Melatonin Mediates Cardiac Tissue Damage under Septic Conditions Induced by Lipopolysaccharide

Lipopolysaccharide (LPS) is known to induce oxidative stress and inflammation, leading to significant damage in cardiac tissues. This study investigates the protective effects of melatonin (MLT) against LPS-induced oxidative damage, inflammation, and apoptosis in rat heart tissue. Rats were divided into four groups (n = 6 per group): control, melatonin-treated, LPS-treated, and LPS + melatonin-treated. Oxidative stress markers, including thiobarbituric acid-reactive substances (TBARSs) and advanced oxidation protein products (AOPPs), were measured. Additionally, inflammatory markers, such as interleukin-6 (IL-6) levels, inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content, and apoptotic markers, caspase-3, caspase-9, and acidic DNase activity, were evaluated. LPS treatment significantly increased TBARS, AOPP, and IL-6 levels, as well as the activity of caspase-3, acidic DNase and iNOS and NO content compared to the control group. Co-treatment with melatonin significantly reduced the levels of TBARS and AOPP levels, and caspase-3 and acidic DNase activities nearly matched those of the control group, while caspse-9 was still slightly increased. Interestingly, IL-6, iNOS and NO levels were significantly decreased but did not fully match the values in the control group. Melatonin mitigates LPS-induced oxidative stress, inflammation, and apoptosis in rat heart tissue by affecting all studied parameters, demonstrating its potential as a therapeutic agent for conditions characterized by oxidative stress and inflammation. Further research is warranted to explore the clinical applications of melatonin in cardiovascular diseases.

Melatonin as a natural anti-inflammatory and anti-oxidant therapy in the testis: a focus on infertility and aging†

Melatonin is a pineal hormone that regulates testicular activity (i.e., steroidogenesis and spermatogenesis) through two complementary mechanisms, indirect effects exerted via the hypothalamic-adenohypophyseal axis and direct actions that take place on the different cell populations of the male gonad. The effects of increased age on the testis and the general mechanisms involved in testicular pathology leading to infertility are still only poorly understood. However, there is growing evidence that link testicular aging and idiopathic male infertility to local inflammatory and oxidative stress events. Because literature data strongly indicate that melatonin exhibits anti-inflammatory and anti-oxidant properties, this review focuses on the potential benefits exerted by this indoleamine at testicular level in male reproductive fertility and aging. Taking into account that the effects of melatonin supplementation on testicular function are currently being investigated, the overview covers not only promising prospects but also many questions concerning the future therapeutic value of this indoleamine as an anti-aging drug as well as in the management of cases of male infertility for which there are no medical treatments currently available.

Melatonin: A look at protozoal and helminths

Melatonin is a pleiotropic neurohormone found in different animal, plant, and microorganism species. It is a product resulting from tryptophan metabolism in the pineal gland and is widely known for its ability to synchronize the circadian rhythm to antitumor functions in different types of cancers. The molecular mechanisms responsible for its immunomodulatory, antioxidant and cytoprotective effects involve binding to high-affinity G protein-coupled receptors and interactions with intracellular targets that modulate signal transduction pathways. In vitro and in vivo studies have reported the therapeutic potential of melatonin in different infectious and parasitic diseases. In this review, the protective and pathophysiological roles of melatonin in fighting protozoan and helminth infections and the possible mechanisms involved against these stressors will be discussed.

Effects of Melatonin on Liver of D-Galactose-Induced Aged Mouse Model

Melatonin, a hormone secreted by the pineal gland of vertebrates, regulates sleep, blood pressure, and circadian and seasonal rhythms, and acts as an antioxidant and anti-inflammatory agent. We investigated the protective effects of melatonin against markers of D-galactose (D-Gal)-induced hepatocellular aging, including liver inflammation, hepatocyte structural damage, and non-alcoholic fatty liver. Mice were divided into four groups: phosphate-buffered saline (PBS, control), D-Gal (200 mg/kg/day), melatonin (20 mg/kg), and D-Gal (200 mg/kg) and melatonin (20 mg) cotreatment. The treatments were administered once daily for eight consecutive weeks. Melatonin treatment alleviated D-Gal-induced hepatocyte impairment. The AST level was significantly increased in the D-Gal-treated groups compared to that in the control group, while the ALT level was decreased compared to the melatonin and D-Gal cotreated group. Inflammatory genes, such as IL1-β, NF-κB, IL-6, TNFα, and iNOS, were significantly increased in the D-Gal aging model, whereas the expression levels of these genes were low in the D-Gal and melatonin cotreated group. Interestingly, the expression levels of hepatic steatosis-related genes, such as LXRα, C/EBPα, PPARα, ACC, ACOX1, and CPT-1, were markedly decreased in the D-Gal and melatonin cotreated group. These results suggest that melatonin suppresses hepatic steatosis and inflammation in a mouse model of D-Gal-induced aging.

Neurotoxicity of furan in juvenile Wistar rats involves behavioral defects, microgliosis, astrogliosis and oxidative stress

Evidence suggests that furan, a widespread environmental and food contaminant, causes liver toxicity and cancer, but its implications in the brain are not well defined. We measured behavioral, glial, and biochemical responses in male juvenile rats exposed orally to 2.5, 5 and 10 mg/kg furan and vitamin E after 28 days. Furan-mediated hyperactivity peaked at 5 mg/kg and did not exacerbate at 10 mg/kg. Enhanced motor defect was also observed at 10 mg/kg. Furan-treated rats elicited inquisitive exploration but showed impaired working memory. Without compromising the blood-brain barrier, furan induced glial reactivity with enhanced phagocytic activity, characterized by parenchyma-wide microglial aggregation and proliferation, which switched from hyper-ramified to rod-like morphology with increasing doses. Furan altered the glutathione-S-transferase-driven enzymatic and non-enzymatic antioxidant defence systems differentially and dose-dependently across brain regions. Redox homeostasis was most perturbed in the striatum and least disrupted in hippocampus/cerebellum. Vitamin E supplementation attenuated exploratory hyperactivity and glial reactivity but did not affect impaired working memory and oxidative imbalance. Overall, sub-chronic exposure of juvenile rats to furan triggered glial reactivity and behavioral defects suggesting the brain's vulnerability during juvenile development to furan toxicity. It remains to be determined whether environmentally relevant furan concentrations interfere with critical brain developmental milestones.

Alpha synuclein post translational modifications: potential targets for Parkinson's disease therapy?

Parkinson's disease (PD) is the most common neurodegenerative disorder with motor symptoms. The neuropathological alterations characterizing the brain of patients with PD include the loss of dopaminergic neurons of the nigrostriatal system and the presence of Lewy bodies (LB), intraneuronal inclusions that are mainly composed of alpha-synuclein (α-Syn) fibrils. The accumulation of α-Syn in insoluble aggregates is a main neuropathological feature in PD and in other neurodegenerative diseases, including LB dementia (LBD) and multiple system atrophy (MSA), which are therefore defined as synucleinopathies. Compelling evidence supports that α-Syn post translational modifications (PTMs) such as phosphorylation, nitration, acetylation, O-GlcNAcylation, glycation, SUMOylation, ubiquitination and C-terminal cleavage, play important roles in the modulation α-Syn aggregation, solubility, turnover and membrane binding. In particular, PTMs can impact on α-Syn conformational state, thus supporting that their modulation can in turn affect α-Syn aggregation and its ability to seed further soluble α-Syn fibrillation. This review focuses on the importance of α-Syn PTMs in PD pathophysiology but also aims at highlighting their general relevance as possible biomarkers and, more importantly, as innovative therapeutic targets for synucleinopathies. In addition, we call attention to the multiple challenges that we still need to face to enable the development of novel therapeutic approaches modulating α-Syn PTMs.

Protection of melatonin treatment and combination with traditional antibiotics against septic myocardial injury

BACKGROUND

Heart failure is a common complication of sepsis with a high mortality rate. It has been reported that melatonin can attenuate septic injury due to various properties. On the basis of previous reports, this study will further explore the effects and mechanisms of melatonin pretreatment, posttreatment, and combination with antibiotics in the treatment of sepsis and septic myocardial injury.

METHODS AND RESULTS

Our results showed that melatonin pretreatment showed an obvious protective effect on sepsis and septic myocardial injury, which was related to the attenuation of inflammation and oxidative stress, the improvement of mitochondrial function, the regulation of endoplasmic reticulum stress (ERS), and the activation of the AMPK signaling pathway. In particular, AMPK serves as a key effector for melatonin-initiated myocardial benefits. In addition, melatonin posttreatment also had a certain degree of protection, while its effect was not as remarkable as that of pretreatment. The combination of melatonin and classical antibiotics had a slight but limited effect. RNA-seq detection clarified the cardioprotective mechanism of melatonin.

