Early changes in hepatic energy metabolism and lipid content in recent-onset type 1 and 2 diabetes mellitus

Cross-sectional association between the isocaloric replacement of carbohydrates with protein and fat in relation to fat compartments distribution and hepatic lipid content in recent-onset type 1 and type 2 diabetes

BACKGROUND

Diets restricted in carbohydrates may be beneficial for diabetes management. However, without reducing energy intake, carbohydrate restriction results in increased protein and fat intake. Understanding how this macronutrient substitution is associated with adipose tissue distribution is important to prevent diabetes progression. Therefore, the aim was to investigate the isocaloric substitution of carbohydrates with fat and protein in relation to subcutaneous (SAT) and visceral adipose tissue (VAT) and hepatic lipid (HL) content in individuals with recent-onset type 1 (T1D) and type 2 diabetes (T2D), accounting for macronutrient quality.

METHODS

This cross-sectional analysis includes participants with T1D (n = 137) and T2D (n = 170) from the German Diabetes Study (GDS). Dietary macronutrient intake was derived from dietary information assessed with a validated food frequency questionnaire. SAT and VAT were measured with magnetic resonance (MR) imaging, while HL content with 1H MR spectroscopy. Isocaloric substitution analyses based on multivariable linear regression models were conducted to examine the replacement of total and higher glycemic index (GI) carbohydrates in energy percent (En%) with total fat, monounsaturated (MUFA), polyunsaturated (PUFA), and saturated fatty acids (SFA), and protein in regard to SAT, VAT and HL content.

RESULTS

In individuals with T1D, substituting carbohydrates with total fat was not associated with SAT, while substituting carbohydrates with protein demonstrated higher SAT [β (95% CI) per 5 En%: 3100 cm3 (25, 6200)]. In individuals with T2D, replacing carbohydrates with total fat or protein showed no association with SAT and VAT. However, substituting carbohydrates with PUFA was associated with lower VAT [-970 cm3 (-1900, -40)] and HL content [-3.3% (-6.9, 0.4)], while replacing carbohydrates with SFA was associated with higher HL content [2.4% (-0.6, 5.4)]. Substituting carbohydrates with protein was associated with lower HL content in individuals with T2D [-2.4% (-4.9, 0.0)], mainly driven by plant-based protein. There were no substantial differences between the replacement of total and higher GI carbohydrates.

CONCLUSIONS

The quality of substituted nutrients may play an important role for adipose tissue and HL accumulation in individuals with T2D. Particularly, integrating PUFAs and plant-based proteins into the diet seems beneficial for VAT and HL content.

Insulin Resistance in Type 1 Diabetes: Pathophysiological, Clinical, and Therapeutic Relevance

People with type 1 diabetes (T1D) are usually considered to exclusively exhibit β-cell failure, but they frequently also feature insulin resistance. This review discusses the mechanisms, clinical features, and therapeutic relevance of insulin resistance by focusing mainly on human studies using gold-standard techniques (euglycemic-hyperinsulinemic clamp). In T1D, tissue-specific insulin resistance can develop early and sustain throughout disease progression. The underlying pathophysiology is complex, involving both metabolic- and autoimmune-related factors operating synergistically. Insulin treatment may play an important pathogenic role in predisposing individuals with T1D to insulin resistance. However, the established lifestyle-related risk factors and peripheral insulin administration inducing glucolipotoxicity, hyperinsulinemia, hyperglucagonemia, inflammation, mitochondrial abnormalities, and oxidative stress cannot always fully explain insulin resistance in T1D, suggesting a phenotype distinct from type 2 diabetes. The mutual interaction between insulin resistance and impaired endothelial function further contributes to diabetes-related complications. Insulin resistance should therefore be considered a treatment target in T1D. Aside from lifestyle modifications, continuous subcutaneous insulin infusion can ameliorate insulin resistance and hyperinsulinemia, thereby improving glucose toxicity compared with multiple injection insulin treatment. Among other concepts, metformin, pioglitazone, incretin-based drugs such as GLP-1 receptor agonists, sodium-glucose cotransporter inhibitors, and pramlintide can improve insulin resistance, either directly or indirectly. However, considering the current issues of high cost, side effects, limited efficacy, and their off-label status, these agents in people with T1D are not widely used in routine clinical care at present.

PNPLA3 gene variation modulates diet-induced improvement in liver lipid content in type 2 diabetes

BACKGROUND&AIMS

Lifestyle-induced weight reduction remains crucial for managing type 2 diabetes and steatotic liver disease, but its effectiveness varies. We postulated that the G allele in the rs738409 single nucleotide polymorphism within patatin-like phospholipase domain-containing protein 3 (PNPLA3), which associates with metabolic dysfunction-associated steatotic liver disease, also modulates diet-related metabolic effects.

METHODS

Participants with type 2 diabetes were randomized to 8-week hypocaloric diets (energy intake: -1,256 kJ/d of, <30 kcal% fat): high in cereal fiber and coffee excluding red meat (HF-RM + C; n = 16), or low in cereal fiber, devoid of coffee, but high in red meat (LF + RM-C; n = 15). Whole-body insulin sensitivity (M value) was assessed using [2H]glucose and hyperinsulinemic-normoglycemic clamps, hepatic lipid content (HCL) and body fat volumes by magnetic resonance spectroscopy/imaging before and after intervention.

RESULTS

Despite comparable weight loss, HCL decreased more in non-carriers (-65 %) than in G-allele carriers (-36 %) upon HF-RM + C diet (both p < 0.05 vs baseline and between groups), but only among non-carriers (-46 %, p < 0.05 vs baseline) upon LF + RM-C. Upon HF-RM + C diet, increase in insulin sensitivity was not different between carriers (+27 % p = 0.051 from baseline) and non-carriers (+21 %, p = 0.032 from baseline), p > 0.05 for between-group comparison. Upon LF + RM-C diet, both groups equally improved their whole-body insulin sensitivity (+42 % for non-carriers and +37 % for carriers, p < 0.05 vs baseline). Upon HF-RM + C diet, non-carriers decreased circulating interleukin-18 from baseline by -31 %, whereas, upon LF + RM-C diet, non-carriers decreased circulating anti-inflammatory interleukin-1 receptor antagonist levels by 14 % (both p < 0.05 vs baseline).

CONCLUSIONS

Humans with the PNPLA3 G-allele show modified dietary-induced effects on steatotic liver disease in type 2 diabetes despite body weight reduction. Registration at Clinicaltrials.gov, Identifier number: NCT01409330.

Alterations of hepatic lipid content following COVID-19 in persons with type 2 diabetes

INTRODUCTION

The study aimed to assess the effect of COVID-19 on hepatic lipid (HL) content, fibrosis risk, and adiposity in persons with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Participants with type 2 diabetes with a history of mild COVID-19 (n=15, age 58±12 years, body mass index 30.9±5.2 kg/m2) were examined before (baseline) and 1 year (12±2 months) after (follow-up) recovery from COVID-19. Investigations for changes in metabolic risk comprised clinical examination, fasting blood sampling and MR-based measurements. Potential changes were corrected with the time course of the respective parameters in a group of participants who did not contract COVID-19 over the same time course (n=14, 61±6 years, 30.0±4.6 kg/m2).

