Tissue-level Biomarkers Research Articles

Active mussel biomonitoring for the health status assessment of the Western Mediterranean Sea

The Western Mediterranean coast is under the influence of anthropogenic pressures, including land use, increasing amounts of dangerous waste and habitat destruction. In 2021, the French RINBIO network (http://www.ifremer.fr/envlit/) originally dedicated to assess chemical contamination in the region, focused on biological effects produced by contaminants and the interaction with natural variability in mussels using an active caging strategy. Cell and tissue level biomarkers were applied for 17 sampling sites divided in three sub-regions categorized by different environmental conditions. Results provide critical information for ecosystem health assessment using mussels as sentinel species in the Western Mediterranean Sea. The influence of natural and confounding factors (trophic condition, reproductive cycle, caging strategy), on biological responses to mild chemical contamination, was discussed and discriminated for health status assessment. Results provide valuable data available as reference values for the assessment of biomarkers and histopathological alterations for large-scale active biomonitoring campaigns in the Western Mediterranean Sea.

Unmet need in rheumatology: reports from the Advances in Targeted Therapies meeting, 2023

The Advances in Targeted Therapies meets annually, convening experts in the field of rheumatology to both provide scientific updates and identify existing scientific gaps within the field. To review the...

Abstract 16786: Integrative Omics in Failing Myocardium Highlights Metabolic Substrate Utilization Defects in Human Heart Failure

Introduction: Changes in substrate utilization may be a biomarker of, or a contributor to, heart failure with reduced ejection fraction (HFrEF). Previous work has described circulating metabolites, proteins and transcripts that reflect myocardial bioenergetics, but direct assessment in relevant tissues is lacking. Here, we leverage integrative omics to identify tissue-level biomarkers and pathways of HFrEF that may play a role in pathogenesis. Methods: Myocardial tissue was obtained from 27 HFrEF donors and 21 non-failing hearts (noHF) from Duke University and the University of Colorado Medical Centers. Targeted (n=139 metabolites) and nontargeted (Metabolon, n=817) metabolic profiling was performed; in addition, 496 proteins were assayed (Olink) and ~31,000 transcripts were quantified via RNA sequencing. Individual metabolites were tested for association with HFrEF in models adjusted for age, sex and diabetes. Metabolomics, proteomics and RNA-seq data were integrated using block sparse partial least squares discriminant analysis (sPLS-DA) to identify correlated biomarkers that discriminate HFrEF from noHF hearts. Results: The targeted metabolomics platform primarily assayed metabolic fuel substrate pathways; 71 analytes (51%) were associated with HFrEF after controlling the false discovery rate (FDR) at 5%. Medium- and long-chain acylcarnitines (C10s-C18s) were significantly lower in tissue from failing hearts, while branched-chain amino acids (BCAA) and ketoacids were higher. In the nontargeted set, 293 metabolites (36%) differed between HFrEF and noHF. BCAA and acylcarnitine associations were recapitulated along with a decrease in malonylcarnitine. The sPLS-DA model selected 25 targeted and 50 nontargeted metabolites, 35 proteins and 35 transcripts, and successfully discriminated HFrEF from no HF (balanced error rate = 3.2%). 39/186 tested KEGG pathways were overrepresented in these analytes, including fatty acid metabolism (FDR q=0.002). Conclusions: Analysis of tissue-level metabolites suggests both decreased use of fatty acids as a fuel and disrupted enzymatic breakdown of BCAAs in the failing heart, while integrative omics pathway analysis also supports the association of disrupted fatty acid metabolism with HF.

