Metabolic Perturbations and Ectopic Fat Deposition in Men With Low Birth Weight: Effects of a 4-Week Carbohydrate Overfeeding Challenge.

Introduction & Objective: Individuals born with low birthweight (LBW) are at elevated risk of developing type 2 diabetes (T2D). We studied postprandial (pp) glucose metabolism during a mixed meal-test in healthy LBW compared with normal birthweight (NBW) men before and after carbohydrate overfeeding (CO). Methods: Twenty-two non-obese, middle-aged LBW men (BW 2797±175g) and 21 age- and BMI-matched NBW controls (BW 3807±176g) were included. Glucose kinetics were assessed by [U-13C]Glucose (meal) and [6,6-D2]Glucose continuous forearm venous infusion during a 5-hour liquid mixed meal-test before and after 4-week CO (+25% energy). Data were analyzed assessing change in pp area under the curve (AUC). Subgroup analysis was performed for five cases of screen-detected non-alcoholic fatty liver disease (NAFLD) among LBW men measured by magnetic resonance spectroscopy. Results: CO resulted in increased weight (P<0.0001) and liver fat content (P=0.009) in both groups. LBW men responded to CO with an increase in pp insulin AUC (P=0.04), with no differences in pp glucose AUC, compared with NBW men. In response to CO, the pp total glucose rate of appearance (Ra) decreased paradoxically by 4.5% in the LBW group (with and without NAFLD), whereas it increased by 6.3% in the NBW group (P=0.03). This, in turn, was explained by a decrease of oral glucose Ra (P=0.01), and not endogenous (hepatic) Ra, in the LBW group. In response to CO, the pp glucose disposal rate (reflecting insulin action) decreased by 26% in the LBW group, whereas it increased by 40% in the NBW group (P=0.08). Conclusion: LBW compared with NBW subjects respond to CO with increased plasma insulin levels, peripheral insulin resistance, and a decline in postprandial Ra of ingested glucose in the main circulation possibly caused by an increased hepatic retention of ingested glucose contributing to increased hepatic lipogenesis, fat storage and NAFLD risk in LBW subjects. Disclosure L.M. Engelhard: None. L. Elingaard-Larsen: None. L. Justesen: None. T. Hansen: None. G. van Hall: None. A.A. Vaag: None. C. Brøns: Stock/Shareholder; Novo Nordisk A/S. Funding NNF, EFSD Organ Crosstalk Program, Trygfonden, Augustinus Fonden and Aase and Ejnar Danielsens Fond

Low birth weight (LBW) individuals have an increased risk of developing insulin resistance and type 2 diabetes compared with normal birth weight (NBW) individuals. We hypothesised that LBW individuals exhibit an increased fatty acid flux into lipogenesis in non-adipose tissue with a resulting accumulation of lipotoxic lipids, including ceramides, in the blood. Therefore, we measured fasting plasma levels of 27 ceramides in 18 young, healthy, LBW men and 25 NBW controls after an isocaloric control diet and a 5-day high-fat, high-calorie diet by HPLC-HRMS. LBW men did not show elevated plasma ceramide levels after the control or high-fat, high-calorie diet. An increased fatty acid oxidation rate in these individuals during both diets may limit ceramide synthesis and thereby compensate for a likely increased fatty acid load to non-adipose tissue. Interestingly, LBW and NBW men decreased d18:0–18:1/d18:1–18:0 and d18:1–24:2/d18:2–24:1 levels and increased the d18:0–24:1a level in response to overfeeding. Plasma d18:0–24:1a and total ceramide levels were positively associated with the fasting blood glucose level and endogenous glucose production after the control diet, and the total ceramide level was in addition positively associated with hepatic insulin resistance. Further studies are needed to determine if lipotoxicity contributes to insulin resistance in LBW individuals.

