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Biomedical subjects

Salvatore Alesci

Publications and source records attributed to Salvatore Alesci.

At least 19 recordsLinked to original sources

Sustained low-grade pro-inflammatory state in unmedicated, remitted women with major depressive disorder as evidenced by elevated serum levels of the acute phase proteins C-reactive protein and serum amyloid A.

BACKGROUND: Major depressive disorder (MDD) shows increased coronary artery disease (CAD) risk of unknown mechanism(s). MDD is more common in women than men; CAD diagnosis can be difficult in women. Elevations of the inflammatory markers C-reactive protein (CRP) and serum amyloid A (SAA) predict increased CAD risk in populations; few data on these markers exist in MDD, particularly in remitted patients. METHODS: We measured fasting am serum CRP (high sensitivity, CRP(hs)) and SAA in 18 unmedicated, remitted women with MDD (mean age 41 +/- (SD)12, body mass index (BMI) 25.2 +/- 4.1 kg/m(2)) and 18 BMI-matched healthy control subjects (age 36 +/- 10, BMI 25.3 +/- 3.8 kg/m(2)) on 2 separate occasions, > or = 6 days apart. RESULTS: Repeat SAA and CRP(hs) measurements strongly correlated across study days (SAA: r = .83, p < .001; CRP(hs): r = .94, p < .001). Both SAA (5.30 +/- 3.39 vs. 2.84 +/- 1.87 mg/L, p < .005) and CRP(hs) (3.23 +/- 3.17 vs. 1.12 +/- 1.45 mg/L; p < .01) were significantly elevated in MDD women versus controls. CONCLUSIONS: Elevated SAA and CRP(hs) in remitted, unmedicated women with MDD indicate a pro-inflammatory state unrelated to current depressive symptoms or pharmacotherapy. These findings suggest that inflammatory mechanisms may in part underlie findings of increased CAD risk in MDD.

Age Factors↗

Intracrine modulation of gene expression by intracellular generation of active glucocorticoids.

Glucocorticoids (GC) by either up-regulating or down-regulating the expression of genes influence cellular processes in every tissue and organ of the body. The enzyme 11beta-hydroxysteroid dehydrogenase Type-1 (11beta-HSD-1) confers bioactivity upon the inactive GC cortisone (E) and prednisone (P) by converting them to cortisol (F) and prednisolone (L), respectively. We sought to investigate whether gene expression modulation by GC is under the regulation of an intracrine mechanism that determines the intracellular concentration of active GC. Human cell lines were transiently and stably co-transfected with an expression construct for 11beta-HSD-1 and a GC-responsive reporter gene and incubated with active and inactive GC. Whereas in cells that were not transfected with the expression construct for 11beta-HSD-1 inactive GC had no transcriptional activity, in both transiently and stably transfected cells E and P demonstrated a dose-dependent transcriptional activity. This transcriptional potency of both inactive GC was effectively abolished by carbenoxolone, an 11beta-HSD-1 inhibitor, and was directly related to the concentration of transfected 11beta-HSD-1. We conclude that gene expression modulation by GC is under a decisive influence of target cell 11beta-HSD-1 that modulates the intracellular concentration of active GC. The intracrine mechanism is an under-appreciated aspect of GC activity that could be a potential target for future therapies aimed at modulating GC effects at the cellular level.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗

Animal models of pheochromocytoma including NIH initial experience.

Mouse models have been used to study the mechanisms underlying the carcinogenesis of a wide variety of human cancer. A considerable number of mouse and rat models, used for the study of elementary tumorgenic mechanisms, were found to develop pheochromocytomas. Some of these models resemble hereditary syndrome-related pheochromocytoma in humans and some may serve as a new starting point for human pheochromocytoma research. Recently, we generated a model of catecholamine-producing metastatic pheochromocytoma in athymic nude mice using tail-vein injection of mouse pheochromocytoma cells (MPCs). This and alternative animal models of metastatic pheochromocytoma are promising avenues in preclinical studies to evaluate new therapeutic approaches for malignant pheochromocytoma.

Adrenal Gland Neoplasms↗

Monoamine oxidase-A is a major target gene for glucocorticoids in human skeletal muscle cells.