Integrated assessment of biological responses to pollution in wild mussels (Mytilus edulis) from subarctic and arctic areas in the Norwegian sea

North Atlantic and Arctic Oceans contain large amount of undiscovered oil and gas reserves. Therefore threat of oil spills and its hazardous ecological consequences are of great importance to the marine environment. Although mussels (Mytilus sp.) respond clearly to contaminants, biomarkers have shown variability linked to biological and environmental changes. In order to help avoiding misinterpretation of biological responses the aim of this study was to reveal the effect of natural variability in the responsiveness to pollution of a battery of cell and tissue-level biomarkers in mussels. Mussels were collected in relatively non-impacted and potentially impacted sites at ports and the vicinity of a waste water treatment plant in Trondheim and Tromsø in autumn of 2016. Although the battery of biomarkers used herein proved to be useful to discriminate impacted and non-impacted mussel populations, some confounding factors altering the biological responses were identified. Geographical/latitudinal factors seemed to be critical regarding the reproductive cycle, reserve material storage and the prevalence of parasites such as Gymnophallus cf. Bursicola trematodes. Mussels from the reference site in Tromsø displayed general stress responses at different levels, which could be influenced by the pathogenic effect of the Gymnophallus cf. Bursicola trematode and by a more advanced gametogenic developmental stage compared to the mussels from Trondheim, which could lead to misinterpretation of the reasons behind the measured stress levels in those mussels. Despite these confounding effects, the use of integrative tools such as IBR index helped to discriminate mussel populations from chemically impacted and non-impacted sites. Overall, this work serves as an anchor point both as a reference of the baseline level values of the analyzed endpoints in the studied geographical area and time of the year, and as an indication of the potential extent of the environmental confounding factors in monitoring programs causing stress on the analyzed mussel populations.

In silico assessment of pharmacotherapy for carbon monoxide induced arrhythmias in healthy and failing human hearts.

Background: Carbon monoxide (CO) is gaining increased attention in air pollution-induced arrhythmias. The severe cardiotoxic consequences of CO urgently require effective pharmacotherapy to treat it. However, existing evidence demonstrates that CO can induce arrhythmias by directly affecting multiple ion channels, which is a pathway distinct from heart ischemia and has received less concern in clinical treatment. Objective: To evaluate the efficacy of some common clinical antiarrhythmic drugs for CO-induced arrhythmias, and to propose a potential pharmacotherapy for CO-induced arrhythmias through the virtual pathological cell and tissue models. Methods: Two pathological models describing CO effects on healthy and failing hearts were constructed as control baseline models. After this, we first assessed the efficacy of some common antiarrhythmic drugs like ranolazine, amiodarone, nifedipine, etc., by incorporating their ion channel-level effects into the cell model. Cellular biomarkers like action potential duration and tissue-level biomarkers such as the QT interval from pseudo-ECGs were obtained to assess the drug efficacy. In addition, we also evaluated multiple specific I Kr activators in a similar way to multi-channel blocking drugs, as the I Kr activator showed great potency in dealing with CO-induced pathological changes. Results: Simulation results showed that the tested seven antiarrhythmic drugs failed to rescue the heart from CO-induced arrhythmias in terms of the action potential and the ECG manifestation. Some of them even worsened the condition of arrhythmogenesis. In contrast, I Kr activators like HW-0168 effectively alleviated the proarrhythmic effects of CO. Conclusion: Current antiarrhythmic drugs including the ranolazine suggested in previous studies did not achieve therapeutic effects for the cardiotoxicity of CO, and we showed that the specific I Kr activator is a promising pharmacotherapy for the treatment of CO-induced arrhythmias.

CTNI-48. TRIAL UPDATE -RESULTS OF A PHASE I WINDOW OF OPPORTUNITY TRIAL EVALUATING A FIRST-IN-CLASS CD29 INHIBITOR, OS2966, IN RECURRENT HIGH-GRADE GLIOMA

