Ectoines as novel anti-inflammatory and tissue protective lead compounds with special focus on inflammatory bowel disease and lung inflammation.

The compatible solute ectoine is one of the most abundant and powerful cytoprotectant in the microbial world. Due to its unique ability to stabilize biological membranes and macromolecules it has been successfully commercialized as ingredient of various over-the-counter drugs, achieving primarily epithelial protection. While trying to elucidate the mechanism of its cell protective properties in in-vitro studies, a significant anti-inflammatory effect was documented for the small molecule. The tissue protective potential of ectoine considerably improved organ quality during preservation. In addition, ectoine and derivatives have been demonstrated to significantly decrease inflammatory cytokine production, thereby alleviating the inflammatory response following organ transplantation, and launching new therapeutic options for pathologies such as Inflammatory Bowel Disease (IBD) and Chronic Obstructive Pulmonary Disease (COPD). In this review, we aim to summarize the knowledge of this fairly nascent field of the anti-inflammatory potential of diverse ectoines. We also point out that this promising field faces challenges in its biochemical and molecular substantiations, including defining the molecular mechanisms of the observed effects and their regulation. However, based on their potent cytoprotective, anti-inflammatory, and non-toxic properties we believe that ectoines represent promising candidates for risk free interventions in inflammatory pathologies with steeply increasing demands for new therapeutics.

The cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) targets the olfactory bulb region.

Olfactory dysfunction is implicated in neurodegenerative disorders and typically manifests years before other symptoms. The cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) is suggested as a risk factor for neurodegenerative disease. Detection of BMAA in air filters has increased the concern that aerosolization may lead to human BMAA exposure through the air. The aim of this study was to determine if BMAA targets the olfactory system. Autoradiographic imaging showed a distinct localization of radioactivity in the right olfactory mucosa and bulb following a unilateral intranasal instillation of 3H-BMAA (0.018 µg) in mice, demonstrating a direct transfer of BMAA via the olfactory pathways to the brain circumventing the blood-brain barrier, which was confirmed by liquid scintillation. Treatment of mouse primary olfactory bulb cells with 100 µM BMAA for 24 h caused a disruption of the neurite network, formation of dendritic varicosities and reduced cell viability. The NMDA receptor antagonist MK-801 and the metabotropic glutamate receptor antagonist MCPG protected against the BMAA-induced alterations, demonstrating the importance of glutamatergic mechanisms. The ionotropic non-NMDA receptor antagonist CNQX prevented the BMAA-induced decrease of cell viability in mixed cultures containing both neuronal and glial cells, but not in cultures with neurons only, suggesting a role of neuron-glial interactions and glial AMPA receptors in the BMAA-induced toxicity. The results show that the olfactory region may be a target for BMAA following inhalation exposure. Further studies on the relations between environmental olfactory toxicants and neurodegenerative disorders are warranted.

Complexes of Ectoine with the Anionic Surfactants as Active Ingredients of Cleansing Cosmetics with Reduced Irritating Potential.

For many years, an increasing number of diagnosed atopy and skin problems have been observed. For people affected by the problem of atopy, the selection of skin care products, including cosmetics, is extremely important. Cleansing cosmetics, due to their ability to cause skin irritations and disturb the hydrolipidic barrier, can increase problems with atopic skin. New solutions to reduce the effects of these products on the skin are very important. In this work, the effect of ectoine on the properties of anionic surfactants was analyzed. Based on model systems, analysis of the effect of ectoine on the irritating effect of four anionic surfactants and their ability to solubilize model sebum was performed. Antioxidant activity was also evaluated, and cytotoxic studies were performed on cell cultures. It was shown that the addition of ectoine to the anionic surfactant solutions improves its safety of use. After introducing ectoine to the surfactant solution, a decrease of irritant potential (about 20%) and a decrease in the ability to solubilize of model sebum (about 10-20%) was noted. Addition of ectoine to surfactant solutions also reduced their cytotoxicity by up to 60%. The obtained results indicate that ectoine may be a modern ingredient that improves the safety of cleansing cosmetics.