<p dir="ltr">Low birthweight (LBW) is a risk factor for type-2 diabetes (T2D). We hypothesized that 4-weeks carbohydrate overfeeding (COF) with +25% energy would unmask key T2D perturbations among 22 non-obese LBW men, including 5 with screen-detected metabolic dysfunction–associated steatotic liver disease (MASLD), compared with 21 healthy normal birthweight (NBW) controls. Body weight, lean and fat mass, as well as hepatic fat content, increased to the same extent in both groups during COF, whereas fasting glucose and insulin resistance increased significantly more in LBW compared with NBW subjects. The differential COF responses were most pronounced among LBW subjects without MASLD, including increased resting energy expenditure. Plasma adiponectin was lower, whereas FGF-21 levels increased more during COF in LBW subjects. Subcutaneous adipose tissue (SAT) density was lower in LBW subjects and decreased during COF in both groups. Serum alanine, phosphatidylcholines, and triglycerides increased significantly more in LBW subjects during COF. Multi-omics analysis of SAT RNA-sequencing, serum lipidomics and metabolomics uncovered impaired PPAR signaling, as well as aberrant collagen and extracellular matrix regulation in LBW subjects. The results document differential and MASLD independent metabolic perturbations in LBW subjects during COF.</p>

<p dir="ltr">Low birthweight (LBW) is a risk factor for type-2 diabetes (T2D). We hypothesized that 4-weeks carbohydrate overfeeding (COF) with +25% energy would unmask key T2D perturbations among 22 non-obese LBW men, including 5 with screen-detected metabolic dysfunction–associated steatotic liver disease (MASLD), compared with 21 healthy normal birthweight (NBW) controls. Body weight, lean and fat mass, as well as hepatic fat content, increased to the same extent in both groups during COF, whereas fasting glucose and insulin resistance increased significantly more in LBW compared with NBW subjects. The differential COF responses were most pronounced among LBW subjects without MASLD, including increased resting energy expenditure. Plasma adiponectin was lower, whereas FGF-21 levels increased more during COF in LBW subjects. Subcutaneous adipose tissue (SAT) density was lower in LBW subjects and decreased during COF in both groups. Serum alanine, phosphatidylcholines, and triglycerides increased significantly more in LBW subjects during COF. Multi-omics analysis of SAT RNA-sequencing, serum lipidomics and metabolomics uncovered impaired PPAR signaling, as well as aberrant collagen and extracellular matrix regulation in LBW subjects. The results document differential and MASLD independent metabolic perturbations in LBW subjects during COF.</p>

Low birth weight (LBW) individuals exhibit a disproportionately increased, incomplete fatty acid oxidation and a decreased glucose oxidation, compared with normal birth weight (NBW) individuals, and furthermore have an increased risk of developing insulin resistance and type 2 diabetes. We hypothesized that changes in amino acid metabolism may occur parallel to alterations in fatty acid and glucose oxidation, and could contribute to insulin resistance. Therefore, we measured fasting plasma levels of 15 individual or pools of amino acids in 18 LBW and 25 NBW men after an isocaloric control diet and after a 5‐day high‐fat, high‐calorie diet. We demonstrated that LBW and NBW men increased plasma alanine levels and decreased valine and leucine/isoleucine levels in response to overfeeding. Also, LBW men had higher alanine, proline, methionine, citrulline, and total amino acid levels after overfeeding compared with NBW men. Alanine and total amino acid levels tended to be negatively associated with the insulin‐stimulated glucose uptake after overfeeding. Therefore, the higher amino acid levels in LBW men could be a consequence of their reduction in skeletal muscle insulin sensitivity due to overfeeding with a possible increased skeletal muscle proteolysis and/or could potentially contribute to an impaired insulin sensitivity. Furthermore, the alanine level was negatively associated with the plasma acetylcarnitine level and positively associated with the hepatic glucose production after overfeeding. Thus, the higher alanine level in LBW men could be accompanied by an increased anaplerotic formation of oxaloacetate and thereby an enhanced tricarboxylic acid cycle activity and as well an increased gluconeogenesis.