Abstract BACKGROUND OS2966 is a first-in-class, humanized, and deimmunized anti-CD29 (β1integrin) monoclonal antibody. CD29 is a mechanosignaling receptor prominently upregulated in glioblastoma. Preclinical studies in mice and non-human primates have demonstrated safety and encouraging efficacy. A phase I clinical trial was therefore initiated to evaluate the safety and feasibility of delivering OS2966 directly to the site of disease via convection-enhanced delivery (CED) in recurrent high-grade glioma patients. METHODS This study employs a 2-part design: In part 1, patients undergo stereotactic tumor biopsy followed by placement of a CED catheter(s) for delivery of OS2966 to the bulk contrast-enhancing tumor. Subsequently, in part 2, patients undergo a clinically-indicated tumor resection followed by placement of CED catheter(s) and delivery of OS2966 to the surrounding tumor-infiltrated brain. Co-convection of gadolinium enables real-time monitoring of therapeutic delivery. A concentration-based accelerated titration design is utilized for dose escalation. Given availability of pre and post-infusion samples, pharmacodynamic data will be analyzed to explore mechanism of action of OS2966. RESULTS Four patients have completed treatment in both study parts. No dose-limiting toxicity or adverse events related to treatment with OS2966 or CED catheter placement have been reported at the first 3 dose levels (ie, doses up to 0.6 mg/mL). For the four patients treated an average of 4.2 mL and 3.2 mL were infused in study parts 1 and 2 respectively. The Vd/Vi ratio ranged from 0.6 to 1.6 in part 1, and from 2.0 to 4.3 in Study Part 2. Analysis of tissue samples collected during the trial has demonstrated decreased VEGF expression post-treatment, with preinfusion samples showing > 50% VEGF expression and post-infusion samples showing 10% expression. Additional pharmacodynamic analysis via tissue-level biomarkers is ongoing and will be presented. CONCLUSION Initial data demonstrate the safety and feasibility of direct intracranial delivery of OS2966.

CTNI-41. INITIAL RESULTS OF A PHASE I WINDOW OF OPPORTUNITY TRIAL EVALUATING A FIRST-IN-CLASS CD29 INHIBITOR, OS2966, IN RECURRENT HIGH-GRADE GLIOMA

Abstract BACKGROUND OS2966 is a first-in-class, humanized and deimmunized monoclonal antibody which antagonizes CD29/β1integrin, a mechanosignaling receptor prominently upregulated in glioblastoma. Preclinical studies in mice and non-human primates have demonstrated safety and encouraging efficacy. A two-part, ascending concentration, phase I clinical trial was therefore initiated to evaluate the safety and feasibility of delivering OS2966 directly to the site of disease via convection-enhanced delivery (CED) in recurrent high-grade glioma patients. METHODS This study has a 2-part design: In part 1, patients undergo stereotactic tumor biopsy followed by placement of a multiport CED catheter for delivery of OS2966 to the bulk contrast enhancing tumor. Subsequently, patients undergo a clinically-indicated tumor resection followed by placement of two CED catheters and delivery of OS2966 to the surrounding tumor-infiltrated brain. A unique concentration-based accelerated titration design is utilized for dose escalation. Given availability of pre and post infusion samples, pharmacodynamic data will be analyzed to explore mechanism of action of OS2966. RESULTS Two subjects have been treated at two corresponding dose levels (0.2mg/mL and 0.4 mg/mL). No dose-limiting toxicity or unexpected safety issues have been identified. To date, reported adverse events were mild (i.e., grade 1) and consistent with underlying disease and surgical procedures. No adverse events were attributed to OS2966 or CED catheter placement. Further, no clinically significant changes from baseline neurological exam have been noted for either patient through initial follow-up. Maximal tumor coverage and concomitant gross total resection were achieved for both patients. Tumor volume measured 1.63 cm3 and 16 cm3 for Patient 1 and 2 respectively with an intratumoral Vd/Vi ratio of 1.3. and 0.94. Pharmacodynamic analysis via tissue-level biomarkers is ongoing and will be presented. CONCLUSION Initial data demonstrates the safety and feasibility of direct intracranial delivery of OS2966.