Skeletal myopathy is a common complication of endogenous and exogenous glucocorticoid excess, yet its pathogenetic mechanisms remain unclear. There is accumulating evidence that mitochondrial dysfunction and oxidative stress are involved in this process. To explore the glucocorticoid-induced transcriptional adaptations that may affect mitochondrial function in skeletal muscle, we studied gene expression profiles in dexamethasone-treated primary human skeletal myocytes using a cDNA microarray, which contains 501 mitochondria-related genes. We found that monoamine oxidase A (MAO-A) was the most significantly up-regulated gene. MAO-A is the primary enzyme metabolizing catecholamines and dietary amines, and its role in skeletal muscle remains largely unexplored. Dexamethasone induced dose- and time-dependent increases of MAO-A gene and protein expression, while its effects on MAO-B were minimal. Both the glucocorticoid receptor (GR) and the Sp1 transcription factor were required for dexamethasone-induced MAO-A mRNA expression, as blockade of the GR with RU 486 or ablation of Sp1 binding with mithramycin abrogated MAO-A mRNA induction. The observed dexamethasone effect was biologically functional, as this steroid significantly increased MAO-mediated hydrogen peroxide production. We suggest that MAO-A-mediated oxidative stress can lead to cell damage, representing a novel pathogenetic mechanism for glucocorticoid-induced myopathy and a potential target for therapeutic intervention.

Adolescent↗

Cardiac implications of increased arterial entry and reversible 24-h central and peripheral norepinephrine levels in melancholia.

The mortality of chronic heart failure (CHF) doubles either when CHF patients are depressed or when their plasma norepinephrine (NE) level exceeds those of controls by approximately 40%. We hypothesized that patients with major depression had centrally driven, sustained, stress-related, and treatment-reversible increases in plasma NE capable of increasing mortality in CHF patients with depression. We studied 23 controls and 22 medication-free patients with melancholic depression. In severely depressed patients before and after electroconvulsive therapy (ECT), we measured cerebrospinal fluid (CSF) NE, plasma NE, plasma epinephrine (EPI), and plasma cortisol hourly for 30 h. In mildly-to-moderately depressed melancholic patients, we assessed basal and stress-mediated arterial NE appearance. Severely depressed patients had significant increases in mean around-the-clock levels of CSF NE (P < 0.02), plasma NE (P < 0.02), plasma EPI (P < 0.02), and plasma cortisol (P < 0.02). CSF NE, plasma NE, and cortisol all rose together throughout the night and peaked in the morning. Each fell to control values after ECT. Mildly-to-moderately melancholic patients also had increased basal (P < 0.05) and stress-related (P < 0.03) arterial NE-appearance rates. Severely melancholic depressed, medication-free patients had around-the-clock increases in plasma NE levels capable of increasing mortality in CHF. Twenty-four-hour indices of central noradrenergic, adrenomedullary, and adrenocortical secretion were also elevated. Concurrent diurnal rhythms of these secretions could potentiate their cardiotoxicity. Even mildly-to-moderately depressed melancholic patients had clinically relevant increases in the arterial NE-appearance rate. These findings will not apply to all clinical subtypes of major depression.

Adult↗

The human glucocorticoid receptor (GR) isoform {beta} differentially suppresses GR{alpha}-induced transactivation stimulated by synthetic glucocorticoids.

The beta-isoform of human glucocorticoid receptor beta (hGRbeta) acts as a natural dominant negative inhibitor of hGRalpha-induced transactivation of glucocorticoid-responsive genes. We determined hGRbeta ability to suppress hGRalpha transactivation that was induced by commonly used synthetic glucocorticoids. HepG2/C3A cells were transiently cotransfected with GR cDNA and a glucocorticoid-responsive promoter, luciferase (MMTV-luc). Transfected cells were incubated for 16 h with glucocorticoid and luciferase. For each compound, a dose-response curve was constructed, and half-maximal effective concentrations and maximal transcriptional activities were compared. hGRbeta, at a 1:1 ratio to hGRalpha, differentially suppressed hGRalpha-induced maximal transcriptional activity stimulated by triamcinolone, dexamethasone, hydrocortisone, and betamethasone (by 96, 68, 62, and 49%, respectively) but not by methylprednisolone. The suppressive effect of hGRbeta on hGRalpha-induced transactivation was stronger at lower concentrations of all tested glucocorticoids, whereas it was blunted at higher concentrations. We conclude that the potency of the dominant negative effect of hGRbeta on hGRalpha-induced transactivation depends on both the type and the dose of the synthetic glucocorticoids in use. These results may provide helpful information concerning the selection of synthetic glucocorticoids for treatment of pathological conditions in which hGRbeta modulates the sensitivity of tissues to glucocorticoids.

