Salwan Maqdasy

Bile acids: from digestion to cancers.

Bile acids (BAs) are cholesterol metabolites that have been extensively studied these last decades. BAs have been classified in two groups. Primary BAs are synthesized in liver, when secondary BAs are produced by intestinal bacteria. Recently, next to their ancestral roles in digestion and fat solubilization, BAs have been described as signaling molecules involved in many physiological functions, such as glucose and energy metabolisms. These signaling pathways involve the activation of the nuclear receptor FXRα or of the G-protein-coupled receptor TGR5. These two receptors have selective affinity to different types of BAs and show different expression patterns, leading to different described roles of BAs. It has been suggested for long that BAs could be molecules linked to tumor processes. Indeed, as many other molecules, regarding analyzed tissues, BAs could have either protective or pro-carcinogen activities. However, the molecular mechanisms responsible for these effects have not been characterized yet. It involves either chemical properties or their capacities to activate their specific receptors FXRα or TGR5. This review highlights and discusses the potential links between BAs and cancer diseases and the perspectives of using BAs as potential therapeutic targets in several pathologies.

Cholesterol and male fertility: What about orphans and adopted?

The link between cholesterol homeostasis and male fertility has been clearly suggested in patients who suffer from hyperlipidemia and metabolic syndrome. This has been confirmed by the generation of several transgenic mouse models or in animals fed with high cholesterol diet. Next to the alteration of the endocrine signaling pathways through steroid receptors (androgen and estrogen receptors); orphan and adopted nuclear receptors, such as the Liver X Receptors (LXRs), the Proliferating Peroxisomal Activated Receptors (PPARs) or the Liver Receptor Homolog-1 (LRH-1), have been involved in this cross-talk. These transcription factors show distinct expression patterns in the male genital tract, explaining the large panel of phenotypes observed in transgenic male mice and highlighting the importance of lipid homesostasis and the complexity of the molecular pathways involved. Increasing our knowledge of the roles of these nuclear receptors in male germ cell differentiation could help in proposing new approaches to either treat infertile men or define new strategies for contraception.

Aggressive silent GH pituitary tumor resistant to multiple treatments, including temozolomide.

Temozolomide (TMZ) has been proposed as a therapeutic option in aggressive pituitary tumors. Among the published cases, GH expressing tumors were rare. We describe a patient with initially benign silent GH adenoma that transformed into an aggressive GH secreting tumor resistant to usual therapy. MGMT expression was high and the MGMT promoter was unmethylated. Before this aggressive course, patient received three cycles of TMZ; no response was observed. Four cases of GH aggressive tumor treated by TMZ have been reported. Response to TMZ was observed in one of these four patients. Predictive factors of failure of TMZ remain unclear.

Acute and Chronic Pheochromocytoma-Induced Cardiomyopathies: Different Prognoses?: A Systematic Analytical Review.

AbstractPheochromocytoma and paraganglioma (PPG) are rare and late-diagnosed catecholamine secreting tumors, which may be associated with unrecognized and/or severe cardiomyopathies.We performed a computer-assisted systematic search of the electronic Medline databases using the MESH terms “myocarditis,” “myocardial infarction,” “Takotsubo,” “stress cardiomyopathy,” “cardiogenic shock”, or “dilated cardiomyopathy,” and “pheochromocytoma” or “paraganglioma” from 1961 to August 2012. All detailed case reports of cardiomyopathy due to a PPG, without coronary stenosis, and revealed by acute symptoms were included and analyzed.A total of 145 cases reports were collected (49 Takotsubo Cardiomyopathies [TTC] and 96 other Catecholamine Cardiomyopathies [CC]). At initial presentation, prevalence of high blood pressure (87.7%), chest pain (49.0%), headaches (47.6%), palpitations (46.9%), sweating (39.3%), and shock (51.0%) were comparable between CC and TTC. Acute pulmonary edema (58.3% vs 38.8%, Pu200a=u200a0.03) was more frequent in CC. There was no difference in proportion of patients with severe left ventricular systolic dysfunction (LV Ejection Fraction [LVEF]u200a<u200a30%) at initial presentation between both groups (Pu200a=u200a0.15). LVEF recovery before (64.9% vs 40.8%, Pu200a=u200a0.005) and after surgical resection (97.7% vs73.3%, Pu200a=u200a0.001) was higher in the TTC group. Death occurred in 11 cases (7.6%). In multivariate analysis, only TTC was associated with a better LV recovery (0.15 [0.03–0.67], Pu200a=u200a0.03).Pheochromocytoma and paraganglioma can lead to different cardiomyopathies with the same brutal and life-threatening initial clinical presentation but with a different recovery rate. Diagnosis of unexplained dilated cardiomyopathy or TTC should lead clinicians to a specific search for PPG.

