Melatonin delivery in solid lipid nanoparticles: prevention of cyclosporine A induced cardiac damage

Melatonin and the nervous system: nanomedicine perspectives

The mechanism of action of melatonin on the nervous system, sleep, cognitive deficits, and aging is not fully understood. Neurodegenerative diseases (ND) are one of the leading causes of disability and mortality worldwide. Sleeping and cognitive impairments also represent common and serious public health problems, particularly deteriorating with the aging process. Melatonin, as a neuromodulatory hormone, regulates circadian rhythms and the sleep-wake cycle, with functions extending to antioxidant, anti-inflammatory, neuroprotective, and anti-aging properties. However, melatonin is a hydrophobic compound with relatively low water solubility and a short half-life. While melatonin can cross the blood-brain barrier, exogenous melatonin administered orally or intravenously has poor bioavailability, undergoes rapid metabolism in the circulation, and shows limited brain accumulation, ultimately compromising its therapeutic efficacy. In recent years, the convergence of melatonin research with nanomedicine ensures safe therapeutic uses, limited drug degradation, and perspectives for targeted drug delivery to the central nervous system. Here we outline the promising neurotherapeutic properties of nanomaterials as carriers loaded with melatonin drug alone or in combinations with other active molecules.

Cardiovascular toxicities by calcineurin inhibitors: Cellular mechanisms behind clinical manifestations

Calcineurin inhibitors (CNI), including cyclosporine A (CsA) and tacrolimus (TAC), are cornerstones of immunosuppressive therapy in solid organ transplant recipients. While extensively recognized for their capacity to induce nephrotoxicity, hypertension, and dyslipidemia, emerging reports suggest potential direct cardiovascular toxicities associated with CNI. Evidence from both in vitro and in vivo studies has demonstrated direct cardiotoxic impact of CNI, manifesting itself as induction of cardiomyocyte apoptosis, enhanced oxidative stress, inflammatory cell infiltration, and cardiac fibrosis. CNI enhances cellular apoptosis through CaSR via activation of the p38 MAPK pathway and deactivation of the ERK pathway, and enhancement of miR-377 axis. Although CNI could attenuate cardiac hypertrophy in certain animal models, CNI concurrently impaired systolic function, enhanced cardiac fibrosis, and increased the risk of heart failure. Evidence from in vivo studies demonstrated that CNI prolong the duration of action potentials through a decrease in potassium current. CNI also exerted direct effects on endothelial cell injury, inducing apoptosis and enhancing oxidative stress. CNI may induce vascular inflammation through TLR4 via MyD88 and TRIF pathways. In addition, CNI affects vascular function by impairing endothelial-dependent vasodilation and promoting vasoconstriction. Clinical studies in transplant patients also revealed an increased incidence of cardiac remodeling. However, the evidence is constrained by the limited number of participants and potential confounding factors. Several studies indicate differing cardiovascular toxicity profiles between CsA and TAC, and these could be potentially due to their different interactions with calcineurin subunits and calcineurin-independent effects. Further studies are needed to clarify these mechanisms to improve cardiovascular outcomes for transplant patients with CNI.

Moderate exercise mitigates cardiac dysfunction and injury induced by cyclosporine A through activation of the PGI2 / PPAR-γ signaling pathway

Background and purpose

The present study investigated the role of the prostaglandin I2/peroxisome proliferator activator receptor (PGI2/PPAR) signaling pathway in cardiac cell proliferation, apoptosis, and systemic hemodynamic variables under cyclosporine A (CsA) exposure alone or combined with moderate exercises.

Experimental approach

Twenty-four male Wistar rats were classified into three groups, namely, control, CsA, and CsA + exercise.

Findings/Results

After 42 days of treatment, the findings showed a significant enhancement in the expression of the β-MHC gene, enhancement in protein expression of Bax and caspase-3, and a significant decline in the protein expression of Bcl-2 expression, as well as increased proliferation intensity in the heart tissue of the CsA group compared to the control group. Systolic pressure, pulse pressure, mean arterial pressure (MAP), QT and QRS duration, and T wave amplitude, as well as QTc amount in the CsA group, showed a significant increase compared to the control group. PPAR-γ and PGI2 showed no significant changes compared to the control group. Moderate exercise along with CsA significantly enhanced the protein expression of PPAR-γ and PGI2 and declined protein expression of Bax, and caspase-3 compared to those in the CsA group. In the CsA + exercise group, systolic pressure, MAP, and Twave showed a significant decrease compared to the CsA group. Moderate exercises along CsA improved heart cell proliferation intensity and significantly reduced β- MHC gene expression compared to the CsA group.