CONCLUSION

Altogether, this study provides a theoretical basis for the application strategy and combination of melatonin in septic myocardial injury.

A phase II, single-center, double-blind, randomized placebo-controlled trial to explore the efficacy and safety of intravenous melatonin in surgical patients with severe sepsis admitted to the intensive care unit

To determine whether IV melatonin therapy improves redox status and inflammatory responses in surgical patients with severe sepsis, a unicenter, phase II double-blind, randomized, placebo-controlled trial was carried out. The study included patients with severe sepsis marked by infectious systemic inflammatory response syndrome (SIRS), associated with organ dysfunction, hypoperfusion or hypotension requiring surgical intervention. IV melatonin at a daily dose of 60 mg, which was dissolved in 500 ml of 5% dextrose serum, was continuously administered to the patients for over 30 min starting on the day of the diagnoses during a 5-day period. A total of 14 patients received a placebo treatment and 15 melatonin doses. Redox status decreased in melatonin-treated patients during the 5 days of treatment as compared to the placebo-treated patients. Procalcitonin performed better in the melatonin group, whose neutrophil to lymphocyte ratio was also significantly reduced, resulting in an improved evolution of the disease. Moreover, hospital stays decreased by 19.60% from 26.64 days for the placebo group to 21.42 days for the melatonin group. The placebo group recorded five mortalities, as compared to three for the melatonin group. IV melatonin administration improved the course of the disease in surgical patients with severe sepsis, with no side effects. Additional studies with higher doses of melatonin and a long duration of therapy need to be carried out to assess its clinical use.

GOODNIGHT, SLEEP TIGHT, DON'T LET THE MICROBES BITE: A REVIEW OF SLEEP AND ITS EFFECTS ON SEPSIS AND INFLAMMATION

ABSTRACT

Sleep is a restorative biological process that is crucial for health and homeostasis. However, patient sleep is frequently interrupted in the hospital environment, particularly within the intensive care unit. Suboptimal sleep may alter the immune response and make patients more vulnerable to infection and sepsis. In addition, hospitalized patients with sepsis experience altered sleep relative to patients without infectious disease, suggesting a bidirectional interplay. Preclinical studies have generated complementary findings, and together, these studies have expanded our mechanistic understanding. This review article summarizes clinical and preclinical studies describing how sleep affects inflammation and the host's susceptibility to infection. We also highlight potential strategies to reverse the detrimental effects of sleep interruption in the intensive care unit.

Melatonin pretreatment modulates anti-inflammatory, antioxidant, YKL-40, and matrix metalloproteinases in endotoxemic rat lung tissue

We aimed to investigate the effects of melatonin administered before and during endotoxemia on the lung tissue of rats, cytokine, YKL-40, matrix metalloproteinase (MMP) and inhibitor levels, oxidative stress parameters, and energy balance. Sepsis was induced with lipopolysaccharide (LPS), the cell wall molecule of gram negative bacteria. Rats were divided into four groups, Control, LPS (Escherichia coli O127:B8, 20 mg/kg), melatonin (10 mg/kg), and melatonin+LPS (M+LPS). After injections, lung tissues samples were taken for experimental analyses. YKL-40, thiobarbituric acid reactive substances (TBARS), glutathione reductase (GR), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) enzymes levels were measured, high-energy components were analyzed; tumor necrosis factor-alpha (TNF-α), MMP-2, YKL-40, MMP-9, myeloperoxidase (MPO), tissue inhibitors of matrix metalloproteinase (TIMP)-1, and interleukin (IL)-10 immunoreactivities were investigated. In LPS group, YKL-40, creatine phosphate (both, p < 0.05), SOD, GR, adenosine mono-phophate (AMP), adenosine tri-phosphate (ATP) (for all, p < 0.01) were significantly decreased, while TBARS and adenosine di-phosphate (ADP) levels were increased (p < 0.01, p < 0.05; respectively) compared to other groups. MMP-2 and -9, TIMP-1, TNF-α, IL-10, and MPO immunoreactivity were investigated in LPS group. On the contrary, in M+LPS group, MMP-9, TIMP-1 immunoreactivities were not found and IL-10 and MMP-2 immunoreactivities were found with little involvement. In M+LPS group, YKL-40, GR, AMP, ATP, creatine phosphate (for all, p < 0.05), and SOD (p < 0.01) levels were significantly increased and TBARS levels were decreased (p < 0.05). In our study, we suggest that melatonin exerts a protective and curative effect by reducing the matrix metalloproteinase levels responsible for tissue damage balance, stimulating the release of antioxidant enzymes, regulating cytokines and energy balance during endotoxemia.

Exogenous Melatonin Alleviates Skeletal Muscle Wasting by Regulating Hypothalamic Neuropeptides Expression in Endotoxemia Rats

To investigate whether exogenous melatonin (MLT) could alleviate skeletal muscle wasting by regulating hypothalamic neuropeptides expression. Adult male Sprague Dawley rats were intraperitoneally injected with lipopolysaccharide (LPS) (10 mg/kg), followed by MLT (30 mg/kg/day) or saline for 3 days. Hypothalamic tissues and skeletal muscle were obtained on day 3. Skeletal muscle wasting was measured by the mRNA expression of two E3 ubiquitin ligases, muscle atrophy F-box and muscle ring finger 1 as well as 3-methylhistidine (3-MH) and tyrosine release. Three hypothalamic neuropeptides (POMC, AgRP, CART) expression were detected in all groups. POMC expression knockdown was achieved by ARC injection of lentiviruses containing shRNA against POMC. Two weeks after ARC viruses injection, rats were i.p. injected with LPS (10 mg/kg) followed by MLT (30 mg/kg/day) or saline for 3 days. Brain tissues were harvested for immunostaining. In septic rats, 3-MH, tyrosine release and muscle atrophic gene expression were significantly decreased in MLT treated group. POMC and CART expression were lower while AgRP expression was higher in MLT treated group. Furthermore, in septic rats treated with MLT, muscle wasting in those with lower expression of neuropeptide POMC did not differ from those with normal POMC expression. Exogenous MLT could alleviate skeletal muscle wasting in septic rats by regulating hypothalamic neuropeptides.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

Melatonin as an immunomodulator in children with Down syndrome

BACKGROUND

Down syndrome (DS) is a disorder characterised by marked immune dysfunction, increased mortality from sepsis, chronic inflammation, increased oxidative stress, sleep disturbance and possibly abnormal endogenous melatonin levels. Melatonin has a myriad of immune functions, and we hypothesised that this therapeutic agent could modulate the innate immune system in this cohort.

METHODS

We investigated neutrophil and monocyte function (CD11b, TLR4 expression by flow cytometry), genes involved in TLR signalling (MyD88, IRAK4, TRIF), the inflammasome (NLRP3, IL-1β), and circadian rhythm (BMAL, CLOCK, CRY) by qPCR, and inflammatory cytokines (IL-2, IL-6, IL-8, IL-18, IL-1β, TNF-α, IFN-γ, IL-10, IL-1ra, VEGF, Epo, GM-CSF) by enzyme-linked immunosorbent assay (ELISA) following immunomodulation with LPS endotoxin and melatonin. 47 children with DS and 23 age- and sex-matched controls were recruited.

RESULTS

We demonstrated that melatonin has several significant effects by reducing CD11b and TLR4 expression, attenuating TLR signalling, genes involved in the inflammasome and has the potential to reduce LPS-induced inflammatory responses.

CONCLUSIONS

Immunomodulatory effects of melatonin were found in both paediatric cohorts with more marked effects in the children with DS. Melatonin mediates immune response through a wide array of mechanisms and this immunomodulator may buffer the inflammatory response by regulating pro and anti-inflammatory signalling.

IMPACT

We highlight that melatonin mediates its immune response through a wide array of mechanisms, its effects appear to be dose dependant and children with Down syndrome may be more receptive to treatment with it. Immunomodulatory effects of melatonin were demonstrated with marked effects in the children with Down syndrome with a reduction of MyD88, IL-1ß and NLRP3 expression in whole-blood samples. Melatonin is a proposed anti-inflammatory agent with a well-established safety profile, that has the potential for mitigation of pro- and anti-inflammatory cytokines in paediatric Down syndrome cohorts, though further clinical trials are warranted.

