Heikentyneen insuliiniherkkyyden, rasvakudoksen tulehdustilan sekä PNPLA3-geenivariantin merkitys alkoholin liittymättömässä rasvamaksataudissa

Non-alcoholic fatty liver disease (NAFLD) may result from obesity accompanied by insulin resistance and adipose tissue inflammation or from the common genetic variants in PNPLA3 (rs738409, C>G/I148M), TM6SF2 (rs58542926, C>T/E167K) and MBOAT7 (rs641738, C>T). These variants increase the liver fat content and the severity of NAFLD without features of insulin resistance. This thesis aimed to determine the following: i) whether NAFLD predicts type 2 diabetes independent of obesity and other known risk factors; ii) whether adipose tissue is inflamed in subjects homozygous for the PNPLA3 I148M variant; iii) whether obesity and insulin resistance rather than liver fat content increase coagulation factor activities and expression; and iv) which factors predict NAFLD and liver stiffness during an 11-year follow-up period. The present thesis includes one systematic review, two cross-sectional studies and one longitudinal study. Study subjects comprised Finnish adult men and women. Liver fat content was measured by proton magnetic resonance spectroscopy (studies II–IV). The gene expression of inflammatory markers in adipose tissue and that of coagulation factors in the liver were measured using qPCR (studies II and III). We conducted a systematic review of prospective longitudinal studies to determine if NAFLD predicts type 2 diabetes for aim i). Based on these studies ultrasound-diagnosed NAFLD and liver enzymes predict type 2 diabetes independent of confounders such as age and obesity. We found no studies indicating that NAFLD associated with genetic risk variants predicting future risk of type 2 diabetes. A group of 82 subjects were divided into two groups based on body mass index and PNPLA3 genotype for aim ii). The liver fat content was similarly increased in obese/insulin-resistant subjects and in carriers of the I148M variant compared to non-obese subjects and non-carriers of this variant. In obese subjects, the adipose tissue expression of pro-inflammatory chemokine MCP-1 was increased and anti-inflammatory ADIPOQ and TWIST1 were decreased compared with non-obese subjects, while these were comparable between carriers and non-carriers of the I148M variant. In study III, 92 non-diabetic subjects were divided into two groups based on insulin sensitivity (HOMA-IR) and PNPLA3 genotype. Coagulation factor activities (FVIII, FIX, FXIII, fibrinogen and VWF:RCo) were increased, and the prothrombin time and activated partial thromboplastin time were shortened in insulin-resistant subjects when compared to insulin-sensitive subjects; yet, these factors were similar in carriers and non-carriers of the I148M variant. The hepatic gene expression of FVIII, FIX and fibrinogen gamma-chain were higher in insulin-resistant subjects with NAFLD (n=13) compared with equally obese insulin-sensitive subjects without NAFLD (n=13). In study IV, 97 subjects were examined twice over an interval of 11 years. The baseline liver fat content independently predicted NAFLD and an increased liver stiffness (measured using transient elastography) at 11.3 years more accurately than routinely available clinical and biochemical parameters. Conclusions: Obesity, adipose tissue inflammation and insulin resistance rather than excess hepatic fat per se are related to an increased risk of type 2 diabetes and a pro-coagulant plasma profile observed often in NAFLD. However, the liver fat content emerges as more important predictor of advanced liver fibrosis