Association between Thyroid Function and Nonalcoholic Fatty Liver Disease in Euthyroid Type 2 Diabetes Patients

Association between non-alcoholic fatty liver disease and subclinical hypothyroidism in children with obesity

PURPOSE

We aimed (i) evaluating the relationship between non-alcoholic fatty liver disease (NAFLD) and thyroid function tests, (ii) testing if the relationship between NAFLD and thyroid dysfunction could be driven by the obesity and the IR degree, and (iii) exploring the influence of the patatin-like phospholipase domain-containing protein-3 (PNPLA3) I148M and the transmembrane 6 superfamily member 2 (TM6SF2) E167K polymorphisms on the association between NAFLD and thyroid function in children.

METHODS

We examined 2275 children and adolescents with obesity. Subclinical hypothyroidism (SH) was defined by thyroid-stimulating hormone (TSH) > 4.2 μUI/ml with normal fT3 and fT4.

RESULTS

Children with NAFLD showed higher SH prevalence than those without NAFLD (15.7% Vs 7.4%;p = 0.001) and showed an adjusted odds ratio (aOR) to have SH of 1.68 (95% CI:1.01-2.80;p = 0.04) while patients with SH had an aOR to show NAFLD of 2.13(95% CI:1.22-3.73;p = 0.008). Patients having severe obesity and IR degree presented an aOR to show both NAFLD and SH of 3.61 (95% CI:1.78-7.33;p < 0.0001). Subjects with NAFLD carrying the TM6SF2 167 K allele had lower TSH levels than non-carriers (p = 0.03) and showed an aOR to have SH of 0.10 (95% CI: 0.01-0.79;p = 0.02). No differences were found in carriers of the PNPLA3 148 M allele. A general linear model for TSH variance showed a significant association of TSH with TM6SF2 genotypes only in the NAFLD group (p = 0.001).

CONCLUSION

Children with obesity and NAFLD presented increase risk of SH and vice versa likely due to the adverse effect of duration of obesity, obesity degree, and IR. The TM6SF2 E167K exerts a protective role against SH in children with obesity and NAFLD.

TSH-SPP1/TRβ-TSH positive feedback loop mediates fat deposition of hepatocyte: Crosstalk between thyroid and liver

Aims

We conducted this study with two aims: (1) whether TRβ could be damaged by NAFLD, thereby represent thyroid hormone resistance-like manifestation and (2) to analyze the potential role of SPP1 in TH signaling pathway on the process of NAFLD. This study is expected to provide a new perspective on the therapeutic mechanism in the pathological course of NAFLD.

Methods

A total of 166 patients diagnosed with type 2 diabetes mellitus (T2DM) were enrolled in this study. All patients had a BMI above 24 kg/m2 and were stratified into two groups: NAFLD and Non-NAFLD groups. Ages, gender, BMI, duration of diabetes and biochemical markers were obtained from participants' records. We downloaded the dataset GSE48452 from GEO. The Pathview library was used to make the thyroid hormone signaling pathway visualization. The CIBERSORT algorithm was applied to calculate the infiltrated immune cells in obese NAFLD patients. C57BL/6 mice were randomly selected to constitute the normal control (NC) group and were fed a normal chow diet; the rest of the mice were fed a high-fat diet (HFD). After 12 weeks HFD feeding, the mice were sacrificed by cervical dislocation, and blood samples were collected. Mouse livers were also collected; one part of each liver was fixed in 10% formalin for histological analysis, and the other part was snap-frozen for subsequent molecular analyses. To explore the relationship between SPP1, TRβ and lipid deposition in hepatocytes, HepG2 cells were treated with 50 μ M concentration of PA and/or 20 ng/ml concentration of rh-SPP1 for 48h. In addition, the PC3.1-TRβ plasmid was constructed for further validation in HepG2 cells. We used THP-1 cells to construct an M1 macrophage model in vitro. We then analyzed THP-1 cells treated with various concentrations of PA or TSH.

Results

(1) After adjusting for all factors that appeared P value less than 0.1 in the univariate analysis, BMI, TSH, and FT3 were significant independent risk factors of NAFLD (ORs were 1.218, 1.694, and 2.259, respectively); (2) A further analysis with BMI stratification indiacted that both FT3 and TSH had a significant change between individuals with NAFLD and Non-NAFLD in obesity subgroup; however, there was no statistic difference in over-weight group; (3) Bioinformatics analysis of GSE48452 had shown that several key molecular (including TRβ) of thyroid hormone pathway affected by NAFLD induced transcriptomic changes and the expression levels of SPP1, FABP4 and RPS4Y1 were significantly higher, while the expression levels of PZP and VIL1 were significantly decreased in NAFLD patients(adjusted p < 0.05, |logFC| > 1.0). The CIBERSORT algorithm showed increased M0 and M1, decreased M2 macrophage infiltration in NAFLD with comparison to healthy obese group; (4) After 12 weeks of HFD-feeding, the obesity mice had significantly higher serum TSH and In IHC-stained liver sections of obesity group, the intensity of SPP1 had a significantly increased, while TRβ reduced; (5) In vitro studies have shown SPP1 aggravated lipid deposition in hepatic cells dependent on down-regulating the expression of TRβ and TSH acts to promote secretion of SPP1 in M1 macrophage cells.