Evaluation of atorvastatin efficacy and toxicity on spermatozoa, accessory glands and gonadal hormones of healthy men: a pilot prospective clinical trial

BackgroundRecommendations for cardiovascular disease prevention advocate lowering both cholesterol and low-density lipoprotein cholesterol systemic levels, notably by statin intake. However, statins are the subject of questions concerning their impact on male fertility. This study aimed to evaluate, by a prospective pilot assay, the efficacy and the toxicity of a decrease of cholesterol blood levels, induced by atorvastatin on semen quality and sexual hormone levels of healthy, normocholesterolaemic and normozoospermic men.MethodsAtorvastatin (10xa0mg daily) was administrated orally during 5xa0months to 17 men with normal plasma lipid and standard semen parameters. Spermatozoa parameters, accessory gland markers, semen lipid levels and blood levels of gonadal hormones were assayed before statin intake, during the treatment, and 3xa0months after its withdrawal.ResultsAtorvastatin treatment significantly decreased circulating low-density lipoprotein cholesterol (LDL-C) and total cholesterol concentrations by 42% and 24% (pu2009<u20090.0001) respectively, and reached the efficacy objective of the protocol. During atorvastatin therapy and/or 3xa0months after its withdrawal numerous semen parameters were significantly modified, such as total number of spermatozoa (-31%, pu2009<u20090.05), vitality (-9.5%, pu2009<u20090.05), total motility (+7.5%, pu2009<u20090.05), morphology (head, neck and midpiece abnormalities, pu2009<u20090.05), and the kinetics of acrosome reaction (pu2009<u20090.05). Seminal concentrations of acid phosphatases (pu2009<u20090.01), α-glucosidase (pu2009<u20090.05) and L-carnitine (pu2009<u20090.05) were also decreased during the therapy, indicating an alteration of prostatic and epididymal functions. Moreover, we measured at least one altered semen parameter in 35% of the subjects during atorvastatin treatment, and in 65% of the subjects after withdrawal, which led us to consider that atorvastatin is unsafe in the context of our study.ConclusionsOur results show for the first time that atorvastatin significantly affects the sperm parameters and the seminal fluid composition of healthy men.Trial registrationClinicalTrials.gov: NCT02094313.

Once and for all, LXRα and LXRβ are gatekeepers of the endocrine system

Liver X receptors (LXRs) α and β are nuclear receptors whose transcriptional activity is regulated by oxysterols, the oxidized forms of cholesterol. Described in the late 1990s as lipid sensors, both LXRs regulate cholesterol and fatty acid homeostasis. Over the years, deep phenotypic analyses of mouse models deficient for LXRα and/or LXRβ have pointed out various other physiological functions including glucose homeostasis, immunology, and neuroprotection. This review enlightens the endocrine functions of LXRs; they deeply impact plasma glucose directly and by modulating insulin signaling, renin-angiotensin-aldosterone axis, thyroid and pituitary hormone levels, and bone homeostasis. Besides, LXR signaling is also involved in adrenal physiology, steroid synthesis, and male and female reproduction. Hence, LXRs are definitely involved in the endocrine system and could thus be considered as endocrine receptors, even though oxysterols do not fully correspond to the definition of hormones. Finally, because they are ligand-regulated transcription factors, LXRs are potential pharmacological targets with promising beneficial metabolic effects.

Identification of the Functions of Liver X Receptor-β in Sertoli Cells Using a Targeted Expression-Rescue Model

Liver X receptors (LXRs) are key regulators of lipid homeostasis and are involved in multiple testicular functions. The Lxrα(-/-);Lxrβ(-/-) mice have illuminated the roles of both isoforms in maintenance of the epithelium in the seminiferous tubules, spermatogenesis, and T production. The requirement for LXRβ in Sertoli cells have been emphasized by early abnormal cholesteryl ester accumulation in the Lxrβ(-/-) and Lxrα(-/-);Lxrβ(-/-) mice. Other phenotypes, such as germ cell loss and hypogonadism, occur later in life in the Lxrα(-/-);Lxrβ(-/-) mice. Thus, LXRβ expression in Sertoli cells seems to be essential for normal testicular physiology. To decipher the roles of LXRβ within the Sertoli cells, we generated Lxrα(-/-);Lxrβ(-/-):AMH-Lxrβ transgenic mice, which reexpress Lxrβ in Sertoli cells in the context of Lxrα(-/-);Lxrβ(-/-) mice. In addition to lipid homeostasis, LXRβ is necessary for maintaining the blood-testis barrier and the integrity of the germ cell epithelium. LXRβ is also implicated in the paracrine action of Sertoli cells on Leydig cells to modulate T synthesis. The Lxrα(-/-);Lxrβ(-/-) and Lxrα(-/-);Lxrβ(-/-):AMH-Lxrβ mice exhibit lipid accumulation in germ cells after the Abcg8 down-regulation, suggesting an intricate LXRβ-dependent cooperation between the Sertoli cells and germ cells to ensure spermiogenesis. Further analysis revealed also peritubular smooth muscle defects (abnormal lipid accumulation and disorganized smooth muscle actin) and spermatozoa stagnation in the seminiferous tubules. Together the present work elucidates specific roles of LXRβ in Sertoli cell physiology in vivo beyond lipid homeostasis.