than the associated metabolic abnormalities. These data support the view that NAFLD is heterogeneous disease.Alkoholiin liittymätön rasvamaksatauti (non-alcoholic fatty liver disease, NAFLD) on yleisin krooninen maksasairaus länsimaissa. Maksan rasvoittuminen on tiiviisti yhteydessä lihavuuteen, rasvakudoksen matala-asteiseen tulehdustilaan, insuliiniherkkyyden heikentymiseen, metaboliseen oireyhtymään, tyypin 2 diabetekseen sekä sydän- ja verisuonisairauksiin ('metabolinen rasvamaksatauti'). Viime vuosina on löydetty yleisiä rasvamaksalle altistavia geenivariantteja, kuten PNPLA3–geenin I148M-variantti, joiden aiheuttaman rasvamaksataudin ('geneettisen rasvamaksataudin') yhteys insuliiniherkkyyteen ja rasvakudoksen tulehdustilaan on epäselvä. Maksan rasvoittuminen voi johtaa maksatulehdukseen (NASH), sidekudoksen muodostumiseen ja kirroosiin. Tämän väitöskirjatutkimuksen tavoitteena oli lisätä ymmärrystä rasvamaksataudin riskitekijöistä, etenemisestä ja yhteydestä aineenvaihdunnallisiin sairauksiin kuten tyypin 2 diabetekseen. Systemaattisen kirjallisuuskatsauksen avulla selvitettiin, että rasvamaksatauti ennustaa tyypin 2 diabetekseen sairastumista riippumatta muista tunnetuista riskitekijöistä. Kirjallisuudesta ei löytynyt seurantatutkimuksia, joissa olisi arvioitu geneettisestä alttiudesta aiheutuneen rasvamaksataudin lisäävän riskiä diabetekseen sairastumiselle. Rasvakudoksen tulehdustilan on ajateltu altistavan rasvamaksataudin kehittymiselle. Toisessa osatyössä määritettiin 82 tutkimushenkilön ihonalaisen rasvakudoksen tulehdustilaa tulehdusta lisäävien ja hillitsevien geenien ilmentymistä mittaamalla. Maksan rasvapitoisuus mitattiin magneettiresonanssispektroskopialla (1H-MRS). Tutkittavat jaettiin kahteen ryhmään painoindeksin sekä PNPLA3-genotyypin perusteella. Ylipainoisilla maksan rasvapitoisuus oli korkeampi kuin hoikemmilla tutkittavilla. Lisäksi heillä esiintyi rasvakudoksen tulehdusta. PNPLA3-variantin kantajilla ei havaittu rasvakudoksen tulehdusta huolimatta yhtälailla korkeammasta maksan rasvapitoisuudesta verrattuna henkilöihin ilman riskivarianttia. Kolmannessa osatyössä tutkittiin hyytymistekijöiden aktiivisuutta 92 tutkimushenkilöllä, jotka jaettiin kahteen ryhmään insuliiniherkkyyttä kuvastavan HOMA-IR -arvon sekä PNPLA3-genotyypin perusteella. Hyytymistekijöiden tuotantoa mitattiin 26 henkilön maksakudoksesta. Veren hyytymisaktiivisuuden sekä hyytymistekijöiden tuotannon havaittiin olevan koholla 'metabolisessa rasvamaksataudissa'. Hyytymistekijöiden aktiivisuuden ei havaittu nousseen PNPLA3-variantin kantajilla verrattuna henkilöihin ilman riskivarianttia. Neljännessä osatyössä selvitettiin, mitkä tekijät ennustavat rasvamaksatautia ja sidekudoksen esiintymistä. Mitä enemmän maksaan kertyy sidekudosta, sitä jäykemmäksi maksa muuttuu. Seurantatutkimus toteutettiin 97 henkilölle, joilta tutkittiin lähtötilanteessa kehonkoostumus, maksan rasvapitoisuus (H-MRS) sekä insuliiniherkkyyteen ja maksasairauksiin liittyviä laboratoriotutkimuksia. Nämä mittaukset toistettiin 11 vuoden päästä yhdessä maksan jäykkyysmittauksen kanssa. Lähtötilanteen maksan rasvapitoisuus ennustaa rasvamaksatautia ja merkittävää sidekudoksen muodostumista. Väitöskirjatutkimus osoittaa, että rasvamaksataudin syyt pikemmin kuin itse rasvoittuminen selittävät, liittyykö tautiin lisääntynyt riski sairastua tyypin 2 diabetekseen tai liitännäishäiriöitä kuten rasvakudoksen tulehdustila tai hyytymistekijöiden lisääntynyt aktiivisuus. Maksan rasvoittuminen syystä riippumatta ennustaa rasvamaksataudin ja merkittävän sidekudosmäärän esiintymistä 11 vuoden päästä