An integrated biomarker approach to assess the welfare status of Ompok bimaculatus (Pabda) in biofloc system with altered C/N ratio and subjected to acute ammonia stress

Biofloc aquaculture is emerging fast as a sustainable technology; however, the system faces challenges from ammonia spikes that affect the physiology of the fishes. Besides, the immuno-stimulatory role of the produced floc in encountering the induced stressor is poorly understood. In this context, the study investigates the effect of different carbon to nitrogen (C/N) ratio on the welfare status of Ompok bimaculatus subjected to acute ammonia stress using an integrated biomarker response (IBR) approach. Four treatments with different C/N ratio of 10, 15, 20 & 25 were designated as C/N10, C/N15, C/N20 and C/N25, alongside a control group with a provision for 80–90% daily water exchange. Twenty-day old O. bimaculatus (average weight = 0.082 ± 0.001 g) larvae were uniformly distributed in each tank (25 l) at a stocking density of 160 nos./tank. At the end of 45-days rearing, fishes were exposed to an acute 96-h ammonia challenge, using a calculated LC50 value of 12.19 mg l−1. Pre- and post-exposure, blood indices like RBC, PVC and Hb were found highest in C/N25, while WBC was highest in C/N20. Plasma total protein, albumin and globulin levels were also elevated in C/N20 group, before and after exposure. Immune scores like lysozyme and respiratory burst activity were found highest in C/N20, whereas the control group showed the lowest activity. Stress biomarkers (glucose and cortisol) showed no significant change (p > 0.05) before exposure, however, levels were elevated in all groups with the highest observed in control and lowest in C/N15 and 20. Before exposure, catalase (CAT) activity was highest in C/N20 in all tissues (liver, gut, muscle); whereas, levels decreased compared to control after exposure. Post exposure, superoxide dismutase (SOD) activity was highest in C/N20 in all tissues (p < 0.05). Before and after ammonia exposure, glutathione peroxidase (GPx) activity in liver was highest in C/N20, whereas, its activity in gut was highest in C/N15. IBR analysis reveals higher values in liver and gut for biomarkers like MDA and GPx, while, SOD showed a plausible level in muscle tissue. Semi-quantitative histological analysis of the gill tissue showed a distinctive pathological damage in all the groups, post-exposure, with the control receiving highest level of alterations, however, not significant with C/N 15 & 25. Probability of survival among groups was highest in C/N20. Overall results from this study indicates a varied immune-stimulatory effect of C/N manipulation with C/N20 delivering highest protection to O. bimaculatus fry against acute ammonia challenge. Further, the IBR approach delineates the probable use of the tissue-level biomarkers for ascertaining the welfare status of O. bimaculatus in the biofloc system.

Food-type may jeopardize biomarker interpretation in mussels used in aquatic toxicological experimentation.

To assess the influence of food type on biomarkers, mussels (Mytilus galloprovincialis) were maintained under laboratory conditions and fed using 4 different microalgae diets ad libitum for 1 week: (a) Isochrysis galbana; (b) Tetraselmis chuii; (c) a mixture of I. galbana and T. chuii; and (d) a commercial food (Microalgae Composed Diet, Acuinuga). Different microalgae were shown to present different distribution and fate in the midgut. I. galbana (≈4 μm Ø) readily reached digestive cells to be intracellularly digested. T. chuii (≈10 μm Ø and hardly digestible) was retained in stomach and digestive ducts for long times and extracellularly digested. Based on these findings, it appeared likely that the presence of large amounts of microalgal enzymes and metabolites might interfere with biochemical determinations of mussel’s biomarkers and/or that the diet-induced alterations of mussels’ digestion could modulate lysosomal and tissue-level biomarkers. To test these hypotheses, a battery of common biochemical, cytological and tissue-level biomarkers were determined in the gills (including activities of pyruvate kinase, phosphoenolpyruvate carboxykinase and cytochrome c oxidase) and the digestive gland of the mussels (including protein, lipid, free glucose and glycogen total content, lysosomal structural changes and membrane stability, intracellular accumulation of neutral lipids and lipofuscins, changes in cell type composition and epithelial thinning, as well as altered tissue integrity). The type of food was concluded to be a major factor influencing biomarkers in short-term experiments though not all the microalgae affected biomarkers and their responsiveness in the same way. T. chuii seemed to alter the nutritional status, oxidative stress and digestion processes, thus interfering with a variety of biomarkers. On the other hand, the massive presence of I. galbana within digestive cells hampered the measurement of cytochemical biomarkers and rendered less reliable the results of biochemical biomarkers (as these could be attributed to both the mussel and the microalgae). Research to optimize dietary food type, composition, regime and rations for toxicological experimentation is urgently needed. Meanwhile, a detailed description of the food type and feeding conditions should be always provided when reporting aquatic toxicological experiments with mussels, as a necessary prerequisite to compare and interpret the biological responses elicited by pollutants.

