Decreased circulating levels of ANGPTL8 in Graves' disease patients

Safety of Antithyroid Drugs in Avoiding Hyperglycemia or Hypoglycemia in Patients With Graves' Disease and Type 2 Diabetes Mellitus: A Literature Review

Graves' disease (GD) may increase the difficulty of glucose control in patients with type 2 diabetes mellitus (T2DM). Therefore, selecting a drug with limited blood glucose side effects is an important issue in patients with T2DM and GD. Antithyroid drugs (ATDs) including propylthiouracil (PTU), methimazole, and carbimazole are commonly prescribed for the treatment of GD. Here, we review and summarize the literature from the last 10 years and discuss the effects of current ATDs used for GD for blood glucose control in patients with T2DM. A search of the literature published between January 1, 2012 and December 1, 2022 was conducted using three major medical databases: Google Scholar, Ovid Medline, and Scopus. An initial search was conducted on PubMed using the MeSH terms "propylthiouracil," "methimazole," "carbimazole," and "hyperglycemia" or "hypoglycemia" in academic databases. All articles included "Graves' disease" and "type 2 diabetes mellitus" in the title. Based on the results of previous studies, the hyperglycemic and hypoglycemic side effects of ATDs can be explained by several possible mechanisms. The most widely accepted hypothesis is that sulfhydryl group drugs (e.g., methimazole and carbimazole) cleave the disulfide bond of insulin and enhance its immunogenicity, resulting in hypoglycemia. Moreover, some reports have indicated that methimazole is associated with hypoglycemia; therefore, if the patient has a history of autoimmune diseases, it is necessary to consider whether to change drugs or actively track the production of autoimmune antibodies. In non-diabetic and diabetic patients with GD, the hyperglycemic and hypoglycemic side effects of PTU (on glycemic variation) were less than that of thiamazole. However, as relatively few reports have investigated the side effects of blood sugar changes, further research is necessary to confirm these effects. In addition to autoimmune diseases, drug side effects may need to be considered. These findings provide considerations for clinicians to select more appropriate ATDs for patients with GD and T2DM, and implement improved care guidelines.

Update on dyslipidemia in hypothyroidism: the mechanism of dyslipidemia in hypothyroidism

Hypothyroidism is often associated with elevated serum levels of total cholesterol, LDL-C and triglycerides. Thyroid hormone (TH) affects the production, clearance and transformation of cholesterol, but current research shows that thyroid-stimulating hormone (TSH) also participates in lipid metabolism independently of TH. Therefore, the mechanism of hypothyroidism-related dyslipidemia is associated with the decrease of TH and the increase of TSH levels. Some newly identified regulatory factors, such as proprotein convertase subtilisin/kexin type 9, angiogenin-like proteins and fibroblast growth factors are the underlying causes of dyslipidemia in hypothyroidism. HDL serum concentration changes were not consistent, and its function was reportedly impaired. The current review focuses on the updated understanding of the mechanism of hypothyroidism-related dyslipidemia.

ANGPTL8 in metabolic homeostasis: more friend than foe?

ANGPTL8 is an important cytokine, which is significantly increased in type 2 diabetes mellitus (T2DM), obesity and metabolic syndrome. Many studies have shown that ANGPTL8 can be used as a bio-marker of these metabolic disorders related diseases, and the baseline ANGPTL8 level has also been found to be positively correlated with retinopathy and all-cause mortality in patients with T2DM. This may be related to the inhibition of lipoprotein lipase activity and the reduction of circulating triglyceride (TG) clearance by ANGPTL8. Consistently, inhibition of ANGPTL8 seems to prevent or improve atherosclerosis. However, it is puzzling that ANGPTL8 seems to have a directing function for TG uptake in peripheral tissues; that is, ANGPTL8 specifically enhances the reserve and buffering function of white adipose tissue, which may alleviate the ectopic lipid accumulation to a certain extent. Furthermore, ANGPTL8 can improve insulin sensitivity and inhibit hepatic glucose production. These contradictory results lead to different opinions on the role of ANGPTL8 in metabolic disorders. In this paper, the correlation between ANGPTL8 and metabolic diseases, the regulation of ANGPTL8 and the physiological role of ANGPTL8 in the process of glucose and lipid metabolism were summarized, and the physiological/pathological significance of ANGPTL8 in the process of metabolic disorder was discussed.