RESULTS

COVID-19 resulted in a relative increase in HL content of 56% (95% CI 18%, 106%; p=0.04) measured as proton density fat fraction (HL-PDFF), corrected for the time course in the absence of COVID-19. While no changes in hepatic stiffness and volume, intramyocellular lipids, whole-body, subcutaneous and visceral adipose tissue volumes as well as homeostatic model assessment of insulin resistance and beta-cell function were observed.

CONCLUSIONS

History of COVID-19 in persons with type 2 diabetes is associated with higher HL-PDFF after 1 year following recovery from infection.

TRIAL REGISTRATION NUMBER

NCT01055093.

Cardiac metabolic index as a predictor of new-onset diabetes in non-alcoholic fatty liver disease patients: a longitudinal cohort analysis

OBJECTIVE

The purpose of this investigation is to assess the clinical risk linked to the onset of diabetes in individuals with non-alcoholic fatty liver disease (NAFLD) through the utilization of the cardiac metabolic index (CMI), which is derived from triglycerides, high-density lipoprotein, height, and waist circumference. Research focusing on the application of CMI for evaluating diabetes risk among NAFLD patients remains scarce, and an exploration of the association between CMI and the emergence of diabetes within this demographic has not been conducted. This investigation aims to illuminate this connection, thereby providing novel insights into the prevention of diabetes progression in individuals with NAFLD.

METHODS

Data were procured from a cross-sectional study involving 15,435 participants conducted by the Japanese government, resulting in a final cohort of 2,503 adults aged 18 and above who met the eligibility criteria for evaluation. The CMI is determined using the formula: TG (mmol/L) / HDL-C (mmol/L) * WHtR. CMI values were categorized into quartiles (Q1 to Q4) based on their scores, arranged from low to high. The investigation utilized logistic regression models, restricted cubic spline analysis, and subgroup analyses, with adjustments made for continuous models to elucidate the association between CMI and diabetes development among individuals with NAFLD, as well as the non-linear relationship between CMI and this outcome.

RESULTS

The investigation comprised 2,503 subjects with an average age of 44.79 ± 8.33 years, of whom 204 were diagnosed with new-onset diabetes (8.15%). Multivariate logistic regression analysis indicated that within the CMI quartile groupings, individuals with NAFLD in the uppermost quartile (Q4) exhibited the greatest likelihood of new-onset diabetes relative to those in the lowest quartile (Q1) (odds ratio, OR = 3.239, 95% confidence interval [CI]: 1.993-5.264, P < 0.001). Additionally, escalating CMI values corresponded to an increasing probability of new-onset diabetes in NAFLD subjects (OR = 1.705, 95% CI: 1.362-2.133, P < 0.001). Restricted cubic spline analysis demonstrated a non-linear connection between CMI and new-onset diabetes in NAFLD patients (P overall < 0.001, P non-linear = 0.035), with a risk inflection point identified at a CMI of 0.5554. Subgroup analysis revealed no significant interactions between gender, age, physical activity, alcohol consumption, or smoking status and the likelihood of new-onset diabetes in this patient population (P for interaction > 0.05).

CONCLUSION

Findings from this study indicate a notable positive non-linear connection between elevated CMI scores and the probability of new-onset diabetes in individuals afflicted with NAFLD.

CLINICAL TRIAL NUMBER

Not applicable.

Evaluation of Hypoglycemic Polyphenolic Compounds in Blueberry Extract: Functional Effects and Mechanisms

Blueberries are rich in polyphenols, which exhibit significant anti-diabetic activity. In this study, polyphenolic compounds with potential hypoglycemic activity were identified from blueberry polyphenol extract (BPE). This research focused on assessing the hypoglycemic effects of BPE and its polyphenolic compounds (dihydroquercetin and gallic acid) on diabetic mice induced by streptozotocin (STZ) and high-fat diet (HFD), as well as the related fundamental mechanisms. The findings revealed that BPE treatment effectively reduced levels of fasting blood glucose (FBG) by decreasing hepatic oxidative stress, regulating lipid metabolism disorders and improving insulin resistance. Investigations into the insulin signaling pathway revealed that BPE can modulate the expression of Egfr, Insr, Irs-1, Pi3k and Akt, thereby influencing glucose metabolism. This study provides a research foundation for considering blueberry polyphenols as a nutritional dietary supplement for the prevention and intervention of diabetes.

Pentachlorophenol increases diabetes risk by damaging β-cell secretion and disrupting gut microbial-related amino acids and fatty acids biosynthesis

Pentachlorophenol (PCP), a ubiquitous environmental pollutant, has been reported as a possible contributor to diabetes. However, evidence for general population is scarce while related mechanisms are largely unknown. Using a representative population-based case-control study in Beijing (n = 1796), we found a positive association between PCP exposure and diabetes risk with the odds ratio reaching 1.68 (95 % confidence interval: 1.30 to 2.18). A further rat experiment revealed that low-dose PCP mimicking real-world human exposure can significantly impair glycemic homeostasis by inducing pancreatic β-cell dysfunction, with non-linear dose-response relationships. Subsequent multi-omics analysis suggested that low-dose PCP led to notable gut microbiota dysbiosis (especially the species from genus Prevotella, such as intermedia, dentalis, ruminicola, denticola, melaninogenica, and oris), decreased serum amino acids (L-phenylalanine, L-tyrosine, and L-tryptophan) and increased serum fatty acids (oleic and palmitic acid) in rats, while strong correlations were observed among alterations of gut microbes, serum metabolites and glycemic-related biomarkers (e.g., fasting blood glucose and insulin). Collectively, these results imply PCP may increase diabetes risk by disrupting gut microbial-related amino acids and fatty acids biosynthesis. This will help guide future in-depth studies on the roles of PCP in the development of human diabetes.

Role of patatin-like phospholipase domain-containing 3 gene for decreasing kidney function in recently diagnosed diabetes mellitus

AIMS

We examined the association of the G allele in the single-nucleotide polymorphism (SNP) rs738409 in the third exon of patatin-like phospholipase domain-containing 3 gene (PNPLA3) gene, with chronic kidney disease in diabetes endotypes.

METHODS

Participants with recent-onset diabetes (n = 707) from the prospective German Diabetes Study (GDS) underwent cluster assignment, detailed phenotyping, genotyping and magnetic resonance spectroscopy to quantify hepatocellular lipid content (HCL).

RESULTS

Severe insulin-resistant diabetes (SIRD) had the lowest glomerular filtration rates (eGFR) and highest HCL compared to severe insulin-deficient, moderate obesity-related, moderate age-related and severe autoimmune diabetes endotypes (all p < 0.05). HCL was negatively associated with eGFR (r = -0.287, p < 0.01) across all groups. Stratification by G-allele carrier status did not reveal any association between HCL and eGFR among the endotypes. However, the proportion of G-allele carriers increased from 44 % for eGFR >60 ml/min to 52 % for eGFR <60 ml/min (p < 0.05).