Influence of season-depending ecological variables on biomarker baseline levels in mussels (Mytilus trossulus) from two Baltic Sea subregions

For reliable mussel monitoring programmes based on biomarkers, regionally relevant reference values and their natural variability need to be known. The Baltic Sea exhibits high inter-regional and seasonal variability in physical factors such as salinity, temperature and primary production. The aim of this pilot study is to depict the effects of season-related environmental factors in a selected battery of biomarkers in two environmentally different subregions of the Baltic Sea to help establishing reference data for biochemical, cellular and tissue-level biomarkers. In order to achieve that, mussels were collected from reference sites in Kiel (Germany) and Tvärminne (Finland) during three seasons: summer and autumn 2016, and spring 2017. Finally, in order to characterize the ecological situation, analysis of the chemical tissue burden was performed and chlorophyll‑a and particulate organic carbon concentration and temperature changes were analyzed at each sampling locality using satellite remote sensing images. An integrated biomarker response index was performed to summarize the biomarker responses of each locality and season. The biochemical endpoints showed seasonal variability regulated by temperature, food supply and reproductive cycle, while among the cellular endpoints only lipofuscin accumulation and lysosomal structural changes showed slight seasonal variation. Seasonal changes in tissue level biomarkers were observed only at the northern Baltic Sea site Tvärminne, dictated by the demanding energetic trade-off caused by reproduction. In conclusion, the characterization of the ecological variables and physico-chemical conditions at each site, is crucial to perform a reliable assessment of the effects of a hypothetical pollution scenario in the Baltic Sea. Moreover, reference levels of biomarkers and their responses to natural environmental conditions must be established.

Collection and transport of sentinel mussels in biomarker-based coastal pollution monitoring: Current flaws and reliable practices

Abstract Biomarkers use to be recorded in sentinel mussels for biological effects assessment in coastal pollution monitoring. There are recommended procedures (e.g., by ICES) for biomarker determination but not for sample collection and transport. However, where and when mussels are collected and how samples are processed can be a major source of variability in biomarker values. Thus, the present study aims at contributing to identify reliable practices for collection and transport of intertidal mussels in biomarker-based coastal pollution monitoring. Mussels, Mytilus galloprovincialis, were handpicked from the high (2.5–3.0 m) and low (0.5–1.0 m) tide-mark levels at autumn tides in Gorliz, a relatively clean locality of the Basque Coast (Bay of Biscay). Then, they were processed by different ways: (a) in situ dissected immediately after sampling; (b) transported to the laboratory either in air or in seawater; and (c) dissected at different time intervals after sampling. Oxidative stress, lysosomal and tissue-level biomarkers were investigated. Oxidative stress and lysosomal biomarkers were significantly affected by collection and transport to the laboratory, due to the combination of air exposure (hypoxia) and digestion process. Consequently, it is recommended that sentinel mussels should be collected the nearest possible to the 0 tide-mark level and processed in situ as soon as possible, and always within 1 h upon collection. If in situ processing is not possible, mussels should be transported in air and processed within the shortest time possible. Finally, details on sampling should be always provided to made possible the proper interpretation and comparison of results.

