Eva Feigerlova

Nutritional models of foetal programming and nutrigenomic and epigenomic dysregulations of fatty acid metabolism in the liver and heart

Barker’s concept of ‘foetal programming’ proposes that intrauterine growth restriction (IUGR) predicts complex metabolic diseases through relationships that may be further modified by the postnatal environment. Dietary restriction and deficit in methyl donors, folate, vitamin B12, and choline are used as experimental conditions of foetal programming as they lead to IUGR and decreased birth weight. Overfeeding and deficit in methyl donors increase central fat mass and lead to a dramatic increase of plasma free fatty acids (FFA) in offspring. Conversely, supplementing the mothers under protein restriction with folic acid reverses metabolic and epigenomic phenotypes of offspring. High-fat diet or methyl donor deficiency (MDD) during pregnancy and lactation produce liver steatosis and myocardium hypertrophy that result from increased import of FFA and impaired fatty acid β-oxidation, respectively. The underlying molecular mechanisms show dysregulations related with similar decreased expression and activity of sirtuin 1 (SIRT1) and hyperacetylation of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). High-fat diet and overfeeding impair AMPK-dependent phosphorylation of PGC-1α, while MDD decreases PGC-1α methylation through decreased expression of PRMT1 and cellular level of S-adenosyl methionine. The visceral manifestations of metabolic syndrome are under the influence of endoplasmic reticulum (ER) stress in overnourished animal models. These mechanisms should also deserve attention in the foetal programming effects of MDD since vitamin B12 influences ER stress through impaired SIRT1 deacetylation of HSF1. Taken together, similarities and synergies of high-fat diet and MDD suggest, therefore, considering their consecutive or contemporary influence in the mechanisms of complex metabolic diseases.

Plasma levels of hsa-miR-152-3p are associated with diabetic nephropathy in patients with type 2 diabetes

Background MicroRNAs (miRNAs) are small non-coding RNAs participating in post-transcriptional regulation of genes. Their key role in modulating the susceptibility to human diseases is now widely recognized, in particular in the context of cardiometabolic disorders. The aim of the present study was to identify miRNAs associated with diabetic nephropathy (DN) in patients with type 2 diabetes (T2D). Methods A next-generation sequencing-based miRNA profiling was performed in a case-control study for DN in plasma samples of 23 T2D patients with DN (cases) and 23 T2D without (controls). The main associations were confirmed using quantitative reverse transcription-polymerase chain reaction and tested for replication in an independent case-control collection of 100 T2D patients, 50 with DN and 50 without. Results From the 381 known mature miRNAs that were found highly expressed in the discovery samples, we observed and replicated an association between increased plasma levels of hsa-miR-152-3p and DN (P = 4.03 × 10-4 in the combined samples). Hsa-miR-152-3p plasma levels were further found to be positively correlated (P = 0.003) to plasma osmolarity, a surrogate marker for solute carrier net activity, whose regulation is controlled by several genes including SLC5A3, one of the predicted targets of hsa-miR-152-3p. Conclusions We observed strong evidence for the association of hsa-miR-152-3p plasma levels and DN in patients with T2D, confirming an association previously observed in patients with type 1 diabetes.

Long-Term Quality of Life and Pregnancy Outcomes of Differentiated Thyroid Cancer Survivors Treated by Total Thyroidectomy and I131 during Adolescence and Young Adulthood

Introduction. Differentiated thyroid cancer (DTC) is rare and confers good prognosis. Long-term health related quality of life (HRQoL) and pregnancy outcomes are not well known in subjects treated during adolescence and young adulthood. Methods. Cross-sectional analysis of HRQoL and global self-esteem, using SF-36 and ISP-25 surveys, and of pregnancy outcomes in female survivors of DTC treated by total thyroidectomy and I131 before age of 25 years. Results. Forty-five of 61 patients (74%) responded to the survey. Cumulative I131 activity was ≤3.85 GBq in 18 subjects and >3.85 GBq in 27 subjects. Mean time from diagnosis was 7.6 ± 5.2 years for the group ≤ 3.85 GBq versus 16.9 ± 11.6 years for the group > 3.85 GBq (P < 0.05). No significant alteration in long-term HRQoL and global self-esteem was observed. Thirty pregnancies after I131 were noted in patients from the group > 3.85 GBq and 10 in patients from the group ≤ 3.85 GBq. Frequency of miscarriages was of 17% (group > 3.85 GBq) and 10% (group ≤ 3.85 GBq) with 9 and 24 live births, respectively. No congenital malformations or first year mortality was noted. Conclusion. Long-term HRQoL, global self-esteem, and pregnancy outcomes are not affected in young female survivors of DTC.