CONCLUSIONS

The PNPLA3 polymorphism may contribute to declining kidney function independently of liver lipids.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet is associated with lower visceral and hepatic lipid content in recent-onset type 1 diabetes and type 2 diabetes

AIM

To investigate the associations of the Dietary Approaches to Stop Hypertension (DASH) score with subcutaneous (SAT) and visceral (VAT) adipose tissue volume and hepatic lipid content (HLC) in people with diabetes and to examine whether changes in the DASH diet were associated with changes in these outcomes.

METHODS

In total, 335 participants with recent-onset type 1 diabetes (T1D) and type 2 diabetes (T2D) from the German Diabetes Study were included in the cross-sectional analysis, and 111 participants in the analysis of changes during the 5-year follow-up. Associations between the DASH score and VAT, SAT and HLC and their changes were investigated using multivariable linear regression models by diabetes type. The proportion mediated by changes in potential mediators was determined using mediation analysis.

RESULTS

A higher baseline DASH score was associated with lower HLC, especially in people with T2D (per 5 points: -1.5% [-2.7%; -0.3%]). Over 5 years, a 5-point increase in the DASH score was associated with decreased VAT in people with T2D (-514 [-800; -228] cm3). Similar, but imprecise, associations were observed for VAT changes in people with T1D (-403 [-861; 55] cm3) and for HLC in people with T2D (-1.3% [-2.8%; 0.3%]). Body mass index and waist circumference changes explained 8%-48% of the associations between DASH and VAT changes in both groups. In people with T2D, adipose tissue insulin resistance index (Adipo-IR) changes explained 47% of the association between DASH and HLC changes.

CONCLUSIONS

A shift to a DASH-like diet was associated with favourable VAT and HLC changes, which were partly explained by changes in anthropometric measures and Adipo-IR.

Reproducibility of absolute quantification of adenosine triphosphate and inorganic phosphate in the liver with localized 31P-magnetic resonance spectroscopy at 3-T using different coils

Concentrations of the key metabolites of hepatic energy metabolism, adenosine triphosphate (ATP) and inorganic phosphate (Pi), can be altered in metabolic disorders such as diabetes mellitus. 31Phosphorus (31P)-magnetic resonance spectroscopy (MRS) is used to noninvasively measure hepatic metabolites, but measuring their absolute molar concentrations remains challenging. This study employed a 31P-MRS method based on the phantom replacement technique for quantifying hepatic 31P-metabolites on a 3-T clinical scanner. Two surface coils with different size and geometry were used to check for consistency in terms of repeatability and reproducibility and absolute concentrations of metabolites. Day-to-day (n = 8) and intra-day (n = 6) reproducibility was tested in healthy volunteers. In the day-to-day study, mean absolute concentrations of γ-ATP and Pi were 2.32 ± 0.24 and 1.73 ± 0.26 mM (coefficient of variation [CV]: 7.3% and 8.8%) for the single loop, and 2.32 ± 0.42 and 1.73 ± 0.27 mM (CVs 6.7% and 10.6%) for the quadrature coil, respectively. The intra-day study reproducibility using the quadrature coil yielded CVs of 4.7% and 6.8% for γ-ATP and Pi without repositioning, and 6.3% and 7.1% with full repositioning of the volunteer. The results of the day-to-day data did not differ between coils and visits. Both coils robustly yielded similar results for absolute concentrations of hepatic 31P-metabolites. The current method, applied with two different surface coils, can be readily utilized in long-term and interventional studies. In comparison with the single loop coil, the quadrature coil also allows measurements at a greater distance between the coil and liver, which is relevant for studying people with obesity.

Conditioned Media from Deer Antler Stem Cells Effectively Alleviate Type 1 Diabetes Mellitus Possibly via Inhibiting the NF-κB Signaling Pathway

BACKGROUND

Type 1 diabetes mellitus (T1D) represents a severe threat to human health. Persistent hyperglycemia and dyslipidemia can lead to damaged liver function, while effective interventions for these complications are currently lacking. Deer antler stem cells (AnSCs), a novel type of adult stem cells, significantly reduced liver injury, which was speculated to be achieved through the paracrine pathway.

METHODS

In this study, AnSC-conditioned medium (AnSC-CM) was used to treat C57BL/6 mice with T1D symptoms induced by streptozotocin (STZ). The therapeutic effects of AnSC-CM on T1D were evaluated, and the underlying mechanism was investigated.

RESULTS

It was shown that AnSC-CM alleviated the T1D symptom: decreased body weight, increased blood glucose levels and islet lesions, and reduced insulin secretion. Moreover, AnSC-CM treatment improved liver function and mitigated liver injury in T1D mice. Impressively, the therapeutic effects of AnSC-CM on T1D were better than those of bone marrow mesenchymal stem cell-CM (BMSC-CM). The mechanistic study revealed that AnSC-CM significantly downregulated the NF-κB signaling pathway in both pancreatic and liver tissues.

CONCLUSIONS

Therapeutic effects of AnSC-CM on STZ-induced T1D and liver injury may be achieved through targeting the NF-κB signaling pathway.

Analysis of type 2 diabetes heterogeneity with a tree-like representation: insights from the prospective German Diabetes Study and the LURIC cohort

BACKGROUND

Heterogeneity in type 2 diabetes can be represented by a tree-like graph structure by use of reversed graph-embedded dimensionality reduction. We aimed to examine whether this approach can be used to stratify key pathophysiological components and diabetes-related complications during longitudinal follow-up of individuals with recent-onset type 2 diabetes.

METHODS

For this cohort analysis, 927 participants aged 18-69 years from the German Diabetes Study (GDS) with recent-onset type 2 diabetes were mapped onto a previously developed two-dimensional tree based on nine simple clinical and laboratory variables, residualised for age and sex. Insulin sensitivity was assessed by a hyperinsulinaemic-euglycaemic clamp, insulin secretion was assessed by intravenous glucose tolerance test, hepatic lipid content was assessed by 1 H magnetic resonance spectroscopy, serum interleukin (IL)-6 and IL-18 were assessed by ELISA, and peripheral and autonomic neuropathy were assessed by functional and clinical measures. Participants were followed up for up to 16 years. We also investigated heart failure and all-cause mortality in 794 individuals with type 2 diabetes undergoing invasive coronary diagnostics from the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort.

FINDINGS

There were gradients of clamp-measured insulin sensitivity (both dimensions: p<0·0001) and insulin secretion (pdim1<0·0001, pdim2=0·00097) across the tree. Individuals in the region with the lowest insulin sensitivity had the highest hepatic lipid content (n=205, pdim1<0·0001, pdim2=0·037), pro-inflammatory biomarkers (IL-6: n=348, pdim1<0·0001, pdim2=0·013; IL-18: n=350, pdim1<0·0001, pdim2=0·38), and elevated cardiovascular risk (nevents=143, pdim1=0·14, pdim2<0·00081), whereas individuals positioned in the branch with the lowest insulin secretion were more prone to require insulin therapy (nevents=85, pdim1=0·032, pdim2=0·12) and had the highest risk of diabetic sensorimotor polyneuropathy (nevents=184, pdim1=0·012, pdim2=0·044) and cardiac autonomic neuropathy (nevents=118, pdim1=0·0094, pdim2=0·06). In the LURIC cohort, all-cause mortality was highest in the tree branch showing insulin resistance (nevents=488, pdim1=0·12, pdim2=0·0032). Significant gradients differentiated individuals having heart failure with preserved ejection fraction from those who had heart failure with reduced ejection fraction.