Carcinoma, Hepatocellular↗

Major depression is associated with significant diurnal elevations in plasma interleukin-6 levels, a shift of its circadian rhythm, and loss of physiological complexity in its secretion: clinical implications.

BACKGROUND: Major depressive disorder (MDD) is associated with increased risk for premature coronary heart disease and bone loss. Single time measurements of plasma IL-6, a good predictor of future risk for both cardiovascular disease and osteoporosis, revealed significant elevations in depressed patients. The objective of this study was to rigorously compare plasma IL-6 levels, measured over 24 h, in MDD patients and healthy controls. Given the activating role of IL-6 on the hypothalamic-pituitary-adrenal (HPA) axis, and the relevance of its dysregulation in MDD, we also analyzed the relations between IL-6 and cortisol levels. METHODS: We studied nine patients and nine controls, individually matched by gender, age (+/-5 yr), body mass index (+/-2 kg/m2), and menstrual cycle phase. Diagnosis of MDD was confirmed by structured clinical interview based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I diagnostic criteria. Self-reported mood ratings were assessed by multiple visual analog scales. The rhythmicity and complexity of IL-6 and cortisol secretion were tested by cosinor analyses, approximate entropy (ApEn) and cross-ApEn algorithms. RESULTS: MDD patients had significant mean IL-6 elevations from 1000-1200 h and at 1500 h (P ranging from <0.05 to <0.01) vs. controls. In addition, in MDD, the circadian rhythm of IL-6 was shifted by 12 h, and its physiological complexity was reduced, with no difference in the cross-ApEn of IL-6 and cortisol between the two groups, and significant time-lagged correlations only in the controls. IL-6 levels correlated significantly with mood ratings. CONCLUSIONS: We report profound morning elevations of plasma IL-6 and a reversal of its circadian rhythm in MDD patients, in the absence of hypercortisolism. These findings may be relevant to the increased risk for coronary heart disease and bone loss in MDD.

Adult↗

Glucocorticoid-induced osteoporosis: from basic mechanisms to clinical aspects.

Glucocorticoid (GC)-induced osteoporosis (GCOP) is the most common cause of osteoporosis in adults aged 20-45 years as well as the most common cause of iatrogenic osteoporosis. GC excess, either endogenous or exogenous, induces bone loss in 30-50% of cases. Indeed, bone loss leading to fractures is perhaps the most incapacitating, sometimes partially irreversible, complication of GC therapy. Nevertheless, GCOP is often underdiagnosed and left untreated. The following article provides an update on the cellular and molecular mechanisms implicated in the pathophysiology of GC-induced bone loss, as well as some guidelines on diagnostic, preventive and therapeutic strategies for this medical condition, in an effort to promote a better knowledge and greater awareness of GCOP by both the patient and the physician.

Animals↗

The glucocorticoid receptor and the orphan nuclear receptor chicken ovalbumin upstream promoter-transcription factor II interact with and mutually affect each other's transcriptional activities: implications for intermediary metabolism.