Conclusions and implications

The results showed moderate exercise alleviated CsA-induced heart tissue apoptosis and proliferation with the corresponding activation of the PGI2/PPAR-γ pathway.

Lipid Nanoparticles: An Effective Tool to Improve the Bioavailability of Nutraceuticals

Nano-range bioactive colloidal carrier systems are envisaged to overcome the challenges associated with treatments of numerous diseases. Lipid nanoparticles (LNPs), one of the extensively investigated drug delivery systems, not only improve pharmacokinetic parameters, transportation, and chemical stability of encapsulated compounds but also provide efficient targeting and reduce the risk of toxicity. Over the last decades, nature-derived polyphenols, vitamins, antioxidants, dietary supplements, and herbs have received more attention due to their remarkable biological and pharmacological health and medical benefits. However, their poor aqueous solubility, compromised stability, insufficient absorption, and accelerated elimination impede research in the nutraceutical sector. Owing to the possibilities offered by various LNPs, their ability to accommodate both hydrophilic and hydrophobic molecules and the availability of various preparation methods suitable for sensitive molecules, loading natural fragile molecules into LNPs offers a promising solution. The primary objective of this work is to explore the synergy between nature and nanotechnology, encompassing a wide range of research aimed at encapsulating natural therapeutic molecules within LNPs.

Cyclosporine A induces cardiac remodeling through TGF-β/Smad3/miR-29 signaling pathway and alters gene expression of miR-30b-5p/CaMKIIδ isoforms pathways: alleviating effects of moderate exercise

BACKGROUND

Cyclosporine A (CsA)-induced cardiac interstitial fibrosis and cardiac hypertrophy are highly known phenomena; however, the basic mechanisms of CsA cardiotoxicity are unclear. The present study evaluated the role of the Transforming growth factor-beta (TGF-β)/Smad3/miR-29b signaling pathway and CaMKIIδ isoforms gene expression in cardiac remodeling under CsA exposure alone or combined with moderate exercise.

METHODS

A total of 24 male Wistar rats were divided into control, cyclosporine (30 mg/kg BW), and cyclosporine-exercise groups.

RESULTS

After 42 days of treatment, the findings revealed a significant decline in miR-29 and miR-30b-5p gene expression and an increase in gene expression of Smad3, calcium/calmodulin-dependent protein kinaseIIδ (CaMKIIδ) isoforms, Matrix Metalloproteinases (MMPs), protein expression of TGF-β, heart tissue protein carbonyl and oxidized LDL (Ox-LDL), and plasma LDL and cholesterol levels in the CsA-treated group compared to the control group. The CsA group presented greater histological heart changes such as fibrosis, necrosis, hemorrhage, infiltrated leukocyte, and left ventricular weight/heart weight than the control group. Moreover, combined moderate exercise and CsA relatively improved gene expression changes and histological alternations compared to the CsA group.

CONCLUSION

TGF-β-Smad3-miR-29 and CaMKIIδ isoforms may mainly contribute to the progression of heart fibrosis and hypertrophy due to CsA exposure, providing new insight into the pathogenesis and treatment of CsA-induced side effects on the heart tissue.

Cardiac-targeted delivery of nuclear receptor RORα via ultrasound targeted microbubble destruction optimizes the benefits of regular dose of melatonin on sepsis-induced cardiomyopathy

BACKGROUND

Large-dose melatonin treatment in animal experiments was hardly translated into humans, which may explain the dilemma that the protective effects against myocardial injury in animal have been challenged by clinical trials. Ultrasound-targeted microbubble destruction (UTMD) has been considered a promising drug and gene delivery system to the target tissue. We aim to investigate whether cardiac gene delivery of melatonin receptor mediated by UTMD technology optimizes the efficacy of clinically equivalent dose of melatonin in sepsis-induced cardiomyopathy.

METHODS

Melatonin and cardiac melatonin receptors in patients and rat models with lipopolysaccharide (LPS)- or cecal ligation and puncture (CLP)-induced sepsis were assessed. Rats received UTMD-mediated cardiac delivery of RORα/cationic microbubbles (CMBs) at 1, 3 and 5 days before CLP surgery. Echocardiography, histopathology and oxylipin metabolomics were assessed at 16-20 h after inducing fatal sepsis.