INTERPRETATION

These data define the pathophysiological underpinnings of the tree structure, which has the potential to stratify diabetes-related complications on the basis of routinely available variables and thereby expand the toolbox of precision diabetes diagnosis.

FUNDING

German Diabetes Center, German Federal Ministry of Health, Ministry of Culture and Science of the state of North Rhine-Westphalia, German Federal Ministry of Education and Research, German Diabetes Association, German Center for Diabetes Research, European Community, German Research Foundation, and Schmutzler Stiftung.

Association of thyroid function with non-alcoholic fatty liver disease in recent-onset diabetes

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) has been linked to type 2 diabetes (T2D), but also to hypothyroidism. Nevertheless, the relationship between thyroid function and NAFLD in diabetes is less clear. This study investigated associations between free thyroxine (fT4) or thyroid-stimulating hormone (TSH) and NAFLD in recent-onset diabetes.

METHODS

Participants with recent-onset type 1 diabetes (T1D, n = 358), T2D (n = 596) or without diabetes (CON, n = 175) of the German Diabetes Study (GDS), a prospective longitudinal cohort study, underwent Botnia clamp tests and assessment of fT4, TSH, fatty liver index (FLI) and in a representative subcohort 1 H-magnetic resonance spectroscopy.

RESULTS

First, fT4 levels were similar between T1D and T2D (p = .55), but higher than in CON (T1D: p < .01; T2D: p < .001), while TSH concentrations were not different between all groups. Next, fT4 correlated negatively with FLI and positively with insulin sensitivity only in T2D (ß = -.110, p < .01; ß = .126, p < .05), specifically in males (ß = -.117, p < .05; ß = .162; p < .01) upon adjustments for age, sex and BMI. However, correlations between fT4 and FLI lost statistical significance after adjustment for insulin sensitivity (T2D: ß = -.021, p = 0.67; males with T2D: ß = -.033; p = .56). TSH was associated positively with FLI only in male T2D before (ß = .116, p < .05), but not after adjustments for age and BMI (ß = .052; p = .30).

CONCLUSIONS

Steatosis risk correlates with lower thyroid function in T2D, which is mediated by insulin resistance and body mass, specifically in men, whereas no such relationship is present in T1D.

Differences in serum selenoprotein P profile between C57BL/6 and BALB/c mice fed high-fat diet

BACKGROUND

C57BL/6 mice generally show hyperglycaemia and insulin resistance when fed a high-fat diet (HFD) compared to those of BALB/c mice. However, whether these strains also show different expression profiles of selenoprotein P, a diabetes-related hepatokine, after HFD feeding is unclear. We investigated the effects of HFD on body weight, glucose metabolism, and plasma selenoprotein P levels in C57BL/6 and BALB/c mice.

METHODS

Male C57BL/6 and BALB/c mice aged seven weeks were divided into normal diet (ND) and HFD groups. Fasting body weights and blood sugar levels were measured weekly. Blood specimens were collected after 16 h of fasting (in weeks 7, 9, and 11) and after 24 h of subsequent refeeding (in weeks 9 and 11) to analyse plasma selenoprotein P and insulin levels.

RESULTS

The mean body weight of the HFD group was consistently higher than that of the ND group for both strains. However, a significant elevation in fasting plasma glucose levels from the early stage was observed only in the HFD group of C57BL/6 mice. In BALB/c mice, a difference in fasting glucose levels between the HFD and ND groups was observed after nine weeks. After seven, nine, and eleven weeks, the fasting plasma insulin levels were higher in the HFD group than in the ND group for both strains. During this period, plasma selenoprotein P levels in the HFD group were significantly higher than those in the ND group of C57BL/6 mice. However, BALB/c mice did not show a significant difference in plasma levels of selenoprotein P between the ND and HFD groups. After refeeding, the plasma insulin and selenoprotein P levels increased compared to those observed during fasting in the ND group for both strains. Elevation of insulin levels, but not of selenoprotein P levels, after refeeding was noticed in the HFD group for both strains. Plasma selenoprotein P level after refeeding was significantly lower than that during fasting in the HFD group of C57BL/6 mice.

CONCLUSION

Unlike C57BL/6 mice, BALB/c mice did not show elevated fasting plasma selenoprotein P levels despite HFD feeding. Additionally, the pattern of selenoprotein P levels in the plasma after refeeding differed between C57BL/6 and BALB/c mice. These differences in selenoprotein P expression among strains may be related to different susceptibilities of individuals to diabetes.

Reduced Insulin Clearance Differently Relates to Increased Liver Lipid Content and Worse Glycemic Control in Recent-Onset Type 2 and Type 1 Diabetes

OBJECTIVE

Diabetes may feature impaired insulin kinetics, which could be aggravated by altered hepatic metabolism and glycemic control. Thus, we examined insulin clearance and its possible determinants in individuals with recent-onset diabetes.

RESEARCH DESIGN AND METHODS

Participants of the German Diabetes Study (GDS) with type 1 diabetes (T1D) (n = 306), type 2 diabetes (T2D) (n = 489), or normal glucose tolerance (control [CON]) (n = 167) underwent hyperinsulinemic-euglycemic clamps for assessment of whole-body insulin sensitivity (M value) and insulin clearance (ICCLAMP). Insulin clearance rates were further calculated during intravenous glucose tolerance tests (ICIVGTT) and mixed-meal tests (ICMMT). Hepatocellular lipid content (HCL) was quantified with 1H-MRS.

RESULTS

Both T1D and T2D groups had lower ICCLAMP (0.12 ± 0.07 and 0.21 ± 0.06 vs. 0.28 ± 0.14 arbitrary units [a.u.], respectively, all P < 0.05) and ICMMT (0.71 ± 0.35 and 0.99 ± 0.33 vs. 1.20 ± 0.36 a.u., all P < 0.05) than CON. In T1D, ICCLAMP, ICIVGTT, and ICMMT correlated negatively with HbA1c (all P < 0.05). M value correlated positively with ICIVGTT in CON and T2D (r = 0.199 and r = 0.178, P < 0.05) and with ICMMT in CON (r = 0.176, P < 0.05). HCL negatively associated with ICIVGTT and ICMMT in T2D (r = -0.005 and r = -0.037) and CON (r = -0.127 and r = -0.058, all P < 0.05). In line, T2D or CON subjects with steatosis featured lower ICMMT than those without steatosis (both P < 0.05).

CONCLUSIONS

Insulin clearance is reduced in both T1D and T2D within the first year after diagnosis but correlates negatively with liver lipid content rather in T2D. Moreover, insulin clearance differently associates with glycemic control and insulin sensitivity in each diabetes type, which may suggest specific mechanisms affecting insulin kinetics.