Individuals who had a low birthweight (LBW) are at an increased risk of insulin resistance and type 2 diabetes when exposed to high-fat overfeeding (HFO). We studied genome-wide mRNA expression and DNA methylation in subcutaneous adipose tissue (SAT) after 5 days of HFO and after a control diet in 40 young men, of whom 16 had LBW. mRNA expression was analysed using Affymetrix Human Gene 1.0 ST arrays and DNA methylation using Illumina 450K BeadChip arrays. We found differential DNA methylation at 53 sites in SAT from LBW vs normal birthweight (NBW) men (false discovery rate <5%), including sites in the FADS2 and CPLX1 genes previously associated with type 2 diabetes. When we used reference-free cell mixture adjustments to potentially adjust for cell composition, 4,323 sites had differential methylation in LBW vs NBW men. However, no differences in SAT gene expression levels were identified between LBW and NBW men. In the combined group of all 40 participants, 3,276 genes (16.5%) were differentially expressed in SAT after HFO (false discovery rate <5%) and there was no difference between LBW men and controls. The most strongly upregulated genes were ELOVL6, FADS2 and NNAT; in contrast, INSR, IRS2 and the SLC27A2 fatty acid transporter showed decreased expression after HFO. Interestingly, SLC27A2 expression correlated negatively with diabetes- and obesity-related traits in a replication cohort of 142 individuals. DNA methylation at 652 CpG sites (including in CDK5, IGFBP5 and SLC2A4) was altered in SAT after overfeeding in this and in another cohort. Young men who had a LBW exhibit epigenetic alterations in their adipose tissue that potentially influence insulin resistance and risk of type 2 diabetes. Short-term overfeeding influences gene transcription and, to some extent, DNA methylation in adipose tissue; there was no major difference in this response between LBW and control participants.

Telomeres are protein-bound regions of repetitive nucleotide sequences (TTAGGG) at the end of human chromosomes, and their length is a marker of cellular aging. Intrauterine growth restriction is associated with shorter blood cell telomeres at birth and individuals with type 2 diabetes have shorter telomeres. Individuals with a low birth weight (LBW) have an increased risk of metabolic disease and type 2 diabetes. Therefore, we aimed to investigate the relationship between birth weight and telomere length and the association between birth weight, telomere length and cardiometabolic phenotype in adulthood. Young, healthy men with LBW (n = 55) and normal birth weight (NBW) (n = 65) were examined including blood pressure, blood samples and body composition. Leukocyte telomere length was determined using a high-throughput qPCR method. The LBW men were more insulin resistant as determined by the HOMA-IR index. There was no difference in telomere length between LBW and NBW subjects. When adjusting for birth weight and cohort effect, significant negative associations between telomere length and fasting glucose (P = 0.003) and HbA1c (P = 0.0008) were found. In conclusion, no significant difference in telomere length was found between LBW and NBW men. The telomere length was negatively associated with glucose concentrations and HbA1c levels within the normal non-diabetic range independent of birth weight.

ABSTRACTAim: The TCF7L2 gene variant rs7903146 has the largest effect on type 2 diabetes risk reported in genome-wide association studies, however its role in adipose tissue development and function is unknown. We investigate the association between gene variant rs7903146 and metabolic parameters and examine in vitro and ex vivo gene expression of TCF7L2 in human adipose tissue and progenitor cells from two independent populations of young healthy men with increased risk of type 2 diabetes due to low birth weight (LBW). Design: Adipose tissue biopsies were excised from 40 healthy young men with low and normal birth weights (NBW) after a control and 5-day high-fat overfeeding diet. In another cohort including 13 LBW and 13 NBW men, adipocyte progenitor cells were isolated and cultivated. Transcriptome-wide expression was performed on RNA extracted from biopsies or cell cultures. Results: Diet-induced peripheral insulin resistance is more pronounced in carriers of the T-risk allele rs7903146, whereas no association with hepatic insulin resistance was shown. TCF7L2 expression increased during adipogenesis in isolated preadipocytes from both LBW and NBW men (p < 0.001) and correlated positively with markers of progenitor cell proliferation and maturation capacity. In the mature adipose tissue, LBW men had lower expression of TCF7L2 compared to NBW men at baseline (p = 0.03) and TCF7L2 expression was suppressed by short-term overfeeding in NBW men (p = 0.005). Conclusions: The results suggest a regulation of TCF7L2 expression during adipogenesis and in mature adipose tissue upon overfeeding, and further that young men exposed to an adverse intrauterine environment have reduced mature adipose tissue TCF7L2 expression.