RESULTS

We observed that patients with sepsis have lower serum melatonin than healthy controls, which was observed in the blood and hearts of Sprague-Dawley rat models with LPS- or CLP-induced sepsis. Notably, a mild dose (2.5 mg/kg) of intravenous melatonin did not substantially improve septic cardiomyopathy. We found decreased nuclear receptors RORα, not melatonin receptors MT1/2, under lethal sepsis that may weaken the potential benefits of a mild dose of melatonin treatment. In vivo, repeated UTMD-mediated cardiac delivery of RORα/CMBs exhibited favorable biosafety, efficiency and specificity, significantly strengthening the effects of a safe dose of melatonin on heart dysfunction and myocardial injury in septic rats. The cardiac delivery of RORα by UTMD technology and melatonin treatment improved mitochondrial dysfunction and oxylipin profiles, although there was no significant influence on systemic inflammation.

CONCLUSIONS

These findings provide new insights to explain the suboptimal effect of melatonin use in clinic and potential solutions to overcome the challenges. UTMD technology may be a promisingly interdisciplinary pattern against sepsis-induced cardiomyopathy.

Nanotechnology-based advances in the efficient delivery of melatonin

N-[2-(5-methoxy-1H-indol-3-yl) ethyl] or simply melatonin is a biogenic amine produced by pineal gland and recently recognized various other organs. Because of a broad range of biological function melatonin is considered as a therapeutic agent with high efficacy in the treatment of multiple disorders, such as cancer, degenerative disorders and immune disease. However, since melatonin can affect receptors on the cellular membrane, in the nucleus and can act as an anti-oxidant molecule, some unwanted effects may be observed after administration. Therefore, the entrapment of melatonin in biocompatible, biodegradable and safe nano-delivery systems can prevent its degradation in circulation; decrease its toxicity with increased half-life, enhanced pharmacokinetic profile leading to improved patient compliance. Because of this, nanoparticles have been used to deliver melatonin in multiple studies, and the present article aims to cumulatively illustrate their findings.

Melatonin-Loaded Nanocarriers: New Horizons for Therapeutic Applications

The use of nanosized particles has emerged to facilitate selective applications in medicine. Drug-delivery systems represent novel opportunities to provide stricter, focused, and fine-tuned therapy, enhancing the therapeutic efficacy of chemical agents at the molecular level while reducing their toxic effects. Melatonin (N-acetyl-5-methoxytriptamine) is a small indoleamine secreted essentially by the pineal gland during darkness, but also produced by most cells in a non-circadian manner from which it is not released into the blood. Although the therapeutic promise of melatonin is indisputable, aspects regarding optimal dosage, biotransformation and metabolism, route and time of administration, and targeted therapy remain to be examined for proper treatment results. Recently, prolonged release of melatonin has shown greater efficacy and safety when combined with a nanostructured formulation. This review summarizes the role of melatonin incorporated into different nanocarriers (e.g., lipid-based vesicles, polymeric vesicles, non-ionic surfactant-based vesicles, charge carriers in graphene, electro spun nanofibers, silica-based carriers, metallic and non-metallic nanocomposites) as drug delivery system platforms or multilevel determinations in various in vivo and in vitro experimental conditions. Melatonin incorporated into nanosized materials exhibits superior effectiveness in multiple diseases and pathological processes than does free melatonin; thus, such information has functional significance for clinical intervention.

Potential role of circular RNA in cyclosporin A-induced cardiotoxicity in rats

Cyclosporin A (CsA) is a well-known and effective drug that is commonly used in autoimmune diseases and allotransplantation. However, kidney toxicity and cardiotoxicity limit its use. Circular RNAs (circRNAs) play a crucial role in disease, especially cardiovascular disease. We aimed to explore the circRNA expression profiles and potential mechanisms during CsA-induced cardiotoxicity. Sixty male adult Wistar rats were randomly divided into two groups. The CsA group was injected with CsA (15 mg/kg/day body weight) intraperitoneally (ip) for 2 weeks, whereas the control group was injected ip with the same volume of olive oil. We assessed CsA-induced cardiotoxicity by light microscopy, transferase-mediated dUTP nick-end labeling (TUNEL) staining, and electron microscopy. Microarray analysis was used to detect the expression profiles of circRNAs deregulated in the heart during CsA-induced cardiotoxicity. We confirmed the changes in circRNAs by quantitative PCR. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of the microarray data were performed. A conventional dose of CsA induced cardiotoxicity in rats. We identified 67 upregulated and 37 downregulated circRNAs compared with those in the control group. Six of 12 circRNAs were successfully verified by quantitative real-time polymerase chain reaction (qRT-PCR). GO analyses of the differentially expressed circRNAs indicated that these molecules might play important roles in CsA-induced cardiotoxicity. KEGG pathway analyses showed that the differentially expressed circRNAs in CsA-induced cardiotoxicity may be related to autophagy or the Hippo signaling pathway. We identified differential circRNA expression patterns and provided more insight into the mechanism of CsA-induced cardiotoxicity. CircRNAs may serve as potential biomarkers or therapeutic targets of CsA-mediated cardiotoxicity in the future.