Cysteamine mitigates torsion/detorsion-induced reperfusion injury via inhibition of apoptosis, oxidative stress and inflammatory responses in experimental rat model

Oxidative stress, inflammation and apoptosis are major pathways in pathophysiology of testicular torsion/detorsion (TTDT) reperfusion injury. This study evaluated the antioxidant, anti-inflammatory and anti-apoptotic role of cysteamine in TTDT-induced injury. Male Wistar rats (n = 32) were grouped into four (n = 8): sham, ischaemia-reperfusion injury (IRI), cysteamine (100 mg/kg and 200 mg/kg) for in vivo study. Samples were taken for biomolecular and histological evaluation 48 hr after detorsion. Tissue SOD, GPx, GSH, GST activity, total thiol, H₂ O₂ and MDA were assessed. Serum levels of NO, MPO, TNF-alpha and IL-6 and sperm motility, count and viability were assessed. Caspase-3 and bax were evaluated by immunohistochemistry. Significant difference was set as p < .05. Significant increase in H₂ O_2, MDA and nitrite but reduction in SOD, GPx, GSH, GST and total thiol in the testicular tissue of IRI rats was reversed by cysteamine. Serum MPO and TNF-α were significantly elevated in RI, while treated-RI rats showed decrease (p < .05) in tissue level of the inflammation markers. Reduced sperm motility in RI was significantly reversed by cysteamine. Increased tissue expression of bax and caspase-3 was reversed by cysteamine. Cysteamine protected the testis against reperfusion injury through anti-inflammatory, antioxidant effects and inhibition of apoptosis in rats.

Melatonin and Microglia

Melatonin interacts in multiple ways with microglia, both directly and, via routes of crosstalk with astrocytes and neurons, indirectly. These effects of melatonin are of relevance in terms of antioxidative protection, not only concerning free-radical detoxification, but also in prevention of processes that cause, promote, or propagate oxidative stress and neurodegeneration, such as overexcitation, toxicological insults, viral and bacterial infections, and sterile inflammation of different grades. The immunological interplay in the CNS, with microglia playing a central role, is of high complexity and includes signaling toward endothelial cells and other leukocytes by cytokines, chemokines, nitric oxide, and eikosanoids. Melatonin interferes with these processes in multiple signaling routes and steps. In addition to canonical signal transduction by MT₁ and MT₂ melatonin receptors, secondary and tertiary signaling is of relevance and has to be considered, e.g., via the upregulation of sirtuins and the modulation of pro- and anti-inflammatory microRNAs. Many details concerning the modulation of macrophage functionality by melatonin are obviously also applicable to microglial cells. Of particular interest is the polarization toward M2 subtypes instead of M1, i.e., in favor of being anti-inflammatory at the expense of proinflammatory activities, which is well-documented in macrophages but also applies to microglia.

Melatonin effects on bone: Implications for use as a therapy for managing bone loss

Melatonin is the primary circadian output signal from the brain and is mainly synthesized in pinealocytes. The rhythm and secretion of melatonin are under the control of an endogenous oscillator located in the SCN or the master biological clock. Disruptions in circadian rhythms by shift work, aging, or light at night are associated with bone loss and increased fracture risk. Restoration of nocturnal melatonin peaks to normal levels or therapeutic levels through timed melatonin supplementation has been demonstrated to provide bone-protective actions in various models. Melatonin is a unique molecule with diverse molecular actions targeting melatonin receptors located on the plasma membrane or mitochondria or acting independently of receptors through its actions as an antioxidant or free radical scavenger to stimulate osteoblastogenesis, inhibit osteoclastogenesis, and improve bone density. Its additional actions on entraining circadian rhythms and improving quality of life in an aging population coupled with its safety profile make it an ideal therapeutic candidate for protecting against bone loss in susceptible populations. The intent of this review is to provide a focused discussion on bone loss and disorders of the bone as it relates to melatonin and conditions that modify melatonin levels with the hope that future therapies include those that include melatonin and correct those factors that modify melatonin levels like circadian disruption.

Melatonin, Its Metabolites and Their Interference with Reactive Nitrogen Compounds

Melatonin and several of its metabolites are interfering with reactive nitrogen. With the notion of prevailing melatonin formation in tissues that exceeds by far the quantities in blood, metabolites come into focus that are poorly found in the circulation. Apart from their antioxidant actions, both melatonin and N¹-acetyl-5-methoxykynuramine (AMK) downregulate inducible and inhibit neuronal NO synthases, and additionally scavenge NO. However, the NO adduct of melatonin redonates NO, whereas AMK forms with NO a stable product. Many other melatonin metabolites formed in oxidative processes also contain nitrosylatable sites. Moreover, AMK readily scavenges products of the CO₂-adduct of peroxynitrite such as carbonate radicals and NO₂. Protein AMKylation seems to be involved in protective actions.

Daily Changes in the Expression of Clock Genes in Sepsis and Their Relation with Sepsis Outcome and Urinary Excretion of 6-Sulfatoximelatonin

BACKGROUND

Whereas the circadian system controls the daily production of melatonin and the daily activity of the immune system, increasing evidences support the association between circadian misalignment with the alterations in the immune response and melatonin rhythm during sepsis. The aim of this study was to analyze the daily changes in clock genes expression and the urinary excretion of 6-SM (6-sulfatoxymelatonin, the major melatonin metabolite), and their connection with the innate immune activity, oxidative status in blood, and clinical outcome during sepsis.

METHODS

Healthy volunteers, non-septic intensive care unit (ICU) patients, and septic ICU patients, were evaluated. The expression of bmal1, per2, clock, and cry1 genes was determined by polymerase chain reaction in blood; 6-SM was assessed in urine by ELISA; plasma cytokines IL-1β, IL-6, IL-8, TNFα, and IL-10 were determined by a multiplex array method, and lipid peroxidation (LPO) and protein oxidation (AOPP) by spectrophotometry. Hematological and biochemical data, and clinical scores of the patients, were also recorded.

RESULTS

Clock gene rhythm was maintained in non-septic patients but blunted in septic ones, whereas the innate immune and the oxidative stress responses were significantly higher in the latter. 6-SM excretion was also more elevated in septic than in non-septic patients, and it correlated with the degree of the immune response and oxidative status. 6-SM also correlated with SOFA and procalcitonin in the patients. Proinflammatory cytokines, LPO, and AOPP were normalized in the patients once recovered from sepsis.

CONCLUSION

Our data suggest a relationship between clock genes rhythm disruption, the immune response, and the oxidative status, with 6-SM acting as a compensatory response. ICU conditions are not a main clock disrupter because of the significant differences found in the responses of septic versus non-septic patients under the same ICU environment.

Bacteriostatic Potential of Melatonin: Therapeutic Standing and Mechanistic Insights

Diseases caused by pathogenic bacteria in animals (e.g., bacterial pneumonia, meningitis and sepsis) and plants (e.g., bacterial wilt, angular spot and canker) lead to high prevalence and mortality, and decomposition of plant leaves, respectively. Melatonin, an endogenous molecule, is highly pleiotropic, and accumulating evidence supports the notion that melatonin's actions in bacterial infection deserve particular attention. Here, we summarize the antibacterial effects of melatonin in vitro, in animals as well as plants, and discuss the potential mechanisms. Melatonin exerts antibacterial activities not only on classic gram-negative and -positive bacteria, but also on members of other bacterial groups, such as Mycobacterium tuberculosis. Protective actions against bacterial infections can occur at different levels. Direct actions of melatonin may occur only at very high concentrations, which is at the borderline of practical applicability. However, various indirect functions comprise activation of hosts' defense mechanisms or, in sepsis, attenuation of bacterially induced inflammation. In plants, its antibacterial functions involve the mitogen-activated protein kinase (MAPK) pathway; in animals, protection by melatonin against bacterially induced damage is associated with inhibition or activation of various signaling pathways, including key regulators such as NF-κB, STAT-1, Nrf2, NLRP3 inflammasome, MAPK and TLR-2/4. Moreover, melatonin can reduce formation of reactive oxygen and nitrogen species (ROS, RNS), promote detoxification and protect mitochondrial damage. Altogether, we propose that melatonin could be an effective approach against various pathogenic bacterial infections.

