb at a low concentration, i.e., 0.025-0.0625 mM Pb(NO3)2, caused a hormesis effect, i.e., stimulation of seedling growth, whereas Pb at higher concentrations, i.e., 0.01-0.325 mM Pb(NO3)2, inhibited growth, which manifested as the inhibition of length and fresh biomass. The differences in the level of the main defence-related phytohormones, such as abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA), and indole-3-acetic acid (IAA)-an auxin stimulating plant cell growth-depended on the dose of Pb, aphid infestation and direct contact of the stress factor with the organ. A high accumulation of soluble sugars in the organs of pea seedlings both at sublethal doses and hormetic doses at early experimental time points was observed. At 0 h and 24 h of the experiment, the hormetic doses of Pb significantly stimulated invertase activities, especially in the roots. Moreover, an increase was observed in the pisatin concentration in pea seedlings growing in the presence of different concentrations of Pb and in the case of cross-talk between Pb and A. pisum in relation to the control. Additionally, a significant induction of the expressions of isoflavone synthase (IFS) and 6α-hydroxymaackiain 3-O-methyltransferase (HMM) genes, which participate in the regulation of the pisatin biosynthesis pathway, in pea seedlings growing under the influence of sublethal 0.5 mM Pb(NO3)2 and hormetic 0.075 mM Pb(NO3)2 doses of Pb was noted. The obtained results showed that the response of P. sativum seedlings depends on the Pb dose applied, direct contact of the stress factor with the organ and the duration of contact.

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.

Promotion of tumor angiogenesis and growth induced by low-dose antineoplastic agents via bone-marrow-derived cells in tumor tissues

Background

More research is needed to solidify the basis for reasonable metronomic chemotherapy regimens due to the inconsistent clinical outcomes from studies on metronomic chemotherapy with antineoplastic agents, along with signs of a nonlinear dose-response relationship at low doses. The present study therefore explored the dose-response relationships of representative antineoplastic agents in low dose ranges and their underlying mechanisms.

Methods

Cyclophosphamide (CPA) and 5-fluorouracil (5-Fu) were employed to observe the effects of the frequent administration of low-dose antineoplastic agents on tumor growth, tumor angiogenesis, and bone-marrow-derived cell (BMDC) mobilization in mouse models. The effects of antineoplastic agents on tumor and endothelial cell functions with or without BMDCs were analyzed in vitro.

Results

Tumor growth and metastasis were significantly promoted after the administration of CPA or 5-Fu at certain low dose ranges, and were accompanied by enhanced tumor angiogenesis and proangiogenic factor expression in tumor tissues, increased proangiogenic BMDC release in the circulating blood, and augmented proangiogenic BMDC retention in tumor tissues. Low concentrations of CPA or 5-Fu were found to significantly promote tumor cell migration and invasion, and enhance BMDC adhesion to endothelial cells in vitro.

Conclusion

These results suggest that there are risks in empirical metronomic chemotherapy using low-dose antineoplastic agents and the optimal dosage and administration schedule of antineoplastic agents need to be determined through further research.

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.

Enemies or Allies? Hormetic and Apparent Non-Dose-Dependent Effects of Natural Bioactive Antioxidants in the Treatment of Inflammation

This review aims to analyze the emerging number of studies on biological media that describe the unexpected effects of different natural bioactive antioxidants. Hormetic effects, with a biphasic response depending on the dose, or activities that are apparently non-dose-dependent, have been described for compounds such as resveratrol, curcumin, ferulic acid or linoleic acid, among others. The analysis of the reported studies confirms the incidence of these types of effects, which should be taken into account by researchers, discarding initial interpretations of imprecise methodologies or measurements. The incidence of these types of effects should enhance research into the different mechanisms of action, particularly those studied in the field of basic research, that will help us understand the causes of these unusual behaviors, depending on the dose, such as the inactivation of the signaling pathways of the immune defense system. Antioxidative and anti-inflammatory activities in biological media should be addressed in ways that go beyond a mere statistical approach. In this work, some of the research pathways that may explain the understanding of these activities are revised, paying special attention to the ability of the selected bioactive compounds (curcumin, resveratrol, ferulic acid and linoleic acid) to form metal complexes and the activity of these complexes in biological media.

Cistanche deserticola Polysaccharide Reduces Inflammation and Aging Phenotypes in the Dermal Fibroblasts through the Activation of the NRF2/HO-1 Pathway

Dermal fibroblasts maintain the skin homeostasis by interacting with the epidermis and extracellular matrix. Their senescence contributes to functional defects in the skin related to aging. Therefore, there is an urgent need for novel therapeutic agents that could inhibit fibroblast senescence. In this study, we investigated the effects of Cistanche deserticola polysaccharide (CDP), a natural anti-inflammatory component, on the progression of senescence in human dermal fibroblasts. Normal human dermal fibroblasts (NHDFs) were cultured in passages, and highly senescent cells were selected as senescent cells. CDP treatment increased the cell proliferation in senescent NHDFs and decreased the proportion of senescence-associated-β-galactosidase-positive cells. The treatment suppressed the senescence-related secretory phenotype, and reactive oxygen species (ROS) production was reduced, alleviating H2O2-induced oxidative stress. CDP mitigated ROS formation via the nuclear factor erythroid 2-related factor/heme oxygenase-1 pathway in senescent cells and was involved in the suppression of upstream p-extracellular signal-regulated kinase. These results indicate that CDP is an antioxidant that can alleviate age-related inflammation and may be a useful compound for skin anti-aging.

[Cannabinoids reduce opioid use in older patients with pain : Retrospective three-year analysis of data from a general practice]

BACKGROUND

Relevant data for the prescription and therapeutic effects of medical cannabinoids (CAM) are still missing in everyday medicine especially for elderly and geriatric patients.

AIM OF THE STUDY

Documentation of prescription (duration, age) of CAM (dronabinol, nabiximols, cannabinoid extracts) and co-medicated opioids in a doctor's office specializing in pain.

METHODS

Analysis of the consumption of opioids (morphine equivalent) and CAM (THC equivalent) for age and gender.

RESULTS

In all, 178 patients with chronic pain were treated for a period of 366 days (median; range 31-2590 days). Median age was 72 years (26-96 years); 115 were women (64.8%). Of these, 34 were younger than 65 years, 42 were 65-80 years and 40 were more than 80 years old. Of the 63 men, 29 were younger than 65 years, 24 were 65-80 years and 10 were older than 80 years. Indications for CAM were chronic pain and the limitations for opioids because of side effects and worsening of quality of life. To total of 1001 CAM were prescribed, 557 (55.6%) dronabinol as liquid, 328 (32.7%) as full spectrum extracts and 66 (6.6%) as oro-mucosal nabiximols spray. 50 prescriptions (5%) contained more than one CAM simultaneously. The daily consumption of dronabinol liquor and extracts were 9.6 mg/day (median), and of spray 13.6 mg. The dosage over time did not change in patients older than 64; in younger patients, there was a non-significant increasing trend. Women requested lower THC dosages compared to men (8.1 mg vs. 14.8 mg). Furthermore, 10 patients (5.6%) stopped CAM because of failing effectivity, 7 (3.9%) because of failing cost coverage and only 5 because of adverse side effects. 115 patients (65%) with CAM also received opioids a median 65 mg/day morphine equivalents. This opioid dosage was significantly reduced in course of time by 24 mg/day morphine equivalents or 50%. This reduction was independent on CAM dosage, age and gender.

