Population dynamics of the endangered seahorse Hippocampus reidi Ginsburg, 1933 in a tropical rocky reef habitat

This study was conducted in Armação de Búzios, Brazil, a municipality where ecosystem degradation has been observed following large increases in tourism and population growth. The goal of this study was to determine seasonal variations in three Búzios populations of the long snout seahorse Hippocampus reidi. Monthly dives were conducted from November 2011 to October 2013. All three subpopulations had low densities of seahorses and no seasonality. The sex ratio differed at each site. The most commonly used microhabitats were the sponge Aplysina fulva and the seaweed Sargassum sp. There was no significant difference in temperature and salinity. The environmental trends could not explain the variation in seahorse density at the three beaches. The population showed no seasonality and no further decline

Cannabidiol causes activated hepatic stellate cell death through a mechanism of endoplasmic reticulum stress-induced apoptosis

The major cellular event in the development and progression of liver fibrosis is the activation of hepatic stellate cells (HSCs). Activated HSCs proliferate and produce excess collagen, leading to accumulation of scar matrix and fibrotic liver. As such, the induction of activated HSC death has been proposed as a means to achieve resolution of liver fibrosis. Here we demonstrate that cannabidiol (CBD), a major non-psychoactive component of the plant Cannabis sativa, induces apoptosis in activated HSCs through a cannabinoid receptor-independent mechanism. CBD elicits an endoplasmic reticulum (ER) stress response, characterized by changes in ER morphology and the initiation of RNA-dependent protein kinase-like ER kinase-, activating transcription factor-6-, and inositol-requiring ER-to-nucleus signal kinase-1 (IRE1)-mediated signaling cascades. Furthermore, CBD induces downstream activation of the pro-apoptotic IRE1/ASK1/c-Jun N-terminal kinase pathway, leading to HSC death. Importantly, we show that this mechanism of CBD-induced ER stress-mediated apoptosis is specific to activated HSCs, as it occurs in activated human and rat HSC lines, and in primary in vivo-activated mouse HSCs, but not in quiescent HSCs or primary hepatocytes from rat. Finally, we provide evidence that the elevated basal level of ER stress in activated HSCs has a role in their susceptibility to the pro-apoptotic effect of CBD. We propose that CBD, by selectively inducing death of activated HSCs, represents a potential therapeutic agent for the treatment of liver fibrosis

Cannabinoids, immune system and cytokine network

How cannabinoids influence immune function has been examined extensively in the last 30 years. Studies on drug-abusing humans and animals, as well as in vitro models employing immune cell cultures, have shown that marijuana, natural and endogenous cannabinoid compounds are immunomodulators. These substances modulate host resistance to bacterial, protozoan and viral infections as well as they can profoundly affect the Th1/Th2 response. Recently, two types of cannabinoid receptor, CB1 and CB2, have been discovered. While CBI is expressed primarily in the brain, CB2 is peculiar of the immune cells. Cannabinoid receptors have been shown to be involved in some but not all of immune effects. Nevertheless, their identification provides a specific mechanism of action in the attempting to find out how exogenous cannabinoids and endogenous cannabinoid system affect the immune apparatus, strengthen the hypothesis of cannabinoids as immunomodulators. As support to this theory, enough evidence exists to suggest that the cannabinoid system significantly affects almost every component of the immune response machinery and impacts the functioning also of the cytokine network. The evaluation of the biological consequences of these drug-induced cytokine changes has also dramatically become important considering not only the impact of cytokines on immune system per se but also envisaging their influence in cancer, inflammation, autoimmune disease, brain injury, hematopoictic colony formation in which cannabinoids have demonstrated a clear role as important modulators