Ciclación Rápida en el Trastorno Bipolar: una Metarevisión / Rapid cycling in bipolar disorder: a meta-review

El descriptor evolutivo "Ciclación Rápida" (CR) en el Trastorno Bipolar constituye uno de los retos más importantes a la hora de realizar un plan terapéutico. Sin embargo, a pesar de su uso habitual en la clínica y los libros generalistas, existe poca bibliografía original y escasas publicaciones de investigación sobre el tema. La presente metarevisión analiza los datos más recientes al respecto, enfatizando especialmente los aspectos etiopatogénicos, evolutivos y de tratamiento. Para ello, hemos utilizado las revisiones y artículos recogidos en las bases de datos PubMed y Psychinfo en los últimos 10 años (entre abril del 2011 y abril del 2021), publicadas en inglés o castellano. Después de descartar duplicados, por consenso pudimos seleccionar 76 publicaciones que cumplían los criterios de inclusión. Como principales resultados, destacan los estudios que relacionan la futura aparición de CR con un inicio más precoz del trastorno bipolar, la comorbilidad con el trastorno límite de la personalidad y con el consumo de sustancias. Entre los factores biológicos favorecedores, estarían las alteraciones tiroideas, la obesidad, las alteraciones de los ritmos circadianos, la migraña y otros factores inflamatorios y (quizás) los tratamientos antidepresivos continuados. Entre los aspectos terapéuticos, destacan los bajos niveles de recomendación y de evidencia entre las pautas propuestas en las diferentes revisiones y guías terapéuticas, lo cual se corresponde también con las dificultades de tratamiento en la práctica clínica. Por otra parte, se evidencia la falta de ensayos clínicos y estudios randomizados adecuados y específicos para poder extraer mejores conclusiones al respecto.(AU)

The clinical descriptor “Rapid Cycling” (RC) in Bipolar Disorder is one of the most important challenges in designing a therapeutic plan. However, despite its usual use in medical practice and in general books, there is little original literature and few publications related to it. This umbrella review analyses most recent publications referred to Rapid Cycling, emphasizing specially in their etiology, outcomes and treatment aspects. Reviews from the databases PubMed and Psychinfo have been collected, including the ones from the last 10 years (between April 2011 and April 2021), published in English or Spanish. After discharging duplicates, we applied a consensus to finally recruit 76 publications that fulfilled the inclusion criteria.As main results it must be mentioned the studies that relate RC to early age of onset, the ones that relate it with Borderline Personality Disorder comorbidity and finally the ones with Substance Abuse. Biological factors considered for the etiology of RC would be thyroidal disorders, obesity, circadian rhythms disorders and other inflammatory factors, migraine and (maybe) the maintained antidepressant treatments. Among the therapeutic aspects, the low level of recommendation and evidence in the different therapeutic guidelines stands out. This corresponds with the treatment difficulties observed in the clinical practice. Finally, it is important to mention the lack of clinical trials and randomized studies that are necessary to obtain better conclusions in the area.(AU)

In situ experimental evidences for responses of abyssal benthic biota to shifts in phytodetritus compositions linked to global climate change.

Abyssal plains cover more than half of Earth's surface, and the main food source in these ecosystems is phytodetritus, mainly originating from primary producers in the euphotic zone of the ocean. Global climate change is influencing phytoplankton abundance, productivity, and distribution. Increasing importance of picoplankton over diatom as primary producers in surface oceans (especially projected for higher latitudes) is projected and hence altering the quantity of organic carbon supplied to the abyssal seafloor as phytodetritus, consequences of which remain largely unknown. Here, we investigated the in situ responses of abyssal biota from viruses to megafauna to different types of phytoplankton input (diatoms or cyanobacteria which were labeled with stable isotopes) at equatorial (oligotrophic) and temperate (eutrophic) benthic sites in the Pacific Ocean (1°N at 4277 m water depth and 39°N at 5260 m water depth, respectively). Our results show that meiofauna and macrofauna generally preferred diatoms as a food source and played a relatively larger role in the consumption of phytodetritus at higher latitudes (39°N). Contrarily, prokaryotes and viruses showed similar or even stronger responses to cyanobacterial than to diatom supply. Moreover, the response of prokaryotes and viruses was very rapid (within 1-2 days) at both 1°N and 39°N, with quickest responses reported in the case of cyanobacterial supply at higher latitudes. Overall, our results suggest that benthic deep-sea eukaryotes will be negatively affected by the predicted decrease in diatoms in surface oceans, especially at higher latitudes, where benthic prokaryotes and viruses will otherwise likely increase their quantitative role and organic carbon cycling rates. In turn, such changes can contribute to decrease carbon transfer from phytodetritus to higher trophic levels, with strong potential to affect oceanic food webs, their biodiversity and consequently carbon sequestration capacity at the global scale.

CO2 leakage from carbon dioxide capture and storage (CCS) systems affects organic matter cycling in surface marine sediments.