DISCUSSION

Patients with chronic pain profit from long-term CAM which safely and significantly lower the consumption of comedicated opioids, even at low dosages (< 7.5 mg/day). For women, low-dose THC may be sufficient. Older patients benefit from CAM, and adverse effects do not limit the (chronic) use and prescription of CAM in the elderly.

Cells Overexpressing ALS-Associated SOD1 Variants Are Differentially Susceptible to CuATSM-Associated Toxicity

CuATSM has repeatedly demonstrated to be therapeutically effective in SOD1 mouse models of amyotrophic lateral sclerosis (ALS), leading to current clinical trials. CuATSM acts to stabilize ALS-associated mutant SOD1 protein by supplying copper. However, in vitro work has demonstrated that CuATSM is only therapeutic for wild-type-like SOD1 mutants, not metal-binding-region mutants, suggesting that CuATSM may have genotype-specific effects. Furthermore, relatively high doses of CuATSM have been shown to produce adverse events in humans and mice. Here, we investigated the genotype-specific therapeutic window of CuATSM. NSC-34 cells transiently expressing copper-binding or non-binding mutations of SOD1 were treated with a broad range of CuATSM concentrations and examined for survival via time-lapse microscopy. Determination of the no-observed-adverse-effect level and the LC₅₀ suggest that CuATSM-associated toxicity is dependent on the amount of copper-depleted SOD1 available as well as the mutant's ability to bind copper. Our results suggest that the particular variant of SOD1 mutant is crucial in not only determining the level of efficacy achieved but also potential adverse events.

The Isopropyl Gallate Counteracts Cyclophosphamide-Induced Hemorrhagic Cystitis in Mice

Hemorrhagic cystitis is the main adverse effect associated with the clinical use of oxazaphosphorine, resulting in increased oxidative stress and proinflammatory cytokines, which culminate in injury of the bladder tissue. The aim of this study was to evaluate the protective effect of isopropyl gallate (IPG) against ifosfamide (IFOS)-induced hemorrhagic cystitis in mice. The induction of the hemorrhagic cystitis model was carried out using a single dose of IFOS (400 mg/kg, i.p.) four hours after oral pretreatment with IPG (6.25, 12.5, 25, and 50 mg/kg) or saline (vehicle). Mesna (positive control; 80 mg/kg, i.p.) was administered four hours before and eight hours after induction of cystitis. In the present study, IPG 25 mg/kg significantly decreased edema and hemorrhage, with a reduction of the bladder wet weight (36.86%), hemoglobin content (54.55%), and peritoneal vascular permeability (42.94%) in urinary bladders of mice. Interestingly, IPG increased SOD activity (89.27%) and reduced MDA levels (35.53%), as well as displayed anti-inflammatory activity by decreasing TNF-α (88.77%), IL-1β (62.87%), and C-reactive protein (56.41%) levels. Our findings demonstrate that IPG has a substantial protective role against IFOS-induced hemorrhagic cystitis in mice by enhancing antioxidant activity and proinflammatory mechanisms. Thus, IPG represents a promising co-adjuvant agent in oxazaphosphorine-based chemotherapy treatments.

The Way forward for the Origin of Life: Prions and Prion-Like Molecules First Hypothesis

In this paper the hypothesis that prions and prion-like molecules could have initiated the chemical evolutionary process which led to the eventual emergence of life is reappraised. The prions first hypothesis is a specific application of the protein-first hypothesis which asserts that protein-based chemical evolution preceded the evolution of genetic encoding processes. This genetics-first hypothesis asserts that an “RNA-world era” came before protein-based chemical evolution and rests on a singular premise that molecules such as RNA, acetyl-CoA, and NAD are relics of a long line of chemical evolutionary processes preceding the Last Universal Common Ancestor (LUCA). Nevertheless, we assert that prions and prion-like molecules may also be relics of chemical evolutionary processes preceding LUCA. To support this assertion is the observation that prions and prion-like molecules are involved in a plethora of activities in contemporary biology in both complex (eukaryotes) and primitive life forms. Furthermore, a literature survey reveals that small RNA virus genomes harbor information about prions (and amyloids). If, as has been presumed by proponents of the genetics-first hypotheses, small viruses were present during an RNA world era and were involved in some of the earliest evolutionary processes, this places prions and prion-like molecules potentially at the heart of the chemical evolutionary process whose eventual outcome was life. We deliberate on the case for prions and prion-like molecules as the frontier molecules at the dawn of evolution of living systems.

Hormesis: Transforming disciplines that rely on the dose response

This article tells the story of hormesis from its conceptual and experimental origins, its dismissal by the scientific and medical communities in the first half of the 20th century, and its rediscovery over the past several decades to be a fundamental evolutionary adaptive strategy. The upregulation of hormetic adaptive mechanisms has the capacity to decelerate the onset and reduce the severity of a broad spectrum of common age-related health, behavioral, and performance decrements and debilitating diseases, thereby significantly enhancing the human health span. Incorporation of hormetic-based lifestyle options within the human population would have profoundly positive impacts on the public health, significantly reducing health care costs.

The Subtle Role of Para-inflammation in Modulating the Progression of Dry Eye Disease

In patients with DED, the continuous stimuli induced by excessive or persistent cold fiber sensors and overstimulation of nociceptors, as well as tear hyperosmolarity induced by evaporative stress, induce a transitory protective adaptation response called para-inflammation to restore ocular surface homeostasis. This mild subclinical inflammatory status (a type of hormetic response) can become chronic if the stimuli or tissue malfunction is present for a sustained period, causing persistent symptoms and damage to ocular surface epithelia.We review the mechanisms that characterize the transition from para-inflammation to a persistent inflammatory status of the ocular surface, including accumulation of biological waste and damaged/dysfunctional proteins, which, in normal conditions, are eliminated by autophagy, activation of the inflammasomes, and what is currently known about their role in DED pathogenesis. Furthermore, we analyze current treatments that can modulate the inflammatory response of the ocular surface and speculate about new possible therapies to treat para-inflammation.