Effects of dietary Pb and Cd and their combination on lysosomal and tissue-level biomarkers and histopathology in digestive gland of the land snail, Cantareus apertus (Born, 1778)

The present study was aimed at determining cell and tissue-level biomarkers and histopathological alterations in the green garden snail, Cantareus apertus (Born, 1778), exposed to different nominal dietary concentrations of Pb (25, 100 and 2500 mg Pb/kg), Cd (5, 10 and 100 mg Cd/kg) and their combination (25 mg Pb + 5 mg Cd/Kg, 100 mg Pb + 10 mg Cd/kg and 2500 mg Pb + 100 mg Cd/ kg) for 1 and 8 weeks. Lead and Cd exerted histopathological effects on the digestive gland in a dose-dependent manner and related to lysosomal and tissue-level biomarkers. The biological responses observed included digestive cell vacuolisation and numerical atrophy, calcium cell hydropic degeneration, excretory cell hypertrophy, inflammatory responses, blood vessel congestion, and disruption of the blood vessel wall and the interstitial connective tissue. Lysosomal enlargement and transient intracellular accumulation of neutral lipids and lipofuscins were also observed, together with alterations in the cell type composition and thinning of the digestive gland epithelium and with diverticular distortion. This response profile fits well with the biological effects reported after metal exposure in gastropods from other regions, as well as with data obtained in parallel studies dealing with metal bioaccumulation and intralysosomal accumulation, mortality, feeding, growth, oxidative stress and neurotoxicity exerted elicited by Pb, Cd and their mixture in green garden snails under the present experimental conditions. Consequently, C. apertus seems to be a suitable model species for the biomarker-based assessment of the biological effects of Pb and Cd, alone or in combinations, thus providing a challenging opportunity to advance in identifying suitable sentinel species for metal pollution biomonitoring and ecosystem health assessment in soil ecosystems in Northern Africa.

Assessment of ecosystem health disturbance in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as sentinel species

This investigation was aimed at contributing to develop a suitable multi-biomarker approach for pollution monitoring in mangrove-lined Caribbean coastal systems using as sentinel species, the mangrove cupped oyster, Crassostrea rhizophorae. A pilot field study was carried out in 8 localities (3 in Nicaragua; 5 in Colombia), characterized by different environmental conditions and subjected to different levels and types of pollution. Samples were collected in the rainy and dry seasons of 2012–2013. The biological effects at different levels of biological complexity (Stress-on-Stress response, reproduction, condition index, tissue-level biomarkers and histopathology) were determined as indicators of health disturbance, integrated as IBR/n index, and compared with tissue burdens of contaminants in order to achieve an integrative biomonitoring approach. Though modulated by natural variables and confounding factors, different indicators of oyster health, alone and in combination, were related to the presence of different profiles and levels of contaminants present at low-to-moderate levels. Different mixtures of persistent (As, Cd, PAHs) and emerging chemical pollutants (musk fragrances), in combination with different levels of organic and particulate matter resulting from seasonal oceanographic variability and sewage discharges, and environmental factors (salinity, temperature) elicited a different degree of disturbance in ecosystem health condition, as reflected in sentinel C. rhizophorae. As a result, IBR/n was correlated with pollution indices, even though the levels of biological indicators of health disturbance and pollutants were low-to-moderate, and seasonality and the incidence of confounding factors were remarkable. Our study supports the use of simple methodological approaches to diagnose anomalies in the health status of oysters from different localities and to identify potential causing agents and reflect disturbances in ecosystem health. Consequently, the easy methodological approach used herein is useful for the assessment of health disturbance in a variety of mangrove-lined Caribbean coastal systems using mangrove cupped oysters as sentinel species.

Imaging Approaches to Stroke and Neurovascular Disease.