Disposition of ß-N-methylamino-l-alanine (L-BMAA), a neurotoxin, in rodents following a single or repeated oral exposure.

ß-N-methylamino-l-alanine (L-BMAA) is produced by cyanobacteria (blue-green algae). Human exposure to L-BMAA occurs via consumption of L-BMAA-contaminated water and food. It is speculated that exposure to L-BMAA, and subsequent brain accumulation, may contribute to an increased incidence of neurodegenerative diseases indicating the need to evaluate risk of L-BMAA exposure to humans. As an initial step in this process, we have evaluated disposition following a single or repeated gavage administration of 1, 10 or 100mg/kg [14C]L-BMAA in rats and mice. L-BMAA was well absorbed following a single gavage administration with minimal dose, species, or sex-related effect. In both species, the main excretion route was as exhaled CO2 (46-61%) with 7-13% and 1.4-8% of the administered dose excreted in the urine and feces, respectively. L-BMAA was distributed to all tissues examined; the total radioactivity in tissues increased with the dose and was significant in both species (8-20%). In male rats, L-BMAA was slowly eliminated from blood and tissues (half-lives ≥48h). Following 1, 5 and 10days of dosing in male rats, levels in tissues increased with the number of doses demonstrating potential for accumulation of BMAA-derived equivalents. There was no greater affinity for accumulation in the brain compared to other organs and tissues. Following repeated exposure in rats, amino acid mass shifts associated with L-BMAA were detected in brain peptides. However, the low frequency of occurrence suggests that the substitution of an amino acid with L-BMAA is not significant relative to substitutions and/or modifications by other L-BMAA-derived equivalents.

Quality measures of imaging mass spectrometry aids in revealing long-term striatal protein changes induced by neonatal exposure to the cyanobacterial toxin ß-N-methylamino-L-alanine (BMAA).

Many pathological processes are not directly correlated to dramatic alterations in protein levels. The changes in local concentrations of important proteins in a subset of cells or at specific loci are likely to play a significant role in disease etiologies, but the precise location might be unknown, or the concentration might be too small to be adequately sampled for traditional proteomic techniques. Matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS) is a unique analytical method that combines analysis of multiple molecular species and of their distribution in a single platform. As reproducibility is essential for successful biomarker discovery, it is important to systematically assess data quality in biologically relevant MALDI IMS experiments. In the present study, we applied four simple tools to study the reproducibility for individual sections, within-group variation, and between-group variation of data acquired from brain sections of 21 animals divided into three treatment groups. We also characterized protein changes in distinct regions of the striatum from six-month-old rats treated neonatally (postnatal days 9-10) with the cyanobacterial toxin ß-N-methylamino-l-alanine (BMAA), which has been implicated in neurodegenerative diseases. The results showed that optimized experimental settings can yield high-quality MALDI IMS data with relatively low variation (14% to 15% coefficient of variance) that allow the characterization of subtle changes in protein expression in various subregions of the brain. This was further exemplified by the dose-dependent reduction of myelin basic protein in the caudate putamen and the nucleus accumbens of adult rats neonatally treated with BMAA (150 and 460 mg/kg). The reduction in myelin basic protein was confirmed through immunohistochemistry and indicates that developmental exposure to BMAA may induce structural effects on axonal growth and/or directly on the proliferation of oligodendrocytes and myelination, which might be important for the previously shown BMAA-induced long-term cognitive impairments.

Supplementing a low-protein diet with dibasic amino acids increases urinary calcium excretion in young women.