Diabetes and Pancreatic Cancer-A Dangerous Liaison Relying on Carbonyl Stress

Both type 2 (T2DM) and type 1 (T1DM) diabetes mellitus confer an increased risk of pancreatic cancer in humans. The magnitude and temporal trajectory of the risk conferred by the two forms of diabetes are similar, suggesting a common mechanism. Carbonyl stress is a hallmark of hyperglycemia and dyslipidemia, which accompanies T2DM, prediabetes, and obesity. Accumulating evidence demonstrates that diabetes promotes pancreatic ductal adenocarcinoma (PDAC) in experimental models of T2DM, a finding recently confirmed in a T1DM model. The carbonyl stress markers advanced glycation end-products (AGEs), the levels of which are increased in diabetes, were shown to markedly accelerate tumor development in a mouse model of Kras-driven PDAC. Consistently, inhibition of AGE formation by trapping their carbonyl precursors (i.e., reactive carbonyl species, RCS) prevented the PDAC-promoting effect of diabetes. Considering the growing attention on carbonyl stress in the onset and progression of several cancers, including breast, lung and colorectal cancer, this review discusses the mechanisms by which glucose and lipid imbalances induce a status of carbonyl stress, the oncogenic pathways activated by AGEs and their precursors RCS, and the potential use of carbonyl-scavenging agents and AGE inhibitors in PDAC prevention and treatment, particularly in high-risk diabetic individuals.

Low Dose Astaxanthin Treatments Trigger the Hormesis of Human Astroglioma Cells by Up-Regulating the Cyclin-Dependent Kinase and Down-Regulated the Tumor Suppressor Protein P53

Astaxanthin (AXT) is a xanthophyll carotenoid known to have potent anti-cancer effects via upregulation of the intracellular reactive oxygen species (ROS) levels, which triggers apoptosis of cancer cells. While several studies have shown that AXT has potential as an anti-cancer drug, its effects in glioblastoma multiforme cells remain relatively unknown. In this study, we investigated the effects of AXT in the astroglioma cell lines U251-MG, T98G, and CRT-MG. We found that the response to AXT varied between cell lines. Moreover, U251-MG cells showed a specific hormetic response to AXT. At high concentrations (20–40 μM), AXT triggered apoptosis in U251-MG cells, as it has been previously shown in other cancer cell lines. However, low concentrations (4–8 μM) of AXT were found to upregulate the proliferative cell cycle. Furthermore, at low concentrations, AXT did not affect the intracellular ROS levels, while the superoxide dismutase activity increased moderately. Western blot analysis showed that treatment with a low concentration of AXT upregulated cyclin-dependent kinase (Cdk) 2 and p-Cdk2/3 levels and downregulated the expression of tumor protein p53. Thus, our results showed that AXT has a hormetic effect in the astroglioma cell line U251-MG.

A decade of toxicological trends: what the papers say

Here we look at popular trends and concepts in toxicology over the decade 2009-2019. The top 10 concepts included methodological approaches such as zebrafish and genomics as well as broader concepts such as personalized medicine and adverse outcome pathways. The total number and rank order for each of the top 10 were tracked year by year via PubMed with >9500 papers contributing to the analysis. The data revealed a slow upward trend in the number of papers across all the concepts from 260 in 2009 to >1700 in 2019. Zebrafish, genomics and personalized medicine remained in the top four slots since 2009 with zebrafish dominating the rankings over the entire decade. Genomics was a strong second until 2013 when it was displaced first by the microbiome in 2014 and secondly by personalized medicine in 2015. Other notable trends were the ascendancy of the microbiome and adverse outcome pathways and the descendancy of hormesis and the 3Rs (replacement, reduction and refinement of animals in testing). The observation that the top four slots have been static over the past 4 years suggests that new ideas are introduced and increase in popularity until they find their place in scientific culture. This may suggest that relatively new concepts such as artificial intelligence and microphysiological systems have yet to find their steady state in the rankings. Similarly, as a relatively new player in toxicology, the full impact of the human microbiome on drug efficacy and safety remains to be seen.

Similarities between the Yin/Yang Doctrine and Hormesis in Toxicology and Pharmacology

Hormesis is a generalizable dose-response relationship characterized by low-dose stimulation and high-dose inhibition. Despite debate over this biphasic dose-response curve, hormesis is challenging central beliefs in the evaluation of chemicals or drugs and has influenced biological model selection, concentration range, study design, and hypothesis testing. We integrate the traditional Chinese philosophy - Yin/Yang doctrine - into the representation of the Western hormetic dose-response relationship and review the Yin/Yang historical philosophy contained in the hormesis concept, aiming to promote general acceptance and wider applications of hormesis. We suggest that the Yin/Yang doctrine embodies the hormetic dose-response, including the relationship between the opposing components, curve shape, and time-dependence, and may afford insights that clarify the hormetic dose-response relationship in toxicology and pharmacology.

Inhibitory Effects of Euphorbia tirucalli Lineu (Euphorbiaceae) Diluted Latex on Human and Canine Melanoma Cells

Euphorbia tirucalli Lineu (Euphorbiaceae) is a tropical and subtropical ornamental and toxic plant. E. tirucalli produces a latex that is commonly used to treat neoplasms. This study aimed to evaluate the effects of diluted E. tirucalli latex (DETL) on human (SK-MEL-28) and canine (CBMY) melanoma cells. SK-MEL-28 (3 × 10³ cells/well) and CBMY (6 × 10³ cells/well) were cultivated in 96-well plates. The cells were treated with 50 μl/well of dilutions (1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256, and 1/512) of a standard solution containing 1 mg/mL of the E. tirucalli latex (ETL) in DMEM. Control group cells received 50 μl/well of DMEM. After 24, 48, and 72 h of treatment, cell viability was assessed by the MTT assay. There was a significant decrease in viability at 48 and 72 hours after treatment for human melanoma cells and at 24, 48, and 72 hours for canine cells, mainly in higher dilutions of ETL. Human melanoma cells presented a typical U shape curve, characteristic of hormesis. To our knowledge, this is the first study showing inhibitory effects of DETL on canine melanoma cells. Therefore, DETL is a potentially new antineoplastic drug.

A molecule inducing androgen receptor degradation and selectively targeting prostate cancer cells

A new molecule induces AR sumoylation and degradation resulting in selective growth inhibition in AR-dependent prostate cancer cells, but its activity is blunted by interference with proteasomes.

Aberrant androgen signaling drives prostate cancer and is targeted by drugs that diminish androgen production or impede androgen–androgen receptor (AR) interaction. Clinical resistance arises from AR overexpression or ligand-independent constitutive activation, suggesting that complete AR elimination could be a novel therapeutic strategy in prostate cancers. IRC117539 is a new molecule that targets AR for proteasomal degradation. Exposure to IRC117539 promotes AR sumoylation and ubiquitination, reminiscent of therapy-induced PML/RARA degradation in acute promyelocytic leukemia. Critically, ex vivo, IRC117539-mediated AR degradation induces prostate cancer cell viability loss by inhibiting AR signaling, even in androgen-insensitive cells. This approach may be beneficial for castration-resistant prostate cancer, which remains a clinical issue. In xenograft models, IRC117539 is as potent as enzalutamide in impeding growth, albeit less efficient than expected from ex vivo studies. Unexpectedly, IRC117539 also behaves as a weak proteasome inhibitor, likely explaining its suboptimal efficacy in vivo. Our studies highlight the feasibility of AR targeting for degradation and off-target effects’ importance in modulating drug activity in vivo.