Melatonin attenuates chemical-induced cardiotoxicity

Environmental chemicals and drugs can induce cardiotoxicity, mainly by generating free radicals. Reactive oxygen species play a critical role in the pathogenesis of cardiac tissue injury. This highlights a need for prevention of cardiotoxicity by scavenging free radicals. Melatonin has been shown to act as a protector against various conditions in which free radicals cause molecular and tissue injury. Some of the mechanisms by which melatonin operates as a free radical scavenger and antioxidant have been identified. The importance of endogenous melatonin in cardiovascular health and the benefits of melatonin supplementation in different cardiac pathophysiological disorders have been shown in a variety of model systems. Melatonin continues to attract attention for its potential therapeutic value for cardiovascular toxicity. The therapeutic potential of melatonin in treatment of cardiotoxicities caused by various chemicals along with suggested molecular mechanisms of action for melatonin is reviewed.

Protective effects of melatonin solid lipid nanoparticles on testis histology after testicular trauma in rats

Testicular traumatic injuries occur frequently, which can result in an alteration in spermatogenesis. These injuries can also cause oxidative stress and male infertility. Antioxidant efficiency of melatonin (MLT), known as a potent antioxidant, will be improved if used in a form of solid lipid nanoparticles (MLT-SLN). The aim of the current study is to evaluate the effect of MLT-loaded SLN on traumatic testis in rats. In this study 32 adult male Wistar rats were divided into 4 groups. Group 1 (sham group), right testicle was drawn out from the scrotum and returned without manipulation. Group 2, right testicle was dropped by 25 g sinker for 4 times. Group 3, animals were received a single dose (25 mg/kg) of MLT intraperitoneally after trauma. Group 4, animals were received a single dose of MLT-SLN intraperitoneally after trauma. Under anaesthesia, rats were sacrificed, and their testicles were removed three days after the surgery. After tissue processing, the sample sections were H&E stained. MLT and MLT-SLN could partially repair spermatogenesis by Johnson’s criteria but the repairs were significant only in MLT-SLN group (P = 0.02). Trauma decreased seminiferous tubule diameter and its epithelium height. MLT could restore epithelium height (P ≤ 0.05) but its NPs improved both epithelium diameter (P ≤ 0.05) and thickness (P ≤ 0.001). The Malondialdehyde increased significantly in trauma group (P = 0.002), but decreased in MLT and NPs groups compared to trauma group (P = 0.098 and P = 0.002 respectively). This decrease was significant only in NPs group. Testicular trauma disturbed spermatogenesis, morphometric, and oxidative parameters. MLT and specially MLT-SLN improved traumatic damages.

Natural Antioxidants as Potential Therapy, and a Promising Role for Melatonin Against Pulmonary Hypertension

Plasma and serum samples, and lung/heart tissue of pulmonary hypertension (PH) patients and animal models of PH display elevated oxidative stress. Moreover, the severity of PH and levels of oxidative stress increase concurrently, which suggests that oxidative stress could be utilized as a biomarker for PH progression. Accumulating evidence has well established that oxidative stress is also key role player in the development of PH. Preclinical studies have demonstrated that natural antioxidants improved PH condition, and, therefore, antioxidant therapy has been proposed as a potential therapeutic strategy against PH. These natural antioxidants include medicinal plant extracts and compounds such as resveratrol and melatonin. Recent studies suggest that melatonin provides health benefit against PH, by enhancing antioxidant capacity, increasing vasodilation, counteracting lung and cardiac fibrosis, and stunting right ventricular (RV) hypertrophy/failure. This chapter comprehensively reviews and discusses a variety of natural antioxidants and their efficacy in modulating experimental PH. This chapter also demonstrates that antioxidant therapy remains a therapeutic strategy for PH, and particularly identifies melatonin as a safe, cost-effective, and promising antioxidant therapy.