Nonalcoholic Fatty Liver Disease in Human Immunodeficiency Virus : The (Not So) New Kid on the Block? Reply

Non peer reviewe

Natural Course of Nonalcoholic Fatty Liver Disease and Type 2 Diabetes in Patients With Human Immunodeficiency Virus With and Without Combination Antiretroviral Therapy-associated Lipodystrophy : A 16-Year Follow-up Study

Background: Abnormal glucose metabolism and nonalcoholic fatty liver disease (NAFLD) are common in patients with human immunodeficiency virus (HIV+ patients), but longitudinal data are lacking. We determined the natural course of NAFLD (liver fat [LFAT]) and type 2 diabetes mellitus (T2DM) in HIV+ patients with and without lipodystrophy (LD+ and LD-, respectively) during a 16-year longitudinal study. Methods: LFAT (by proton magnetic resonance spectroscopy) and clinical characteristics were measured in 41 HIV+ patients at baseline and after 16 years. Liver fibrosis was estimated by measuring liver stiffness using transient elastography (TE) and magnetic resonance elastography (MRE) at 16 years. We also longitudinally studied 28 healthy subjects. Results: During follow-up, the HIV+ patients gained more body fat (8.6% 0.7%) than the control patients (4.5% 0.6%, P <.001). Features of insulin resistance increased significantly in the HIV+ patients but not the control patients. A significant proportion (20%, P <.01 vs 0% at baseline) of the HIV+ but none of the control patients developed T2DM. LFAT was significantly higher at baseline in the LD+ (4.3 [1.9-11.8]) than the LD- (1.0 [0.5-1.5]; P <.001) HIV+ patients. LFAT remained stable during follow-up in all groups. At follow-up, liver stiffness measured with TE was similar among all HIV, LD+, LD-, and control patients and between the LD+ and LD- patients measured with MRE. Advanced fibrosis by MRE was observed in 3 of LD+ and none of LD- patients. Conclusions: During 16 years of follow-up, progression of NAFLD is rare compared to development of T2DM in HIV+ patients.Peer reviewe

In vitro cytocompatibility of antibacterial silver and copper-doped bioactive glasses

Fighting the formation of bacterial biofilm and simultaneously providing a bioactive environment for bone regeneration during the treatment of orthopedic infections is one of the greatest challenges in surgery. Moreover, the major global threat of rapidly increasing antimicrobial resistance calls for non-antibiotic alternatives. Bioactive glasses doped with antibacterial metal ions silver (Ag), or copper (Cu), offer a potential solution. However, an added challenge is the cytocompatibility of these antimicrobial biomaterials, which could be compromised due to the possible cytotoxic effect of the dopants. This work evaluates the cytocompatibility of two bioactive glasses, SBA2 and SBA3, either doped with Ag- (Ag-SBA2) or Cu-ions (Cu-SBA3) via ion-exchange process. The viability, proliferation, and morphology of human adipose stem cells (hASCs) were evaluated using different culture conditions: i) direct culture on glass discs, with and without pre-incubation, and ii) in medium containing glass dissolution byproducts. The release kinetics of the doped ions was evaluated in α-MEM and during cell culture. Moreover, the effect of protein adsorption on the cell response was studied by introducing a layer of fibronectin on the glass discs before direct culture with hASCs. Ag-SBA2 and Cu-SBA3 both initially inhibited the hASC viability in direct cell culture. However, cells remain viable with healthy morphology when cultured directly on pre-treated discs, or indirectly with the glass dissolution byproducts. This suggests that the cytotoxicity effect seems to arise from the contact toxicity between the cells and the material surface. Fibronectin adsorption significantly improved the cytocompatibility of Ag-SBA2, while Cu-SBA3 requires further optimization. To conclude, Ag-SBA2, through its contact toxicity, has the potential for treating early infection, without compromising long-term cytocompatibility and bioactivity. However, further optimization of the Cu-SBA3 glass is needed due to its cytotoxicity towards hASCs.Peer reviewe

Predictors of Liver Fat and Stiffness in Non-Alcoholic Fatty Liver Disease (NAFLD) - an 11-Year Prospective Study