One carbon metabolism and bone homeostasis and remodeling: A review of experimental research and population studies

Homocysteine (HCY) is a degradation product of the methionine pathway. The B vitamins, in particular vitamin B12 and folate, are the primary nutritional determinant of HCY levels and therefore their deficiencies result in hyperhomocysteinaemia (HHCY). Prevalence of hyperhomocysteinemia (HHCY) and related dietary deficiencies in B vitamins and folate increase with age and have been related to osteoporosis and abnormal development of epiphyseal cartilage and bone in rodents. Here we provide a review of experimental and population studies. The negative effects of HHCY and/or B vitamins and folate deficiencies on bone formation and remodeling are documented by cell models, including primary osteoblasts, osteoclast and bone progenitor cells as well as by animal and human studies. However, underlying pathophysiological mechanisms are complex and remain poorly understood. Whether these associations are the direct consequences of impaired one carbon metabolism is not clarified and more studies are still needed to translate these findings to human population. To date, the evidence is limited and somewhat conflicting, however further trials in groups most vulnerable to impaired one carbon metabolism are required.

Circulating Concentrations of Redox Biomarkers Do Not Improve the Prediction of Adverse Cardiovascular Events in Patients With Type 2 Diabetes Mellitus

Background Despite pathophysiological relevance and promising experimental data, the usefulness of biomarkers of oxidative stress for cardiac risk prediction is unclear. The aim of our study was to investigate the prognostic value of 6 biomarkers exploring different pathways of oxidative stress for predicting adverse cardiovascular outcomes in patients with type 2 diabetes mellitus beyond established risk factors. Methods and Results The SURDIAGENE (Survie, Diabete de type 2 et Genetique) prospective cohort study consecutively recruited 1468 patients with type 2 diabetes mellitus. Assays were performed at baseline, and incident cases of major adverse cardiovascular events (MACE)—first occurrence of cardiovascular death, nonfatal myocardial infarction, or stroke—were recorded during a median of 64 months. Advanced oxidation protein products, oxidative hemolysis inhibition assay, ischemia‐modified albumin, and total reductive capacity of plasma were not associated with the risk of MACE in univariate analyses. Fluorescent advanced glycation end products and carbonyls were associated with MACE (hazard ratio=1.38 per SD, 95% confidence interval 1.24‐1.54, P<0.001 and hazard ratio=1.15 per SD, 95% confidence interval 1.04‐1.27, P=0.006, respectively) in univariate analysis, but when added to a multivariate predictive model including traditional risk factors for MACE, these markers did not significantly improve c‐statistics or integrated discrimination index of the model. Conclusions These plasma concentrations of 6 markers, which cover a broad spectrum of oxidative processes, were not significantly associated with MACE occurrence and were not able to improve MACE risk discrimination and classification beyond classical risk factors in type 2 diabetes mellitus patients.

Foetal programming by methyl donor deficiency produces steato-hepatitis in rats exposed to high fat diet.

Non-alcoholic steatohepatitis (NASH) is a manifestation of metabolic syndrome, which emerges as a major public health problem. Deficiency in methyl donors (folate and vitamin B12) during gestation and lactation is frequent in humans and produces foetal programming effects of metabolic syndrome, with small birth weight and liver steatosis at day 21 (d21), in rat pups. We investigated the effects of fetal programming on liver of rats born from deficient mothers (iMDD) and subsequently subjected to normal diet after d21 and high fat diet (HF) after d50. We observed increased abdominal fat, ASAT/ALAT ratio and angiotensin blood level, but no histological liver abnormality in d50 iMDD rats. In contrast, d185 iMDD/HF animals had hallmarks of steato-hepatitis, with increased markers of inflammation and fibrosis (caspase1, cleaved IL-1β, α1(I) and α2(I) collagens and α-SMA), insulin resistance (HOMA-IR and Glut 2) and expression of genes involved in stellate cell stimulation and remodelling and key genes triggering NASH pathomechanisms (transforming growth factor beta super family, angiotensin and angiotensin receptor type 1). Our data showed a foetal programming effect of MDD on liver inflammation and fibrosis, which suggests investigating whether MDD during pregnancy is a risk factor of NASH in populations subsequently exposed to HF diet.

Thyroid Disorders and Bone Mineral Homeostasis

Thyroid hormones play a crucial role in the skeletal growth, peak bone mass acquisition and maintenance of bone mass. Abnormalities in hypothalamic–pituitary–thyroid axis in infancy and childhood have been shown to interfere with a normal linear growth and skeletal maturation. Hypothyroidism compromises normal bone formation and results in slowing of linear growth. Thyrotoxicosis leads to growth acceleration, diminution of bone mass and advance in bone age. Studies in animal models have demonstrated the importance of thyroid hormone signaling in the maintenance of bone mass in adulthood. Increased risk of fracture has been demonstrated in both hypothyroidism and hyperthyroidism. The thyroid hormone, 3,5,3’-triiodothyronine (T3), has long been considered to play a primordial role in the skeletal homeostasis. However, recent studies have shown that TSH acts as a direct regulator of bone remodeling, highlighting the importance of integrity of the hypothalamopituitary-thyroid axis.