Carbon dioxide capture and storage (CCS), involving the injection of CO2 into the sub-seabed, is being promoted worldwide as a feasible option for reducing the anthropogenic CO2 emissions into the atmosphere. However, the effects on the marine ecosystems of potential CO2 leakages originating from these storage sites have only recently received scientific attention, and little information is available on the possible impacts of the resulting CO2-enriched seawater plumes on the surrounding benthic ecosystem. In the present study, we conducted a 20-weeks mesocosm experiment exposing coastal sediments to CO2-enriched seawater (at 5000 or 20,000 ppm), to test the effects on the microbial enzymatic activities responsible for the decomposition and turnover of the sedimentary organic matter in surface sediments down to 15 cm depth. Our results indicate that the exposure to high-CO2 concentrations reduced significantly the enzymatic activities in the top 5 cm of sediments, but had no effects on subsurface sediment horizons (from 5 to 15 cm depth). In the surface sediments, both 5000 and 20,000 ppm CO2 treatments determined a progressive decrease over time in the protein degradation (up to 80%). Conversely, the degradation rates of carbohydrates and organic phosphorous remained unaltered in the first 2 weeks, but decreased significantly (up to 50%) in the longer term when exposed at 20,000 ppm of CO2. Such effects were associated with a significant change in the composition of the biopolymeric carbon (due to the accumulation of proteins over time in sediments exposed to high-pCO2 treatments), and a significant decrease (∼20-50% at 5000 and 20,000 ppm respectively) in nitrogen regeneration. We conclude that in areas immediately surrounding an active and long-lasting leak of CO2 from CCS reservoirs, organic matter cycling would be significantly impacted in the surface sediment layers. The evidence of negligible impacts on the deeper sediments should be considered with caution and further investigated simulating the intrusion of CO2 from a subsurface source, as occurring during real CO2 leakages from CCS sites.

Impact of CO2 leakage from sub-seabed carbon dioxide capture and storage (CCS) reservoirs on benthic virus-prokaryote interactions and functions.

Atmospheric CO2 emissions are a global concern due to their predicted impact on biodiversity, ecosystems functioning, and human life. Among the proposed mitigation strategies, CO2 capture and storage, primarily the injection of CO2 into marine deep geological formations has been suggested as a technically practical option for reducing emissions. However, concerns have been raised that possible leakage from such storage sites, and the associated elevated levels of pCO2 could locally impact the biodiversity and biogeochemical processes in the sediments above these reservoirs. Whilst a number of impact assessment studies have been conducted, no information is available on the specific responses of viruses and virus-host interactions. In the present study, we tested the impact of a simulated CO2 leakage on the benthic microbial assemblages, with specific focus on microbial activity and virus-induced prokaryotic mortality (VIPM). We found that exposure to levels of CO2 in the overlying seawater from 1,000 to 20,000 ppm for a period up to 140 days, resulted in a marked decrease in heterotrophic carbon production and organic matter degradation rates in the sediments, associated with lower rates of VIPM, and a progressive accumulation of sedimentary organic matter with increasing CO2 concentrations. These results suggest that the increase in seawater pCO2 levels that may result from CO2 leakage, can severely reduce the rates of microbial-mediated recycling of the sedimentary organic matter and viral infections, with major consequences on C cycling and nutrient regeneration, and hence on the functioning of benthic ecosystems.

Marine litter distribution and density in European seas, from the shelves to deep basins.

Anthropogenic litter is present in all marine habitats, from beaches to the most remote points in the oceans. On the seafloor, marine litter, particularly plastic, can accumulate in high densities with deleterious consequences for its inhabitants. Yet, because of the high cost involved with sampling the seafloor, no large-scale assessment of distribution patterns was available to date. Here, we present data on litter distribution and density collected during 588 video and trawl surveys across 32 sites in European waters. We found litter to be present in the deepest areas and at locations as remote from land as the Charlie-Gibbs Fracture Zone across the Mid-Atlantic Ridge. The highest litter density occurs in submarine canyons, whilst the lowest density can be found on continental shelves and on ocean ridges. Plastic was the most prevalent litter item found on the seafloor. Litter from fishing activities (derelict fishing lines and nets) was particularly common on seamounts, banks, mounds and ocean ridges. Our results highlight the extent of the problem and the need for action to prevent increasing accumulation of litter in marine environments.

Biotic and human vulnerability to projected changes in ocean biogeochemistry over the 21st century.

Ongoing greenhouse gas emissions can modify climate processes and induce shifts in ocean temperature, pH, oxygen concentration, and productivity, which in turn could alter biological and social systems. Here, we provide a synoptic global assessment of the simultaneous changes in future ocean biogeochemical variables over marine biota and their broader implications for people. We analyzed modern Earth System Models forced by greenhouse gas concentration pathways until 2100 and showed that the entire world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. In contrast, only a small fraction of the world's ocean surface, mostly in polar regions, will experience increased oxygenation and productivity, while almost nowhere will there be ocean cooling or pH elevation. We compiled the global distribution of 32 marine habitats and biodiversity hotspots and found that they would all experience simultaneous exposure to changes in multiple biogeochemical variables. This superposition highlights the high risk for synergistic ecosystem responses, the suite of physiological adaptations needed to cope with future climate change, and the potential for reorganization of global biodiversity patterns. If co-occurring biogeochemical changes influence the delivery of ocean goods and services, then they could also have a considerable effect on human welfare. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by simultaneous changes in ocean biogeochemistry. These results highlight the high risk of degradation of marine ecosystems and associated human hardship expected in a future following current trends in anthropogenic greenhouse gas emissions.