Liver X receptors interfere with the deleterious effect of diethylstilbestrol on testicular physiology

Liver X receptors LXRα (NR1H3) and LXRβ (NR1H2) are transcription factors belonging to the nuclear receptor superfamily, activated by specific oxysterols, oxidized derivatives of cholesterol. These receptors are involved in the regulation of testis physiology. Lxr-deficient mice pointed to the physiological roles of these nuclear receptors in steroid synthesis, lipid homeostasis and germ cell apoptosis and proliferation. Diethylstilbestrol (DES) is a synthetic estrogen considered as an endocrine disruptor that affects the functions of the testis. Various lines of evidences have made a clear link between estrogens, their nuclear receptors ERα (NR3A1) and ERβ (NR3A2), and Lxrα/β. As LXR activity could also be regulated by the nuclear receptor small heterodimer partner (SHP, NR0A2) and DES could act through SHP, we wondered whether LXR could be targeted by estrogen-like endocrine disruptors such as DES. For that purpose, wild-type and Lxr-deficient mice were daily treated with 0.75 μg DES from days 1 to 5 after birth. The effects of DES were investigated at 10 or 45 days of age. We demonstrated that DES induced a decrease of the body mass at 10 days only in the Lxr-deficient mice suggesting a protective effect of Lxr. We defined three categories of DES-target genes in testis: those whose accumulation is independent of Lxr; those whose accumulation is enhanced by the lack of both Lxrα/β; those whose accumulation is repressed by the absence of Lxrα/β. Lipid accumulation is also modified by neonatal DES injection. Lxr-deficient mice present different lipid profiles, demonstrating that DES could have its effects in part due to Lxrα/β. Altogether, our study shows that both nuclear receptors Lxrα and Lxrβ are not only basally important for testicular physiology but could also have a preventive effect against estrogen-like endocrine disruptors.

Heart rate variability in type 2 diabetes mellitus: A systematic review and meta– analysis

Background Cardiac autonomic neuropathy in type 2 dibetes mellitus (T2DM) patients is frequent and associated with high cardiovascular mortality. Heart rate variability (HRV) is the gold standard to measure cardiac autonomic neuropathy. We aimed to conduct a systematic review and meta–analysis to evaluate the impact of T2DM on HRV parameters. Methods The PubMed, Cochrane Library, Embase and Science Direct databases were searched on 1st October 2017 using the keywords “diabetes” AND (“heart rate variability” OR “HRV”). Included articles had to report HRV parameters in T2DM patients and healthy controls measured during 24 hours with a Holter–electrocardiogram. Measurements of HRV retieved were: RR–intervals (or Normal to Normal intervals—NN), standard deviation of RR intervals (SDNN), percetange of adjacent NN intervals differing by more than 50 milliseconds (pNN50), square root of the mean squared difference of successive RR intervals (RMSSD), total power, Low Frequency (LF), High Frequency (HF) and LF/HF ratio, as per Task Force recommendations. Results We included twenty-five case-control studies with 2,932 patients: 1,356 with T2DM and 1,576 healthy controls. T2DM patients had significantly (P<0.01) lower RR–intervals (effect size = –0.61; 95%CI –1.21 to –0.01), lower SDNN (–0.65; –0.83 to –0.47), lower RMSSD (–0.92; –1.37 to –0.47), lower pNN50 (–0.46; –0.84 to –0.09), lower total power (–1.52; –2.13 to –0.91), lower LF (–1.08; –1.46 to –0.69]), and lower HF (–0.79; –1.09 to –0.50). LF/HF did not differ between groups. Levels of blood glucose and HbA1c were associated with several HRV parameters, as well as Time from diagnosis of T2DM Conclusions T2DM was associated with an overall decrease in the HRV of T2DM patients. Both sympathetic and parasympathetic activity were decreased, which can be explained by the deleterious effects of altered glucose metabolism on HRV, leading to cardiac autonomic neuropathy.

Infundibuloneurohypophysitis Associated With Sjögren Syndrome Successfully Treated With Mycophenolate Mofetil: A Case Report.

AbstractHypophysitis is an inflammatory disorder of the pituitary gland and corticosteroids are usually recommended as the first-line treatment. Hypophysitis related to primary Sjögren syndrome (pSS) is uncommon. We describe the unusual case of a patient with infundibuloneurohypophysitis associated with pSS successfully treated with mycophenolate mofetil (MMF).We describe a case of a 60-year-old man with a medical history of pSS presented with central diabetes insipidus and panhypopituitarism. Magnetic resonance imaging (MRI) revealed a thickening of the pituitary stalk and intense enhancement of the posterior pituitary, pituitary stalk, and hypothalamus. We diagnosed infundibuloneurohypophysitis associated with pSS. Hormonal replacement was started immediately and MMF was introduced without corticosteroids.After 9 months of treatment, MRI of the pituitary revealed a complete regression of the nodular thickening of the pituitary stalk, with normal enhancement and appearance of the pituitary. The pituitary axes had completely recovered, whereas the diabetes insipidus was partially restored.Our findings suggest that MMF is an effective alternative to corticosteroids for the treatment of lymphocytic hypophysitis associated with an autoimmune disease. Furthermore, this report could contribute to extend the spectrum of the neurological and endocrinological manifestations of pSS.