Conclusions

SPP1 secretion induced by M1 macrophage polarization, which may down-regulates TRβ in hepatocytes via paracrine manner, on the one hand, the lipid deposition aggravating in liver, on the other hand, a compensatory increase of TSH in serum. The increased TSH can further lead to the following SPP1 secretion of M1 macrophage. The positive feedback crosstalk between thyroid and liver, may be plays an important role in maintaining and amplifying pathological process of NAFLD.

Associations among FT4 level, FT3/FT4 ratio, and non-alcoholic fatty liver disease in Chinese patients with hypopituitarism

Non-alcoholic fatty liver disease (NAFLD) is the most common hepatic metabolic disorder. Thyroid function is associated with NAFLD in different populations; however, little attention has been paid in patients with hypopituitarism. To analyze the association between thyroid function and NAFLD, we included 134 patients with hypopituitarism admitted to the Tianjin Medical University General Hospital between June 2013 and May 2019. Participants were divided into the NAFLD(-) and NAFLD(+) groups based on abdominal ultrasonography findings. We evaluated 68 male and 66 female patients with hypopituitarism. The prevalence of NAFLD was 52.24%. The NAFLD(+) group had a significantly higher free triiodothyronine/free thyroxine (FT₃/FT₄) ratio than the NAFLD(-) group (p = 0.003). The NAFLD(+) group showed significantly lower levels of FT₄ and the growth hormone (GH) than the NAFLD(-) group (p = 0.003 and 0.016, respectively). We observed an association of the FT₄ level and FT₃/FT₄ ratio with NAFLD in the univariate model, which was non-significant after adjustment for metabolic parameters (BMI, HDL-C, triglycerides, serum uric acid, blood pressure, fasting glucose). To better understand the role of each metabolic parameters, we performed additional models for each of those predictors individually after adjustment for age and gender, the association between FT₄ level and FT₃/FT₄ ratio lost significance after adjustment for HDL-C and TG, but not for other predictors. Our findings suggest that thyroid dysfunction may be crucially involved in NAFLD by regulating whole-body metabolism, especially lipid utilization. Therefore, sufficient thyroid hormone replacement therapy for patients with hypopituitarism is recommended from the early stage.

Selected Organ and Endocrine Complications According to BMI and the Metabolic Category of Obesity: A Single Endocrine Center Study

Obesity is a chronic and complex disease associated with metabolic, organ and endocrine complications. In the study, we analyzed a group of 105 patients suffering from obesity without any other previously recognized serious disorders who had been referred to a single endocrine center. The study aimed to assess the prevalence of selected organ and endocrine complications by subdividing the group, firstly according to body mass index (BMI) and secondly with regard to metabolic syndrome (MetS), pre-MetS and the metabolically healthy obesity (MHO) category. We have observed that in our groups, the prevalence of hyperlipidemia, hypertension, asthma, obstructive sleep apnea (OSA) depended on BMI category, whereas the incidence of hyperlipidemia, hypertension, OSA, hypothyroidism, non-alcoholic fatty liver disease, prediabetes, and type 2 diabetes was related to the metabolic category. We concluded that the distribution of particular organ and endocrine complications change significantly with increased BMI and with the shift from MHO to pre-MetS and MetS. Thus, to determine the risk of organ and endocrine complications more effectively, BMI and metabolic status should be assessed during the examination of patients with obesity.

Effect of Liraglutide on Serum TSH Levels in Patients with NAFLD and its Underlying Mechanisms