Neuromodulatory Action of Picomolar Extracellular Aβ42 Oligomers on Presynaptic and Postsynaptic Mechanisms Underlying Synaptic Function and Memory

Failure of anti-amyloid-β peptide (Aβ) therapies against Alzheimer's disease (AD), a neurodegenerative disorder characterized by high amounts of the peptide in the brain, raised the question of the physiological role of Aβ released at low concentrations in the healthy brain. To address this question, we studied the presynaptic and postsynaptic mechanisms underlying the neuromodulatory action of picomolar amounts of oligomeric Aβ42 (oAβ42) on synaptic glutamatergic function in male and female mice. We found that 200 pm oAβ42 induces an increase of frequency of miniature EPSCs and a decrease of paired pulse facilitation, associated with an increase in docked vesicle number, indicating that it augments neurotransmitter release at presynaptic level. oAβ42 also produced postsynaptic changes as shown by an increased length of postsynaptic density, accompanied by an increased expression of plasticity-related proteins such as cAMP-responsive element binding protein phosphorylated at Ser133, calcium-calmodulin-dependent kinase II phosphorylated at Thr286, and brain-derived neurotrophic factor, suggesting a role for Aβ in synaptic tagging. These changes resulted in the conversion of early into late long-term potentiation through the nitric oxide/cGMP/protein kinase G intracellular cascade consistent with a cGMP-dependent switch from short- to long-term memory observed in vivo after intrahippocampal administration of picomolar amounts of oAβ42 These effects were present upon extracellular but not intracellular application of the peptide and involved α7 nicotinic acetylcholine receptors. These observations clarified the physiological role of oAβ42 in synaptic function and memory formation providing solid fundamentals for investigating the pathological effects of high Aβ levels in the AD brains.SIGNIFICANCE STATEMENT High levels of oligomeric amyloid-β42 (oAβ42) induce synaptic dysfunction leading to memory impairment in Alzheimer's disease (AD). However, at picomolar concentrations, the peptide is needed to ensure long-term potentiation (LTP) and memory. Here, we show that extracellular 200 pm oAβ42 concentrations increase neurotransmitter release, number of docked vesicles, postsynaptic density length, and expression of plasticity-related proteins leading to the conversion of early LTP into late LTP and of short-term memory into long-term memory. These effects require α7 nicotinic acetylcholine receptors and are mediated through the nitric oxide/cGMP/protein kinase G pathway. The knowledge of Aβ function in the healthy brain might be useful to understand the causes leading to its increase and detrimental effect in AD.

Cynanchum wilfordii Etanolic Extract Controls Blood Cholesterol: A Double-blind, Randomized, Placebo-Controlled, Parallel Trial

We evaluated the effects of Cynanchum wilfordii (CW) ethanolic extract on blood cholesterol levels in adults with high low-density lipoprotein cholesterol (LDL-C) levels. In a double-blind, randomized, placebo-controlled, parallel trial, 84 subjects were recruited. Participants were randomly divided into two groups with a low-dose (300 mg/d) or high-dose (600 mg/d) of CW. Levels of very low-density lipoprotein (p = 0.022) and triglycerides (p = 0.022) were significantly lower in the low-dose CW group than in the placebo group after 8 weeks. In a subgroup of participants with LDL-C≥ 150 mg/dL (n = 33), there was a significant decrease in total cholesterol (low-dose, p = 0.012; high-dose, p = 0.021), apolipoprotein B (low-dose, p = 0.022; high-dose, p = 0.016), and cholesteryl ester transfer protein (low-dose, p = 0.037; high-dose, p = 0.016) after 8 weeks of CW. The correlation between changes in total cholesterol and baseline LDL-C levels was significant in the groups that received both doses of CW (low-dose, p = 0.010; high-dose, p = 0.015). These results show that the CW ethanolic extract can regulate blood cholesterol in subjects with LDL-C≥ 150 mg/dL.

Chemotherapeutic agent 5-fluorouracil increases survival of SOD1 mouse model of ALS

Amyotrophic lateral sclerosis (ALS) is a lethal motor neuron disease with no cure. Currently there are only two ALS drugs approved by the FDA, both with a limited therapeutic effect. In the search for drug candidates for ALS, we studied the effect of known stem cell mobilizing agents (treatment) and antimetabolite 5-fluorouracil (5-FU) (anti-treatment) in SOD1G93A model of ALS. Surprisingly, we found that anti-cancer drug 5-FU increases lifespan, delays the disease onset and improves motor performance in ALS mice. Although we were not able to demonstrate the mechanistic basis of the beneficial 5-FU action in ALS mice, our findings suggest that 5-FU or similar drugs are possible drug candidates for the treatment of motor neuron diseases through drug repurposing.

QSAR and Molecular Docking Studies of the Inhibitory Activity of Novel Heterocyclic GABA Analogues over GABA-AT

We have previously reported the synthesis, in vitro and in silico activities of new GABA analogues as inhibitors of the GABA-AT enzyme from Pseudomonas fluorescens, where the nitrogen atom at the γ-position is embedded in heterocyclic scaffolds. With the goal of finding more potent inhibitors, we now report the synthesis of a new set of GABA analogues with a broader variation of heterocyclic scaffolds at the γ-position such as thiazolidines, methyl-substituted piperidines, morpholine and thiomorpholine and determined their inhibitory potential over the GABA-AT enzyme from Pseudomonas fluorescens. These structural modifications led to compound 9b which showed a 73% inhibition against this enzyme. In vivo studies with PTZ-induced seizures on male CD1 mice show that compound 9b has a neuroprotective effect at a 0.50 mmole/kg dose. A QSAR study was carried out to find the molecular descriptors associated with the structural changes in the GABA scaffold to explain their inhibitory activity against GABA-AT. Employing 3D molecular descriptors allowed us to propose the GABA analogues enantiomeric active form. To evaluate the interaction with Pseudomonas fluorescens and human GABA-AT by molecular docking, the constructions of homology models was carried out. From these calculations, 9b showed a strong interaction with both GABA-AT enzymes in agreement with experimental results and the QSAR model, which indicates that bulky ligands tend to be the better inhibitors especially those with a sulfur atom on their structure.