Melatonin alleviates sepsis-induced heart injury through activating the Nrf2 pathway and inhibiting the NLRP3 inflammasome

Melatonin improved the outcome of septic cardiomyopathy by inhibiting NLRP3 priming induced by reactive oxygen species. To get insights into these events, we studied the melatonin/Nrf2 antioxidant pathways during sepsis in the heart of NLRP3-deficient mice. Sepsis was induced by cecal ligation and puncture and melatonin was given at a dose of 30 mg/kg. Nuclear turnover of Nrf2 and p-Ser40 Nrf2 and expression of ho-1 were enhanced in nlrp3+/+ and nlrp3-/- mice during sepsis. Sepsis caused higher mitochondria impairment, apoptotic and autophagic events in nlrp3+/+ mice than in nlrp3-/- animals. These findings were accompanied by greater levels of Parkin and PINK-1, and lower Mfn2/Drp-1 ratio in nlrp3+/+ than in nlrp3-/- mice during sepsis, supporting less mitophagy in the latter. Ultrastructural analysis of myocardial tissue further confirmed these observations. The activation of NLRP3 inflammasome accounted for most of the deleterious effects of sepsis, whereas the Nrf2-dependent antioxidative response activation in response to sepsis was unable to neutralize these events. In turn, melatonin further enhanced the Nrf2 response in both mice strains and reduced the NLRP3 inflammasome activation in nlrp3+/+ mice, restoring myocardial homeostasis. The data support that the anti-inflammatory efficacy of melatonin against sepsis depends, at least in part, on Nrf2 activation.

Kolaviron ameliorates hepatic and renal dysfunction associated with multiwalled carbon nanotubes in rats

The increase in the exposure to carbon nanotubes (CNTs) and their incorporation into industrial, electronic, and biomedical products have required several scientific investigations into the toxicity associated with CNTs. Studies have shown that the metabolism and clearance of multiwalled CNTs (MWCNTs) from the body involve biotransformation in the liver and its excretion via the kidney. Since oxidative stress and inflammation underlines the toxicity of MWCNT, we investigated the ameliorative effect of kolaviron (KV), a natural antioxidant and anti-inflammatory agent, on hepatorenal damage in rats. Exposure to MWCNTs for 15 days significantly increased serum activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase thereby suggesting hepatic dysfunction. Kidney function, which was monitored by urea and creatinine levels, was also impaired by MWCNTs. Additionally, MWCNTs markedly increased myeloperoxidase activity, nitric oxide level, reactive oxygen and nitrogen species, and tumor necrosis factor level in both tissues. However, KV in a dose-dependent manner markedly attenuated MWCNT-induced markers of hepatorenal function in the serum and MWCNT-associated inflammation in the liver and kidney. Also, MWCNTs elicited significant inhibition of superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase activities. There was a significant diminution in glutathione level (GSH) and enhanced production of malondialdehyde (MDA) in MWCNTs-exposed rats. KV treatment was able to significantly increase the antioxidant enzymes and enhance the GSH level with a subsequent reduction in the MDA level. Taken together, KV elicited ameliorative effects against hepatorenal damage via its anti-inflammatory and antioxidant properties. Thus, KV could be an important intervention strategy for the hepatorenal damage associated with MWCNTs exposure.

Clinical trial to test the efficacy of melatonin in COVID-19

The pharmacological properties of melatonin are well known. However, there is noticeable the lack of clinical trials that confirm the efficacy, security, absence of side effects in the short and long term, and the effective doses of melatonin. This point is especially important in diseases with high morbidity and mortality including COVID-19. There is not treatment for COVID-19, and several anti-inflammatory and antiviral molecules are being tested, and different vaccines are in preparation. Although the SARS-CoV-2 pandemic is apparently improving, it is expected new resurges next fall. Thus, looking for an effective treatment of COVID-19 is mandatory. Melatonin has significant anti-inflammatory, antioxidant, and mitochondrial protective effects, and its efficacy has been demonstrated in multiple experimental models of disease and in a clinical trial in sepsis. Because COVID-19 courses with a severe septic response, multiple reviews proposing melatonin as a treatment for COVID-19 have been published. Nevertheless, there is a lack of experimental and clinical data on the use of melatonin on SARS-CoV-2 infection. Accordingly, we designed a clinical trial with an injectable formulation of melatonin for intravenous perfusion in ICU patients suffering from COVID-19 that has been just approved by the Spanish Agency of Medicines and Medical Devices (AEMPS). The trial will allow by the first time understand the doses and efficacy of melatonin against COVID-19.

The newly synthesized compounds (NCHDH and NTHDH) attenuates LPS-induced septicemia and multi-organ failure via Nrf2/HO1 and HSP/TRVP1 signaling in mice

The sepsis is considered as serious clinic-pathological condition related with high rate of morbidity and mortality in critical care settings. In the proposed study, the hydrazides derivatives N-(benzylidene)-2-((2-hydroxynaphthalen-1-yl)diazenyl)benzohydrazides (1-2) (NCHDH and NTHDH) were investigated against the LPS-induced sepsis in rodents. The NCHDH and NTHDH markedly improved the physiological sign and symptoms associated with the sepsis such as mortality, temperature, and clinical scoring compared to negative control group, which received only LPS (i.p.). The NCHDH and NTHDH also inhibited the production of the NO and MPO compared to the negative control. Furthermore, the treatment control improved the histological changes markedly of all the vital organs. Additionally, the Masson's trichrome and PAS (Periodic Acid Schiff) staining also showed improvement in the NCHDH and NTHDH treated group in contrast to LPS-induced group. The antioxidants were enhanced by the intervention of the NCHDH and NTHDH and the level of the MDA and POD were attenuated marginally compared to the LPS-induced group. The hematology study showed marked improvement and the reversal of the LPS-induced changes in blood composition compared to the negative control. The synthetic function of the liver and kidney were preserved in the NCHDH and NTHDH treated group compared to the LPS-induced group. The NCHDH and NTHDH markedly enhanced the Nrf2, HO-1 (Heme oxygenase-1), while attenuated the Keap1 and TRPV1 expression level as compared to LPS treated group. Furthermore, the NCHDH and NTHDH treatment showed marked increased in the mRNA expression level of the HSP70/90 proteins compared to the negative control.

Nigral and ventral tegmental area lesioning induces testicular and sperm morphological abnormalities in a rotenone model of Parkinson's disease

Although sexual health is affected by Parkinson's disease (PD), the effect on testicular health and/or sperm quality is not well discussed. After 21 days of rotenone lesioning, we observed dopaminergic neuronal degeneration in the substantia nigra and hypothalamus. There were minimal SPACA-1-expressing epididymal spermatozoa with morphological abnormalities, scanty luminal spermatozoa and reduced testicular spermatids and post-meiotic germ cells indicating hypospermatogenesis. Occludin-expressing sertoli cells were dispersed over a wide area indicating compromised blood-testes barrier. Activated caspase-3 expression was intense while immunoreactivity of spermatogenic-enhancing SRY and GADD45 g was weak. Although serum follicle stimulating hormone level was not affected, the lesion was associated with reduced serum testosterone level, testicular oxidative damage and inhibition of acetylcholinesterase activity, even when rotenone was not detected in the testes. Together, dopaminergic lesions may mediate testicular and sperm abnormalities via the brain-hypothalamic-testicular circuit independent of the pituitary, thereby establishing a causal link between Parkinsonism and reproductive dysfunction.

Lack of NLRP3 Inflammasome Activation Reduces Age-Dependent Sarcopenia and Mitochondrial Dysfunction, Favoring the Prophylactic Effect of Melatonin

To investigate the role of NLRP3 inflammasome in muscular aging, we evaluated here the morphological and functional markers of sarcopenia in the NLRP3-knockout mice, as well as the beneficial effect of melatonin supplementation. The gastrocnemius muscles of young (3 months), early-aged (12 months), and old-aged (24 months) NLRP3-knockout female mice were examined. Moreover, locomotor activity and apoptosis were assessed. The results revealed early markers of sarcopenia at the age of 12 months, including reduction of lactate, ratio of muscle weight to body weight, muscle fibers number, and mitochondrial number. Increased interstitial tissues, apoptosis, and muscle fibers area, as well as mitochondrial damage were detected, with little muscular activity effects. In the old-aged, these alterations progressed with a reduction in locomotor activity, mitochondrial cristae destruction, nuclear fragmentation, tubular aggregates (TAs) formation, and increased frailty index. Oral melatonin supplementation preserved the normal muscular structure, muscle fibers number, and muscular activity in old age. Melatonin enhanced lactate production, recovered mitochondria, inhibited TAs formation, reduced apoptosis, and normalized frailty index. The fewer sarcopenic changes as well as the highly detectable prophylactic effects of melatonin treatment reported here in the muscle of NLRP3-knockout mice comparing with that previously detected in wild-type mice, confirming NLRP3 inflammasome implication in muscular aging and sarcopenia onset and progression.