Glucocorticoids exert their metabolic effect via their intracellular receptor, the glucocorticoid receptor (GR). In a yeast two-hybrid screening, we found the chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), an orphan nuclear receptor that plays important roles in glucose, cholesterol, and xenobiotic metabolism, as a partner of GR. In an in vitro glutathione-S-transferase pull-down assay, COUP-TFII interacted via its DNA-binding domain with the hinge regions of both GRalpha and its splicing variant GRbeta, whereas COUP-TFII formed a complex with GRalpha, but not with GRbeta, in an in vivo chromatin immunoprecipitation and a regular immunoprecipitation assay. Accordingly, GRalpha, but not GRbeta, enhanced COUP-TFII-induced transactivation of the simple COUP-TFII-responsive 7alpha-hydroxylase promoter through the transcriptional activity of its activation function-1 domain, whereas COUP-TFII repressed GRalpha-induced transactivation of the glucocorticoid-responsive promoter by attracting the silencing mediator for retinoid and thyroid hormone receptors. Importantly, mutual protein-protein interaction of GRalpha and COUP-TFII was necessary for glucocorticoid-induced enhancement of the promoter activity and the endogenous mRNA expression of the COUP-TFII-responsive phosphoenolpyruvate carboxykinase, the rate-limiting enzyme of hepatic gluconeogenesis. We suggest that COUP-TFII may participate in some of the metabolic effects of glucocorticoids through direct interactions with GRalpha. These interactions influence the transcription of both COUP-TFII- and GRalpha-responsive target genes, seem to be promoter specific, and can be in either a positive or negative direction.

Animals↗

L-Carnitine and acetyl-L-carnitine in the treatment of complications associated with HIV infection and antiretroviral therapy.

L-Carnitine (LC) and acetyl-L-carnitine (ALC) play major roles in cell energy and lipid metabolism. Supplementation with these nutrients, which are highly popular in USA, has been associated with favorable effects, including anti-oxidant action, neuro- and cardioprotection, immunomodulation, and cognitive enhancement. Patients with HIV infection and undergoing highly active antiretroviral therapy (HAART) often develop complications, such as polyneuropathy, skeletal myopathy, dyslipidemia and lipodystrophy, which have been linked to mitochondrial dysfunction. Moreover, these patients are often LC-deficient. Thus, they may benefit from LC and ALC supplementation. Indeed, oral, i.v., or i.m. administration of large doses of LC and/or ALC to HIV positive subjects untreated/treated with HAART was shown to: (1) increase the number of CD4 cells and reduce lymphocyte apoptosis; (2) improve symptoms of polyneuropathy; (3) prevent cardiovascular damage from wasting and diarrhea syndromes; (4) decrease serum levels of triglycerides and TNFalpha. No significant toxicities were associated with LC and ALC treatment. Although promising, most of these findings derive from small uncontrolled clinical trials. Further research is warranted to prove the efficacy and safety of LC and ALC supplementation in patients with complications of HIV infection and HAART.

Journal Article↗

Changes of noradrenergic activity and lipolysis in the subcutaneous abdominal adipose tissue of hypo- and hyperthyroid patients: an in vivo microdialysis study.

Thyroid function plays an important role in the regulation of overall metabolic rate and lipid metabolism. However, it is uncertain whether thyroid hormones directly affect lipolysis in adipose tissue and to what extent those changes contribute to overall metabolic phenotype. Our study was designed, using the microdialysis technique, to determine basal and isoprenaline-stimulated local lipolysis and to determine local concentrations of lipolysis-regulating catecholamines in abdominal subcutaneous adipose tissue in 12 patients with hypothyroidism, 6 patients with hyperthyroidism, and 12 healthy control subjects. Plasma norepinephrine (NE) concentrations in hypothyroid subjects were significantly higher than in the control and hyperthyroid groups. In contrast, systemic, adipose NE levels in hypothyroid patients were decreased relative to controls. Hyperthyroidism, on the other hand, resulted in four-fold higher adipose NE levels. Basal lipolysis measured by glycerol concentrations in adipose tissue was significantly attenuated in hypothyroid patients and markedly increased in hyperthyroid patients in comparison with the control group. In addition to differences in basal lipolysis, hypothyroidism resulted in attenuated, and hyperthyroidism in enhanced, lipolytic response to local stimulation with beta(1,2)-adrenergic agonist isoprenaline. These results demonstrate that lipolysis in abdominal subcutaneous adipose tissue is strongly modulated by thyroid function. We suggest that thyroid hormones regulate lipolysis primarily by affecting local NE concentration and/or adrenergic postreceptor signaling.

Abdomen↗

Modulatory effects of L-carnitine on glucocorticoid receptor activity.

