Publications by authors named "Claudia Camerino"

20 Publications

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Oxtr/TRPV1 expression and acclimation of skeletal muscle to cold-stress in male mice.

J Endocrinol 2021 Mar 1. Epub 2021 Mar 1.

C Camerino, 3Department of Biomedical Sciences and Human Oncology (Section of Pharmacology), School of Medicine, University of Bari, Bari, Italy.

We explored the involvement of Oxytocin receptor (Oxtr)/ Transient-receptor-potential-vanilloid-1 (TRPV1) genes and Oxytocin (Oxt) on the adaptation of skeletal muscle to cold stress challenge in mice. Oxtr expression in hypothalamic paraventricular (PVN), supraoptic nuclei (SON), and hippocampus (HIPP) were evaluated by immunohistochemistry in parallel with the measurement of circulating Oxt. The Oxtr and TRPV1 gene expression in Soleus (SOL) and Tibialis Anterior (TA) muscles were investigated by RT-PCR. Histological studies of the cardiac muscle after cold stress were also performed. Male mice (n=15) were divided into controls maintained at room temperature (RT=24°C), exposed to cold stress (CS) at T=4°C for 6 hours (6h), and 5 days (5d). Immunohistochemical studies showed that Oxtr protein expression increased by 2-fold (p=0.01) in PVN and by 1.5-fold (p=0.0001) in HIPP after 6h and 5d CS, but decreased by 2-fold (p=0.026) in SON at 5d. Both Oxtr and TRPV1 gene expression increased after 6h and 5d CS in SOL and TA muscles. Oxtr vs TRPV1 gene expression in SOL and TA muscles evaluated by regression analysis was linearly correlated following CS at 6h and 5d but not at control temperature of 24+1°C, supporting the hypothesis of coupling between these genes. The circulating levels of Oxt are unaffected after 6h CS but decreased by 0.2-fold (p=0.0141) after 5d CS. This is the first report that Oxtr and TRPV1 expression are upregulated in response to cold acclimation in skeletal muscle. The up-regulation of Oxtr in PVN and HIPP balances the decrease of circulating Oxt.
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http://dx.doi.org/10.1530/JOE-20-0346DOI Listing
March 2021

The New Frontier in Oxytocin Physiology: The Oxytonic Contraction.

Authors:
Claudia Camerino

Int J Mol Sci 2020 Jul 21;21(14). Epub 2020 Jul 21.

Department of Biomedical Sciences and Human Oncology School of Medicine, University of Bari Aldo Moro, 70100 Bari, Italy.

Oxytocin (Oxt) is a nine amino acid peptide important in energy regulation and is essential to stress-related disorders. Specifically, low Oxt levels are associated with obesity in human subjects and diet-induced or genetically modified animal models. The striking evidence that Oxt is linked to energy regulation is that Oxt- and oxytocin receptor (Oxtr)-deficient mice show a phenotype characterized by late onset obesity. Oxt-/- or Oxtr-/- develop weight gain without increasing food intake, suggesting that a lack of Oxt reduce metabolic rate. Oxt is differentially expressed in skeletal muscle exerting a protective effect toward the slow-twitch muscle after cold stress challenge in mice. We hypothesized that Oxt potentiates the slow-twitch muscle as it does with the uterus, triggering "the oxytonic contractions". Physiologically, this is important to augment muscle strength in fight/flight response and is consistent with the augmented energetic need at time of labor and for the protection of the offspring when Oxt secretion spikes. The normophagic obesity of Oxt-/- or Oxtr-/- mice could have been caused by decreased skeletal muscle tonicity which drove the metabolic phenotype. In this review, we summarized our findings together with the recent literature on this fascinating subjects in a "new perspective" over the physicology of Oxt.
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http://dx.doi.org/10.3390/ijms21145144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404128PMC
July 2020

Oxytocin/Osteocalcin/IL-6 and NGF/BDNF mRNA Levels in Response to Cold Stress Challenge in Mice: Possible Oxytonic Brain-Bone-Muscle-Interaction.

Front Physiol 2019 27;10:1437. Epub 2019 Nov 27.