Efficacy of melatonin as an adjunct in the treatment of acute mania: a double-blind and placebo-controlled trial

This is a double-blind, placebo-controlled, parallel-grouped clinical trial, which was designed to investigate the potential effects of melatonin add-on treatment with lithium and risperidone on acute manic episodes in patients with bipolar disorder (BD). A total of 54 patients were included and randomly assigned into two groups of melatonin and placebo. The trial group received 3 mg/day risperidone, 900 mg/day lithium, and 6 mg/day melatonin. The placebo group received the same dose of risperidone and lithium plus placebo. The participants were evaluated at four sessions, consisting of baseline, weeks 1, 4, and 6. The manic symptoms and overall clinical improvement of the patients were assessed using the Young Mania Rating Scale (YMRS) and Clinical Global Impressions-Improvement (CGI-I), respectively. Two trial groups were matched based on all baseline characteristics. The patients in two trial groups had comparable serum lithium levels at weeks 1, 4, and 6. Our results from the general linear model repeated measures analysis showed a significant effect for time × treatment interaction on YMRS scores (P = 0.021 and F-value = 3.7). Furthermore, outcomes of the CGI-I rating scale demonstrated that patients in the melatonin group had better clinical improvements compared to the placebo group (P = 0.018). Our results provided preliminary evidence supporting melatonin as an effective adjunctive treatment leading to significant improvements in manic symptoms and overall clinical status in acute episodes of mania.

Melatonin prevents sepsis-induced renal injury via the PINK1/Parkin1 signaling pathway

Melatonin (N-acetyl-5-methoxytryptamine; MT) has been shown to have a protective effect against sepsis-induced renal injury, however, the mechanisms underlying the function of MT remain to be elucidated. Therefore, in the present study, the potential mechanisms underlying the preventive role of MT in sepsis-induced renal injury were investigated. Hematoxylin and eosin staining was used to detect the effect of MT on the reduction of renal tissue damage, and immunohistochemistry (IHC), ELISA and western blot analysis were performed to determine the influence of MT on the protein expression of PTEN-induced putative kinase 1 (PINK1), nucleotide-oligomerization binding domain and leucine-rich repeat pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC1), interleukin (IL)-18, IL-1β, IL-6 and cleaved caspase-1. Finally, a TUNEL assay was used to compare the rate of apoptosis of renal tissues among the sham, cecal ligation and puncture (CLP), and CLP + MT groups. The extent of tissue damage in the CLP group was the highest and the extent of tissue damage in the sham group was the lowest. The IHC and western blot analysis showed that the sham group had the highest protein level of PINK1, whereas the CLP group had the lowest protein level of PINK1. By contrast, the sham group had the lowest protein level of NLRP, whereas the CLP group had the highest level of NLRP3. Furthermore, CLP treatment enhanced the protein expression of ASC1 and cleaved caspase-1, whereas the administration of MT reduced the protein expression of ASC1 and cleaved caspase-1 to a certain degree. Finally, the apoptotic rate was found to be the highest in the CLP group and the lowest in the sham group. Taken together, in evaluating the therapeutic effect of MT on sepsis-induced renal injury, the results of the present study showed that MT alleviated sepsis-induced renal injury by regulating the expression of PINK1, Parkin1, NLRP3, ASC and cleaved caspase-1 in rats.

Antidepressant and Antiaging Effects of Açaí (Euterpe oleracea Mart.) in Mice

Depression is a mental disorder that affects 300 million people of all ages worldwide, but fewer than half of those with the condition receive adequate treatment. In addition, the high pharmacological refractoriness (affecting 30%-50% of patients) and toxicity of some classical antidepressants support the pursuit of new therapies. People with this condition show depressed mood, loss of pleasure, high levels of oxidative stress, and accelerated biological aging (decreased telomere length and expression of the telomerase reverse transcriptase (TERT), the enzyme responsible for telomere maintenance). Because of the close relationship between depression and oxidative stress, nutraceuticals with antioxidant properties are excellent candidates for therapy. This study represents the first investigation of the possible antidepressant and antiaging effects of commercial samples of clarified açaí (Euterpe oleracea) juice (EO). This fruit is rich in antioxidants and widely consumed. In this study, mice were treated with saline or EO (10 μL/g, oral) for 4 days and then with saline or lipopolysaccharide (0.5 mg/kg, i.p.) to induce depressive-like behavior. Only four doses of EO were enough to abolish the despair-like and anhedonia behaviors and alterations observed in electromyographic measurements. The antidepression effect of EO was similar to that of imipramine and associated with antioxidant and antiaging effects (preventing lipid peroxidation and increasing TERT mRNA expression, respectively) in three major brain regions involved in depression (hippocampus, striatum, and prefrontal cortex). Additionally, EO significantly protected hippocampal cells, preventing neuronal loss associated with the depressive-like state and nitrite level increases (an indirect marker of nitric oxide production). Moreover, EO alone significantly increased TERT mRNA expression, revealing for the first time a potent antiaging action in the brain that suggests neuroprotection against long-term age-related consequences.

Protective Effect of Melatonin Against Polymicrobial Sepsis Is Mediated by the Anti-bacterial Effect of Neutrophils

Sepsis is an infection- or toxin-mediated systemic inflammatory syndrome. Previous studies have shown that melatonin, the primary hormone produced by the pineal gland, attenuates the effect of polymicrobial infection-mediated septic shock in animals. However, the mechanism of the anti-septic effect of melatonin during polymicrobial infection has not been well-studied. In this study, we investigated how melatonin protects mice from polymicrobial sepsis. Melatonin treatment inhibited peripheral tissue inflammation and tissue damage in a cecal ligation puncture (CLP)-induced polymicrobial sepsis model, consequently reducing the mortality of the mice. We found that macrophages and neutrophils expressed melatonin receptors. Upon depletion of neutrophils, melatonin-induced protection against polymicrobial infection failed in the mice, but melatonin treatment in macrophage-depleted mice attenuated the mice mortality resulting from polymicrobial sepsis. Moreover, melatonin treatment promoted the development of the neutrophil extracellular trap (NET), which contributed to anti-bacterial activity during polymicrobial infection, whereas the phagocytic activities of neutrophils were inhibited by melatonin. The data from this study support previously unexplained antiseptic effects of melatonin during a polymicrobial infection and could be potentially useful for human patients with sepsis.

Neuroprotective role of kolaviron in striatal redo-inflammation associated with rotenone model of Parkinson's disease

Parkinson's disease is the most prevalent movement disorder. Currently, therapies are palliative with associated irreversible behavioural incompetence. Here, we investigated the ability of kolaviron (KV), an anti-inflammatory biflavonoid isolated form Garcinia kola seeds, to rescue striatal neuronal damage and redo-inflammation in rats exposed to rotenone (ROT). Aged rats exposed to 11 days of rotenone intoxication were treated with KV either concurrently or for 18 days. The 18-day regimen included 7 days of pre-treatment prior 11-day concurrent ROT-KV treatment. Rotenone-exposed rats lost weight appreciably and travelled less distance with reduced speed, decline efficiency to maintain a straight path, enhanced freezing, increased immobile episodes and poor hole recognition. The motor incompetence was attributed to enhanced striatal neurodegeneration, increased alpha synuclein formation and reduced tyrosine hydroxylase expression. ROT intoxication significantly increased reactive species production, which co-existed with induction of striatal antioxidant system and damage to biomolecules. ROT additionally upregulated COX-2 expression, enhanced myeloperoxidase activity and increased concentration of striatal inteleukine-6 (IL-6), IL-1β and tumour necrosis factor (TNF-α). Treatment with kolaviron reversed the rotenone-associated locomotor impairment and exploratory deficits, motor/neuromuscular incompetence, striatal neurodegeneration, neurobiochemical imbalance, altered antioxidant defence system and neuroinflammation. KV-treated rats showed improved capacity to maintain efficient gait with minimal rigidity and enhanced coordination. Taken together, kolaviron exhibited neuroprotective properties, which may be beneficial for the prevention and management of Parkinson's disease, via antioxidant, anti-inflammatory and anti-apoptotic mechanisms.