Increasing dietary protein within a physiologic range stimulates intestinal calcium absorption, but it is not known if specific amino acids or dietary protein as a whole are responsible for this effect. Therefore, we selectively supplemented a low-protein (0.7 g/kg) diet with either the calcium-sensing receptor-activating amino acids (CaSR-AAAs) L-tryptophan, L-phenylalanine, and L-histidine, or the dibasic amino acids (DAAs) L-arginine and L-lysine, to achieve intakes comparable to the content of a high-protein diet (2.1 g/kg) and measured intestinal calcium absorption. Fourteen young women took part in a placebo-controlled, double-blind, crossover feeding trial in which each participant ingested a 6-d low-protein diet supplemented with CaSR-AAAs, DAAs, or methylcellulose capsules (control) after an 11-d adjustment period. All participants ingested all 3 diets in random order. Intestinal calcium absorption was measured between days 5 and 6 using dual-stable calcium isotopes ((42)Ca, (43)Ca, and (44)Ca). There was no difference in calcium absorption between the diet supplemented with CaSR-AAAs (22.9 ± 2.0%) and the control diet (22.3 ± 1.4%) (P = 0.64). However, calcium absorption tended to be greater during the DAA supplementation period (25.2 ± 1.4%) compared with the control diet period (22.3 ± 1.4%) (P < 0.10). Larger and longer clinical trials are needed to clarify the possible benefit of arginine and lysine on calcium absorption.

A natural tetrahydropyrimidine, ectoine, ameliorates ischemia reperfusion injury after intestinal transplantation in rats.

BACKGROUND/AIMS: Ischemia reperfusion (I/R) injury after small bowel transplantation leads to inflammatory reactions and loss of structural integrity with subsequent graft contractile dysfunction in the early postoperative phase. The natural tetrahydropyrimidine ectoine (1-,4-,5-,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid; THP) protects the ileal mucosa and muscularis against effects of I/R injury in an experimental model of isolated graft reperfusion. The effects of THP treatment were evaluated in an established experimental intestinal transplant model. METHODS: Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (6 h cold ischemia time). Perioperative THP treatment (intraluminal/intravascular) groups were compared to vehicle-treated animals (after 3 and 24 h) and non-transplanted controls (n = 5/group). Park's score defined the effects of I/R injury. The infiltration of neutrophils, monocytes and macrophages, mRNA expression of IL-6 and TNF-α, serum levels of IL-6 and NO and smooth muscle contractility were evaluated. RESULTS: Improved graft outcome after intraluminal and intravascular THP treatment was defined by considerably ameliorated neutrophil infiltration and less histological signs of I/R injury (p ≤ 0.05). In the presence of THP, mRNA expression of IL-6 and TNF-α and IL-6 and NO serum levels were reduced and smooth muscle function was improved. CONCLUSION: THP treatment offers protection against the effects of I/R injury in intestinal transplantation in vivo, however, only as supplementary treatment option.

The active natural anti-oxidant properties of chamomile, milk thistle, and halophilic bacterial components in human skin in vitro.

The number of skin cancers continues to rise, accounting for approximately 40% of all cancers reported in the United States and approximately 9,500 deaths per year. Studies have shown reactive oxygen species (ROS) type free radicals are linked to skin cancer and aging. Therefore, it is important for us to identify agents that have anti-oxidant properties to protect skin against free radical damage. The purpose of this research is to investigate the anti-oxidant properties of bisabolol, silymarin, and ectoin that are components from chamomile, milk thistle, and halophilic bacteria, respectively. We measured the ability of bisabolol, silymarin, and ectoin to modulate the hydrogen peroxide (H2O2)-induced upregulation of ROS free radicals in normal human skin fibroblasts in vitro. Using a flow cytometry-based assay, we demonstrated that varying concentrations of these natural components were able to inhibit upregulation of H2O2-generated free radicals in human skin fibroblasts in vitro. Our results indicate components of chamomile, milk thistle, and halophilic bacteria exhibit anti-oxidant capabilities and warrant further study in clinical trials to characterize their anti-cancer and anti-aging capabilities.

BMAA inhibits nitrogen fixation in the cyanobacterium Nostoc sp. PCC 7120.

Cyanobacteria produce a range of secondary metabolites, one being the neurotoxic non-protein amino acid ß-N-methylamino-L-alanine (BMAA), proposed to be a causative agent of human neurodegeneration. As for most cyanotoxins, the function of BMAA in cyanobacteria is unknown. Here, we examined the effects of BMAA on the physiology of the filamentous nitrogen-fixing cyanobacterium Nostoc sp. PCC 7120. Our data show that exogenously applied BMAA rapidly inhibits nitrogenase activity (acetylene reduction assay), even at micromolar concentrations, and that the inhibition was considerably more severe than that induced by combined nitrogen sources and most other amino acids. BMAA also caused growth arrest and massive cellular glycogen accumulation, as observed by electron microscopy. With nitrogen fixation being a process highly sensitive to oxygen species we propose that the BMAA effects found here may be related to the production of reactive oxygen species, as reported for other organisms.