Recent developments in solid lipid nanoparticle and surface-modified solid lipid nanoparticle delivery systems for oral delivery of phyto-bioactive compounds in various chronic diseases

Solid lipid nanoparticle (SLN) delivery systems have a wide applicability in the delivery of phyto-bioactive compounds to treat various chronic diseases, including diabetes, cancer, obesity and neurodegenerative diseases. The multiple benefits of SLN delivery include improved stability, smaller particle size, leaching prevention and enhanced lymphatic uptake of the bioactive compounds through oral delivery. However, the burst release makes the SLN delivery systems inadequate for the oral delivery of various phyto-bioactive compounds that can treat such chronic diseases. Recently, the surface-modified SLN (SMSLN) was observed to overcome this limitation for oral delivery of phyto-bioactive compounds, and there is growing evidence of an enhanced uptake of curcumin delivered orally via SMSLNs in the brain. This review focuses on different SLN and SMSLN systems that are useful for oral delivery of phyto-bioactive compounds to treat various chronic diseases.

Melatonin, a Full Service Anti-Cancer Agent: Inhibition of Initiation, Progression and Metastasis

There is highly credible evidence that melatonin mitigates cancer at the initiation, progression and metastasis phases. In many cases, the molecular mechanisms underpinning these inhibitory actions have been proposed. What is rather perplexing, however, is the large number of processes by which melatonin reportedly restrains cancer development and growth. These diverse actions suggest that what is being observed are merely epiphenomena of an underlying more fundamental action of melatonin that remains to be disclosed. Some of the arresting actions of melatonin on cancer are clearly membrane receptor-mediated while others are membrane receptor-independent and involve direct intracellular actions of this ubiquitously-distributed molecule. While the emphasis of melatonin/cancer research has been on the role of the indoleamine in restraining breast cancer, this is changing quickly with many cancer types having been shown to be susceptible to inhibition by melatonin. There are several facets of this research which could have immediate applications at the clinical level. Many studies have shown that melatonin's co-administration improves the sensitivity of cancers to inhibition by conventional drugs. Even more important are the findings that melatonin renders cancers previously totally resistant to treatment sensitive to these same therapies. Melatonin also inhibits molecular processes associated with metastasis by limiting the entrance of cancer cells into the vascular system and preventing them from establishing secondary growths at distant sites. This is of particular importance since cancer metastasis often significantly contributes to death of the patient. Another area that deserves additional consideration is related to the capacity of melatonin in reducing the toxic consequences of anti-cancer drugs while increasing their efficacy. Although this information has been available for more than a decade, it has not been adequately exploited at the clinical level. Even if the only beneficial actions of melatonin in cancer patients are its ability to attenuate acute and long-term drug toxicity, melatonin should be used to improve the physical wellbeing of the patients. The experimental findings, however, suggest that the advantages of using melatonin as a co-treatment with conventional cancer therapies would far exceed improvements in the wellbeing of the patients.

Melatonin Pharmacological Blood Levels Increase Total Antioxidant Capacity in Critically Ill Patients

In this study, the aim was to test the biochemical effects of melatonin supplementation in Intensive Care Unit (ICU) patients, since their blood levels are decreased. Sixty-four patients were enrolled in the study. From the evening of the 3rd ICU day, patients were randomized to receive oral melatonin (3 mg, group M) or placebo (group P) twice daily, at 20:00 and 24:00, until discharged. Blood was taken (at 00:00 and 14:00), on the 3rd ICU day to assess basal nocturnal melatonin values, and then during the treatment period on the 4th and 8th ICU days. Melatonin, total antioxidant capacity, and oxidative stress were evaluated in serum. Melatonin circadian rhythm before treatment was similar in the two groups, with a partial preservation of the cycle. Four hours from the 1st administration (4th ICU day, 00:00), melatonin levels increased to 2514 (982.3; 7148) pg·mL⁻¹ in group M vs. 20.3 (14.7; 62.3) pg·mL⁻¹ in group P (p < 0.001). After five treatment days (8th ICU day), melatonin absorption showed a repetitive trend in group M, while in group P nocturnal secretion (00:00) was impaired: 20 (11.5; 34.5) pg·mL⁻¹ vs. 33.8 (25.0; 62.2) on the 3rd day (p = 0.029). Immediately from the beginning of treatment, the total antioxidant capacity was significantly higher in melatonin treated subjects at 00:00; a significant correlation was found between total antioxidant capacity and blood melatonin values (ρ = 0.328; p < 0.001). The proposed enteral administration protocol was adequate, even in the early phase, to enhance melatonin blood levels and to protect the patients from oxidative stress. The antioxidant effect of melatonin could play a meaningful role in the care and well-being of these patients.