The ethanol leaf extract of Andrographis paniculata blunts acute renal failure in cisplatin-induced injury in rats through inhibition of Kim-1 and upregulation of Nrf2 pathway

Background Cisplatin (CP) is a novel drug of choice in the treatment of cancer but its major limitation is nephrotoxicity, which is dose limiting. Andrographis paniculata (AP) is a common Indian dietary component. It is well known for its medicinal properties. This present study investigated the nephroprotective effect of ethanol leaf extract of Andrographis paniculata (EEAP) on CP-induced nephrotoxicity. Methods CP was used to induce nephrotoxicity in male Wistar rats to study the effect of EEAP on renal damages using hematological parameters, biochemical parameters, histology, and immunohistochemistry studies. Results The effects of EEAP were determined by CP-induced changes in different kidney tissue on antioxidant enzymes, markers of oxidative stress, serum creatinine, and urine parameters. Administration of EEAP (200 mL/kg and 400 mg/kg orally), prior to and following a single dose CP treatment (10 mg/kg i.p), significantly mitigated the CP-induced decrease in antioxidant enzymes, and increase in markers of oxidative stress, serum creatinine, and urinary protein. On histopathological examination of the kidney tissue, there was severe glomerular degeneration and infiltration of inflammatory cells in CP only treated rats, mild glomerular degeneration, and infiltration of inflammatory cells in EEAP pre-treated rats. Furthermore, EEAP activated Nrf2 and mitigated Kim-1 pathways in CP-induced nephrotoxicity. Conclusions The results showed the protective effect of EEAP against CP-induced nephrotoxicity.

Ischemia-Reperfusion Injury in Aged Livers-The Energy Metabolism, Inflammatory Response, and Autophagy

Because of the lack of adequate organs, the number of patients with end-stage liver diseases, acute liver failure or hepatic malignancies waiting for liver transplantation is constantly increasing. Accepting aged liver grafts is one of the strategies expanding the donor pool to ease the discrepancy between the growing demand and the limited supply of donor organs. However, recipients of organs from old donors may show an increased posttransplantation morbidity and mortality due to enhanced ischemia-reperfusion injury. Energy metabolism, inflammatory response, and autophagy are 3 critical processes which are involved in the aging progress as well as in hepatic ischemia-reperfusion injury. Compared with young liver grafts, impairment of energy metabolism in aged liver grafts leads to lower adenosine triphosphate production and an enhanced generation of free radicals, both aggravating the inflammatory response. The aggravated inflammatory response determines the extent of hepatic ischemia-reperfusion injury and augments the liver damage. Autophagy protects cells by removal of damaged organelles, including dysfunctional mitochondria, a process impaired in aging and involved in ischemia-reperfusion-related apoptotic cell death. Furthermore, autophagic degradation of cellular compounds relieves intracellular adenosine triphosphate level for the energy depressed cells. Strategies targeting the mechanisms involved in energy metabolism, inflammatory response, and autophagy might be especially useful to prevent the increased risk for ischemia-reperfusion injury in aged livers after major hepatic surgery.

Melatonin and inflammation-Story of a double-edged blade

Melatonin is an immune modulator that displays both pro- and anti-inflammatory properties. Proinflammatory actions, which are well documented by many studies in isolated cells or leukocyte-derived cell lines, can be assumed to enhance the resistance against pathogens. However, they can be detrimental in autoimmune diseases. Anti-inflammatory actions are of particular medicinal interest, because they are observed in high-grade inflammation such as sepsis, ischemia/reperfusion, and brain injury, and also in low-grade inflammation during aging and in neurodegenerative diseases. The mechanisms contributing to anti-inflammatory effects are manifold and comprise various pathways of secondary signaling. These include numerous antioxidant effects, downregulation of inducible and inhibition of neuronal NO synthases, downregulation of cyclooxygenase-2, inhibition of high-mobility group box-1 signaling and toll-like receptor-4 activation, prevention of inflammasome NLRP3 activation, inhibition of NF-κB activation and upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2). These effects are also reflected by downregulation of proinflammatory and upregulation of anti-inflammatory cytokines. Proinflammatory actions of amyloid-β peptides are reduced by enhancing α-secretase and inhibition of β- and γ-secretases. A particular role in melatonin's actions seems to be associated with the upregulation of sirtuin-1 (SIRT1), which shares various effects known from melatonin and additionally interferes with the signaling by the mechanistic target of rapamycin (mTOR) and Notch, and reduces the expression of the proinflammatory lncRNA-CCL2. The conclusion on a partial mediation by SIRT1 is supported by repeatedly observed inhibitions of melatonin effects by sirtuin inhibitors or knockdown.

The role of melatonin, a multitasking molecule, in retarding the processes of ageing

Biological ageing is generally accompanied by a gradual loss of cellular functions and physiological integrity of organ systems, the consequential enhancement of vulnerability, senescence and finally death. Mechanisms which underlie ageing are primarily attributed to an array of diverse but related factors including free radical-induced damage, dysfunction of mitochondria, disruption of circadian rhythms, inflammaging, genomic instability, telomere attrition, loss of proteostasis, deregulated sensing of nutrients, epigenetic alterations, altered intercellular communication, and decreased capacity for tissue repair. Melatonin, a prime regulator of human chronobiological and endocrine physiology, is highly reputed as an antioxidant, immunomodulatory, antiproliferative, oncostatic, and endocrine-modulatory molecule. Interestingly, several recent reports support melatonin as an anti-ageing agent whose multifaceted functions may lessen the consequences of ageing. This review depicts four categories of melatonin's protective effects on ageing-induced molecular and structural alterations. We also summarize recent findings related to the function of melatonin during ageing in various tissues and organs.

Short- and Long-Term Protective Effects of Melatonin in a Mouse Model of Sepsis-Associated Encephalopathy

Brain dysfunction is a common complication after sepsis and is an independent risk factor for a poor prognosis, which is partly attributed to the dysregulated inflammatory response and oxidative damage. Melatonin regulates the sleep-wake cycle and also has potent anti-inflammatory and antioxidant properties, yet the protective effects of melatonin on sepsis-induced neurobehavioral dysfunction remain to be elucidated. In the present study, melatonin was administered intraperitoneally daily at a dose of 10 mg/kg for three consecutive days immediately (early treatment) or 7 days (delayed treatment) after sham operation or cecal ligation and puncture (CLP), followed by an additional treatment in drinking water until the end of behavioral tests. The concentrations of pro-inflammatory cytokines (tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL-6, IL-10), malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) were determined at the indicated time points. Compared with the CLP + vehicle group, we found that early melatonin treatment resulted in increased survival rate but not improvement in measures of neurobehavioral outcomes, which was accompanied by significantly lower plasma level of IL-1β. Intriguingly, delayed melatonin treatment improved neurobehavioral dysfunction by normalization of hippocampal BDNF and GDNF expressions. In conclusion, our study suggests the beneficial effects of both early and delayed melatonin treatment after sepsis development, which implicates melatonin has a potential therapeutic value in sepsis-associated organ damage including brain dysfunction.

A Novel Role of a Chemotherapeutic Agent in a Rat Model of Endotoxemia: Modulation of the STAT-3 Signaling Pathway

Sepsis caused by lipopolysaccharide (LPS) is a life-threatening disease accompanied by multiple organ failure. This study investigated the curative effects of imatinib (IMA) against hepatic, renal, and pulmonary responses caused by a single administration of LPS (10 mg/kg, i.p.) in rats. Treatment with IMA (15 mg/kg, i.p.) 30 min after LPS antagonized the LPS-induced boost of liver enzymes (ALT, AST), kidney functions (BUN, sCr) as well as the elevated pulmonary vascular permeability and edema. IMA declined tissue contents of NF-κB, STAT-3, P38-MAPK, TNF-α, IL-1β, and iNOS. It also amplified the anti-inflammatory cytokine IL-10 as well as the Bcl-2/Bax ratio, a cardinal indicator of the anti-apoptotic effect. Meanwhile, the rats exhibited marked reduction of the broncho-alveolar lavage fluid (BALF) contents of TNF-α, IL-1β, IFN-γ, and neutrophil count; however, they revealed prominent augmentation of the BALF content IL-10. In conclusion, these findings suggest that IMA is endowed with anti-inflammatory, anti-oxidant, and anti-apoptotic properties and hence may provide a novel agent for the management of sepsis.