The Effectiveness of the Bacteria Derived Extremolyte Ectoine for the Treatment of Allergic Rhinitis.

Nonpharmacological therapies with a good tolerability and safety profile are of interest to many patients with allergic rhinitis, as a relevant proportion of them have reservations about guideline-concordant pharmacological therapies due to their local irritations and side effects. Ectoine is a bacterial-derived extremolyte with an ability to protect proteins and biological membranes against damage caused by extreme conditions of salinity, drought, irradiation, pH, and temperature. Evidence from preclinical and clinical studies attests its effectiveness in the treatment of several inflammatory diseases, including allergic rhinitis. In this review, we analyzed 14 recent clinical trials investigating ectoine nasal spray in patients with allergic rhinitis and/or conjunctivitis, including sensitive patient groups like children or pregnant women. Some studies investigated monotherapy with ectoine; others investigated combination therapy of ectoine and an antihistamine or a corticosteroid. Analysis of the study results demonstrated that patients with mild-to-moderate symptoms of allergic rhinitis can be successfully treated with ectoine-containing nasal spray. When applied as monotherapy, ectoine exerted noninferior effects compared to first-line therapies such as antihistamines and cromoglicic acid. Using ectoine as an add-on therapy to antihistamines or intranasal glucocorticosteroids accelerated symptom relief by days and improved the level of symptom relief. Importantly, concomitant treatment with ectoine was proven beneficial in a group of difficult-to-treat patients suffering from moderate-to-severe rhinitis symptoms. Taken together, the natural substance ectoine represents a viable alternative for allergic rhinitis and conjunctivitis patients who wish to avoid local reactions and side effects associated with pharmacological therapies.

Ectoine in the Treatment of Irritations and Inflammations of the Eye Surface.

The ocular surface is facing various unspecific stress factors resulting in irritation and inflammation of the epithelia, causing discomfort to the patients. Ectoine is a bacteria-derived extremolyte with the ability to protect proteins and biological membranes from damage caused by extreme environmental conditions like heat, UV-light, high osmolarity, or dryness. Evidence from preclinical and clinical studies attest its effectiveness in treating several epithelium-associated inflammatory diseases, including the eye surface. In this review, we analysed 16 recent clinical trials investigating ectoine eye drops in patients with allergic conjunctivitis or with other unspecific ocular inflammations caused by e.g. ophthalmic surgery. Findings from these studies were reviewed in context with other published work on ectoine. In summary, patients with irritations and unspecific inflammations of the ocular surface have been treated successfully with ectoine-containing eye drops. In these patients, significant improvement was observed in ocular symptoms of allergic rhinoconjunctivitis, postoperative secondary dry eye syndrome, or ocular reepithelisation after surgery. Using ectoine as an add-on therapy to antihistamines, in allergy patients accelerated symptom relief by days, and its use as an add-on to antibiotics resulted in faster wound closure. Ectoine is a natural substance with an excellent tolerability and safety profile thus representing a helpful alternative for patients with inflammatory irritation of the ocular surface, who wish to avoid local reactions and side effects associated with pharmacological therapies or wish to increase the efficacy of standard treatment regimen.

The compatible solute ectoine protects against nanoparticle-induced neutrophilic lung inflammation.