Global prevalence of non-alcoholic fatty liver disease in type 2 diabetes mellitus: an updated systematic review and meta-analysis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with type 2 diabetes mellitus (T2DM) as a major predictor. Insulin resistance and chronic inflammation are key pathways in the pathogenesis of T2DM leading to NAFLD and vice versa, with the synergistic effect of NAFLD and T2DM increasing morbidity and mortality risks. This meta-analysis aims to quantify the prevalence of NAFLD and the prevalence of clinically significant and advanced fibrosis in people with T2DM.

METHODS

MEDLINE and Embase databases were searched from inception until 13 February 2023. The primary outcomes were the prevalence of NAFLD, non-alcoholic steatohepatitis (NASH) and fibrosis in people with T2DM. A generalised linear mixed model with Clopper-Pearson intervals was used for the analysis of proportions with sensitivity analysis conducted to explore heterogeneity between studies.

RESULTS

156 studies met the inclusion criteria, and a pooled analysis of 1 832 125 patients determined that the prevalence rates of NAFLD and NASH in T2DM were 65.04% (95% CI 61.79% to 68.15%, I2=99.90%) and 31.55% (95% CI 17.12% to 50.70%, I2=97.70%), respectively. 35.54% (95% CI 19.56% to 55.56%, I2=100.00%) of individuals with T2DM with NAFLD had clinically significant fibrosis (F2-F4), while 14.95% (95% CI 11.03% to 19.95%, I2=99.00%) had advanced fibrosis (F3-F4).

CONCLUSION

This study determined a high prevalence of NAFLD, NASH and fibrosis in people with T2DM. Increased efforts are required to prevent T2DM to combat the rising burden of NAFLD.

PROSPERO REGISTRATION NUMBER

CRD42022360251.

Intramyocellular Triglyceride Content During the Early Course of Type 1 and Type 2 Diabetes

Intramyocellular lipid content (IMCL) is elevated in insulin-resistant humans, but it changes over time, and relationships with comorbidities remain unclear. We examined IMCL during the initial course of diabetes and its associations with complications. Participants of the German Diabetes Study (GDS) with recent-onset type 1 (n = 132) or type 2 diabetes (n = 139) and glucose-tolerant control subjects (n = 128) underwent 1H-MRS to measure IMCL and muscle volume, whole-body insulin sensitivity (hyperinsulinemic-euglycemic clamps; M-value), and cycling spiroergometry (VO2max). Subgroups underwent the same measurements after 5 years. At baseline, IMCL was ∼30% higher in type 2 diabetes than in other groups independently of age, sex, BMI, and muscle volume. In type 2 diabetes, the M-value was ∼36% and ∼62% lower compared with type 1 diabetes and control subjects, respectively. After 5 years, the M-value decreased by ∼29% in type 1 and ∼13% in type 2 diabetes, whereas IMCL remained unchanged. The correlation between IMCL and M-value in type 2 diabetes at baseline was modulated by VO2max. IMCL also associated with microalbuminuria, the Framingham risk score for cardiovascular disease, and cardiac autonomic neuropathy. Changes in IMCL within 5 years after diagnosis do not mirror the progression of insulin resistance in type 2 diabetes but associate with early diabetes-related complications.

ARTICLE HIGHLIGHTS

Intramyocellular lipid content (IMCL) can be elevated in insulin-resistant humans, but its dynamics and association with comorbidities remain unclear. Independently of age, sex, body mass, and skeletal muscle volume, IMCL is higher in recent-onset type 2, but not type 1 diabetes, and remains unchanged within 5 years, despite worsening insulin resistance. A degree of physical fitness modulates the association between IMCL and insulin sensitivity in type 2 diabetes. Whereas higher IMCL associates with lower insulin sensitivity in people with lower physical fitness, there is no association between IMCL and insulin sensitivity in those with higher degree of physical fitness. IMCL associates with progression of microalbuminuria, cardiovascular disease risk, and cardiac autonomic neuropathy.

Alterations of hepatic energy metabolism in murine models of obesity, diabetes and fatty liver diseases

BACKGROUND

Disturbed hepatic energy metabolism contributes to non-alcoholic fatty liver (NAFLD), but the development of changes over time and obesity- or diabetes-related mechanisms remained unclear.

METHODS

Two-day old male C57BL/6j mice received streptozotocin (STZ) or placebo (PLC) and then high-fat (HFD) or regular chow diet (RCD) from week 4 (W4) to either W8 or W16, yielding control [CTRL = PLC + RCD], diabetes [DIAB = STZ + RCD], obesity [OBES = PLC + HFD] and diabetes-related non-alcoholic steatohepatitis [NASH = STZ + HFD] models. Mitochondrial respiration was measured by high-resolution respirometry and insulin-sensitive glucose metabolism by hyperinsulinemic-euglycemic clamps with stable isotope dilution.

FINDINGS

NASH showed higher steatosis and NAFLD activity already at W8 and liver fibrosis at W16 (all p < 0.01 vs CTRL). Ballooning was increased in DIAB and NASH at W16 (p < 0.01 vs CTRL). At W16, insulin sensitivity was 47%, 58% and 75% lower in DIAB, NASH and OBES (p < 0.001 vs CTRL). Hepatic uncoupled fatty acid oxidation (FAO)-associated respiration was reduced in OBES at W8, but doubled in DIAB and NASH at W16 (p < 0.01 vs CTRL) and correlated with biomarkers of unfolded protein response (UPR), oxidative stress and hepatic expression of certain enzymes (acetyl-CoA carboxylase 2, Acc2; carnitine palmitoyltransferase I, Cpt1a). Tricarboxylic acid cycle (TCA)-driven respiration was lower in OBES at W8 and doubled in DIAB at W16 (p < 0.0001 vs CTRL), which positively correlated with expression of genes related to lipolysis.

INTERPRETATION

Hepatic mitochondria adapt to various metabolic challenges with increasing FAO-driven respiration, which is linked to dysfunctional UPR, systemic oxidative stress, insulin resistance and altered lipid metabolism. In a diabetes model, higher TCA-linked respiration reflected mitochondrial adaptation to greater hepatic lipid turnover.

FUNDING

Funding bodies that contributed to this study were listed in the acknowledgements section.

Mitochondrial alterations in fatty liver diseases

Fatty liver diseases can result from common metabolic diseases, as well as from xenobiotic exposure and excessive alcohol use, all of which have been shown to exert toxic effects on hepatic mitochondrial functionality and dynamics. Invasive or complex methodology limits large-scale investigations of mitochondria in human livers. Nevertheless, abnormal mitochondrial function, such as impaired fatty acid oxidation and oxidative phosphorylation, drives oxidative stress and has been identified as an important feature of human steatohepatitis. On the other hand, hepatic mitochondria can be flexible and adapt to the ambient metabolic condition to prevent triglyceride and lipotoxin accumulation in obesity. Experience from studies on xenobiotics has provided important insights into the regulation of hepatic mitochondria. Increasing awareness of the joint presence of metabolic disease-related (lipotoxic) and alcohol-related liver diseases further highlights the need to better understand their mutual interaction and potentiation in disease progression. Recent clinical studies have assessed the effects of diets or bariatric surgery on hepatic mitochondria, which are also evolving as an interesting therapeutic target in non-alcoholic fatty liver disease. This review summarises the current knowledge on hepatic mitochondria with a focus on fatty liver diseases linked to obesity, type 2 diabetes and xenobiotics.

