Angiopoietin-like 3 (ANGPTL3) is a regulator of plasma triglyceride (TRG) levels due to its inhibitory action on the activity of lipoprotein lipase (LPL). ANGPTL3 is proteolytically cleaved by proprotein convertases to generate an active N-terminal domain, which forms a complex with ANGPTL8 orchestrating LPL inhibition. ANGPTL3-4-8 mouse model studies indicate that these three ANGPTL family members play a significant role in partitioning the circulating TRG to specific tissues according to nutritional states. Recent data indicate a positive correlation of ANGPTL3 with plasma glucose, insulin, and homeostatic model assessment of insulin resistance (HOMA-IR) in insulin-resistant states. The aim of this review is to critically present the metabolic effects of ANGPTL3, focusing on the possible mechanisms involved in the dysregulation of carbohydrate homeostasis by this protein. Heterozygous and homozygous carriers of ANGPTL3 loss-of-function mutations have reduced risk for type 2 diabetes mellitus. Suggested mechanisms for the implication of ANGPTL3 in carbohydrate metabolism include the (i) increment of free fatty acids (FFAs) owing to the enhancement of lipolysis in adipose tissue, which can induce peripheral as well as hepatic insulin resistance; (ii) promotion of FFA flux to white adipose tissue during feeding, leading to the attenuation of de novo lipogenesis and decreased glucose uptake and insulin sensitivity; (iii) induction of hypothalamic LPL activity in mice, which is highly expressed throughout the brain and is associated with enhanced brain lipid sensing, reduction of food intake, and inhibition of glucose production (however, the effects of ANGPTL3 on hypothalamic LPL in humans need more clarification); and (iv) upregulation of ANGPTL4 expression (owing to the plasma FFA increase), which possibly enhances insulin resistance due to the selective inhibition of LPL in white adipose tissue leading to ectopic lipid accumulation and insulin resistance. Future trials will reveal if ANGPTL3 inhibition could be considered an alternative therapeutic target for dyslipidemia and dysglycemia.

Background: Hyponatremia is frequent in acute stroke patients, and it is associated with worse outcomes and increased mortality. Summary: Nonstroke-related causes of hyponatremia include patients’ comorbidities and concomitant medications, such as diabetes mellitus, chronic kidney disease, heart failure, and thiazides. During hospitalization, “inappropriate” administration of hypotonic solutions, poor solute intake, infections, and other drugs, such as mannitol, could also lower sodium levels in patients with acute stroke. On the other hand, secondary adrenal insufficiency due to pituitary ischemia or hemorrhage, syndrome of inappropriate antidiuretic hormone secretion, and cerebral salt wasting are additional stroke-related causes of hyponatremia. Although it is yet unclear whether the appropriate restoration of sodium level improves outcomes in patients with acute stroke, the restoration of the volume depletion remains the cornerstone of treatment in hypovolemic hyponatremia. In case of hyper- and euvolemic hyponatremia, apart from the correction of the underlying cause (e.g., withdrawal of an offending drug), fluid restriction, administration of hypertonic solution, loop diuretics, and vasopressin-receptor antagonists (vaptans) are among the therapeutic options. Key Messages: Hyponatremia is frequent in patients with acute stroke. The plethora of underlying etiologies warrants a careful differential diagnosis which should take into consideration comorbidities, concurrent medication, findings from the clinical examination, and laboratory measurements, which in turn will guide management decisions. However, it is yet unclear whether the appropriate restoration of sodium level improves outcomes in patients with acute stroke.

The direct oral anticoagulant rivaroxaban is useful in various indications that include venous deep vein thrombosis prophylaxis/treatment after knee/hip replacement surgery and prevention of stroke in patients with non-valvular atrial fibrillation. Its mechanism of action has been mostly associated with hemorrhage-related adverse effects; thus a number of non-hemorrhage-related adverse effects of the drug have received less attention or go unrecognized. These adverse effects mainly include liver injury, hypersensitivity reactions, leukocytoclastic vasculitis and hair loss. Clinicians should be aware of these rare adverse reactions and advise their patients to contact them as soon as they observe any unexpected clinical response.

Summary Apolipoprotein CIII (ApoCIII), a small protein that resides on the surface of lipoprotein particles, is a key regulator of triglyceride metabolism. The inhibition of lipoprotein lipase (LPL), the increased assembly and secretion of very low‐density lipoproteins (VLDL) and the decreased reuptake of triglyceride‐rich lipoproteins (TRLs) by the liver are mechanisms associating elevated serum ApoCIII levels and hypertriglyceridemia. ApoCIII concentration is high in individuals with diabetes mellitus, indicating a possible positive correlation with impairment of glucose metabolism. The aim of this review (based on a Pubmed search until August 2018) is to present the possible mechanisms linking ApoCIII and deterioration of carbohydrate homeostasis. ApoCIII enhances pancreatic β‐cells apoptosis via an increase of the cytoplasmic Ca2+ levels in the insulin‐producing cells. In addition, overexpression of ApoCIII enhances non‐alcoholic fatty liver disease and exacerbates inflammatory pathways in skeletal muscles, affecting insulin signalling and thereby inducing insulin resistance. Moreover, recent studies reveal a possible mechanism of body weight increase and glucose production through a potential ApoCIII‐induced LPL inhibition in the hypothalamus. Also, the presence of ApoCIII on the surface of high‐density lipoprotein particles is associated with impairment of their antiglycemic and atheroprotective properties. Modulating ApoCIII may be a potent therapeutic approach to manage hypertriglyceridemia and improve carbohydrate metabolism.

Patients with heart failure often exhibit electrolyte abnormalities, such as hyponatremia or hypokalemia/hyperkalemia. Although not as common as the other electrolyte disturbances observed in patients with heart failure, phosphate imbalance is also of high importance in this population. The aim of this review is to present the mechanisms of low or high phosphate serum levels in patients with heart failure and its role in the pathogenesis and progression of heart dysfunction. Hypophosphatemia in patients with heart failure may be the result of co-existing electrolyte and acid-base abnormalities, pharmacological treatments, decreased intestinal absorption or secondary to sympathetic nervous system activation and co-morbidities, such as diabetes mellitus or heavy alcohol consumption. Hypophosphatemia can affect multiple organ systems including the cardiovascular system. Depletion of phosphate can lead to ventricular arrhythmias and elimination of ATP synthesis, resulting in reversible myocardial dysfunction. Hyperphosphatemia, observed mainly in patients with chronic kidney failure, is also associated with cardiac hypertrophy, which may worsen cardiac contractility and heart failure. Studies have also shown an association of high-normal serum phosphate levels with vascular and valvular calcification. Therefore, serum phosphate imbalances may exhibit a causal role in the pathogenesis and progression of heart failure.