L-carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a conditionally essential nutrient with a major role in cellular energy metabolism. It is available in the United States as both a prescription drug and an over-the-counter nutritional supplement. Accumulating evidence from both animal and human studies indicates that pharmacologic doses of L-carnitine (LCAR) have immunomodulatory effects resembling those of glucocorticoids (GC). On the other hand, in contrast to GC, which cause bone loss, LCAR seems to have positive effects on bone metabolism. To explore the molecular bases of this GC-like activity of LCAR, we investigated its effects on glucocorticoid receptor (GR)-modulated cytokine release ex vivo, and on the transcriptional activity, intracellular trafficking, and binding of GR in vitro. At high noncytotoxic doses, LCAR (a) suppressed the lipopolysaccharide-stimulated release of tumor necrosis factor alpha and interleukin-12 from primary human monocytes in a GC-like fashion, (b) stimulated the transcriptional activity of GR on the GC-responsive promoters, (c) triggered nuclear translocation of green fluorescent protein (GFP)-fused GR, and (d) reduced the whole cell binding of [(3)H]-dexamethasone to GR. These results suggest that LCAR is a "nutritional modulator" of the GR, by acting as an agonist-like compound. Since LCAR appears to have positive effects on bone metabolism, in contrast to GC, LCAR may share some of the therapeutic properties of GC, particularly on the immune system, but not their deleterious side effects on some of other organs/tissues. Thus, LCAR is potentially a useful alternative compound of GC in particular therapeutic situations. The clinical and therapeutic implications of these findings, as well as a better understanding of their mechanisms, warrant further research.

Carnitine↗

Interaction of the glucocorticoid receptor and the chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII): implications for the actions of glucocorticoids on glucose, lipoprotein, and xenobiotic metabolism.

Glucocorticoids exert their extremely diverse effects on numerous biologic activities of humans via only one protein module, the glucocorticoid receptor (GR). The GR binds to the glucocorticoid response elements located in the promoter region of target genes and regulates their transcriptional activity. In addition, GR associates with other transcription factors through direct protein-protein interactions and mutually represses or stimulates each other's transcriptional activities. The latter activity of GR may be more important than the former one, granted that mice harboring a mutant GR, which is active in terms of protein-protein interactions but inactive in terms of transactivation via DNA, survive and procreate, in contrast to mice with a deletion of the entire GR gene that die immediately after birth. We recently found that GR physically interacts with the chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII), which plays a critical role in the metabolism of glucose, cholesterol, and xenobiotics, as well as in the development of the central nervous system in fetus. GR stimulates COUP-TFII-induced transactivation by attracting cofactors via its activation function-1, while COUP-TFII represses the GR-governed transcriptional activity by tethering corepressors, such as the silencing mediator for retinoid and thyroid hormone receptors (SMRT) and the nuclear receptor corepressors (NCoRs) via its C-terminal domain. Their mutual interaction may play an important role in gluconeogenesis, lipoprotein metabolism, and enzymatic clearance of clinically important compounds and bioactive chemicals, by regulating their rate-limiting enzymes and molecules, including the phosphoenolpyruvate carboxykinase (PEPCK), the cytochrome P450 CYP3A and CYP7A, and several apolipoproteins. It appears that glucocorticoids exert their intermediary effects partly via physical interaction with COUP-TFII.

Animals↗

L-Carnitine is a modulator of the glucocorticoid receptor alpha.

L-Carnitine (LC) is a nutrient with an essential role in cellular energy production. At high doses, LC can mimic some of the biological activities of glucocorticoids, particularly immunomodulation. To explore the molecular bases of this property, we tested the influence of LC on glucocorticoid receptor-a (GRalpha) functions. LC reduced the binding capacity of GRalpha, induced its nuclear translocation, and stimulated its transcriptional activity. Moreover, LC suppressed TNFalpha and IL-12 release from human monocytes in glucocorticoid-like fashion. We conclude that pharmacologic doses of LC can activate GRalpha and, via this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids.

Animals↗

L-carnitine: A nutritional modulator of glucocorticoid receptor functions.

