Malaria and COVID-19 may have similar aspects and seem to have a strong potential for mutual influence. They have already caused millions of deaths, and the regions where malaria is endemic are at risk of further suffering from the consequences of COVID-19 due to mutual side effects, such as less access to treatment for patients with malaria due to the fear of access to healthcare centers leading to diagnostic delays and worse outcomes. Moreover, the similar and generic symptoms make it harder to achieve an immediate diagnosis. Healthcare systems and professionals will face a great challenge in the case of a COVID-19 and malaria syndemic. Here, we present an overview of common and different findings for both diseases with possible mutual influences of one on the other, especially in countries with limited resources.

Osteoporosis is a disease characterized by low bone mass and alterations of bone microarchitecture, with an increased risk of fractures. It is a multifactorial disorder that is more frequent in postmenopausal women but can be associated to other diseases (inflammatory and metabolic diseases). At present, several options are available to treat osteoporosis trying to block bone reabsorption and reduce the risk of fracture. Anyway, these drugs have safety and tolerance problems in long-term treatment. Recently, gut microbiota has been highlighted to have strong influence on bone metabolism, becoming a potential new target to modify bone mineral density. Such evidences are mainly based on mouse models, showing an involvement in modulating the interaction between the immune system and bone cells. Germ-free mice represent a basic model to understand the interaction between microbiota, immune system, and bone cells, even though data are controversial. Anyway, such models have unequivocally demonstrated a connection between such systems, even if the mechanism is unclear. Gut microbiota is a complex system that influences calcium and vitamin D absorption and modulates gut permeability, hormonal secretion, and immune response. A key role is played by the T helper 17 lymphocytes, TNF, interleukin 17, and RANK ligand system. Other important pathways include NOD1, NOD2, and Toll-like receptor 5. Prebiotics and probiotics are a wide range of substances and germs that can influence and modify microbiota. Several studies demonstrated actions by different prebiotics and probiotics in different animals, differing according to sex, age, and hormonal status. Data on the effects on humans are poor and controversial. Gut microbiota manipulation appears a possible strategy to prevent and treat osteopenia and/or osteoporosis as well as other possible bone alterations, even though further clinical studies are necessary to identify correct procedures in humans.

Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine tumour deriving from the adrenal cortex. A correct therapeutic strategy requires a multidisciplinary approach between endocrinologist, surgeon and oncologist. Surgery is the mainstay treatment in ACC while mitotane, deriving from the insecticide dichloro-diphenyl-trichloro-ethane, is the main base of the medical treatment of ACC in consideration of its adrenocytolitic activity. However, the use of mitotane as adjuvant therapy is still controversial, also in consideration of the retrospective nature of several studies. A prospective randomised trial (ADIUVO), recruiting patients with low-intermediate risk of recurrence, is evaluating the utility of adjuvant treatment with mitotane in this setting. The therapeutic response is observed with plasma levels of mitotane >14 mg/L. However, the major difficulty in the management of mitotane treatment is related to side effects and to the risk of toxicity, which is related to plasmatic levels >20 mg/L, that is considered the upper limit of the therapeutic window. Mitotane therapy results in adrenal insufficiency, and glucocorticoid replacement therapy has to be administered at higher doses than those used in other aetiologies of primary adrenal insufficiency. Furthermore, other endocrine side effects related to mitotane should be considered, in particular on thyroid hormone and testosterone metabolism. Waiting for new medical strategies on molecular targets, it will be mandatory to optimise the current knowledge by prospective trials and, in consideration of the rarity of the disease, collaborative studies between endocrinologists and oncologists are necessary.