Ameliorative effect of Azadirachta indica on sodium fluoride-induced hypertension through improvement of antioxidant defence system and upregulation of extracellular signal regulated kinase 1/2 signaling

BACKGROUND

Toxicities due to fluoride exposure from natural and industrial sources occur commonly in man and animals with severe consequences ranging from mild cardiac derangements to sudden death. In this study, we investigated the protective effects of the methanol extract of Azadirachta indica (AI) against sodium fluoride (NaF)-induced hypertension and genotoxicity in rats.

METHODS

Sixty rats were divided into six groups of ten rats each as follows: Group A, the control group received distilled water; Group B rats were administered NaF at 600 ppm in drinking water; Groups C and D rats were pre-treated with the methanol extract of AI and thereafter administered NaF at 600 ppm in drinking water for 7 consecutive days; Groups E and F rats were co-administered with AI and NaF.

RESULTS

The administration of NaF caused significant (p<0.05) increases in the blood pressure, markers of oxidative stress, serum myeloperoxidase, xanthine oxidase values in NaF-alone treated rats, compared with the control. Significant (p<0.05) decreases were observed in cardiac and renal antioxidant defence system in rats administered NaF alone compared with the control group. NaF treatment also resulted in a reduction in the expressions of extracellular signal-regulated kinase (ERK) 1/2 in cardiac and renal tissues of NaF-treated rats. Moreover, NaF treatment elicited an increase in the frequency of micronucleated polychromatic erythrocytes when compared with the control group.

CONCLUSIONS

This study shows the protective effect of AI on NaF-induced hypertension and genotoxicity through antioxidant and ERK 1/2 signaling in rats.

Responses of Transgenic Melatonin-Enriched Goats on LPS Stimulation and the Proteogenomic Profiles of Their PBMCs

The anti-inflammatory activity of melatonin (MT) has been well documented; however, little is known regarding endogenously occurring MT in this respect, especially for large animals. In the current study, we created a MT-enriched animal model (goats) overexpressing the MT synthetase gene Aanat. The responses of these animals to lipopolysaccharide (LPS) stimulation were systematically studied. It was found that LPS treatment exacerbated the inflammatory response in wild-type (WT) goats and increased their temperature to 40 °C. In addition, their granulocyte counts were also significantly elevated. In contrast, these symptoms were not observed in transgenic goats with LPS treatment. The rescue study with MT injection into WT goats who were treated with LPS confirmed that the protective effects in transgenic goats against LPS were attributed to a high level of endogenously produced MT. The proteomic analysis in the peripheral blood mononuclear cells (PBMCs) isolated from the transgenic animals uncovered several potential mechanisms. MT suppressed the lysosome formation as well as its function by downregulation of the lysosome-associated genes Lysosome-associated membrane protein 2 (LAMP2), Insulin-like growth factor 2 receptor (IGF2R), and Arylsulfatase B (ARSB). A high level of MT enhanced the antioxidant capacity of these cells to reduce the cell apoptosis induced by the LPS. In addition, the results also uncovered previously unknown information that showed that MT may have protective effects on some human diseases, including tuberculosis, bladder cancer, and rheumatoid arthritis, by downregulation of these disease-associated genes. All these observations warranted further investigations.

Melatonin and cardioprotection against ischaemia/reperfusion injury: What's new? A review

Melatonin is a pleiotropic hormone with several functions. It binds to specific receptors and to a number of cytosolic proteins, activating a vast array of signalling pathways. Its potential to protect the heart against ischaemia/reperfusion damage has attracted much attention, particularly in view of its possible clinical applications. This review will focus mainly on the possible signalling pathways involved in melatonin-induced cardioprotection. In particular, the role of the melatonin receptors and events downstream of receptor activation, for example, the reperfusion injury salvage kinase (RISK), survivor activating factor enhancement (SAFE) and Notch pathways, the sirtuins, nuclear factor E2-related factor 2 (Nrf2) and translocases in the outer membrane (TOM70) will be discussed. Particular attention is given to the role of the mitochondrion in melatonin-induced cardioprotection. In addition, a brief overview will be given regarding the status quo of the clinical application of melatonin in humans.

Intranasal melatonin nanoniosomes: pharmacokinetic, pharmacodynamics and toxicity studies

AIM

Intranasal melatonin encapsulated in nanosized niosomes was preclinically evaluated.

METHODOLOGY

A formula of melatonin niosomes (MN) was selected through physicochemical and cytotoxic data for pharmacokinetic, pharmacodynamics and toxicity studies in male Wistar rats.

RESULTS

Intranasal MN was bioequivalent to intravenous injection of melatonin, providing therapeutic level doses. Acute and subchronic toxicity screening showed no abnormal signs, symptoms or hematological effects in any animals. Transient nasal irritations with no inflammation were observed with intranasal MN, leading it to be categorized as relatively harmless.

CONCLUSION

The intranasal MN could deliver melatonin to the brain to induce sleep and provide delayed systemic circulation, relative to intravenous injection and also distribute to peripheral tissue.

Melatonin levels in human diabetic dental pulp tissue and its effects on dental pulp cells under hyperglycaemic conditions

AIM

To investigate melatonin (MEL) levels in human dental pulp tissue (hDP) in type 2 diabetic (T2D) participants and the underlying molecular mechanisms of its effects in human dental pulp cells (hDPCs) under hyperglycaemia.

METHODOLOGY

The study included 16 healthy and 16 T2D participants who underwent vital pulp extirpation for hDP and four healthy participants undergoing third molar extraction for hDPCs analyses. MTT and NRU were used as tests for cytotoxicity. The pulp tissue levels of MEL, inducible NO synthase (iNOS) and superoxide dismutase (SOD) activity, as well as iNOS, histone acetyltransferase p300 (p300) and SOD activity levels in hDPCs incubated with MEL (0.1 and 1.0 mmol L^-1 ) under normoglycaemia and hyperglycaemia were measured by enzyme-linked immunosorbent assay. Comparisons between the two groups were made by unpaired t-tests or Mann-Whitney test whilst the chi-square test was used for dichotomous variables. To compare more groups, the Kruskal-Wallis test with Dunn's multiple comparison was used, whilst Spearman correlation was used to assess association between two variables.

RESULTS

Melatonin was decreased (124.30 ± 21.6 vs. 240.0 ± 19.1 pg mL^-1 , P < 0.01), whilst iNOS levels increased (0.92 ± 0.08 vs. 0.32 ± 0.09 ng mL^-1 , P < 0.01) in hDP from T2D compared to nondiabetic participants. In hDPCs, MEL (0.1 and 1.0 mmol L^-1 ) had no cytotoxicity. Incubation with 1.0 mmol L^-1 of MEL (24 h) decreased hyperglycaemia-induced increases of iNOS (0.34 ± 0.01 ng mL^-1 vs. 0.40 ± 0.01 ng mL^-1 , P < 0.01) and p300 (11.59 ± 0.58 ng mL^-1 vs. 16.12 ± 0.39 ng mL^-1 , P < 0.01), and also, increased SOD activity (87.11 ± 3.10% vs. 68.56 ± 3.77%, P < 0.01) to the levels comparable to the normoglycaemic; iNOS and p300 protein expression levels showed strong positive correlation under hyperglycaemia (Spearman r = 0.8242, P < 0.001).

CONCLUSION

Type 2 diabetic participants had decreased MEL in hDP. At pharmacological concentrations, MEL is not cytotoxic for hDPCs and normalizes iNOS and SOD activity levels in hyperglyceamic hDPCs suggesting its antioxidant and protective effects in human dental pulp tissue under hyperglycaemia.

Ameliorative effect of gallic acid on doxorubicin-induced cardiac dysfunction in rats

BACKGROUND

The use of doxorubicin (DOX) as an antineoplastic agent has been greatly limited because of the myriad of toxic sequelae associated with it. The aim of this study was to assess the protective effects of gallic acid (GA) on DOX-induced cardiac toxicity in rats.

METHODS

Sixty male rats (Wistar strain) were used in this study. They were divided into six groups (A-F) each containing 10 animals. Group A was the control. Rats in Groups B, C, and D were treated with DOX at the dosage of 15 mg/kg body weight i.p. Prior to this treatment, rats in Groups C and D had been treated orally with GA for 7 days at the dosage of 60 and 120 mg/kg, respectively. Animals from Groups E and F received only 60 and 120 mg/kg GA, respectively, which were administered orally for 7 days.

RESULTS

The exposure of rats to DOX led to a significant (p<0.05) decrease in the cardiac antioxidant defence system and elevation of creatine kinase myocardial band and lactate dehydrogenase. The electrocardiography results showed a significant decrease in heart rate, QRS, and QT-segment prolongation. GA alone improved the antioxidant defence system.