Synergy Between Proline-Rich Antimicrobial Peptides and Small Molecule Antibiotics Against Selected Gram-Negative Pathogens in vitro and in vivo

As monotherapy, modified proline-rich antimicrobial peptides (PrAMPs) protect animals from experimental bacteremia in a dose-dependent manner. We evaluated the in vitro synergy of a modified PrAMP, A3-APO, a dimer, previously shown to inhibit the 70 kDa bacterial heat shock protein DnaK, with imipenem or colistin against two antibiotic-resistant pathogens; a carbapenemase-expressing Klebsiella pneumoniae strain K97/09 and Acinetobacter baumannii (ATCC BAA-1605). Combining antimicrobials resulted in synergy for PrAMP/colistin combination against both K. pneumoniae and A. baumannii (ΣFIC = 0.08 both) and additive activity for the A3-APO/imipenem combination against K. pneumoniae (ΣFIC = 0.53). Chex1-Arg20, (designated as ARV-1502 in preclinical development), the single chain PrAMP monomer of A3-APO, showed synergy with meropenem against a carbapenem-resistant uropathogenic Escherichia coli strain (ΣFIC = 0.38). In a murine bacteremia model using K97/09, A3-APO at 1 mg/kg demonstrated improved survival when co-administered with standard (10 mg/kg) or subtherapeutic (1 mg/kg) doses of colistin at 36 h (p < 0.05). Surprisingly, the survival benefit of A3-APO was augmented when the A3-APO dose was decreased by 50% to 0.5 mg/kg (p < 0.02) in conjunction with a subtherapeutic colistin dose (1 mg/kg). ARV-1502, as monotherapy demonstrated prolonged (>24 h) activity in a mouse Escherichia coli infection assay. Co-treatment with ARV-1502 and subtherapeutic doses of ceftazidime (150 mg/kg) was studied in a mouse model of melioidosis. ARV-1502 provided a 50% improvement in long-term (62 days) survival, but only at the lowest of 3 administered doses; survival advantage was demonstrated at 2.5 mg/kg but not at 5 or 10 mg/kg. The mortality benefit of combination therapies was not routinely accompanied by a parallel decline in blood or tissue bacterial counts in surviving animals, suggesting that the anti-infective activity of the host defense peptides (HDP) is broader than simply bacterial eradication. In fact, the hormetic effect observed in either animal models suggest that low dose HDP treatment may change the dominant mode of action in experimental bacteremia.

Hormetic approaches to the treatment of Parkinson's disease: Perspectives and possibilities

Age-related changes in the brain reflect a dynamic interaction of genetic, epigenetic, phenotypic, and environmental factors that can be temporally restricted or more longitudinally present throughout the lifespan. Fundamental to these mechanisms is the capacity for physiological adaptation through modulation of diverse molecular and biochemical signaling occurring from the intracellular to the network-systemic level throughout the brain. A number of agents that affect the onset and progression of Parkinson's disease (PD)-like effects in experimental models exhibit temporal features, and mechanisms of hormetic dose responses. These findings have particular significance since the hormetic dose response describes the amplitude and range of potential therapeutic effects, thereby affecting the design and conduct of studies of interventions against PD (and other neurodegenerative diseases), and may also be important to a broader consideration of hormetic processes in resilient adaptive responses that might afford protection against the onset and/or progression of PD and related disorders.

Biphasic effects of THC in memory and cognition

A generally undesired effect of cannabis smoking is a reversible disruption of short-term memory induced by delta-9-tetrahydrocannabinol (THC), the primary psychoactive component of cannabis. However, this paradigm has been recently challenged by a group of scientists who have shown that THC is also able to improve neurological function in old animals when chronically administered at low concentrations. Moreover, recent studies demonstrated that THC paradoxically promotes hippocampal neurogenesis, prevents neurodegenerative processes occurring in animal models of Alzheimer's disease, protects from inflammation-induced cognitive damage and restores memory and cognitive function in old mice. With the aim to reconcile these seemingly contradictory facts, this work will show that such paradox can be explained within the framework of hormesis, defined as a biphasic dose-response.

R(+)-Thioctic Acid Effects on Oxidative Stress and Peripheral Neuropathy in Type II Diabetic Patients: Preliminary Results by Electron Paramagnetic Resonance and Electroneurography

Objectives

Diabetic neuropathy is the most common complication of diabetes. The idea of alterations in energy metabolism in diabetes is emerging. The biogenic antioxidant R(+)-thioctic acid has been successfully used in the treatment of diabetic polyneuropathic (DPN) patients.

Methods

The effects of R(+)-thioctic acid (1 tablet, 1.6 g) administration were evaluated in 12 DPN patients at baseline and at 15, 30, 60, and 120 administration days throughout the assessment of oxidative stress (OxS); ROS production rate by electron paramagnetic resonance (EPR) technique; and oxidative damage biomarkers (thiobarbituric acid reactive substances (TBARS) and protein carbonyls (PC)), electroneurography (ENG) and visual analogue scale.

Results

Supplementation induced significant changes (p < 0.05) at 30 and 60 days. ROS production rate up to -16%; TBARS (-31%), PC (-38%), and TAC up to +48%. Motor nerve conduction velocity in SPE and ulnar nerves (+22% and +16%) and sensor conduction velocity in sural and median nerves (+22% and +5%). Patients reported a general wellness sensation improvement (+35%) at 30 days: lower limb pain sensation (-40%) and upper limbs (-23%).

Conclusion

The results strongly indicate that an increased antioxidant capacity plays an important role in OxS, nerve conduction velocity, pain, and general wellness improvement. Nevertheless, the effects of the antioxidant compound were found positive up to 60 days. Then, a hormesis effect was observed. Novelty of the research would be a challenge for investigators to carefully address issues, including dose range factors, appropriate administration time, and targeting population to counteract possible "boomerang effects." The great number of monitored parameters would firmly stress these conclusions.

Clinical efficacy of implementing Bio Immune(G)ene MEDicine in the treatment of chronic asthma with the objective of reducing or removing effectively corticosteroid therapy: A novel approach and promising results

Asthma is one of the diseases that demonstrates a wide range of variation in its clinical expression, in addition to an important heterogeneity in the pathophysiological mechanisms present in each case. The ever-increasing knowledge of the molecular signalling routes and the development of the Bio Immune(G)ene Medicine [BI(G)MED] therapy in line with this knowledge has revealed a whole novel potential set of self-regulation biological molecules, that may be used to promote the physiological immunogenic self-regulation mechanisms and re-establish the homeostatic balance at a genomic, proteomic and cellular level. The aim of the present study is to demonstrate that the sublingual use of a therapeutic protocol based on BI(G)MED regulatory BIMUREGs in the treatment of chronic asthma may reduce or suppress corticosteroid therapy and avoid its harmful side effects which some patients suffer when using this treatment on a long-term basis. The clinical efficacy of BI(G)MED for chronic asthma was evaluated through a multi-centre study carried out in 2016 implementing a 6-month BI(G)MED treatment protocol for Bronchial Asthma. A total of 61 patients from private medical centres and of European countries including Germany, Austria, France, Belgium and Spain participated. The manuscript describes in detail the clinical efficacy of Bio Immune(G)ene regulatory BI(G)MED treatment protocol that allows the reduction or total removal of the corticosteroid dose in patients with chronic asthma. No adverse reactions were observed. The BI(G)MED regulatory therapy brings novel therapeutic possibilities as an effective and safe treatment of chronic asthma. BI(G)MED was demonstrated to significantly reduce asthma severity when parameter compositions were all analysed by categorical outcomes. Therefore, it is considered a good therapeutic alternative for patients who respond poorly to steroids.