RATIONALE: Inflammatory reactions of the airways induced by nanoparticles of occupational and environmental origin contribute to organ-specific and systemic human diseases. Because this kind of exposure in modern societies is often unavoidable, a strategy of molecular prevention on an individual level could help to prevent inflammation-derived secondary diseases. OBJECTIVES: To test whether the compatible solute ectoine [(S)-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid], which is known to reduce cell stress effects on a molecular level, prevents nanoparticle-induced lung inflammation. METHODS: Inflammatory parameters were studied in Fischer 344 rats treated with model carbon nanoparticles. The molecular effects of ectoin on proinflammatory signal transduction were demonstrated in the rat and in the human system using cultured lung epithelial cells. MEASUREMENTS AND MAIN RESULTS: Ectoine, given with or before the nanoparticles, dose-dependently reduced neutrophil inflammation in the lung. This preventive effect was not observed when lung inflammation was induced by bacterial lipopolysaccharide. Analyses of the underlying mode of action revealed that ectoine acted on lung epithelial cells. Ectoine administration inhibited nanoparticle-induced signaling, which is known to be responsible for proinflammatory reactions in rat lung epithelial cells in vitro as well as in vivo. These findings were corroborated and extended in experiments with cultured human bronchial epithelial cells in which ectoine inhibited nanoparticle-triggered cell signaling and IL-8 induction. CONCLUSIONS: Because compatible solutes are compliant natural products without known toxic potential, we propose that this group of substances may be used for the prevention of particle-induced airway inflammation in humans.

Parkinson-dementia complex and development of a new stable isotope dilution assay for BMAA detection in tissue.

Beta-methylamino-L-alanine (BMAA) has been proposed as a global contributor to neurodegenerative diseases, including Parkinson-dementia complex (PDC) of Guam and Alzheimer's disease (AD). The literature on the effects of BMAA is conflicting with some but not all in vitro data supporting a neurotoxic action, and experimental animal data failing to replicate the pattern of neurodegeneration of these human diseases, even at very high exposures. Recently, BMAA has been reported in human brain from individuals afflicted with PDC or AD. Some of the BMAA in human tissue reportedly is freely extractable (free) while some is protein-associated and liberated by techniques that hydrolyze the peptide bond. The latter is especially intriguing since BMAA is a non-proteinogenic amino acid that has no known tRNA. We attempted to replicate these findings with techniques similar to those used by others; despite more than adequate sensitivity, we were unable to detect free BMAA. Recently, using a novel stable isotope dilution assay, we again were unable to detect free or protein-associated BMAA in human cerebrum. Here we review the development of our new assay for tissue detection of BMAA and show that we are able to detect free BMAA in liver but not cerebrum, nor do we detect any protein-associated BMAA in mice fed this amino acid. These studies demonstrate the importance of a sensitive and specific assay for tissue BMAA and seriously challenge the proposal that BMAA is accumulating in human brain.

BMAA neurotoxicity in Drosophila.

We report the establishment of an in vivo model using the fruit fly Drosophila melanogaster to investigate the toxic effects of L-BMAA. We found that dietary intake of BMAA reduced the lifespan as well as the neurological functions of flies. Furthermore, we have developed an HPLC method to reliably detect both free and protein-bound BMAA in fly tissue extracts.

Testing an Ectoin Containing Emollient for Atopic Dermatitis.

AIM: To describe the methodology in studying patient's acceptability and efficacy of an ectoin containing emollient for atopic dermatitis (AD). METHODS: We described the methodology that we used in studying emollients and moisturisers, and patient acceptability of a group of AD patients before and following usage of an ectoin-containing proprietary emollient. These data were also compared with other brand emollients that we previously reported, namely Restoradom®, Ezerra® and Ezerra plus®. RESULTS: 30 subjects (50% Male, Mean (SD) age: 9.8 (3.6) years with AD used the trial emollient W for four weeks. AD severity of subjects (by objective SCORAD) was moderate (n=22) and severe (n=8). Compliance was good and patients generally managed to use the moisturisers daily, with individual reports of a 'tingly' sensation by some subjects when applied to inflamed wounds. 63% reported "very good" or "good", whereas 37% reported "fair" or "poor" acceptability of the moisturisers. Following use of the trial emollient, area affected, disease intensity and severity significantly improved, as demonstrated in objective SCORAD (p=0.002). There were also significant improvements in POEM (p=0.035), and PADQLQ scores (p=0.017). For skin measurements, only transepidermal water loss had improved (p=0.035) after the treatment. There was no significant improvement of itch or sleep scores, skin hydration, pH, S. aureus colonization status, or need for use of topical medications. When compared with historical data of other emollients, the mean age of patients on emollient W was younger; efficacy and acceptability among these emollients were similar. CONCLUSION: Methodology of emollient research is described. Doctors should provide evidencebased information about the efficacy of emollients. The ectoin-containing proprietary emollient improves disease and quality of life following its use in 4 weeks. Efficacy and acceptability are similar among 4 proprietary emollients.

