The Microalgae Phaeodactylum tricornutum Is Well Suited as a Food with Positive Effects on the Intestinal Microbiota and the Generation of SCFA: Results from a Pre-Clinical Study

Microalgae such as Phaeodactylum tricornutum (PT) are a sustainable source of nutrients, especially eicosapentaenoic acid (EPA), fucoxanthin (Fx), and chrysolaminarin (Chrl), the concentrations of which can vary depending on the culture conditions. We generated three types of diets containing either an EPA- and Fx-rich (EPA/Fx) or Chrl-rich microalgae (with 5, 15, or 25% added to the diet) or an isocaloric control diet (CD). These diets were evaluated over 14 days in young C57BL/6J mice for safety and bioavailability, short-chain fatty acid (SCFA) production, and microbiome analysis. Both microalgae diets increased body weight gain dose-dependently compared to the CD. Microalgae-derived EPA was well absorbed, resulting in increased liver and fat tissue levels and a decrease in the n-6:n-3 ratio in liver tissue. Both microalgae diets increased the production of selected SCFA and decreased the Firmicutes/Bacteriodota ratio, whereas the Chrl-rich diet led to an increase in Akkermansia. Doses of up to 4621 mg Chrl, 920 mg EPA, and 231 mg Fx per kg body weight daily were tolerated without adverse effects. This pre-clinical study shows that PT is suitable for mouse feed, with positive effects on microbiota composition and SCFA production, suggesting beneficial effects on gut health.     

Adrenal-sparing surgery for phaeochromocytoma

BACKGROUND: Adrenalectomy is the current treatment for phaeochromocytoma. Consequently, patients with bilateral adrenal phaeochromocytoma become steroid dependent. An adrenal-sparing surgical technique was introduced in 1985. The results of this treatment have been reviewed. METHODS: Since 1985, 39 patients with adrenal phaeochromocytoma (16 men and 23 women, aged 10-76 years) have been treated. Thirty-three patients had unilateral and six had bilateral phaeochromocytomas. Seven of the former 33 had a contralateral adrenal tumour resected previously. All 39 patients were re-evaluated biochemically and clinically for ipsilateral recurrence. RESULTS: Adrenal-sparing surgery was performed successfully in 37 of the 39 patients. In one, adrenal-sparing resection was impossible anatomically and total adrenalectomy was necessary. Another patient with bilateral tumours had retroperitoneal haemorrhage and became steroid dependent. None of the remaining 12 patients who had bilateral adrenal surgery required steroid replacement. Adrenocortical function was normal in eight and mildly impaired in two of the ten patients who had evaluation by adrenocorticotrophic hormone stimulation. After a mean follow-up of 73 months, one patient with von Hippel-Lindau disease developed a recurrence in the ipsilateral adrenal gland. Genetic testing revealed that 26 of the 39 patients, including half of those with a unilateral tumour, had hereditary phaeochromocytoma. CONCLUSION: Adrenal-sparing surgery is safe and effective, and may become the treatment of choice in patients with hereditary phaeochromocytoma.     

Responses of foraging ant populations to high-intensity wildfire,salvage logging and natural regeneration processes in Eucalyptus regnans regrowth forest of the Victorian Central Highlands

The effects of high-intensity wildfire plus salvage logging and fire-induced natural regeneration processes on foraging ants (Formicidae) were assessed in multiple-use Eucalyptus regnans (Mountain Ash) regrowth forest approximately 60 km east of Melbourne in the Victorian Central Highlands. The study was based on 35 912 ant specimens, and on 69 493 epigeal non-ant arthropods of 27 taxa, contained in 2,160 pitfall trap samples collected at three sites over a single pre-fire year and two post-fire years.

Twenty ant species of sub-families Dolichoderinae, Formicinae, Myrmeciinae, Myrmicinae and Ponerinae were identified, but only Notoncus spinisquamis, Myrmecia pilosula and Chelaner sculpturatus could be validated. Two species were placed into the newly erected genus OcheteUus (Dolichoderinae), and one species of Myrmicinae could not be identified below sub-family rank. The biology and taxonomy of the majority of these species is uncertain, although the most commonly trapped ant, Prolasius? pallidus, is a recognised seed harvester, and two other species of Prolasius plus C. sculpturatus are suspected seed harvesters. The second most frequently trapped species, Iridomyrmex? foetans, is a carnivore and scavenger. Chelaner sculpturatus was the most frequently trapped among 18 “minor” species.

The rapid replacement of the ecologically complex regrowth forest by young even-aged regeneration of E. regnans through wildfire effects and salvage logging caused a substantial increase in foraging activity of P. pallidus during the first post-fire autumn period, and activity remained high for up to 14 months depending on elevation of the forested landscape. Activity of I. foetans declined immediately after the fire, but eight months later it was significantly higher than “control plot” levels for up to four months. The response of the less frequently trapped “minor” species to the wildfire, logging and regeneration processes remained uncertain because of the low numbers trapped before and after the fire. Prolific regeneration of E. regnans emerged in the burnt forest, suggesting that fire-induced seed fall was sufficiently large and extensive to have caused predator satiation. The implications of this for artificial regeneration programs in E. regnans forest are discussed.     

Annexin A1, formyl peptide receptor,and NOX1 orchestrate epithelial repair

N-formyl peptide receptors (FPRs) are critical regulators of host defense in phagocytes and are also expressed in epithelia. FPR signaling and function have been extensively studied in phagocytes, yet their functional biology in epithelia is poorly understood. We describe a novel intestinal epithelial FPR signaling pathway that is activated by an endogenous FPR ligand, annexin A1 (ANXA1), and its cleavage product Ac2-26, which mediate activation of ROS by an epithelial NADPH oxidase, NOX1. We show that epithelial cell migration was regulated by this signaling cascade through oxidative inactivation of the regulatory phosphatases PTEN and PTP-PEST, with consequent activation of focal adhesion kinase (FAK) and paxillin. In vivo studies using intestinal epithelial specific Nox1^–/–IEC and AnxA1^–/– mice demonstrated defects in intestinal mucosal wound repair, while systemic administration of ANXA1 promoted wound recovery in a NOX1-dependent fashion. Additionally, increased ANXA1 expression was observed in the intestinal epithelium and infiltrating leukocytes in the mucosa of ulcerative colitis patients compared with normal intestinal mucosa. Our findings delineate a novel epithelial FPR1/NOX1-dependent redox signaling pathway that promotes mucosal wound repair.