Extracellular vesicles as immune mediators in response to kidney injury

Important progress has been made on cytokine signaling in response to kidney injury in the past decade, especially cytokine signaling mediated by extracellular vesicles (EVs). For example, EVs released by injured renal tubular epithelial cells (TECs) can regulate intercellular communications and influence tissue recovery via both regulating the expression and transferring cytokines, growth factors, as well as other bioactive molecules at the site of injury. The effects of EVs on kidney tissue seem to vary depending on the sources of EVs; however, the literature data are often inconsistent. For example, in rodents EVs derived from mesenchymal stem cells (MSC-EVs) and endothelial progenitor cells (EPC-EVs) can have both beneficial and harmful effects on injured renal tissue. Caution is thus needed in the interpretation of these data as contradictory findings on EVs may not only be related to the origin of EVs, they can also be caused by the different methods used for EV isolation and the physiological and pathological states of the tissues/cells under which they were obtained. Here, we review and discuss our current understanding related to the immunomodulatory function of EVs in renal tubular repair in the hope of encouraging further investigations on mechanisms related to their antiinflammatory and reparative role to better define the therapeutic potential of EVs in renal diseases.

Cytokines in Endocrine Dysfunction of Plasma Cell Disorders

Monoclonal gammopathies (MG) are classically associated with lytic bone lesions, hypercalcemia, anemia, and renal insufficiency. However, in some cases, symptoms of endocrine dysfunction are more prominent than these classical signs and misdiagnosis can thus be possible. This concerns especially the situation where the presence of M-protein is limited and the serum protein electrophoresis (sPEP) appears normal. To understand the origin of the endocrine symptoms associated with MG, we overview here the current knowledge on the complexity of interactions between cytokines and the endocrine system in MG and discuss the perspectives for both the diagnosis and treatments for this class of diseases. We also illustrate the role of major cytokines and growth factors such as IL-6, IL-1β, TNF-α, and VEGF in the endocrine system, as these tumor-relevant signaling molecules not only help the clonal expansion and invasion of the tumor cells but also influence cellular metabolism through autocrine, paracrine, and endocrine mechanisms. We further discuss the broader impact of these tumor environment-derived molecules and proinflammatory state on systemic hormone signaling. The diagnostic challenges and clinical work-up are illustrated from the point of view of an endocrinologist.

Methyl donor deficiency impairs bone development via peroxisome proliferator-activated receptor-γ coactivator-1α–dependent vitamin D receptor pathway

Deficiency in methyl donor (folate and vitamin B12) and in vitamin D is independently associated with altered bone development. Previously, methyl donor deficiency (MDD) was shown to weaken the activity of nuclear receptor coactivator, peroxisome proliferator‐activated receptor‐γ coactivator‐1α (PGC1α), for nuclear signaling in rat pups, including estrogen receptor‐α and estrogen‐related receptor‐a; its effect on vitamin D receptor (VDR) signaling, however, is unknown. We studied bone development under MDD in rat pups and used human MG‐63 preosteoblast cells to better understand the associated molecular mechanism. In young rats, MDD decreased total body bone mineral density, reduced tibia length, and impaired growth plate maturation, and in preosteoblasts, MDD slowed cellular proliferation. Mechanistic studies revealed decreased expression of VDR, estrogen receptor‐a, PGC1α, arginine methyltransferase 1, and sirtuin 1 in both rat proximal diaphysis of femur and in MG‐63, as well as decreased nuclear VDR–PGC1α interaction in MG‐63 cells. The weaker VDR–PGC1α interaction could be attributed to the reduced protein expression, imbalanced PGC1α methylation/acetylation, and nuclear VDR sequestration by heat shock protein 90 (HSP90). These together compromised bone development, which is reflected by lowered bone alkaline phosphatase and increased proadipogenic peroxisome proliferator‐activated receptor‐γ, adiponectin, and estrogen‐related receptor‐α expression. Of interest, under MDD, the bone development effects of 1,25‐dihydroxyvitamin D3 were ineffectual and these could be rescued by the addition of S‐adenosylmethionine, which restored expression of arginine methyltransferase 1, PGC1α, adiponectin, and HSP90. In conclusion, MDD inactivates vitamin D signaling via both disruption of VDR–PGC1α interaction and sequestration of nuclear VDR attributable to HSP90 overexpression. These data suggest that vitamin D treatment may be ineffective under MDD.—Feigerlova, E., Demarquet, L., Melhem, H., Ghemrawi, R., Battaglia‐Hsu, S.‐F., Ewu, E., Alberto, J.‐M., Helle, D., Weryha, G., Guéant, J.‐L. Methyl donor deficiency impairs bone development via peroxisome proliferator‐activated receptor‐γ coactivator‐1α–dependent vitamin D receptor pathway. FASEB J. 30, 3598–3612 (2016). www.fasebj.org