Department of Pharmacy-Pharmaceutical Sciences, University of Bari Aldo Moro, Bari, Italy.

Oxytocin (Oxt), osteocalcin (Ost), and NGF/BDNF have a role in bone homeostasis, reproduction, and cognition. Oxt/Ost is required for muscle repair. We investigated gene response of muscle and the inter-organ communication following cold stress (CS). The mRNA quantity of , , , , , , , , , , and genes in bone, brain, soleus (SOL), and (TA) muscles from adult mice following CS were investigated. The myosin heavy-chain , , , and gene expression were investigated. Mice were maintained at = 23°C or 4°C for 6 h and 5-days (5d). CS mice did not show signs of muscle degeneration. An upregulation of and genes by 2 and 1.5 folds, respectively, in TA after 6 h CS and by 4 and 22 folds in SOL muscle after 6 h and 5d CS, respectively, was observed; while after 6 h CS was downregulated in either muscle. was unaffected, while after 5d CS was upregulated in TA. was downregulated in SOL by 0.9-folds at 5d. Following 5d CS, and genes were upregulated, respectively, by 1 and 1.5 folds in SOL. A downregulation of , respectively, by 0.96 and 0.88-folds after 6 h and 5d CS in SOL and was also downregulated by 0.88-fold after 5d CS in TA. and were not affected. Changes in the expression levels of genes in TA and SOL muscles, bone, and brain following CS were regulated by IL6 and Oxt. CS potentiates the slow-twitch phenotype of SOL which is in line with the metabolic need of this muscle, and the potentiation of the slow-twitch phenotype in TA. Oxt and IL6 coordinate a phenotype-dependent tonic effect of slow-twitch muscle and Oxt regulates the inter-organ interaction between brain and SOL muscle. Muscle tropism is maintained by NGF signaling following CS.
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http://dx.doi.org/10.3389/fphys.2019.01437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6890828PMC
November 2019

Evaluation of Short and Long Term Cold Stress Challenge of Nerve Grow Factor, Brain-Derived Neurotrophic Factor, Osteocalcin and Oxytocin mRNA Expression in BAT, Brain, Bone and Reproductive Tissue of Male Mice Using Real-Time PCR and Linear Correlation Analysis.

Front Physiol 2017 11;8:1101. Epub 2018 Jan 11.

Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy.

The correlation between the and , Osteocalcin-/ and Oxytocin- genes, was challenged investigating their mRNA levels in 3 months-old mice after cold-stress (CS). Uncoupling protein-1 ( was used as positive control. Control mice were maintained at room temperature T = 25°C, CS mice were maintained at T = 4°C for 6 h and 5-days ( = 15 mice). RT-PCR experiments showed that and genes were up-regulated after 6 h CS in brown adipose tissues (BAT), respectively, by 2 and 1.5-folds; was upregulated also after 5-days, while and genes were downregulated after 6 h and 5-days CS in BAT. and were upregulated in bone and testis following 5-days, and in testis after 6 h CS. was instead up-regulated in bone following 5-days CS and down-regulated in testis. was upregulated by 16 and 3-fold in bone and BAT, respectively, following 5-days CS. was upregulated after 6 h in brain, while ( gene was downregulated. gene was upregulated by 5-fold following 5-days CS in bone. was upregulated by 0.5 and 0.3-fold, respectively, following 6 h and 5-days CS in brain. and were downregulated in testis and in BAT. The changes in the expression levels of control genes vs. genes following 6 h and 5-days CS were correlated in all tissues, but not in BAT. Correlation in BAT was improved eliminating data. The correlation in brain was lost eliminating data. In sum, potentiation in BAT after cold stress is associated with early -response in the same tissue and trophic action in bone and testis. In contrast, BDNF exerts bone and neuroprotective effects. Similarly to ( signaling is enhanced in bone and BAT while it may exert local neuroprotective effects thought its receptor. regulates the adaptation to CS through a feed-back loop in BAT. regulates the gene-response to CS through a feed-forward loop in brain. Overall these results expand the understanding of the physiology of these molecules under metabolic thermogenesis.
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http://dx.doi.org/10.3389/fphys.2017.01101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5768886PMC
January 2018

Risk of Myopathy in Patients in Therapy with Statins: Identification of Biological Markers in a Pilot Study.