Ectoine-Containing Inhalation Solution versus Saline Inhalation Solution in the Treatment of Acute Bronchitis and Acute Respiratory Infections: A Prospective, Controlled, Observational Study.

PURPOSE: This study investigated an inhalation solution containing ectoine, a bacterial-derived extremolyte, for the treatment of acute bronchitis and acute respiratory infections in comparison with saline inhalation solution. METHODS: This prospective, controlled, observational study comprised an inclusion visit (day 1), a final visit (day 7), and a follow-up questionnaire (day 17). The treatment itself was administered from day 1 to day 7. The Bronchitis Severity Score, patients' general health, general effectiveness of the treatment, tolerability, and adverse events were compared between two groups. RESULTS: In total, 135 patients were recruited; 79 patients received ectoine inhalation solution and 56 saline inhalation solution. After treatment, symptom scores decreased significantly in both groups (P < 0.05); the reduction in symptom scores was slightly greater in the ectoine group than in the saline group. The first significant reduction in symptom scores (P < 0.05) occurred earlier in the ectoine group than in the saline group. The differences in the area under the curve for the symptoms of dyspnea and auscultation findings were significant in favor of ectoine (P < 0.05). After treatment, more patients and physicians in the ectoine group assessed their or their patients' condition as "completely recovered" or "greatly improved" than those in the saline group. Almost all patients and physicians assessed the tolerability of both treatments as "good" or "very good". CONCLUSIONS: Ectoine inhalation solution seems to be slightly more effective than saline inhalation solution for the treatment of acute bronchitis and acute respiratory infections.

Small stress molecules inhibit aggregation and neurotoxicity of prion peptide 106-126.

In prion diseases, the posttranslational modification of host-encoded prion protein PrP(c) yields a high beta-sheet content modified protein PrP(sc), which further polymerizes into amyloid fibrils. PrP106-126 initiates the conformational changes leading to the conversion of PrP(c) to PrP(sc). Molecules that can defunctionalize such peptides can serve as a potential tool in combating prion diseases. In microorganisms during stressed conditions, small stress molecules (SSMs) are formed to prevent protein denaturation and maintain protein stability and function. The effect of such SSMs on PrP106-126 amyloid formation is explored in the present study using turbidity, atomic force microscopy (AFM), and cellular toxicity assay. Turbidity and AFM studies clearly depict that the SSMs-ectoine and mannosylglyceramide (MGA) inhibit the PrP106-126 aggregation. Our study also connotes that ectoine and MGA offer strong resistance to prion peptide-induced toxicity in human neuroblastoma cells, concluding that such molecules can be potential inhibitors of prion aggregation and toxicity.

Ionic liquid - microemulsions assisting in the transdermal delivery of Dencichine: Preparation, in-vitro and in-vivo evaluations, and investigation of the permeation mechanism.