L-carnitine is an essential nutrient with a major role in cellular energy production. There is evidence that, at high doses, L-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. To explore the molecular basis of this effect, we tested the influence of L-carnitine on glucocorticoid receptor-alpha (GRalpha) functions. Millimolar concentrations of L-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [3H]dexamethasone to GRalpha by decreasing the affinity of this receptor for its steroid ligand. At the same concentrations, L-carnitine was able to trigger nuclear translocation of green fluorescent protein (GFP)-fused human GRalpha and transactivate the glucocorticoid-responsive mouse mammary tumor virus (MMTV) and TAT3 promoters in a dose-dependent fashion. This effect was solely dependent on the presence of glucocorticoid-responsive elements on the promoter and on the expression of functional GRalpha by the cell. Finally, similarly to glucocorticoids, L-carnitine suppressed tumor necrosis factor-alpha (TNFalpha) and interleukin-12 release by human primary monocytes stimulated with lipopolysaccharide ex vivo. Both GRalpha transactivation and cytokine suppression by L-carnitine were abrogated by the GRalpha-antagonist RU 486. Taken together, our results suggest that pharmacological doses of L-carnitine can activate GRalpha and, through this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids.

Active Transport, Cell Nucleus↗

Loss of meal-induced decrease in plasma ghrelin levels in patients with anorexia nervosa.

Studies have shown that ghrelin plays a major role in energy homeostasis and modulation of feeding behavior. However, little is known about the influence of food consumption on plasma ghrelin levels in humans. Therefore, we investigated responses of plasma ghrelin to food intake, meal volume and meal nutritional value in healthy volunteers and women with anorexia nervosa (AN). After overnight fasting, all subjects received either a standardized breakfast or fiber. Plasma ghrelin levels were measured before and after the meal. Fasting plasma ghrelin was significantly higher in AN patients than in controls (1,800.6 +/- 47.0 vs. 795.9 +/- 24.3 pg/ml, P < 0.001) (606.8 +/- 15.8 vs. 268.2 +/- 8.2 pmol/l, P < 0.001), and correlated negatively with percentage of body fat in both groups. Ghrelin levels markedly fell after consumption of either a standardized meal or fiber in controls, but not in anorexic women. Thus, we concluded that the acute plasma ghrelin response to food intake, which in healthy individuals is independent of meal caloric value, is impaired in women with AN. This abnormality may be part of a chronic adaptation to prolonged food restriction, which attempts to restore a normal feeding conduct by maintaining the drive to eat.

Adipose Tissue↗

Effects of hypo- and hyperthyroidism on noradrenergic activity and glycerol concentrations in human subcutaneous abdominal adipose tissue assessed with microdialysis.

Thyroid hormones play a major role in lipid metabolism. However, whether they directly affect lipolysis locally in the adipose tissue remains unknown. Therefore, we measured abdominal sc adipose tissue norepinephrine (NE), basal, and isoprenaline-stimulated lipolysis in 12 hypothyroid patients (HYPO), six hyperthyroid patients (HYPER), and 12 healthy controls by in vivo microdialysis. Adipose tissue NE was decreased in HYPO and increased in HYPER compared with controls (90.4 +/- 2.9 and 458.0 +/- 69.1 vs. 294.9 +/- 19.5 pmol/liter, P < 0.01). Similarly, basal lipolysis, assessed by glycerol assay, was lower in HYPO and higher in HYPER than in controls (88.2 +/- 9.9 and 566.0 +/- 42.0 vs. 214.3 +/- 5.1 micromol/liter P < 0.01). The relative magnitude of isoprenaline-induced glycerol increase was smaller in HYPO (39 +/- 19.4%, P < 0.05 vs. basal) and higher in HYPER (277 +/- 30.4%, P < 0.01) than in controls (117 +/- 5.6%, P < 0.01). The corresponding changes in NE after isoprenaline stimulation were as follows: 120 +/- 9.2% (P < 0.05), 503 +/- 113% (P < 0.01), and 267 +/- 17.2 (P < 0.01). In summary, by affecting local NE levels and adrenergic postreceptor signaling, thyroid hormones may influence the lipolysis rate in the abdominal sc adipose tissue.

Abdomen↗