Front Pharmacol 2017 27;8:500. Epub 2017 Jul 27.

Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari Aldo MoroBari, Italy.

Statin therapy may induce skeletal muscle damage ranging from myalgia to severe rhabdomyolysis. Our previous preclinical studies showed that statin treatment in rats involves the reduction of skeletal muscle ClC-1 chloride channel expression and related chloride conductance (gCl). An increase of the activity of protein kinase C theta (PKC theta) isoform, able to inactivate ClC-1, may contribute to destabilize sarcolemma excitability. These effects can be detrimental for muscle function leading to drug-induced myopathy. Our goal is to study the causes of statin-induced muscle side effects in patients at the aim to identify biological markers useful to prevent and counteract statin-induced muscle damage. We examined 10 patients, who experienced myalgia and hyper-CK-emia after starting statin therapy compared to 9 non-myopathic subjects not using lipid-lowering drugs. Western Blot (WB) analysis showed a 40% reduction of ClC-1 protein and increased expression of phosphorylated PKC in muscle biopsies of statin-treated patients with respect to untreated subjects, independently from their age and statin type. Real-time PCR analysis showed that despite reduction of the protein, the ClC-1 mRNA was not significantly changed, suggesting post-transcriptional modification. The mRNA expression of a series of genes was also evaluated. MuRF-1 was increased in accord with muscle atrophy, MEF-2, calcineurin (CN) and GLUT-4 transporter were reduced, suggesting altered transcription, alteration of glucose homeostasis and energy deficit. Accordingly, the phosphorylated form of AMPK, measured by WB, was increased, suggesting cytoprotective process activation. In parallel, mRNA expression of Notch-1, involved in muscle cell proliferation, was highly expressed in statin-treated patients, indicating active regeneration. Also, PGC-1-alpha and isocitrate-dehydrogenase increased expression together with increased activity of mitochondrial citrate-synthase, measured by spectrophotometric assay, suggests mitochondrial biogenesis. Thus, the reduction of ClC-1 protein and consequent sarcolemma hyperexcitability together with energy deficiency appear to be among the most important alterations to be associated with statin-related risk of myopathy in humans. Thus, it may be important to avoid statin treatment in pathologies characterized by energy deficit and chloride channel malfunction. This study validates the measure of ClC-1 expression as a reliable clinical test for assessing statin-dependent risk of myopathy.
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http://dx.doi.org/10.3389/fphar.2017.00500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5529355PMC
July 2017

Nerve Growth Factor, Brain-Derived Neurotrophic Factor and Osteocalcin Gene Relationship in Energy Regulation, Bone Homeostasis and Reproductive Organs Analyzed by mRNA Quantitative Evaluation and Linear Correlation Analysis.

Front Physiol 2016 13;7:456. Epub 2016 Oct 13.

Department of Pharmacy - Drug Sciences, University of Bari Bari, Italy.

Nerve Growth Factor (NGF)/Brain-derived Neurotrophic Factor (BDNF) and osteocalcin share common effects regulating energy, bone mass, reproduction and neuronal functions. To investigate on the gene-relationship between NGF, BDNF, and Osteocalcin we compared by RT-PCR the transcript levels of and as well as of their receptors , and in brain, bone, white/brown adipose tissue (WAT/BAT) and reproductive organs of 3 months old female and male mice. Brain and bone were used as positive controls for NGF/BDNF and Osteocalcin respectively. The role of oxitocin() and its receptor() was also investigated. expression shows an opposite trend compared to . / expression is 50% higher in BAT than brain, in both genders, but lower in bone. In contrast, expression in bone is higher than in brain, but low in BAT/WAT. We found gene expressed in brain in both genders, but expression is low in brain and BAT/WAT. As expected, gene is expressed in bone. gene was markedly expressed in brain, in the ovaries and in fat and bone in both genders. is highly expressed in reproductive tissues and mRNA levels are respectively 300, 100, and 50% higher in testis/ovaries/uterus than in brain. In contrast, BDNF genes are not expressed in reproductive tissues. As expected, is expressed in testis but not in the ovaries/uterus. A significant correlation was found between the expression levels of the gene ligands and their receptors in brain, BAT and testis suggesting a common pathway of different genes in these tissues in either male and female. Changes in the expression levels of , or genes may mutually affect the expression levels of the others. Moreover, it may be possible that different ligands may operate through different receptor subtypes. and failed to show significant correlation. The up-regulation of / in BAT is consistent with NGF as an energy regulator and with BDNF regulating bone.
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http://dx.doi.org/10.3389/fphys.2016.00456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5061807PMC
October 2016