A novel microemulsion was developed and characterized for topical delivery of Dencichine (Den). Two imidazaolium ionic liquid, 1-hydroxyethyl-3-methylimidazolium chloride ([HOEIM]Cl) and 1-butyl-3-methylimidazolium dodecanesulfate ([BMIM]C12SO3) were incorporated into the aqueous and surfactant phases respectively for the remarkable enhancement on skin permeation. The nano-carrier was developed and optimized based on a pseudo-ternary phase diagram. The optimized formulation was composed of 50% water/[HOEIM]Cl mix (1:1) as water phase, 20% Tween 80/[BMIM]C12SO3 mix (1:1) as surfactant, 10% propylene glycol as co-surfactant and 20% IPM as oil phase. The o/w microemulsion was then characterized for droplets sizes (47.7±1.5nm), zeta potential (-14.83±3.64mV), viscosity (31±4 mPa) and pH (6.71±0.04). In-vitro skin permeation assay suggested the strong enhancement of ILs formulation on the topical delivery of Den, which was approximately 10-fold that of the drug aqueous solution. It was found that the nano-carrier can reduce the skin barrier properties by disrupting the regular and compact arrangements of corneocytes, and moderating the surface properties of the stratum corneum, as evidenced by Transdermal Water Loss Evaluation (TEWL), Differential Scanning Calorimetery (DSC) and attenuated total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR). Furthermore, the in-vivo pharmacodynamic evaluation indicated the significant hemostatic activity of Den by the topical application of the vehicle. Additionally, the formulation showed minor cell toxicity and skin irritation. Therefore, our work suggested that the ionic liquid microemulsion can be a promising nano-scale vehicle for the topical application of Den to produce desirable pharmacological effects.

Potential for dietary exposure to ß-N-methylamino-L-alanine and microcystin from a freshwater system.

The suggested link between ß-N-methylamino-L-alanine (BMAA) and the onset of neurodegenerative diseases and the detection of this cyanotoxin in aquatic organisms has prompted research into the potential human exposure risk associated with sourcing food items from eutrophied water bodies worldwide. The Hartbeespoort Dam reservoir in the North West province of South Africa has persistent cyanobacterial blooms and is used extensively by anglers, many of whom consume their catch. The commercial sale of fish species harvested from this reservoir as part of a recent biomanipulative remediation strategy may pose an additional hazard. BMAA and Microcystins (MC) were detected in fish sourced from this reservoir. BMAA levels of up to 1630 ng g-1 dry weight and MC concentrations of up to 29.44 ng g-1 dry weight were detected in fish sourced during an extensive bloom episode, with a clear correlation between the total amount of BMAA detected in the fish muscle tissue and their relative position in the Hartbeespoort Dam reservoir food web. Interestingly, fish sourced from this reservoir in winter when dense cyanobacterial blooms were lacking contained BMAA levels of up to 3055 ng g-1 dry weight. We also comment on the observed seasonal variations of BMAA levels in phytoplankton and fish sourced from this water body as well as the potential exposure risks associated with harvesting food items from this reservoir.

The Evaluation of BMAA Inhalation as a Potential Exposure Route Using a rat Model.

Chronic inhalation of aerosolized ß-N-methylamino-L-alanine (BMAA) could serve as potenital route for exposure to this cyanobacterial neurotoxin implicated in the development of neurodegenerative disease. We investigated environmental aerosol BMAA loads and the fate of inhaled isotopically labeled aerosolized BMAA in adult male Sprague Dawley rats, with doses corresponding to chronic aerosolized environmental BMAA exposure of over 65 days and up to 266 years. Environmental BMAA aerosol concentrations ranged from 6-39 pg L¯1. No clinical signs of toxicity were observed in rats exposed to aerosol containing BMAA at concentrations far exceeding the maximum recorded environmental BMAA aerosol load. Surprisingly, no labeled BMAA was observed in the brain, liver or lung tissues of exposed rats. However, a dose-dependent reduction in the Gln:Glu ratio was observed in brain and liver tissues together with an increase in 2,3 diaminopropanoic acid,15N2, the demethylated L-BMAA-4,4,4-d3,15N2 product, in liver tissues. This confirmed both BMAA uptake and distribution throughout the body. The increase in 2,3 diaminopropanoic acid,15N2 did however not account for the total loss of administered L-BMAA-4,4,4-d3,15N2 and thus, the absence of detectable L-BMAA-4,4,4-d3,15N2 in tissues and feces, together with the absence of other known BMAA catabolites, N-acetylated BMAA and methylamine, additional metabolic reactions are indicated. Significant biochemical responses to BMAA were only observed in doses corresponding to an unrealistic chronic exposure timeframe, suggesting that the inhalation of environmental levels of aerosolized BMAA might not be sufficient to elicit a biochemical response in adults.