Emerging Roles of NDUFS8 Located in Mitochondrial Complex I in Different Diseases

NADH:ubiquinone oxidoreductase core subunit S8 (NDUFS8) is an essential core subunit and component of the iron-sulfur (FeS) fragment of mitochondrial complex I directly involved in the electron transfer process and energy metabolism. Pathogenic variants of the NDUFS8 are relevant to infantile-onset and severe diseases, including Leigh syndrome, cancer, and diabetes mellitus. With over 1000 nuclear genes potentially causing a mitochondrial disorder, the current diagnostic approach requires targeted molecular analysis, guided by a combination of clinical and biochemical features. Currently, there are only several studies on pathogenic variants of the NDUFS8 in Leigh syndrome, and a lack of literature on its precise mechanism in cancer and diabetes mellitus exists. Therefore, NDUFS8-related diseases should be extensively explored and precisely diagnosed at the molecular level with the application of next-generation sequencing technologies. A more distinct comprehension will be needed to shed light on NDUFS8 and its related diseases for further research. In this review, a comprehensive summary of the current knowledge about NDUFS8 structural function, its pathogenic mutations in Leigh syndrome, as well as its underlying roles in cancer and diabetes mellitus is provided, offering potential pathogenesis, progress, and therapeutic target of different diseases. We also put forward some problems and solutions for the following investigations.

Modulatory effect of camel milk on intestinal microbiota of mice with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disease of life, usually caused by unhealthy diet and lifestyle. Compared to normal individuals, the structure of the intestinal flora of NAFLD patients is altered accordingly. This study investigates the effect of camel milk on the regulation of intestinal flora structure in mice with high-fat diet-induced NAFLD. NAFLD model was established by feeding C57BL/6J mice a high-fat diet for 12 weeks, meanwhile camel milk (3.0 g/kg/d), cow milk (3.0 g/kg/d), and silymarin (200 mg/kg/d) were administered by gavage, respectively. Food intake and changes of physiological indexes in mice were observed and recorded. The 16S rRNA gene V3-V4 region was sequenced and the intestinal flora diversity and gene function were predicted in the colon contents of mice from different group. The results showed that camel milk enhanced glucolipid metabolism by downregulate the levels of blood glucose and triglyceride (TG) in serum, reduced lipid accumulation by downregulate the level of TG in the liver and improved liver tissue structure in NAFLD mice (p < 0.05). Meanwhile, camel milk had a positive modulatory effect on the intestinal flora of NAFLD mice, increasing the relative abundance of beneficial bacteria and decreasing the relative abundance of harmful bacteria in the intestinal flora of NAFLD mice, and silymarin had a similar modulatory effect. At the genus level, camel milk increased the relative abundance of Bacteroides, norank_f_Muribaculaceae and Alloprevotella and decreased the relative abundance of Dubosiella and Coriobacteriaceae_UCG-002 (p < 0.05). Camel milk also enhanced Carbohydrate metabolism, Amino acid metabolism, Energy metabolism, Metabolism of cofactors and vitamins and Lipid metabolism in NAFLD mice, thus reducing the degree of hepatic lipid accumulation in NAFLD mice and maintaining the normal structure of the liver. In conclusion, camel milk can improve the structure and diversity of intestinal flora and enhance the levels of substance and energy metabolism in NAFLD mice, which has a positive effect on alleviating NAFLD and improving the structure of intestinal flora.

Leptin increases hepatic triglyceride export via a vagal mechanism in humans

Recombinant human leptin (metreleptin) reduces hepatic lipid content in patients with lipodystrophy and overweight patients with non-alcoholic fatty liver disease and relative hypoleptinemia independent of its anorexic action. In rodents, leptin signaling in the brain increases very-low-density lipoprotein triglyceride (VLDL-TG) secretion and reduces hepatic lipid content via the vagus nerve. In this randomized, placebo-controlled crossover trial (EudraCT Nr. 2017-003014-22), we tested whether a comparable mechanism regulates hepatic lipid metabolism in humans. A single metreleptin injection stimulated hepatic VLDL-TG secretion (primary outcome) and reduced hepatic lipid content in fasted, lean men (n = 13, age range 20-38 years) but failed to do so in metabolically healthy liver transplant recipients (n = 9, age range 26-62 years) who represent a model for hepatic denervation. In an independent cohort of lean men (n = 10, age range 23-31 years), vagal stimulation by modified sham feeding replicated the effects of metreleptin on VLDL-TG secretion. Therefore, we propose that leptin has anti-steatotic properties that are independent of food intake by stimulating hepatic VLDL-TG export via a brain-vagus-liver axis.

NAFLD and thyroid function: pathophysiological and therapeutic considerations

Nonalcoholic fatty liver disease (NAFLD) is a worldwide rising challenge because of hepatic, but also extrahepatic, complications. Thyroid hormones are master regulators of energy and lipid homeostasis, and the presence of abnormal thyroid function in NAFLD suggests pathogenic relationships. Specifically, persons with hypothyroidism feature dyslipidemia and lower hepatic β-oxidation, which favors accumulation of triglycerides and lipotoxins, insulin resistance, and subsequently de novo lipogenesis. Recent studies indicate that liver-specific thyroid hormone receptor β agonists are effective for the treatment of NAFLD, likely due to improved lipid homeostasis and mitochondrial respiration, which, in turn, may contribute to a reduced risk of NAFLD progression. Taken together, the possible coexistence of thyroid disease and NAFLD calls for increased awareness and optimized strategies for mutual screening and management.

Fatty liver indices and their association with glucose metabolism in pregnancy - An observational cohort study

AIMS

Non-invasive hepatic steatosis indices can be used to assess the risk for metabolic (dysfunction) associated fatty liver disease (MAFLD). This may be helpful to detect metabolic disorders in pregnancy, specifically gestational diabetes (GDM). We aimto examine the association of these indices with parameters of glucose metabolism.

METHODS

109 women underwent a metabolic characterization at 16 weeks of gestation andwere classified according to the fatty-liver index (FLI) andhepatic-steatosis index (HSI) into low (G1), intermediate (G2) and high risk (G3). At 26 weeks, participants received an oral glucose tolerance test (OGTT) to assess insulin action, β-cell function and GDM status.

RESULTS

Both MAFLD indices wereassociated with impaired insulin sensitivityand compensatory increase of insulin release. G3 groups showedimpaired insulin action. The higher circulating insulin concentrations were not able to compensate for insulin resistance in women with higher MAFLD scores, resulting in an increased risk of GDM(OR: 1.05, 95% CI 1.03 to 1.08, p < 0.001 for FLI). MAFLD scores were associated with fetal overgrowth.

CONCLUSIONS

Maternal MAFLD represents a high-risk obstetric condition. Hepatic steatosis indices are associated with impaired glucose regulation and may provide a useful tool for early risk assessment for impaired glucose metabolism.