Statin-induced myotoxicity is exacerbated by aging: A biophysical and molecular biology study in rats treated with atorvastatin.

Toxicol Appl Pharmacol 2016 09 1;306:36-46. Epub 2016 Jul 1.

Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari - Aldo Moro, Bari, Italy. Electronic address:

Statin-induced skeletal muscle damage in rats is associated to the reduction of the resting sarcolemmal chloride conductance (gCl) and ClC-1 chloride channel expression. These drugs also affect the ClC-1 regulation by increasing protein kinase C (PKC) activity, which phosphorylate and close the channel. Also the intracellular resting calcium (restCa) level is increased. Similar alterations are observed in skeletal muscles of aged rats, suggesting a higher risk of statin myotoxicity. To verify this hypothesis, we performed a 4-5-weeks atorvastatin treatment of 24-months-old rats to evaluate the ClC-1 channel function by the two-intracellular microelectrodes technique as well as transcript and protein expression of different genes sensitive to statins by quantitative real-time-PCR and western blot analysis. The restCa was measured using FURA-2 imaging, and histological analysis of muscle sections was performed. The results show a marked reduction of resting gCl, in agreement with the reduced ClC-1 mRNA and protein expression in atorvastatin-treated aged rats, with respect to treated adult animals. The observed changes in myocyte-enhancer factor-2 (MEF2) expression may be involved in ClC-1 expression changes. The activity of PKC was also increased and further modulate the gCl in treated aged rats. In parallel, a marked reduction of the expression of glycolytic and mitochondrial enzymes demonstrates an impairment of muscle metabolism. No worsening of restCa or histological features was found in statin-treated aged animals. These findings suggest that a strong reduction of gCl and alteration of muscle metabolism coupled to muscle atrophy may contribute to the increased risk of statin-induced myopathy in the elderly.
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http://dx.doi.org/10.1016/j.taap.2016.06.032DOI Listing
September 2016

Chronic Psychosocial Stress Impairs Bone Homeostasis: A Study in the Social Isolation Reared Rat.

Front Pharmacol 2016 8;7:152. Epub 2016 Jun 8.

Department of Experimental and Clinical Medicine, University of Foggia Foggia, Italy.

Chronic psychosocial stress is a key player in the onset and aggravation of mental diseases, including psychosis. Although a strong association between this psychiatric condition and other medical co-morbidities has been recently demonstrated, few data on the link between psychosis and bone homeostasis are actually available. The aim of this study was to investigate whether chronic psychosocial stress induced by 4 or 7 weeks of social isolation in drug-naïve male Wistar rats could alter bone homeostasis in terms of bone thickness, mineral density and content, as well as markers of bone formation and resorption (sclerostin, cathepsin K, and CTX-I). We found that bone mineral density was increased in rats exposed to 7 weeks of social isolation, while no differences were detected in bone mineral content and area. Moreover, 7 weeks of social isolation lead to increase of femur thickness with respect to controls, suggesting the development of a hyperostosis condition. Isolated rats showed no changes in sclerostin levels, a marker of bone formation, compared to grouped animals. Conversely, bone resorption markers were significantly altered after 7 weeks of social isolation in terms of decrease in cathepsin K and increase of CTX-I. No alterations were found after 4 weeks of isolation rearing. Our observations suggest that chronic psychosocial stress might affect bone homeostasis, more likely independently from drug treatment. Thus, the social isolation model might help to identify possible new therapeutic targets to treat the burden of chronic psychosocial stress and to attempt alternative therapy choices.
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http://dx.doi.org/10.3389/fphar.2016.00152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4896906PMC
July 2016

Therapeutic Approaches to Genetic Ion Channelopathies and Perspectives in Drug Discovery.