Background: Low birth weight (LBW) individuals are at increased risk of developing Type 2 diabetes (T2D) , especially when exposed to an affluent dietary pattern. Impaired subcutaneous adipose tissue expandability and ectopic fat storage may represent key features explaining the link between LBW and risk of T2D. We hypothesized that a 4-week simple carbohydrate overfeeding challenge (+25% energy) (COF) would adversely influence dysmetabolic traits including hepatic fat content in LBW compared to normal birth weight (NBW) men. Methods: Twenty-two non-obese LBW and 21 age- and BMI-matched NBW men with a mean age of 37.6 years were included. Body composition, hepatic fat (MR spectroscopy) , glucose and insulin metabolism, hepatic glucose production (HGP; deuterium glucose) , energy metabolism (indirect calorimetry) and selected plasma biomarkers (multiplex ELISA) were measured before and after 4 weeks COF. Results: Fasting plasma glucose and C-peptide levels, as well as energy expenditure (EE) and fat oxidation (FOX) rates increased significantly more in response to COF among the LBW compared to NBW subjects (all P&amp;lt;0.05) . However, despite significantly increased baseline hepatic fat content, COF resulted in similar body weight and hepatic fat content increments in LBW compared to NBW subjects. HGP and hepatic insulin resistance were unaffected by COF in both groups. Fasting plasma adiponectin levels were significantly reduced in LBW versus NBW subjects before and after COF, whereas plasma leptin and FGF21 levels were increased (both P&amp;lt;0.005) after COF in LBW men only. Conclusion: LBW compared to NBW subjects respond to COF with differential increments in plasma glucose, C-peptide, leptin and FGF21 levels, as well as increased EE and FOX rates. The results underscore the importance of LBW individuals avoiding simple carbohydrate overfeeding. Further studies are needed to understand the role of increased hepatic fat and insulin resistance as key mechanisms linking LBW with increased risk of T2D. Disclosure C.Brøns: Stock/Shareholder; Novo Nordisk. A.B.Thuesen: None. L.Justesen: None. L.Elingaard-larsen: None. J.Størling: None. E.R.Danielsen: None. T.Hansen: None. A.A.Vaag: Stock/Shareholder; AstraZeneca. Funding Novo Nordisk Foundation (NNF15OC0016692) , Aase and Ejnar Danielsens Fond, Augustinus Foundation, Simon Spies Fonden, TrygFonden.

Fasting unmasks differential fat and muscle transcriptional regulation of metabolic gene sets in low versus normal birth weight men.

The effects of short-term carbohydrate overfeeding and prior exercise on resting metabolic rate and diet-induced thermogenesis

PD09-01 LOW BIRTH WEIGHT IS ASSOCIATED WITH SPERM DNA FRAGMENTATION AND ASSISTED REPRODUCTIVE TECHNOLOGY OUTCOMES IN PRIMARY INFERTILE MEN—RESULTS OF A CROSS-SECTIONAL STUDY