Imaging is paramount to the diagnosis and management of ischemic stroke, offering a battery of structural and functional probes of cerebrovascular physiology. The technical underpinnings of stroke imaging continue to evolve, bringing the neuroscience community increasingly closer to high-resolution, tissue-level biomarkers of brain perfusion, metabolism, and viability. The rapid expansion of neuroimaging in this domain has met with controversies, and in many respects, a lack of generalizable conclusions regarding optimized use in cerebrovascular disease. This review aims to provide the reader with the depth and scope of both established and emerging techniques, and an overview of prevailing viewpoints regarding neuroimaging in acute ischemic stroke.

Imaging Approaches to Stroke and Neurovascular Disease.

Imaging is paramount to the diagnosis and management of ischemic stroke, offering a battery of structural and functional probes of cerebrovascular physiology. The technical underpinnings of stroke imaging continue to evolve, bringing the neuroscience community increasingly closer to high-resolution, tissue-level biomarkers of brain perfusion, metabolism, and viability. The rapid expansion of neuroimaging in this domain has met with controversies, and in many respects, a lack of generalizable conclusions regarding optimized use in cerebrovascular disease. This review aims to provide the reader with the depth and scope of both established and emerging techniques, and an overview of prevailing viewpoints regarding neuroimaging in acute ischemic stroke.

Assessment of the effects of Cu and Ag in oysters Crassostrea gigas (Thunberg, 1793) using a battery of cell and tissue level biomarkers

Oysters are considered sentinel organisms in environmental water quality monitoring programs in which cell and tissue level biomarkers are reliable tools. Copper (Cu) and silver (Ag) are present in relatively high concentrations in several estuaries, potentially affecting environmental and human health. Crassostrea gigas oysters were exposed during 28 days to a range of environmentally relevant concentrations of Cu and Ag alone or in mixture. Effects were studied through cell and tissue level biomarkers approach. Results indicated: changes in the Condition Index (CI), altered digestive gland epithelium and presence of histopathological alterations in the gonad and digestive gland of exposed oysters. A time-dependent increase in lipofuscin contents in exposed oysters and an increase in intralysosomal metal accumulation in digestive cells through the experiment were also recorded. The Integrative Biological Response (IBR) Index showed that even at low exposure levels, Ag and Cu can produce alterations on oysters' health status.

Histopathological assessment and inflammatory response in the digestive gland of marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots

Although tissue-level biomarkers have been widely applied in environmental toxicology studies, the knowledge using this approach in marine invertebrates exposed to engineered nanomaterials (ENMs) remains limited. This study investigated histopathological alterations and inflammatory responses induced by Cd-based quantum dots (QDs), in comparison with their dissolved counterparts, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd at the same concentration (10μg Cd L−1) for 14days and a total of 15 histopathological alterations and 17 histomorphometric parameters were analysed in the digestive gland along with the determination of histopathological condition indices (Ih). A multivariate analysis showed that the mussel response to QDs was more related to exposure time, inflammatory conditions (frequency of haemocytic infiltration and granulocytomas) and changes of cell-type composition (especially the rate between basophilic and digestive cells) when compared to dissolved Cd, while the response to dissolved Cd was associated with histomorphometric parameters of the epithelium and lumen of digestive tubules and increase of the atrophic tubule frequency. Both Cd forms induced higher Ih compared to unexposed mussels indicating a significant decrease in the health status of digestive gland in a Cd form and time-dependent pattern. Results indicate that the multiparametric tissue-level biomarkers in the digestive gland provide a suitable approach to assess the ecotoxicity and mode of action of metal-based ENMs in marine bivalves.

Use of multiple cell and tissue-level biomarkers in mussels collected along two gas fields in the northern Adriatic Sea as a tool for long term environmental monitoring

As a consequence of the growing global demand of energy supplies, intense oil and gas exploration and exploitation programs have been carried out worldwide especially within the marine environments. The release of oil-derived compounds in the sea from anthropogenic sources both as effluents or accidental spill is perceived as a major environmental concern. An approach based on a combination of biomarkers and the distribution of some classes of environmentally relevant pollutants was used to investigate the occurrence of a stress syndrome in mussels (Mytilus galloprovincialis) collected at three gas platforms placed in two distinct oceanographic districts within the Adriatic Sea. Biological responses were integrated by a ranking algorithm which demonstrated both a range of biological effects reflecting exposure gradients and a temporal related trend in the investigated responses. The overall results demonstrate a moderate to absent pollution from studied gas platforms with low but remarkable biological disturbance in sentinel organisms.