Front Pharmacol 2016 10;7:121. Epub 2016 May 10.

Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy.

In the human genome more than 400 genes encode ion channels, which are transmembrane proteins mediating ion fluxes across membranes. Being expressed in all cell types, they are involved in almost all physiological processes, including sense perception, neurotransmission, muscle contraction, secretion, immune response, cell proliferation, and differentiation. Due to the widespread tissue distribution of ion channels and their physiological functions, mutations in genes encoding ion channel subunits, or their interacting proteins, are responsible for inherited ion channelopathies. These diseases can range from common to very rare disorders and their severity can be mild, disabling, or life-threatening. In spite of this, ion channels are the primary target of only about 5% of the marketed drugs suggesting their potential in drug discovery. The current review summarizes the therapeutic management of the principal ion channelopathies of central and peripheral nervous system, heart, kidney, bone, skeletal muscle and pancreas, resulting from mutations in calcium, sodium, potassium, and chloride ion channels. For most channelopathies the therapy is mainly empirical and symptomatic, often limited by lack of efficacy and tolerability for a significant number of patients. Other channelopathies can exploit ion channel targeted drugs, such as marketed sodium channel blockers. Developing new and more specific therapeutic approaches is therefore required. To this aim, a major advancement in the pharmacotherapy of channelopathies has been the discovery that ion channel mutations lead to change in biophysics that can in turn specifically modify the sensitivity to drugs: this opens the way to a pharmacogenetics strategy, allowing the development of a personalized therapy with increased efficacy and reduced side effects. In addition, the identification of disease modifiers in ion channelopathies appears an alternative strategy to discover novel druggable targets.
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http://dx.doi.org/10.3389/fphar.2016.00121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861771PMC
May 2016

Microgravity during spaceflight directly affects in vitro osteoclastogenesis and bone resorption.

FASEB J 2009 Aug 27;23(8):2549-54. Epub 2009 Mar 27.

Department of Human Anatomy and Histology, University of Bari Medical School, Policlinico, Piazza G. Cesare 11, I-70124 Bari, Italy.

During space flight, severe losses of bone mass are observed. Both bone formation and resorption are probably involved, but their relative importance remains unclear. The purpose of this research is to understand the role of osteoclasts and their precursors in microgravity-induced bone loss. Three experiments on isolated osteoclasts (OCs) and on their precursors, OSTEO, OCLAST, and PITS, were launched in the FOTON-M3 mission. The OSTEO experiment was conducted for 10 d in microgravity within bioreactors with a perfusion system, where the differentiation of precursors, cultured on a synthetic 3-dimensional bonelike biomaterial, skelite, toward mature OCs was assessed. In OCLAST and in PITS experiments, differentiated OCs were cultured on devitalized bovine bone slices for 4 d in microgravity. All of the experiments were replicated on ground in the same bioreactors, and OCLAST also had an inflight centrifuge as a control. Gene expression in microgravity, compared with ground controls, demonstrated a severalfold increase in genes involved in osteoclast maturation and activity. Increased bone resorption, proved by an increased amount of collagen telopeptides released VS ground and centrifuge control, was also found. These results indicate for the first time osteoclasts and their precursors as direct targets for microgravity and mechanical forces.
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http://dx.doi.org/10.1096/fj.08-127951DOI Listing
August 2009

Low sympathetic tone and obese phenotype in oxytocin-deficient mice.

Authors:
Claudia Camerino

Obesity (Silver Spring) 2009 May 26;17(5):980-4. Epub 2009 Feb 26.

Department of Human Anatomy and Histology, Medical School, University of Bari, Bari, Italy.