The Impact of Psoriasis and Metabolic Syndrome on the Systemic Inflammation and Oxidative Damage to Nucleic Acids

BACKGROUND

Psoriasis is a chronic systemic inflammatory disease associated with a wide range of comorbidities, including metabolic syndrome (MetS). Serum calprotectin, ANGPTL8, and oxidative damage to nucleic acids might be associated with both diseases. The presented study describes the influence of psoriasis and MetS on the serum levels of markers of systemic inflammation (calprotectin and ANGPTL8) and markers of oxidative damage to nucleic acids. The applicability of serum levels of calprotectin and ANGPTL8 for monitoring of the activity of psoriasis (diagnostic markers) is also evaluated.

METHODS

Clinical examination (PASI score, MetS), enzyme-linked immunosorbent assay (ELISA), and Enzyme Immunoassay (EIA). Serum calprotectin, ANGPTL8, 8-hydroxy-2'-deoxyguanosine, 8-hydroxyguanosine, and 8-hydroxyguanine. Results and Conclusions. The psoriasis significantly increased the serum level of calprotectin and the serum level of oxidative damage to nucleic acids, however not the serum level of ANGPTL8. The presence of MetS did not significantly affect the serum levels of calprotectin, ANGPTL8, and oxidative damage to nucleic acids in either psoriasis patients or controls. It seems that the serum level of calprotectin (but not the serum level of ANGPTL8) could be used as a biomarker for monitoring the activity of psoriasis.

ANGPTL8 enhances insulin sensitivity by directly activating insulin-mediated AKT phosphorylation

ANGPTL8 is a 22-KDa protein in the angiopoietin-like family. It is a liver-derived hormone that dynamically regulates glucose metabolism after refeeding. The mechanism of its regulation of glucose metabolism is unclear. We analyzed the effect of ANGPTL8 overexpression on glucose tolerance in the mouse liver by tail vein hydrodynamic transfection. The mechanism of ANGPTL8 improving insulin sensitivity was analyzed by the overexpression or knockdown of ANGPTL8 in mouse primary hepatocytes through in vitro synthetic mRNA and siRNA technology. The key site of ANGPTL8 protein regulating this signal pathway was screened by DNA point mutation and fragment truncation. The results showed that ANGPTL8 may directly regulate AKT protein phosphorylation in the insulin-mediated PI3K/AKT signaling pathway to improve insulin sensitivity. Ser94 and Thr98 are the key sites of ANGPTL8 protein in activating AKT protein phosphorylation. Present results indicate that ANGPTL8 may be a potential new agent to reduce postprandial blood glucose.

Regulation of angiopoietin-like protein 8 expression under different nutritional and metabolic status

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with increasing prevalence worldwide. Angiopoietin-like protein 8 (ANGPTL8), a member of the angiopoietin-like protein family, is involved in glucose metabolism, lipid metabolism, and energy homeostasis and believed to be associated with T2DM. Expression levels of ANGPTL8 are often significantly altered in metabolic diseases, such as non-alcoholic fatty liver disease (NAFLD) and diabetes mellitus. Studies have shown that ANGPTL8, together with other members of this protein family, such as angiopoietin-like protein 3 (ANGPTL3) and angiopoietin-like protein 4 (ANGPTL4), regulates the activity of lipoprotein lipase (LPL), thereby participating in the regulation of triglyceride related lipoproteins (TRLs). In addition, members of the angiopoietin-like protein family are varyingly expressed among different tissues and respond differently under diverse nutritional and metabolic status. These findings may provide new options for the diagnosis and treatment of diabetes, metabolic syndromes and other diseases. In this review, the interaction between ANGPTL8 and ANGPTL3 or ANGPTL4, and the differential expression of ANGPTL8 responding to different nutritional and metabolic status during the regulation of LPL activity were reviewed.