The role of mitochondria in the pathophysiology and treatment of common metabolic diseases in humans

Common metabolic diseases such as obesity, type 2 diabetes mellitus and non-alcoholic fatty liver disease significantly contribute to morbidity and mortality worldwide. They frequently associate with insulin resistance and altered mitochondrial functionality. Insulin-responsive tissues can show changes in mitochondrial features such as oxidative capacity, mitochondrial content and turnover, which do not necessarily reflect abnormalities but rather adaption to a certain metabolic condition. Lifestyle modifications and classic or novel drugs can modify these alterations and help treating these metabolic diseases. This review addresses the role of mitochondria in human metabolic diseases and discusses potential future research directions.

Impaired Hepatic Mitochondrial Capacity in Nonalcoholic Steatohepatitis Associated With Type 2 Diabetes

OBJECTIVE

Individuals with type 2 diabetes are at higher risk of progression of nonalcoholic fatty liver (steatosis) to steatohepatitis (NASH), fibrosis, and cirrhosis. The hepatic metabolism of obese individuals adapts by upregulation of mitochondrial capacity, which may be lost during the progression of steatosis. However, the role of type 2 diabetes with regard to hepatic mitochondrial function in NASH remains unclear.

RESEARCH DESIGN AND METHODS

We therefore examined obese individuals with histologically proven NASH without (OBE) (n = 30; BMI 52 ± 9 kg/m2) or with type 2 diabetes (T2D) (n = 15; 51 ± 7 kg/m2) as well as healthy individuals without liver disease (CON) (n = 14; 25 ± 2 kg/m2). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamps with d-[6,6-2H2]glucose. Liver biopsies were used for assessing mitochondrial capacity by high-resolution respirometry and protein expression.

RESULTS

T2D and OBE had comparable hepatic fat content, lobular inflammation, and fibrosis. Oxidative capacity in liver tissue normalized for citrate synthase activity was 59% greater in OBE than in CON, whereas T2D presented with 33% lower complex II-linked oxidative capacity than OBE and higher H2O2 production than CON. Interestingly, those with NASH and hepatic fibrosis score ≥1 had lower oxidative capacity and antioxidant defense than those without fibrosis.

CONCLUSIONS

Loss of hepatic mitochondrial adaptation characterizes NASH and type 2 diabetes or hepatic fibrosis and may thereby favor accelerated disease progression.

Novel Antidiabetic Strategies and Diabetologists' Views in Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide with high prevalence, especially in individuals with obesity and type 2 diabetes. Among individuals with type 2 diabetes, the severe insulin resistant subgroup has the greatest risk of NAFLD, likely due to dysfunctional adipose tissue mass but also genetic factors, and may progress earlier to inflammatory and profibrotic nonalcoholic steatohepatitis (NASH). NASH has been associated with increased liver-related as well as cardiovascular morbidity and mortality. International diabetes associations recommend certain screening and treatment strategies for NASH in type 2 diabetes, which, however, bear several limitations such as lack of accurate noninvasive diagnostic tools and targeted treatments. Currently, antihyperglycemic drug concepts based on glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter 2 inhibitors offer metabolic as well as cardiorenal benefits and provide treatment options for both hyperglycemia and NASH in type 2 diabetes.

Non-alcoholic fatty liver disease in type 1 diabetes: Prevalence and pathophysiology

Non-alcoholic fatty liver disease (NAFLD) is the most frequent chronic liver disease in the general population with a global prevalence of 25%. It is often associated with metabolic syndrome and type 2 diabetes, as insulin resistance and hyperinsulinemia are known to be favoring factors. Recent studies have described growing incidence of NAFLD in type 1 diabetes (T1D) as well. Although increasing prevalence of metabolic syndrome in these patients seems to explain part of this increase in NAFLD, other underlying mechanisms may participate in the emergence of NAFLD. Notably, some genetic factors are more associated with fatty liver disease, but their prevalence in T1D has not been evaluated. Moreover, oxidative stress, poor glucose control and long-lasting hyperglycemia, as well as exogenous insulin administration play an important role in intrahepatic fat homeostasis. The main differential diagnosis of NAFLD in T1D is glycogenic hepatopathy, which needs to be considered mostly in T1D patients with poor glycemic control. This article aims to review the prevalence and pathophysiology of NAFLD in T1D and open perspectives for clinicians taking care of T1D patients with potential hepatopathy.

Mechanisms and therapeutic strategies of immune checkpoint molecules and regulators in type 1 diabetes

BACKGROUND

Considered a significant risk to health and survival, type 1 diabetes (T1D) is a heterogeneous autoimmune disease characterized by hyperglycemia caused by an absolute deficiency of insulin, which is mainly due to the immune-mediated destruction of pancreatic beta cells.

SCOPE OF REVIEW

In recent years, the role of immune checkpoints in the treatment of cancer has been increasingly recognized, but unfortunately, little attention has been paid to the significant role they play both in the development of secondary diabetes with immune checkpoint inhibitors and the treatment of T1D, such as cytotoxic T-lymphocyte antigen 4(CTLA-4), programmed cell death protein-1(PD-1), lymphocyte activation gene-3(LAG-3), programmed death ligand-1(PD-L1), and T-cell immunoglobulin mucin protein-3(TIM-3). Here, this review summarizes recent research on the role and mechanisms of diverse immune checkpoint molecules in mediating the development of T1D and their potential and theoretical basis for the prevention and treatment of diabetes.

MAJOR CONCLUSIONS

Immune checkpoint inhibitors related diabetes, similar to T1D, are severe endocrine toxicity induced with immune checkpoint inhibitors. Interestingly, numerous treatment measures show excellent efficacy for T1D via regulating diverse immune checkpoint molecules, including co-inhibitory and co-stimulatory molecules. Thus, targeting immune checkpoint molecules may exhibit potential for T1D treatment and improve clinical outcomes.

The role of selenium in type-2 diabetes mellitus and its metabolic comorbidities

This review addresses the role of the essential trace element, selenium, in type-2 diabetes mellitus (T2DM) and its metabolic co-morbidities, i.e., metabolic syndrome, obesity and non-alcoholic fatty liver disease. We refer to the dietary requirements of selenium and the key physiological roles of selenoproteins. We explore the dysregulated fuel metabolism in T2DM and its co-morbidities, emphasizing the relevance of inflammation and oxidative stress. We describe the epidemiology of observational and experimental studies of selenium in diabetes and related conditions, explaining that the interaction between selenium status and glucose control is not limited to hyperglycemia but extends to hypoglycemia. We propose that the association between high plasma/serum selenium and T2DM/fasting plasma glucose observed in many cross-sectional studies may rely on the upregulation of hepatic selenoprotein-P biosynthesis in conditions of hyperglycemia and insulin resistance. While animal studies have revealed potential molecular mechanisms underlying adverse effects of severe selenium/selenoprotein excess and deficiency in the pathogenesis of insulin resistance and β-cell dysfunction, their translational significance is rather limited. Importantly, dietary selenium supplementation does not appear to be a major causal factor for the development of T2DM in humans though we cannot currently exclude a small contribution of selenium on top of other risk factors, in particular if it is ingested at high (supranutritional) doses. Elevated selenium biomarkers that are often measured in T2DM patients are more likely to be a consequence, rather than a cause, of diabetes.