CONCLUSIONS

The GA pretreatment significantly alleviated GA-associated ECG abnormalities, restored the antioxidant status and prevented cardiac damage.

Postnatal melatonin treatment protects against affective disorders induced by early-life immune stimulation by reducing the microglia cell activation and oxidative stress

BACKGROUND

Systemic inflammation induced by neonatal infection may result as long-term hyper-activation of microglial cells followed by an overproduction of pro-inflammatory cytokines, such as tumor necrosis factor-alpha, nitric oxide and lipid peroxidation. Those inflammation mediators can trigger behavioral disruption and/or cognitive disorders.

OBJECTIVE

The present work aims to evaluate the effect of melatonin (a cytokine release modulator and antioxidant agent) in the reduction of the prefrontal microglia activation and depressive-like behaviors induced by lipopolysaccharide (LPS) injection in adult rats.

RESULTS

The effect of melatonin (5 mg/kg) was compared to minocycline (50 mg/kg), a well-known anti-inflammatory drug with potent inhibitory effect on microglial activation. Our results showed that LPS injection induced a significant increase in prefrontal cortex tumor necrosis factor-alpha and nitric oxide levels. Furthermore, lipid peroxidation and microglial activation were highly increased in the prefrontal cortex compared to control. The melatonin treatment induced a significant decrease on nitric oxide and lipid peroxidation levels in the prefrontal cortex and significant decrease on tumor necrosis factor-alpha and microglia activation. Melatonin can also induce a significant reduction in the anxiety and depression-like effect induced by PND9 LPS administration.

CONCLUSION

Our results demonstrated that melatonin possesses potent protective effect against the depression and anxiety induced by LPS. The underlying effect of melatonin is probably due to the reduction of nitric oxide toxic effect and lipid peroxidation in addition to its anti-inflammatory effect.

Maternal administration of melatonin exerts short- and long-term neuroprotective effects on the offspring from lipopolysaccharide-treated mice

Preterm birth is a major contributor to early and delayed physical and cognitive impairment. Epidemiological and experimental data indicate that maternal infections are a significant and preventable cause of preterm birth. Recently, melatonin has been suggested to exert neuroprotective effects in several models of brain injury. Here, we sought to investigate whether the administration of melatonin is able to prevent lipopolysaccharide (LPS)-induced fetal brain damage in a model of LPS-induced preterm labor. For this purpose, 15-day pregnant BALB/c mice received intraperitoneally 2 doses of LPS or vehicle: the first one at 10:00 hours (0.26 mg/kg) and the second at 13:00 hours (0.52 mg/kg). On day 14 of pregnancy, a group of mice was subcutaneously implanted with a pellet of 25 mg melatonin. This experimental protocol resulted in 100% of preterm birth and pup death in the LPS group and a 50% of term birth and pup survival in the melatonin + LPS group. In the absence of melatonin, fetuses from LPS-treated mothers showed histological signs of brain damage, microglial/macrophage activation, and higher levels of IL-1β, inducible nitric oxide synthase (NOS), and neuronal NOS mRNAs as well as increased histone acetyltransferase activity and histone H3 hyperacetylation. In contrast, antenatal administration of melatonin prevented LPS-induced fetal brain damage. Moreover, when behavioral traits were analyzed in the offspring from control, melatonin, and melatonin + LPS, no significant differences were found, suggesting that melatonin prevented LPS-induced long-term neurodevelopmental impairments. Collectively, our results suggest that melatonin could be a new therapeutic tool to prevent fetal brain damage and its long-term consequences induced by maternal inflammation.

Melatonin, clock genes and mitochondria in sepsis

After the characterization of the central pacemaker in the suprachiasmatic nucleus, the expression of clock genes was identified in several peripheral tissues including the immune system. The hierarchical control from the central clock to peripheral clocks extends to other functions including endocrine, metabolic, immune, and mitochondrial responses. Increasing evidence links the disruption of the clock genes expression with multiple diseases and aging. Chronodisruption is associated with alterations of the immune system, immunosenescence, impairment of energy metabolism, and reduction of pineal and extrapineal melatonin production. Regarding sepsis, a condition coursing with an exaggerated response of innate immunity, experimental and clinical data showed an alteration of circadian rhythms that reflects the loss of the normal oscillation of the clock. Moreover, recent data point to that some mediators of the immune system affects the normal function of the clock. Under specific conditions, this control disappears reactivating the immune response. So, it seems that clock gene disruption favors the innate immune response, which in turn induces the expression of proinflammatory mediators, causing a further alteration of the clock. Here, the clock control of the mitochondrial function turns off, leading to a bioenergetic decay and formation of reactive oxygen species that, in turn, activate the inflammasome. This arm of the innate immunity is responsible for the huge increase of interleukin-1β and entrance into a vicious cycle that could lead to the death of the patient. The broken clock is recovered by melatonin administration, that is accompanied by the normalization of the innate immunity and mitochondrial homeostasis. Thus, this review emphasizes the connection between clock genes, innate immunity and mitochondria in health and sepsis, and the role of melatonin to maintain clock homeostasis.

Melatonin Treatment Reduces Oxidative Damage and Normalizes Plasma Pro-Inflammatory Cytokines in Patients Suffering from Charcot-Marie-Tooth Neuropathy: A Pilot Study in Three Children

Charcot-Marie-Tooth neuropathy (CMT) is a motor and sensory neuropathy comprising a heterogeneous group of inherited diseases. The CMT1A phenotype is predominant in the 70% of CMT patients, with nerve conduction velocity reduction and hypertrophic demyelination. These patients have elevated oxidative stress and chronic inflammation. Currently, there is no effective cure for CMT; herein, we investigated whether melatonin treatment may reduce the inflammatory and oxidative damage in CMT1A patients. Three patients, aged 8–10 years, were treated with melatonin (60 mg at 21:00 h plus 10 mg at 09:00 h), and plasma levels of lipid peroxidation (LPO), nitrites (NOx), IL-1β, IL-2, IL-6, TNF-α, INF-γ, oxidized to reduced glutathione (GSSG/GSH) ratio, and the activities of superoxide dismutase (SOD), glutathione-S transferase (GST), glutathione peroxidase (GPx), and reductase (GRd), were determined in erythrocytes at 3 and 6 months of treatment. Healthy age- and sex-matched subjects were used as controls. The results showed increased activities of SOD, GST, GPx, and GRd in CMT1A patients, which were reduced at 3 and 6 months of treatment. The GSSG/GSH ratio significantly increased in the patients, returning to control values after melatonin treatment. The inflammatory process was confirmed by the elevation of all proinflammatory cytokines measured, which were also normalized by melatonin. LPO and NOx, which also were elevated in the patients, were normalized by melatonin. The results document beneficial effects of the use of melatonin in CMT1A patients to reduce the hyperoxidative and inflammatory condition, which may correlate with a reduction of the degenerative process.

The effect of melatonin on gene expression of calcitonin gene-related peptide and some proinflammatory mediators in patients with pure menstrual migraine

The neuropeptide calcitonin gene-related peptide (CGRP), a potent vasoactive and a marker of trigeminal inflammation, has been considered as an important mediator in various types of migraine such as pure menstrual migraine. Earlier studies have shown that CGRP can modulate the synthesis and release of other inflammatory factor including nitric oxide (NO) and interleukin-1beta (IL-1β) from trigeminal ganglion glial cells. Exogenous melatonin protects the tissues from inflammatory damages. The goal of this study was to determine the anti-inflammatory effects of melatonin on the CGRP expression, inducible nitric oxide synthase (iNOS) activity, NO, and IL-1β release in cultured peripheral blood mononuclear cells (PBMCs) from pure menstrual migraine patients and healthy subjects. This study was performed on 12 pure menstrual migraine patients and 12 age-and sex-matched healthy subjects. PBMCs were isolated and treated with melatonin for 12 h at pharmacological dose. Gene expression was evaluated by real-time PCR. CGRP and IL-1β proteins in culture supernatant were determined by ELISA method. iNOS activity in PBMCs was determined by colorimetric assays. Total nitrite as an indicator of NO concentrations in the culture supernatants was measured using Griess method. We found that melatonin treatment significantly decreases mRNA expression of CGRP release, NO production, and iNOS activity in the patient groups. Taken together, it appears that melatonin reduces inflammation through decreasing CGRP level and iNOS activity in the patients with migraine; however, further studies are needed in this regard.