Health status assessment through an integrative biomarker approach in mussels of different ages with a different history of exposure to the Prestige oil spill

A battery of cell and tissue-level biomarkers was applied in mussels of 6 size-classes collected from Galicia and the Basque coast in summer 2007 in an attempt to examine the health status of individuals affected as adults (mature before 2003), affected during their developmental or juvenile stages (2003–2004 offspring), or not directly affected by the Prestige oil spill (POS) exposure (presumably 2005–2006 offspring). This battery of biomarkers was akin to those formerly applied on mussels of 3.5–4.5cm shell length for which there exist biomarker reference values in the studied geographical areas. The cause–effect relationship between biological responses and the different history of exposure to POS fuel oil was intricate for different reasons: (a) growth rate was dissimilar in mussels of the two studied localities and much lower than expected, (b) a chronological basis could not be directly associated to POS events (all mussels except the smallest from Galicia had been subjected to the direct POS impact at one or another stage of their life-cycle); and (c) some biomarkers and histopathology seemingly depended on size/age irrespectively of the locality and the POS chronology. As a whole, the present study gives a very useful set of reference values of biomarkers obtained for Mytilus galloprovincialis of different size-classes. Finally, it is recommended that Mussel Watch programmes should be designed by standardising the age of the sentinel mussels rather than their size, especially if the programme covers large or diverse geographical areas, if long-term trends are relevant or if significant pollution effects on growth are expected.

Lysosomal and tissue-level biomarkers in mussels cross-transplanted among four estuaries with different pollution levels

A 3–4wk cross-transplantation experiment was carried out in order to investigate the sensitivity, rapidity, durability and reversibility of lysosomal and tissue-level biomarkers in the digestive gland of mussels. Four localities in the Basque coast with different levels of chemical pollution and environmental stress were selected. Lysosomal membrane stability (LP) and lysosomal structural changes (VvL; S/VL; NvL) and changes in cell-type composition in digestive gland epithelium (VvBAS) were investigated to determine short (2d) and mid-term (3–4wk) responses after cross-transplantation. Mussels from Txatxarramendi presented VvBAS<0.1μm3/μm3 (unstressed) whilst VvBAS>0.12μm3/μm3 was recorded in mussels from Plentzia (moderate stress) and VvBAS>0.2μm3/μm3 in Arriluze and Muskiz (high stress). Accordingly, LP<10min (high stress) was recorded in mussels from Muskiz and Arriluze and LP~15min (low-to-moderate stress) in those from Plentzia and Txatxarramendi. According to the VvL, S/VL and NvL data, a certain lysosomal enlargement was envisaged in mussels from Arriluze in comparison with those from Txatxarramendi and Plentzia. Mussels from Muskiz exhibited a peculiar endo-lysosomal system made of abundant tiny lysosomes (low VvL and high S/VL and NvL values). Lysosomal and tissue-level biomarkers were responsive after 2d cross-transplantation between the reference and the polluted localities, which indicated that these biomarkers were quickly induced and, to a large extent, reversible. Moreover, the tissue-level biomarker values were maintained during the entire period (3–4wk) of cross-transplantation, which evidenced the durability of the responsiveness. In contrast, comparisons in the mid-term were unfeasible for lysosomal biomarkers as these exhibited a seasonal winter attenuation resulting from low food availability and low temperatures. In conclusion, lysosomal enlargement and membrane stability and changes in cell-type composition were sensitive, rapid and reversible responses to changes in environmental stress whilst durability of the response could not be demonstrated for lysosomal responses by interferences with the seasonal variability.