Cationic solid lipid nanoparticles enhance ocular hypotensive effect of melatonin in rabbit

The study was aimed at evaluating whether the ocular hypotensive effect of melatonin (MEL) was enhanced by its encapsulation in cationic solid lipid nanoparticles (cSLN), as well as at determining the tolerability of these formulations on the ocular surface. MEL was loaded in cSLN that had already been shown to be suitable for ophthalmic use. The formulations were prepared using Softisan(®) 100 as the main lipid matrix, with the presence of either stearic (SA) or palmitic acid (PA) as lipid modifiers. A fixed positive charge was provided by the addition of a cationic lipid (didecyldimethylammonium bromide). The ocular hypotensive effect was evaluated by measuring the intraocular pressure (IOP) during 24h in albino rabbits. MEL elicited a significant (p<0.01) IOP reduction in rabbit eye. All the formulations tested in vivo demonstrated a good tolerability. The nanocarrier containing SA was the most effective in terms of IOP reduction (maximum IOP reduction: -7 mmHg), and its effect lasted approximately 24h. The experimental data indicate that the new formulations based on cSLN loaded with MEL represent a potent anti-glaucoma treatment with a safe profile, warranting further clinical evaluation of the proposed nanotechnological strategy.

Use of antioxidants to prevent cyclosporine a toxicity

Cyclosporine A (CsA) is a potent immunosuppressor that is widely used in transplant surgery and the treatment of several autoimmune diseases. However, major side effects of CsA such as nephrotoxicity, hepatotoxicity, neurotoxicity and cardiovascular diseases have substantially limited its usage. Although molecular mechanisms underlying these adverse effects are not clearly understood, there is some evidence that suggests involvement of reactive oxygen species (ROS) . In parallel, protective effects of various antioxidants have been demonstrated by many research groups. Extensive studies of CsA-induced nephrotoxcity have confirmed that the antioxidants can restore the damaged function and structure of kidney. Subsequently, there have appeared numerous reports to demonstrate the positive antioxidant effects on liver and other organ damages by CsA. It may be timely to review the ideas to envisage the relationship between ROS and the CsA-induced toxicity. This review is comprised of a brief description of the immunosuppressive action and the secondary effects of CsA, and a synopsis of reports regarding the antioxidant treatments against the ROS-linked CsA toxicity. A plethora of recent reports suggest that antioxidants can help reduce many CsA’s adverse effects and therefore might help develop more effective CsA treatment regimens.

Protective effect of curcumin on cyclosporin A-induced endothelial dysfunction, antioxidant capacity, and oxidative damage

Cyclosporin A (CsA) is the most widely used immunosuppressive drug for preventing graft rejection and autoimmune disease. However, the therapeutic treatment induces several side effects such as nephrotoxicity, cardiotoxicity, hypertension, and hepatotoxicity. Curcumin has been successfully used as a potent antioxidant against many pathophysiological states. This experimental study was performed to test, during CsA treatment, the alterations of curcumin antioxidant properties against CsA-induced endothelial dysfunction. Rats were divided into four groups: control, curcumin alone, CsA, and CsA + curcumin; each group containing eight animals. The animals in the CsA + curcumin group were treated with CsA (10 days, 25 mg/kg, orally) and curcumin (15 days, 200 mg/kg, orally, starting 5 days before CsA administration). At the end of the treatments, the animals were killed; serum and aorta tissue were treated for biochemical and morphological analyses. The results indicate that CsA-induced aortic endothelial dysfunction was characterized by morphological and ultrastructural alterations in tissue architecture, changes in malondialdehyde and ferric reducing/antioxidant power levels, and increase in endothelial nitric oxide synthase and terminal-deoxynucleotidyl-transferase mediated dUTP nick end labeling (TUNEL) expression. In conclusion, our data suggest that the imbalance between production of free oxygen radicals and antioxidant defence systems, due to CsA administration, is a mechanism responsible for oxidative stress. Moreover, we show that curcumin plays a protective action against CsA-induced endothelial dysfunction and oxidative stress, as supported by biochemical, ultrastructural, immunohistochemical, and TUNEL results.