Low birth weight (LBW) associates with increased risk of developing type 2 diabetes. LBW individuals exhibit disproportionately reduced peripheral insulin action and increased fat oxidation after a 5-day high-fat overfeeding (HFO) challenge. Furthermore, LBW men exhibit increased nocturnal fat oxidation during energy balance and low energy expenditure (EE) during fasting. We hypothesized that short-term HFO could further unmask key defects of whole-body energy metabolism in LBW men. Eighteen LBW (2717±268g) and 26 normal birth weight (NBW) (3893±207g) healthy young men were included in a 5-day HFO (60 E% fat, +50% calories) study. The 24-h EE, respiratory quotient and substrate oxidation rates were assessed by indirect calorimetry using respiratory chambers. After adjusting for body composition, the LBW subjects displayed increased nighttime EE (P=0.02) compared with NBW controls during HFO. Nighttime glucose oxidation rate was decreased (P=0.06, adjusted P=0.05), while both adjusted 24-h (P=0.07) and nighttime (P=0.02) fat oxidation rate was elevated in LBW subjects. The relative contribution of fat oxidation to EE was increased in LBW compared with NBW men during the entire 24-h period (P=0.06) and during nighttime (P=0.03). We suggest that disproportionally enhanced fat oxidation in LBW individuals during short-term HFO represents a compensatory response to reduced subcutaneous adipose tissue expandability and storage capacity. The extent to which this mechanism may lead to, or be replaced by insulin resistance, ectopic fat accumulation and/or glucose intolerance during long-term HFO in LBW needs further studies.

Individuals born with low birth weight (LBW) risk cardiometabolic complications later in life. However the impact of LBW on general health status and male reproductive function has been scantly analysed. We investigated the clinical and seminal impact of different birth weights (BW) in white-European men presenting for primary couple’s infertility. Demographic, clinical, and laboratory data from 827 primary infertile men were compared with those of 373 consecutive fertile men. Patients with BW ≤2500, 2500–4200, and ≥4200gr were classified as having LBW, normal (NBW), and high BW (HBW), respectively. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Testicular volume was assessed with a Prader orchidometer. Semen analysis values were assessed based on 2010 WHO reference criteria. Descriptive statistics and regression models tested associations between semen parameters, clinical characteristics and BW categories. LBW, NBW and HBW were found in 71 (8.6%), 651 (78.7%) and 105 (12.7%) infertile men, respectively. LBW was more frequent in infertile patients than fertile men (p = 0.002). Infertile patients with LBW had a higher rate of comorbidities (p = 0.003), lower mean testicular volume (p = 0.007), higher FSH (p = 0.02) and lower tT levels (p = 0.04) compared to other BW groups. Higher rates of asthenozoospermia (p = 0.02) and teratozoospermia (p = 0.03) were also found in LBW men. At logistic regression models, LBW was univariably associated with pathologic progressive motility (p≤0.02) and pathologic sperm morphology (p<0.005). At multivariable logistic regression analysis, LBW achieved independent predictor status for both lower sperm motility and pathologic sperm morphology (all p≤0.04). Only LBW independently predicted higher CCI values (p<0.001). In conclusion, we found that LBW was more frequent in infertile than in fertile men. Infertile individuals with LBW showed a higher rate of comorbidities and significantly worse clinical, endocrine and semen parameters compared to other BW groups.

The extent to which increased liver fat content influences differences in circulating metabolites and/or lipids between low-birth-weight (LBW) individuals, at increased risk of type 2 diabetes (T2D), and normal-birth-weight (NBW) controls is unknown. The objective of the study was to perform untargeted serum metabolomics and lipidomics analyses in 26 healthy, non-obese early-middle-aged LBW men, including five men with screen-detected and previously unrecognized non-alcoholic fatty liver disease (NAFLD), compared with 22 age- and BMI-matched NBW men (controls). While four metabolites (out of 65) and fifteen lipids (out of 279) differentiated the 26 LBW men from the 22 NBW controls (p ≤ 0.05), subgroup analyses of the LBW men with and without NAFLD revealed more pronounced differences, with 11 metabolites and 56 lipids differentiating (p ≤ 0.05) the groups. The differences in the LBW men with NAFLD included increased levels of ornithine and tyrosine (PFDR ≤ 0.1), as well as of triglycerides and phosphatidylcholines with shorter carbon-chain lengths and fewer double bonds. Pathway and network analyses demonstrated downregulation of transfer RNA (tRNA) charging, altered urea cycling, insulin resistance, and an increased risk of T2D in the LBW men with NAFLD. Our findings highlight the importance of increased liver fat in the pathogenesis of T2D in LBW individuals.