Liver fat can be non-invasively measured by proton magnetic resonance spectroscopy (H-1-MRS) and fibrosis estimated as stiffness using transient elastography (FibroScan). There are no longitudinal data on changes in liver fat in Europids or on predictors of liver stiffness using these methods. We determined liver fat (1H-MRS) and clinical characteristics including features of insulin resistance at baseline and after a median follow-up period of 11.3 (range 7.3-13.4) years in 97 Finnish subjects. Liver stiffness was measured at 11.3 years. Liver fat content decreased by 5% (p <0.05) over time. Values at baseline and 11.3 years were closely interrelated (r = 0.81, p <0.001). Baseline liver fat (OR 1.32; 95% CI: 1.15-1.50) and change in BMI (OR 1.67; 95% CI: 1.24-2.25) were independent predictors of liver fat at 11.3 years (AUROC 0.90; 95% CI: 0.83-0.96). Baseline liver fat (AUROC 0.84; 95% CI: 0.76-0.92) predicted liver fat at 11.3 years more accurately than routinely available parameters (AUROC 0.76; 95% CI: 0.65-0.86, p = 0.02). At 11.3 years, 29% of the subjects had increased liver stiffness. Baseline liver fat (OR 2.17; 95% CI: 1.05-4.46) was an independent predictor of increased liver stiffness. These data show that liver fat is more important than the associated metabolic abnormalities as the predictor of future liver fat and fibrosis.Peer reviewe

Effects of Weighted Hula-Hooping Compared to Walking on Abdominal Fat, Trunk Muscularity, and Metabolic Parameters in Overweight Subjects : A Randomized Controlled Study

Background: Weighted hula-hoops have gained popularity, but whether they indeed reshape the trunk or have beneficial metabolic effects in overweight subjects is unknown. Objectives: To determine effects of hula-hooping and walking matched for energy expenditure on android fat %, trunk muscle mass, and metabolic parameters in a randomized cross-over study. Design: We recruited 55 overweight nondiabetic subjects, who were randomized to hula-hooping (HULA) for 6 weeks using a 1.5-kg weighted hula-hoop followed by walking (WALK) for another 6 weeks or vice versa. The increments in energy expenditure were similar by HULA and WALK. Body composition (dual-energy X-ray absorptiometry) and metabolic parameters were measured at baseline and after HULA and WALK. The primary endpoint was the change in fat % in the android region. Results: A total of 53subjects (waist 92 +/- 1 cm, body mass index 28 +/- 1 kg/m(2)) completed the study. Body weight changed similarly (-0.6 +/- 0.2 vs. -0.5 +/- 0.2 kg, nonsignificant; HULA vs. WALK). During the intervention the subjects hula-hooped on average 12.8 +/- 0.5 min/day and walked 9,986 +/- 376 steps/day. The % fat in the android region decreased significantly by HULA but not by WALK (between-group change p <0.001). Trunk muscle mass increased more by HULA than by WALK (p <0.05). Waist circumference decreased more by HULA than by WALK (-3.1 +/- 0.3 cm vs. -0.7 +/- 0.4 cm, p <0.001; HULA vs. WALK). WALK but not HULA significantly lowered systolic blood pressure and increased HDL cholesterol while HULA significantly decreased LDL cholesterol. Conclusions: Hula-hooping with a weighted hula-hoop can be used to decrease abdominal fat % and increase trunk muscle mass in overweight subjects. Its LDL lowering effect resembles that described for resistance training. (c) 2019 The Author(s) Published by S. Karger AG, BaselPeer reviewe

Työn fyysisen kuormittavuuden yhteys fyysiseen toimintakykyyn alle 40-vuotiailla kunta-alan työntekijöillä

Vertaisarvioitu. English summary.Peer reviewe

Obesity/insulin resistance rather than liver fat increases coagulation factor activities and expression in humans