Bone marrow derived-mesenchymal stem cell improves diabetes-associated fatty liver via mitochondria transformation in mice

Background

Non-alcoholic fatty liver disease (NAFLD) has become a global epidemic disease. Its incidence is associated with type 2 diabetes mellitus (T2DM). Presently, there is no approved pharmacological agents specially developed for NAFLD. One promising disease-modifying strategy is the transplantation of stem cells to promote metabolic regulation and repair of injury.

Method

In this study, a T2DM model was established through 28-week high-fat diet (HFD) feeding resulting in T2DM-associated NAFLD, followed by the injection of bone marrow mesenchymal stem cells (BMSCs). The morphology, function, and transfer of hepatocyte mitochondria were evaluated in both vivo and in vitro.

Results

BMSC implantation resulted in the considerable recovery of increasing weight, HFD-induced steatosis, liver function, and disordered glucose and lipid metabolism. The treatment with BMSC transplantation was accompanied by reduced fat accumulation. Moreover, mitochondrial transfer was observed in both vivo and vitro studies. And the mitochondria-recipient steatotic cells exhibited significantly enhanced OXPHOS activity, ATP production, and mitochondrial membrane potential, and reduced reactive oxygen species levels, which were not achieved by the blocking of mitochondrial transfer.

Conclusion

Mitochondrial transfer from BMSCs is a feasible process to combat NAFLD via rescuing dysfunction mitochondria, and has a promising therapeutic effect on metabolism-related diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02663-5.

The Programming of Antioxidant Capacity, Immunity, and Lipid Metabolism in Dojo Loach (Misgurnus anguillicaudatus) Larvae Linked to Sodium Chloride and Hydrogen Peroxide Pre-treatment During Egg Hatching

Non-nutritional stress during early life period has been reported to promote the metabolic programming in fish induced by nutritional stimulus. Sodium chloride (NaCl) and hydrogen peroxide (H₂O₂) have been widely applied during fish egg hatching, but the influences on health and metabolism of fish in their later life remain unknown. In the present study, H₂O₂ treatment at 400mg/L but not 200mg/L significantly increased the loach hatchability and decreased the egg mortality, while NaCl treatment at 1,000 and 3,000mg/L showed no significant influences on the loach hatchability nor egg mortality. Further studies indicated that 400mg/L H₂O₂ pre-treatment significantly enhanced the antioxidant capacity and the mRNA expression of genes involved in immune response of loach larvae, accompanied by the increased expression of genes involved in fish early development. However, the expression of most genes involved in lipid metabolism, including catabolism and anabolism of loach larvae, was significantly upregulated after 200mg/L H₂O₂ pre-treatment. NaCl pre-treatment also increased the expression of antioxidant enzymes; however, only the expression of C1q within the detected immune-related genes was upregulated in loach larvae. One thousand milligram per liter NaCl pre-treatment significantly increased the expression of LPL and genes involved in fish early development. Thus, our results suggested the programming roles of 400mg/L H₂O₂ pre-treatment during egg hatching in enhancing antioxidant capacity and immune response of fish larvae via promoting fish early development.

Non-Invasive Analysis of Human Liver Metabolism by Magnetic Resonance Spectroscopy

The liver is a key node of whole-body nutrient and fuel metabolism and is also the principal site for detoxification of xenobiotic compounds. As such, hepatic metabolite concentrations and/or turnover rates inform on the status of both hepatic and systemic metabolic diseases as well as the disposition of medications. As a tool to better understand liver metabolism in these settings, in vivo magnetic resonance spectroscopy (MRS) offers a non-invasive means of monitoring hepatic metabolic activity in real time both by direct observation of concentrations and dynamics of specific metabolites as well as by observation of their enrichment by stable isotope tracers. This review summarizes the applications and advances in human liver metabolic studies by in vivo MRS over the past 35 years and discusses future directions and opportunities that will be opened by the development of ultra-high field MR systems and by hyperpolarized stable isotope tracers.

Tetrahedral Framework Nucleic Acids Ameliorate Insulin Resistance in Type 2 Diabetes Mellitus via the PI3K/Akt Pathway

Insulin resistance (IR) is one of the essential conditions in the development of type 2 diabetes mellitus (T2DM). IR occurs in hepatic cells when the insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway is downregulated; thus, activating this pathway can significantly improve insulin sensitivity and ameliorate T2DM. Tetrahedral framework nucleic acids (tFNAs), a DNA nanomaterial, are synthesized from four single-stranded DNA molecules. tFNAs possess excellent biocompatibility and good water solubility and stability. tFNAs can promote cell proliferation, cell autophagy, wound healing, and nerve regeneration by activating the PI3K/Akt pathway. Herein, we explore the effects and underlying mechanisms of tFNAs on IR. The results displayed that tFNAs could increase glucose uptake and ameliorate IR by activating the IRS-1/PI3K/Akt pathway in glucosamine (GlcN)-stimulated HepG2 cells. By employing a PI3K inhibitor, we confirmed that tFNAs reduce IR through the PI3K/Akt pathway. Moreover, tFNAs can promote hepatic cell proliferation and inhibit GlcN-induced cell apoptosis. In a T2DM mouse model, tFNAs reduce blood glucose levels and ameliorate hepatic IR via the PI3K/Akt pathway. Taken together, tFNAs can improve hepatic IR and alleviate T2DM through the PI3K/Akt pathway, making contribution to the potential application of tFNAs in T2DM.

Targeting Mitochondria in Diabetes

Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes.

Improving insulin sensitivity, liver steatosis and fibrosis in type 2 diabetes by a food-based digital education-assisted lifestyle intervention program: a feasibility study

PURPOSE

Recent trials demonstrated remission of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) following formula diet-induced weight loss. To improve the outreach for populations in need, many mobile health apps targeting weight loss have been developed with limited scientific evaluation of these apps. The present feasibility study investigated the effects of a novel approach incorporating a regular 'whole food-based' low-calorie diet combined with app-based digital education and behavioral change program on glucose metabolism and disease management.

METHODS

Twenty-four individuals with type 2 diabetes followed this approach supported by weekly coaching calls for 12 weeks. Phenotyping included bioimpedance analysis, mixed-meal tolerance test, magnetic resonance spectroscopy and transient elastography for assessing liver fat content and liver stiffness.

RESULTS

Over 12 weeks, participants reduced their body weight by 9% (97 ± 13 to 88 ± 12 kg), body mass index (BMI; 33 ± 5 to 29 ± 4 kg/m²), total fat mass (31 ± 10 to 27 ± 10%) (all p < 0.01) and liver fat by 50% alongside with decreased liver stiffness. Target HbA1c (< 6.5%) was achieved by 38% and resolution of NAFLD (liver fat content < 5.6%) was observed in 30% of the participants.

CONCLUSION

This novel approach combining digital education with a low-calorie diet results in effective improvements of body weight, glycemic control and NAFLD and could complement existing care for patients with type 2 diabetes.

TRIAL REGISTRATION

NCT04509245.