Melatonin restores muscle regeneration and enhances muscle function after crush injury in rats

The goal of this study was to provide evidence that melatonin improves muscle healing following blunt skeletal muscle injury. For this purpose, we used 56 rats and induced an open muscle injury. After injury, all animals received either daily melatonin or vehicle solution intraperitoneally. Subsequent observations were performed at day 1, 4, 7, and 14 after injury. After assessment of fast twitch and tetanic muscle force, we analyzed leukocyte infiltration, satellite cell number, and cell apoptosis. We further quantified the expression of the melatonin receptor and the activation of extracellular-signal-regulated kinase (ERK). Chronic treatment with melatonin significantly increased the twitch and tetanic force of the injured muscle at day 4, 7, and 14. At day 1, melatonin significantly reduced the leukocyte infiltration and significantly increased the number of satellite cells when compared to the control group. Consistent with this observation, melatonin significantly reduced the number of apoptotic cells at day 4. Furthermore, phosphorylation of ERK reached maximal values in the melatonin group at day 1 after injury. Additionally, we detected the MT1a receptor in the injured muscle and showed a significant up-regulation of the MT1a mRNA in the melatonin group at day 4. These data support the hypothesis that melatonin supports muscle restoration after muscle injury, inhibits apoptosis via modulation of apoptosis-associated signaling pathways, increases the number of satellite cells, and reduces inflammation.

Follicular dynamic and immunoreactions of the vitrified ovarian graft after host treatment with variable regimens of melatonin

PROBLEM

This study investigates dose-dependent effects of melatonin on ovarian graft.

METHOD OF STUDY

Vitrified-thawed whole ovaries of newborn mice were grafted into ovariectomized mature ones. Melatonin (20, 50, 100, and 200 mg/kg/day) was administrated to separate groups of host mice for 32 days. IgM and IgG antibodies, Th1 and Th2 cytokines, and melatonin in recipient's blood were measured. Subsequent survival of the grafted ovaries was scored. An assessment of follicular morphology was performed using TUNEL assay and hematoxylin-eosin staining.

RESULTS

The administration of melatonin did not disturb the circadian rhythm of melatonin concentration. The ovarian graft lifespan was prolonged at 200 mg/kg/day melatonin (P < 0.001). However, in doses of higher than 20 mg/kg/day melatonin, the proportion of healthy follicles and ovary size decreased. Th1 cytokines levels were reduced dose dependently. However, the effect of melatonin on Th2 cytokines was not pronounced. IgM and IgG2a decreased in recipients receiving 200 mg/kg/day melatonin in comparison with non-treated group (P < 0.001), while this variables were significantly increased at the dose of 50 mg/kg/day (P < 0.001).

CONCLUSION

Melatonin at 200 mg/kg/day has an immunosuppresent effect and produce prolongation of graft survival. However, the associated reduction in healthy follicles suggests that melatonin in doses of higher than 20 mg/kg/day has no preventative ischemic action.

Nanocarrier possibilities for functional targeting of bioactive peptides and proteins: state-of-the-art

This review attempts to provide an updated compilation of studies reported in the literature pertaining to production of nanocarriers encasing peptides and/or proteins, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to bioactive proteins and peptides, with a special focus on those from dairy sources (including physicochemical characteristics and properties, and biopharmaceutical application possibilities of e.g. lactoferrin and glycomacropeptide), as well as to nanocarrier functional targeting. Features associated with micro- and (multiple) nanoemulsions, micellar systems, liposomes and solid lipid nanoparticles, together with biopharmaceutical considerations, are presented in the text in a systematic fashion.

Melatonin stimulates the growth of new bone around implants in the tibia of rabbits

This study evaluated the effect of the topical application of melatonin in accelerating bone formation associated with implants 2 months after their application to the tibiae of rabbits. Twenty New Zealand rabbits were used. Twenty implants treated with melatonin and 20 control implants without melatonin were placed in the proximal metaphyseal area of each tibia. Studies of new bone formation were subsequently made at 15, 30, 45 and 60 days. Cortical width and cortical length of new bone formation were measured. Following implantation, an anteroposterior and lateral radiologic study was carried out. Collected samples were sectioned at 5 μm and stained using hematoxylin-eosin, Masson's trichromic and Gordon-Switt reticulin stains. After a 60 day treatment period, melatonin increased the length of cortical bone (95.13±0.42%) versus that around control implants (62.91±1.45%). Related to the perimeter of cortical bone of the tibiae, melatonin induced new bone 88.35±1.56% versus 60.20±1.67% in the control implants. Melatonin regenerated the width and length of cortical bone around implants in tibiae of rabbits more quickly than around control implants without the addition of melatonin.