Increased liver fat may be caused by insulin resistance and adipose tissue inflammation or by the common I148M variant in PNPLA3 at rs738409, which lacks both of these features. We hypothesised that obesity/insulin resistance rather than liver fat increases circulating coagulation factor activities. We measured plasma prothrombin time (PT, Owren method), activated partial thromboplastin time (APTT), activities of several coagulation factors, VWF:RCo and fibrinogen, and D-dimer concentration in 92 subjects divided into groups based on insulin sensitivity [insulin-resistant ('IR') versus insulin-sensitive ('IS')] and PNPLA3 genotype (PNPLA3(148MM/MI) vs PNPLA3(148II)). Liver fat content (H-1-MRS) was similarly increased in 'IR' (13 +/- 1%) and PNPLA3(148MM/MI) (12 +/- 2%) as compared to 'IS' (6 +/- 1%, pPeer reviewe

Assessment of Lifestyle Factors Helps to Identify Liver Fibrosis Due to Non-Alcoholic Fatty Liver Disease in Obesity

Only some individuals with obesity develop liver fibrosis due to non-alcoholic fatty liver disease (NAFLD-fibrosis). We determined whether detailed assessment of lifestyle factors in addition to physical, biochemical and genetic factors helps in identification of these patients. A total of 100 patients with obesity (mean BMI 40.0 ± 0.6 kg/m2) referred for bariatric surgery at the Helsinki University Hospital underwent a liver biopsy to evaluate liver histology. Physical activity was determined by accelerometer recordings and by the Modifiable Activity Questionnaire, diet by the FINRISK Food Frequency Questionnaire, and other lifestyle factors, such as sleep patterns and smoking, by face-to-face interviews. Physical and biochemical parameters and genetic risk score (GRS based on variants in PNPLA3, TM6SF2, MBOAT7 and HSD17B13) were measured. Of all participants 49% had NAFLD-fibrosis. Independent predictors of NAFLD-fibrosis were low moderate-to-vigorous physical activity, high red meat intake, low carbohydrate intake, smoking, HbA1c, triglycerides and GRS. A model including these factors (areas under the receiver operating characteristics curve (AUROC) 0.90 (95% CI 0.84–0.96)) identified NAFLD-fibrosis significantly more accurately than a model including all but lifestyle factors (AUROC 0.82 (95% CI 0.73–0.91)) or models including lifestyle, physical and biochemical, or genetic factors alone. Assessment of lifestyle parameters in addition to physical, biochemical and genetic factors helps to identify obese patients with NAFLD-fibrosis

Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy

miRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. the endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and whitening of interscapular brown fat. Additionally, KO of dicer in cultured brown preadipocytes promoted a white adipocyte-like phenotype and reduced expression of several miRNAs. Brown preadipocyte whitening was partially reversed by expression of miR-365, a miRNA known to promote brown fat differentiation; however, introduction of other miRNAs, including miR-346 and miR-362, also contributed to reversal of the loss of the dicer phenotype. Interestingly, fat samples from patients with HIV-related lipodystrophy exhibited a substantial downregulation of dicer mRNA expression. Together, these findings indicate the importance of miRNA processing in white and brown adipose tissue determination and provide a potential link between this process and HIV-related lipodystrophy.NIHEllison FoundationJoslin Diabetes and Endocrinology Research Center coresMary K. Iacocca ProfessorshipAcademy of FinlandSigrid Juselius FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Harvard Univ, Sch Med, Joslin Diabet Ctr, Sect Integrat Physiol & Metab, Boston, MA 02115 USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilAstraZeneca R&D, Cardiovasc & Metab Dis iMed, Molndal, SwedenUniv Helsinki, Dept Med, Helsinki, FinlandMinerva Fdn, Inst Med Res, Helsinki, FinlandUniv Massachusetts, Sch Med, Program Mol Med, Worcester, MA USAMassachusetts Gen Hosp, Program Nutr Metab, Boston, MA 02114 USAHarvard Univ, Sch Med, Boston, MA USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilNIH: DK082659NIH: DK033201NIH: AI060354NIH: DK040561NIH: U24-DK093000Joslin Diabetes and Endocrinology Research Center cores: DK036836FAPESP: 2010/52557-0Web of Scienc