Behavioral, Biochemical and Molecular Characterization of a Parkinson's Disease Mouse Model Using the Neurotoxin 2'-CH3-MPTP: A Novel Approach

The neurotoxin MPTP has long been used to create a mouse model of Parkinson's disease (PD). Indeed, several MPTP analogues have been developed, including 2'-CH₃-MPTP, which was shown to induce nigrostriatal DA neuronal depletion more potently than MPTP. However, no study on behavioral and molecular alterations in response to 2'-CH₃-MPTP has been carried out so far. In the present work, 2'-CH₃-MPTP was administered to mice (2.5, 5.0 and 10 mg/kg per injection, once a day, 5 days) and histological, biochemical, molecular and behavioral alterations were evaluated. We show that, despite a dose-dependent-like pattern observed for nigrostriatal dopaminergic neuronal death and dopamine depletion, dose-specific alterations in dopamine metabolism and in the expression of dopaminergic neurotransmission-associated genes could be related to specific motor deficits elicited by the different doses tested. Interestingly, 2'-CH₃-MPTP leads to increased DAT and MAO-B transcription, which could explain, respectively, its higher potency and the requirement of higher doses of MAO inhibitors to prevent nigrostriatal neuronal death when compared to MPTP. Also, perturbations in dopamine metabolism as well as possible alterations in dopamine bioavailability in the synaptic cleft were also identified and correlated with strength and ambulation deficits in response to specific doses. Overall, the present work brings new evidence supporting the distinct effects of 2'-CH₃-MPTP when compared to its analogue MPTP. Moreover, our data highlight the utmost importance of a precise experimental design, as different administration regimens and doses yield different biochemical, molecular and behavioral alterations, which can be explored to study specific aspects of PD.

Efficacy of Bioactive Cyclic Peptides in Rheumatoid Arthritis: Translation from In Vitro to In Vivo Models

Using a novel drug discovery technology reported in previous issues of this journal cyclic peptides have been created which are able to down-regulate secretion of inflammatory cytokines, in vitro, by stimulated cells of the macrophage cell line J774. The cytokines in question, TNF-alpha and IL-6, are strongly implicated in etiology of diseases such as rheumatoid arthritis. Studies are reported here using the CAIA animal model for rheumatoid arthritis, which show that the peptides identified are indeed able to impact on inflammation of joints, induced in vivo. The results suggest that these peptides are effective at a dose which could be viable in man, and at which no adverse side effects are evident in the short term.

How does hormesis impact biology, toxicology, and medicine?

Hormesis refers to adaptive responses of biological systems to moderate environmental or self-imposed challenges through which the system improves its functionality and/or tolerance to more severe challenges. The past two decades have witnessed an expanding recognition of the concept of hormesis, elucidation of its evolutionary foundations, and underlying cellular and molecular mechanisms, and practical applications to improve quality of life. To better inform future basic and applied research, we organized and re-evaluated recent hormesis-related findings with the intent of incorporating new knowledge of biological mechanisms, and providing fundamental insights into the biological, biomedical and risk assessment implications of hormesis. As the literature on hormesis is expanding rapidly into new areas of basic and applied research, it is important to provide refined conceptualization of hormesis to aid in designing and interpreting future studies. Here, we establish a working compartmentalization of hormesis into ten categories that provide an integrated understanding of the biological meaning and applications of hormesis.

Role of Ambient Gas Composition on Cold Physical Plasma-Elicited Cell Signaling in Keratinocytes

A particularly promising medical application of cold physical plasma is the support of wound healing. This is presumably achieved by modulating inflammation as well as skin cell signaling and migration. Plasma-derived reactive oxygen and nitrogen species (ROS/RNS) are assumed the central biologically active plasma components. We hypothesized that modulating the environmental plasma conditions from pure nitrogen (N₂) to pure oxygen (O₂) in an atmospheric pressure argon plasma jet (kINPen) will change type and concentration of ROS/RNS and effectively tune the behavior of human skin cells. To investigate this, HaCaT keratinocytes were studied in vitro with regard to cell metabolism, viability, growth, gene expression signature, and cytokine secretion. Flow cytometry demonstrated only slight effects on cytotoxicity. O₂ shielding provided stronger apoptotic effects trough caspase-3 activation compared to N₂ shielding. Gene array technology revealed induction of signaling and communication proteins such as immunomodulatory interleukin 6 as well as antioxidative and proproliferative molecules (HMOX1, VEGFA, HBEGF, CSF2, and MAPK) in response to different plasma shielding gas compositions. Cell response was correlated to reactive species: oxygen-shielding plasma induces a cell response more efficiently despite an apparent decrease of hydrogen peroxide (H₂O₂), which was previously shown to be a major player in plasma-cell regulation, emphasizing the role of non-H₂O₂ ROS like singlet oxygen. Our results suggest differential effects of ROS- and RNS-rich plasma, and may have a role in optimizing clinical plasma applications in chronic wounds.

To What Extent Are the Terminal Stages of Sepsis, Septic Shock, Systemic Inflammatory Response Syndrome, and Multiple Organ Dysfunction Syndrome Actually Driven by a Prion/Amyloid Form of Fibrin?

A well-established development of increasing disease severity leads from sepsis through systemic inflammatory response syndrome, septic shock, multiple organ dysfunction syndrome, and cellular and organismal death. Less commonly discussed are the equally well-established coagulopathies that accompany this. We argue that a lipopolysaccharide-initiated (often disseminated intravascular) coagulation is accompanied by a proteolysis of fibrinogen such that formed fibrin is both inflammatory and resistant to fibrinolysis. In particular, we argue that the form of fibrin generated is amyloid in nature because much of its normal α-helical content is transformed to β-sheets, as occurs with other proteins in established amyloidogenic and prion diseases. We hypothesize that these processes of amyloidogenic clotting and the attendant coagulopathies play a role in the passage along the aforementioned pathways to organismal death, and that their inhibition would be of significant therapeutic value, a claim for which there is considerable emerging evidence.