Actions of melatonin mixed with collagenized porcine bone versus porcine bone only on osteointegration of dental implants

This study evaluated the effect of the topical application of melatonin mixed with collagenized porcine bone on the osteointegration on the rough discrete calcium deposit (DCD) surface implants in Beagle dogs 3 months after their insertion. In preparation for subsequent insertion of dental implants, lower molars were extracted from 12 Beagle dogs. Each mandible received two parallel wall expanded platform implants with a DCD surface of 4 mm in diameter and 10 mm in length. The implants were randomly assigned to the distal sites on each mandible in the molar area and the gaps were filled with 5 mg lyophilized powdered melatonin and porcine bone and collagenized porcine bone alone. Ten histological sections per implant were obtained for histomorphometric studies. After a 4-wk treatment period, melatonin plus porcine bone significantly increased the perimeter of bone that was in direct contact with the treated implants (P < 0.0001), bone density (P < 0.0001), and new bone formation (P < 0.0001) in comparison with porcine bone alone around the implants. Melatonin plus collagenized porcine bone on DCD surface may act as a biomimetic agent in the placement of endo-osseous dental implants and enhance the osteointegration. Melatonin combined with porcine bone on DCD implants reveals more bone in implant contact at 12 wk (84.5 +/- 1.5%) compared with porcine bone alone treated area (67.17 +/- 1.2%).

Melatonin suppresses cyclosporine A-induced autophagy in rat pituitary GH3 cells

Cyclosporine A (CsA) is a powerful immunosuppressive drug with side effects including the induction of chronic nephrotoxicity including endoplasmic reticulum (ER) stress in tubular cells. Recently, it was reported that autophagy is induced by ER stress and serves to alleviate the associated deleterious effects. In the current study, CsA treatment (0-100 microm) decreased cell survival of rat pituitary GH3 cells in a dose-dependent manner. At concentrations ranging from 1.0 to 10 microm, CsA induced a dose-dependent increase in the expression of microtubule-associated protein 1 light chain 3 (LC3)-I and LC3-II. Cells treated with 2.5 microm CsA exhibited cytoplasmic vacuolation, indicating that CsA induces autophagy in rat pituitary GH3 cells. In the presence of 1.0-10 microm CsA, the expression of catalase decreased while that of the ER stress markers, ER luminal binding protein (BiP) and inositol-requiring enzyme 1 alpha (IRE1alpha), increased as compared those levels in untreated cells. These results suggested that CsA-induced autophagy is dependent on ER stress. To determine whether melatonin would protect cells against CsA-induced autophagy, we treated rat pituitary GH3 cells with melatonin in the presence of CsA. Melatonin treatment (100 and 200 microm) suppressed autophagy induced by 2.5 and 5 microm CsA. Furthermore, co-treatment with 100 microm melatonin inhibited LC3-II expression, and increased catalase and phosphorylated p-ERK levels in the presence of 2.5 and 5 microm CsA. BiP and IRE1alpha expression in melatonin-co-treated cells was superior to that in cells treated with 2.5 and 5 microm CsA alone. Thus, melatonin suppresses CsA-mediated autophagy in rat pituitary GH3 cells.

Chapter 6 - Solid lipid nanoparticle formulations pharmacokinetic and biopharmaceutical aspects in drug delivery

Solid lipid nanoparticles (SLNs) have emerged as important tools to modify the release profile for a large number of drugs including protein and peptide molecules. SLNs are produced from biocompatible and biodegradable lipid materials, making them a promising therapeutic strategy for drug targeting and delivery, and surmounting the inherent limitations of regulation acceptance. Due to their versatility in loading both lipophilic and hydrophilic molecules in the solid lipid matrix, SLNs depict the ability to prolong, extend or sustain the release profile of the loaded molecules, therefore reducing the repeated administration, and increasing the therapeutic value of a certain treatment. Additional advantages include reduction of drug toxicity and increase of drug bioavailability. To develop SLN formulations for drug targeting and delivery, a basic pharmacokinetic understanding of drug distribution is of major relevance, as well as the biopharmaceutical aspects of the administration route. This chapter provides a fundamental understanding of the pharmacokinetic properties of SLNs, which influence both biopharmaceutical and clinical profiles of the loaded molecules.