Species-Specific Effects of Microplastics On Juvenile Fishes

Microplastics contamination have been extensively reported in aquatic ecosystem and organisms. It is wildly acknowledged that the ingestion, accumulation and elimination of microplastics in fishes are species-specific, which mainly depending on the feeding behavior. This study aims to investigate the effects of microplastics on the morphology and inflammatory response in intestines of fishes with different feeding types. Largemouth bass (carnivorous fish), grass carp (herbivorous fish) and Jian carp (omnivorous fish) were used as organism model. The contributing concentration and size of microplastics are explored as well as the response time and legacy effect in fishes. Two different sizes of polystyrene microplastics (8 μm and 80 nm) were set at three concentrations. And samples were analyzed at different exposure times and depuration times. Histological analysis indicated that multiple abnormalities in intestines are presented in three species fishes after acute exposure microplastics. The mRNA abundance of immune-related genes in the intestine tissues of fishes were significantly induced or restrained. There were differential expressions of genes coping with differential sizes and concentrations of microplastics exposure in different fishes. The reason for the difference effects of microplastics on fishes was still unclear but could be due to the difference in the structure and function of the digestive system. These results provide a theoretical basis to further analysis of the mechanism of fish intestinal pathology caused by microplastics.

Legacy in Cardiovascular Risk Factors Control: From Theory to Future Therapeutic Strategies?

In medicine, a legacy effect is defined as the sustained beneficial effect of a given treatment on disease outcomes, even after cessation of the intervention. Initially described in optimized control of diabetes, it was also observed in clinical trials exploring intensification strategies for other cardiovascular risk factors, such as hypertension or hypercholesterolemia. Mechanisms of legacy were particularly deciphered in diabetes, leading to the concept of metabolic memory. In a more discreet manner, other memory phenomena were also described in preclinical studies that demonstrated long-lasting deleterious effects of lipids or angiotensin II on vascular wall components. Interestingly, epigenetic changes and reactive oxygen species (ROS) appear to be common features of “memory” of the vascular wall.

The direct and legacy effects of drying-rewetting cycles on active and relatively resistant soil carbon decomposition

Global climate change is expected to increase the frequency of drought and heavy precipitation, which could create more frequent drying-rewetting cycles (DWC) in the soils. Although DWC effects on SOC decomposition has been widely studied, the effect of DWC and the subsequent legacy effect on the decomposition of different SOC pools is still unclear. We conducted a 128-d laboratory incubation to investigate the DWC effects by using soils from old-field for 15 years (OF, representing active SOC), bare-fallow for 15 years (BF), and bare-fallow for 23 years plus extra 815-d incubation (BF+, representing relatively resistant SOC). The experiment included nine 10-d DWC of three treatments: 1) constant-moisture at 60% WHC, 2) mild DWC with 10-d drying to 40% WHC and rewetting to 80% WHC, and 3) strong DWC with 10-d drying to 20% WHC and rewetting to 100% WHC. Following DWC period, there was a 10-d stabilization period (adjusting all treatments to 60% WHC), and then a 28-d extended incubation. During DWC period, the strong DWC had strong effect on CO2 release compared with the constant-moisture control, reducing the SOC decomposition from OF by 8% and BF by 10%, while increasing the SOC decomposition of BF+ by 16%. During extended period, both mild and strong DWC significantly increased SOC mineralization of OF, but decreased that of BF and BF+. This legacy effect compensated the changes in CO2 release during DWC period, resulting in the minor response of SOC decomposition of OF and BF+ to the DWC during the entire incubation.

Understanding Metabolic Memory: The Prolonged Influence of Glycemia During the Diabetes Control and Complications Trial (DCCT) on Future Risks of Complications During the Study of the Epidemiology of Diabetes Interventions and Complications (EDIC)

The Diabetes Control and Complications Trial (DCCT, 1983-1993) showed that intensive therapy (mean HbA1c 7.2%) compared with conventional therapy (mean HbA1c 9.0%) markedly reduced the risks of retinopathy, nephropathy and neuropathy, and these reductions in complications were entirely attributable, statistically, to the difference in mean HbA1c levels. The DCCT cohort has been followed in the Epidemiology of Diabetes Interventions and Complications study (EDIC, 1994 to date). <p>Early in EDIC, mean HbA1c levels in the former intensively and conventionally treated groups converged. Nevertheless, the beneficial effects of DCCT intensive versus conventional therapy on microvascular complications not only persisted but increased during EDIC. The differences in complications during EDIC were wholly explained, statistically, by differences between groups in HbA1c levels during DCCT. These observations give rise to the concept of metabolic memory. Subsequent similar findings from the UKPDS gave rise to a similar concept, which they called the legacy effect. </p> <p>In this report, we present the evidence to support metabolic memory as both a biological and epidemiological phenomenon, and discuss potential underlying mechanisms. We also compare metabolic memory and the legacy effect and conclude that the two are likely biologically similar, with comparable effects on long-term outcomes.</p> <p>The long-term influence of metabolic memory on the risk of micro- and macrovascular complications supports the implementation of intensive therapy, with the goal of maintaining near normal levels of glycemia, as early and as long as safely possible in order to limit the risk of complications.</p>

Understanding Metabolic Memory: The Prolonged Influence of Glycemia During the Diabetes Control and Complications Trial (DCCT) on Future Risks of Complications During the Study of the Epidemiology of Diabetes Interventions and Complications (EDIC)

The Diabetes Control and Complications Trial (DCCT, 1983-1993) showed that intensive therapy (mean HbA1c 7.2%) compared with conventional therapy (mean HbA1c 9.0%) markedly reduced the risks of retinopathy, nephropathy and neuropathy, and these reductions in complications were entirely attributable, statistically, to the difference in mean HbA1c levels. The DCCT cohort has been followed in the Epidemiology of Diabetes Interventions and Complications study (EDIC, 1994 to date). <p>Early in EDIC, mean HbA1c levels in the former intensively and conventionally treated groups converged. Nevertheless, the beneficial effects of DCCT intensive versus conventional therapy on microvascular complications not only persisted but increased during EDIC. The differences in complications during EDIC were wholly explained, statistically, by differences between groups in HbA1c levels during DCCT. These observations give rise to the concept of metabolic memory. Subsequent similar findings from the UKPDS gave rise to a similar concept, which they called the legacy effect. </p> <p>In this report, we present the evidence to support metabolic memory as both a biological and epidemiological phenomenon, and discuss potential underlying mechanisms. We also compare metabolic memory and the legacy effect and conclude that the two are likely biologically similar, with comparable effects on long-term outcomes.</p> <p>The long-term influence of metabolic memory on the risk of micro- and macrovascular complications supports the implementation of intensive therapy, with the goal of maintaining near normal levels of glycemia, as early and as long as safely possible in order to limit the risk of complications.</p>