How gastrin-releasing peptide receptor (GRPR) and αvβ3 integrin expression reflect reorganization features of tumors after hyperthermia treatments

The outcome of tumor treatment via hyperthermia in the clinic has been reported to be heterogeneous. Here, we assessed how the presence of gastrin-releasing peptide receptor (GRPR) and αvβ3 integrin together with the morphology of the vascularization reflects the growth behavior of tumors after hyperthermia treatment. MDA-MB-231 tumor bearing mice were treated either with high (46 °C) or low dose (42 °C) water hyperthermia for 60 min. Changes of GRPR and αvβ3 integrin expression were assessed via multiplexed optical imaging. Vascularization was reconstructed and quantified by µCT imaging after contrast agent injection. We found that high dose hyperthermia is capable of increasing the expression of GRPR, αvβ3 integrin, CD31, and Ki67 in tumors. Also the morphology of tumor vasculature changed (increased relative blood volume and small-diameter vessel density, decreased expression of α-SMA). Low dose hyperthermia induced comparatively moderate effects on the investigated protein expression pattern and vascular remodeling. We conclude that under defined circumstances, specific temperature doses affect the reorganization of tumor regrowth, which is triggered by residual "dormant" cells even though tumor volumes are transiently decreasing. Further on, GRPR, αvβ3 integrin expression are versatile tools to surveil potential tumor regrow during therapy, beyond the conventional determination of tumor volumes.

Mediterranean diet and inflammaging within the hormesis paradigm

A coherent set of epidemiological data shows that the Mediterranean diet has beneficial effects capable of preventing a variety of age-related diseases in which low-grade, chronic inflammation/inflammaging plays a major role, but the underpinning mechanism(s) is/are still unclear. It is suggested here that the Mediterranean diet can be conceptualized as a form of chronic hormetic stress, similar to what has been proposed regarding calorie restriction, the most thoroughly studied nutritional intervention. Data on the presence in key Mediterranean foods of a variety of compounds capable of exerting hormetic effects are summarized, and the mechanistic role of the nuclear factor erythroid 2 pathway is highlighted. Within this conceptual framework, particular attention has been devoted to the neurohormetic and neuroprotective properties of the Mediterranean diet, as well as to its ability to maintain an optimal balance between pro- and anti-inflammaging. Finally, the European Commission-funded project NU-AGE is discussed because it addresses a number of variables not commonly taken into consideration, such as age, sex, and ethnicity/genetics, that can modulate the hormetic effect of the Mediterranean diet.

Berberine protects against 6-OHDA-induced neurotoxicity in PC12 cells and zebrafish through hormetic mechanisms involving PI3K/AKT/Bcl-2 and Nrf2/HO-1 pathways

Berberine (BBR) is a renowned natural compound that exhibits potent neuroprotective activities. However, the cellular and molecular mechanisms are still unclear. Hormesis is an adaptive mechanism generally activated by mild oxidative stress to protect the cells from further damage. Many phytochemicals have been shown to induce hormesis. This study aims to investigate whether the neuroprotective activity of BBR is mediated by hormesis and the related signaling pathways in 6-OHDA-induced PC12 cells and zebrafish neurotoxic models. Our results demonstrated that BBR induced a typical hormetic response in PC12 cells, i.e. low dose BBR significantly increased the cell viability, while high dose BBR inhibited the cell viability. Moreover, low dose BBR protected the PC12 cells from 6-OHDA-induced cytotoxicity and apoptosis, whereas relatively high dose BBR did not show neuroprotective activity. The hormetic and neuroprotective effects of BBR were confirmed to be mediated by up-regulated PI3K/AKT/Bcl-2 cell survival and Nrf2/HO-1 antioxidative signaling pathways. In addition, low dose BBR markedly mitigated the 6-OHDA-induced dopaminergic neuron loss and behavior movement deficiency in zebrafish, while high dose BBR only slightly exhibited neuroprotective activities. These results strongly suggested that the neuroprotection of BBR were attributable to the hormetic mechanisms via activating cell survival and antioxidative signaling pathways.

Hormetic effect of panaxatriol saponins confers neuroprotection in PC12 cells and zebrafish through PI3K/AKT/mTOR and AMPK/SIRT1/FOXO3 pathways

Hormesis is an adaptive response of living organisms to a moderate stress. However, its biomedical implication and molecular mechanisms remain to be intensively investigated. Panaxatriol saponins (PTS) is the major bioactive components extracted from Panax notoginseng, a widely used herbal medicine for cerebrovascular diseases. This study aims to examine the hormetic and neuroprotective effects of PTS in PC12 cells and zebrafish Parkinson's disease (PD) models. Our results demonstrated that PTS stimulated PC12 cell growth by about 30% at low doses, while PTS at high doses inhibited cell growth, which is a typical hormetic effect. Moreover, we found that low dose PTS pretreatment significantly attenuated 6-OHDA-induced cytotoxicity and up-regulated PI3K/AKT/mTOR cell proliferation pathway and AMPK/SIRT1/FOXO3 cell survival pathway in PC12 cells. These results strongly suggested that neuroprotective effects of PTS may be attributable to the hormetic effect induced by PTS through activating adaptive response-related signaling pathways. Notably, low dose PTS could significantly prevent the 6-OHDA-induced dopaminergic neuron loss and improve the behavior movement deficiency in zebrafish, whereas relative high dose PTS exhibited neural toxicity, further supporting the hormetic and neuroprotective effects of PTS. This study indicates that PTS may have the potential in the development of future therapeutic medicines for PD.

Functional Implications of Cardiac Mitochondria Clustering

The spatio-temporal organization of mitochondria in cardiac myocytes facilitates myocyte-wide, cluster-bound, mitochondrial inner membrane potential oscillatory depolarizations, commonly triggered by metabolic or oxidative stressors. Local intermitochondrial coupling can be mediated by reactive oxygen species (ROS) that activate inner membrane pores to initiate a ROS-induced-ROS-release process that produces synchronized limit cycle oscillations of mitochondrial clusters within the whole mitochondrial network. The network's dynamic organization, structure and function can be assessed by quantifying dynamic local coupling constants and dynamic functional clustering coefficients, both providing information about the network's response to external stimuli. In addition to its special organization, the mitochondrial network of cardiac myocytes exhibits substrate-sensitive coupling constants and clustering coefficients. The myocyte's ability to form functional clusters of synchronously oscillating mitochondria is sensitive to conditions such as substrate availability (e.g., glucose, pyruvate, β-hydroxybutyrate), antioxidant status, respiratory chain activity, or history of oxidative challenge (e.g., ischemia-reperfusion). This underscores the relevance of quantitative methods to characterize the network's functional status as a way to assess the myocyte's resilience to pathological stressors.