This study aimed to evaluate the effect of liraglutide on serum thyroid-stimulating hormone (TSH) levels in patients with type 2 diabetes mellitus (T2DM) and explore the underlying mechanisms via bioinformatics analysis. A total of 49 obese/overweight patients with T2DM received liraglutide during outpatient visits or hospitalization in the Department of Endocrinology. Meanwhile, the control group included 49 patients with T2DM but without nonalcoholic fatty liver disease (NAFLD) who were matched for age and sex (baseline from July 2016 to June 2021). Follow-up data on the last use of liraglutide were also retrieved. Age, sex, body mass index (BMI), and duration of diabetes were obtained from the participants' records. All patients were tested for biochemical markers hemoglobin A1c (HbA1c), alanine transaminase, aspartate transaminase, free triiodothyronine, free thyroxine (FT4), and TSH at baseline and follow-up. After adjusting for all factors with a p-value < 0.05, BMI, HbA1c, LDL, FT4, and TSH were identified as significant independent risk factors for NAFLD in the univariate analysis. Following liraglutide therapy (average time 16 months), these patients had significantly lower BMI, HbA1c, and TSH but higher high-density lipoprotein (HDL) levels than those in the baseline data (all p < 0.05), and further subgroup analysis stratified by duration of liraglutide use showed that the test for time trends had statistical differences in BMI and TSH but not in HbA1c and HDL. After the therapy, the NAFLD and NASH groups showed significantly decreased TSH levels after liraglutide therapy compared with the corresponding baseline data. Furthermore, the expression of THRB, which encodes TRβ, was significantly decreased in the NAFLD group, which may explain the thyroid hormone resistance-like manifestation in the clinical findings. In conclusion, liraglutide improves hepatic thyroid hormone resistance in T2DM with NAFLD, and restoration of impaired TRβ expression in NAFLD is a potential mechanism involved in the process of liraglutide therapy.

TSH Levels as an Independent Risk Factor for NAFLD and Liver Fibrosis in the General Population

Thyroid hormones may be a risk factor for the development of non-alcoholic fatty liver disease (NAFLD) and its progression to liver fibrosis. The aim of this study is to investigate the relationship between thyroid stimulating hormone (TSH) levels, NAFLD, and liver fibrosis in the general population. A descriptive cross-sectional study was performed in subjects aged 18–75 years randomly selected from primary care centers between 2012 and 2016. Each subject underwent clinical evaluation, physical examination, blood tests and transient elastography. Descriptive and multivariate logistic regression analyses were used to identify factors associated with NAFLD and fibrosis. We included 2452 subjects (54 ± 12 years; 61% female). Subjects with TSH ≥ 2.5 μIU/mL were significantly associated with obesity, atherogenic dyslipidemia, metabolic syndrome (MetS), hypertransaminasemia and altered cholesterol and triglycerides. The prevalence of NAFLD and liver fibrosis was significantly higher in subjects with TSH ≥ 2.5 (μIU/mL). We found a 1.5 times increased risk of NAFLD, 1.8 and 2.3 times increased risk of liver fibrosis for cut-off points of ≥8.0 kPa and ≥9.2 kPa, respectively, in subjects with TSH ≥ 2.5 μIU/mL compared with TSH < 2.5 μIU/mL (control group), independent of the presence of MetS. These findings remained significant when stratifying TSH, with values ≥ 10 μIU/mL.

High-Normal Serum Thyrotropin Levels Increased the Risk of Non-Alcoholic Fatty Liver Disease in Euthyroid Subjects with Type 2 Diabetes

PURPOSE

The aim of this study was to investigate the association between high-normal thyrotropin (TSH) levels and the prevalence of non-alcoholic fatty liver disease (NAFLD) in euthyroid patients with T2DM.

METHODS

A total of 2289 euthyroid adults with T2DM were included in this cross-sectional study conducted at the Third Affiliated Hospital of Sun Yat-sen University from January 2016 to December 2018. NAFLD was diagnosed by abdominal ultrasound. Thyroid function parameters, including the levels of TSH, free triiodothyronine (FT3) and free thyroxine (FT4), were analyzed. The patients were stratified by quartiles (Q1-4) of TSH levels. Multivariate logistic regression models were used to evaluate the association between the quartiles of TSH levels and the risk of NAFLD in euthyroid adults with T2DM.

RESULTS

There were 940 (41.1%) euthyroid adults with T2DM who were diagnosed with NAFLD. The subjects were divided according to the thyroid function parameter quartiles. The prevalence of NAFLD increased with increasing TSH level quartiles (Q1 to Q4: 34.8%, 37.5%, 44.9% and 47.0%, P<0.01) but not with increasing FT3 or FT4 level quartiles. In the multivariate logistic regression model, compared with the lowest TSH level quartile (Q1), the highest TSH level quartile (Q4) (OR=1.610, 95% CI=1.131-2.289, P=0.008) was independently associated with an increased risk of NAFLD in euthyroid adults with T2DM after adjusting for multiple confounders. After additional stratification by the level of glycosylated haemoglobin (HbA1c) and body mass index (BMI), the highest TSH level quartile was still independently associated with an increased risk of NAFLD in euthyroid patients with T2DM who had an HbA1c level≥7% or a BMI<28 kg/m².

CONCLUSION

High-normal serum TSH levels are significantly associated with the presence of NAFLD in T2DM patients with euthyroid function, which provide novel insight for treating NAFLD.