Shining light on the head: Photobiomodulation for brain disorders

Photobiomodulation (PBM) describes the use of red or near-infrared light to stimulate, heal, regenerate, and protect tissue that has either been injured, is degenerating, or else is at risk of dying. One of the organ systems of the human body that is most necessary to life, and whose optimum functioning is most worried about by humankind in general, is the brain. The brain suffers from many different disorders that can be classified into three broad groupings: traumatic events (stroke, traumatic brain injury, and global ischemia), degenerative diseases (dementia, Alzheimer's and Parkinson's), and psychiatric disorders (depression, anxiety, post traumatic stress disorder). There is some evidence that all these seemingly diverse conditions can be beneficially affected by applying light to the head. There is even the possibility that PBM could be used for cognitive enhancement in normal healthy people. In this transcranial PBM (tPBM) application, near-infrared (NIR) light is often applied to the forehead because of the better penetration (no hair, longer wavelength). Some workers have used lasers, but recently the introduction of inexpensive light emitting diode (LED) arrays has allowed the development of light emitting helmets or "brain caps". This review will cover the mechanisms of action of photobiomodulation to the brain, and summarize some of the key pre-clinical studies and clinical trials that have been undertaken for diverse brain disorders.

European Union's strategy on endocrine disrupting chemicals and the current position of Slovenia

In view of the European Union regulations 1107/2009 and 528/2012, which say that basic substances in plant protection and biocidal products marketed in the European Union (EU) should not have an inherent capacity to cause endocrine disruption, an initiative was started to define scientific criteria for the identification of endocrine disruptors (EDs). The objectives of the EU strategy on EDs are to protect human health and the environment, to assure the functioning of the market, and to provide clear and coherent criteria for the identification of EDs that could have broad application in the EU legislation. Policy issues were to be addressed by the Ad-hoc group of Commission Services, EU Agencies and Member States established in 2010, whereas the scientific issues were to be addressed by the Endocrine Disruptors Expert Advisory Group (ED EAG), established in 2011. The ED EAG adopted the 2002 World Health Organization (WHO) definition of endocrine disruptor and agreed that for its identification it is necessary to produce convincing evidence of a biologically plausible causal link between an adverse effect and endocrine disrupting mode of action. In 2014, the European Commission proposed four ED identification criteria options and three regulatory options, which are now being assessed for socio-economic, environmental, and health impact. Slovenia supports the establishing of identification criteria and favours option 4, according to which ED identification should be based on the WHO definition with the addition of potency as an element of hazard characterisation. As for regulatory options, Slovenia favours the risk-based rather than hazard-based regulation.

Differential cytotoxic effects of 7-dehydrocholesterol-derived oxysterols on cultured retina-derived cells: Dependence on sterol structure, cell type, and density

Tissue accumulation of 7-dehydrocholesterol (7DHC) is a hallmark of Smith-Lemli-Opitz Syndrome (SLOS), a human inborn error of the cholesterol (CHOL) synthesis pathway. Retinal 7DHC-derived oxysterol formation occurs in the AY9944-induced rat model of SLOS, which exhibits a retinal degeneration characterized by selective loss of photoreceptors and associated functional deficits, Müller cell hypertrophy, and engorgement of the retinal pigment epithelium (RPE) with phagocytic inclusions. We evaluated the relative effects of four 7DHC-derived oxysterols on three retina-derived cell types in culture, with respect to changes in cellular morphology and viability. 661W (photoreceptor-derived) cells, rMC-1 (Müller glia-derived) cells, and normal diploid monkey RPE (mRPE) cells were incubated for 24 h with dose ranges of either 7-ketocholesterol (7kCHOL), 5,9-endoperoxy-cholest-7-en-3β,6α-diol (EPCD), 3β,5α-dihydroxycholest-7-en-6-one (DHCEO), or 4β-hydroxy-7-dehydrocholesterol (4HDHC); CHOL served as a negative control (same dose range), along with appropriate vehicle controls, while staurosporine (Stsp) was used as a positive cytotoxic control. For 661W cells, the rank order of oxysterol potency was: EPCD > 7kCHOL >> DHCEO > 4HDHC ≈ CHOL. EC50 values were higher for confluent vs. subconfluent cultures. 661W cells exhibited much higher sensitivity to EPCD and 7kCHOL than either rMC-1 or mRPE cells, with the latter being the most robust when challenged, either at confluence or in sub-confluent cultures. When tested on rMC-1 and mRPE cells, EPCD was again an order of magnitude more potent than 7kCHOL in compromising cellular viability. Hence, 7DHC-derived oxysterols elicit differential cytotoxicity that is dose-, cell type-, and cell density-dependent. These results are consistent with the observed progressive, photoreceptor-specific retinal degeneration in the rat SLOS model, and support the hypothesis that 7DHC-derived oxysterols are causally linked to that retinal degeneration as well as to SLOS.

Can Exercise Make You Smarter, Happier, and Have More Neurons? A Hormetic Perspective

Exercise can make you smarter, happier and have more neurons depending on the dose (intensity) of the training program. It is well recognized that exercise protocols induce both positive and negative effects depending on the intensity of the exercise, among other key factors, a process described as a hormetic-like biphasic dose-response. However, no evidences have been reported till very recently about the biphasic response of some of the potential mediators of the exercise-induced actions. This hypothesis and theory will focus on the adult hippocampal neurogenesis (AHN) as a putative physical substrate for hormesis responses to exercise in the context of exercise-induced actions on cognition and mood, and on the molecular pathways which might potentially be mediating these actions.

Effects of Extreme Dilutions of Apis mellifica Preparations on Gene Expression Profiles of Human Cells

Gene expression analysis has been employed in the past to test the effects of high dilutions on cell systems. However, most of the previous studies were restricted to the investigation of few dilutions, making it difficult to explore underlying mechanisms of action. Using whole-genome transcriptomic analysis, we investigated the effects of a wide range of Apis mellifica dilutions on gene expression profiles of human cells. RWPE-1 cells, a nonneoplastic adult human epithelial prostate cell line, were exposed to Apis mellifica preparations (3C, 5C, 7C, 9C, 12C, 15C, and 30C) or to the reference solvent solutions for 24 hours; nonexposed cells were also checked for gene expression variations. Our results showed that even the most diluted solutions retained the ability to trigger significant variations in gene expression. Gene pathway analysis revealed consistent variations in gene expression induced by Apis mellifica when compared to nonexposed reference cells but not to reference solvent solutions. Since the effects of Apis Mellifica at extreme dilutions did not show dose–effect relationships, the biological or functional interpretation of these results remains uncertain.

HORMESIS: A Fundamental Concept with Widespread Biological and Biomedical Applications

Hormesis is a biphasic dose response with specific quantitative features for the amplitude and width of the stimulation. It is highly generalizable and independent of biological model, endpoint, inducing agent, level of biological organization and mechanism. Hormesis may be induced via a direct stimulation or by overcompensation to a disruption of homeostasis. The induction of hormesis by low-level stressor agents not only rapidly upregulates adaptive processes to repair damage but also protects the adapted system from damage due to a subsequent challenging dose (toxic) within a definable temporal window. The striking consistency of the amplitude of hormetic response suggests that hormesis provides a quantitative description of biological plasticity. Knowledge of hormesis has particular potential biomedical significance with respect to slowing or retarding both normal aging processes and the progression of severe neurological diseases.