Oxytocin (Oxt) is secreted both peripherally and centrally and is involved in several functions including parturition, milk let-down reflex, social behavior, and food intake. Recently, it has been shown that mice deficient in Oxt receptor develop late-onset obesity. In this study, we characterized a murin model deficient in Oxt peptide (Oxt(-/-)) to evaluate food intake and body weight, glucose tolerance and insulin tolerance, leptin and adrenaline levels. We found that Oxt(-/-) mice develop late-onset obesity and hyperleptinemia without any alterations in food intake in addition to having a decreased insulin sensitivity and glucose intolerance. The lack of Oxt in our murin model also results in lower adrenalin levels which led us to hypothesize that the metabolic changes observed are associated with a decreased sympathetic nervous tone. It has been shown that Oxt neurons in the paraventricular nucleus (PVN) are a component of a leptin-sensitive signaling circuit between the hypothalamus and caudal brain stem for the regulation of food intake and energy homeostasis. Nevertheless, the lack of Oxt in these mice does not have a direct impact on feeding behavior whose regulation is probably dependent on the complex interplay of several factors. The lack of hyperphagia evident in the Oxt(-/-) mice may, in part, be attributed to the developmental compensation of other satiety factors such as cholecystokinin or bombesin-related peptides which merits further investigation. These findings identify Oxt as an important central regulator of energy homeostasis.
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http://dx.doi.org/10.1038/oby.2009.12DOI Listing
May 2009

Osteoblasts cultured on three-dimensional synthetic hydroxyapatite implanted on a chick allantochorial membrane induce ectopic bone marrow differentiation.

Ann N Y Acad Sci 2007 Nov 21;1116:306-15. Epub 2007 Jun 21.

Department of Human Anatomy and Histology, School of Medicine, University of Bari, Bari, Italy.

Osteoblast (OB) activities have been studied on hydroxyapatite three-dimensional (3D) scaffolds in comparison with traditional planar substrata. OBs cultured on 3D displayed increased proliferation, differentiation, and matrix protein synthesis, when compared to 2D cultures on the same substrata. Confluent cultures, however, could not be maintained for long, due to insufficient fluid diffusion within 3D scaffolds that impaired cell viability. Thus, confluent OB 3D cultures were implanted on the allantochorial membrane of chick embryos. Vessels from the embryo colonized the bone-like network giving rise in the presence of OBs to an ectopic bone marrow formation in the intratrabecular spaces. In the absence of OBs, when the biomaterial alone was implanted, blood vessels were still present but hematopoietic marrow was absent. In both cases osteoclasts (OCs) derived from the host were found on the implant surface. These results indicated that scaffolds with cells can be easily vascularized and confirmed the role of OBs in the definition of the microenvironment that induce blood marrow differentiation in the intratrabecular spaces.
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http://dx.doi.org/10.1196/annals.1402.008DOI Listing
November 2007

First evaluation of the potential effectiveness in muscular dystrophy of a novel chimeric compound, BN 82270, acting as calpain-inhibitor and anti-oxidant.

Neuromuscul Disord 2006 Apr 15;16(4):237-48. Epub 2006 Mar 15.

Unit of Pharmacology, Department of Pharmacobiology, Faculty of Pharmacy, University of Bari, Bari, Italy.

BN 82270 is a membrane-permeable prodrug of a chimeric compound (BN 82204) dually acting as calpain inhibitor and anti-oxidant. Acute in vivo injection of dystrophic mdx mice (30 mg/kg, s.c.) fully counteracted calpain overactivity in diaphragm. A chronic 4-6 weeks administration significantly prevented in vivo the fore limb force drop occurring in mdx mice exercised on treadmill. Ex vivo electrophysiological recordings showed that BN 82270 treatment contrasted the decrease in chloride channel function (gCl) in diaphragm, an index of spontaneous degeneration, while it was less effective on both exercise-impaired gCl and calcium-dependent mechanical threshold of the hind limb extensor digitorum longus (EDL) muscle fibres. The BN 82270 treated mdx mice showed a marked reduction of plasma creatine kinase and of the pro-fibrotic cytokine TGF-beta1 in both hind limb muscles and diaphragm; however, the histopathological profile of gastrocnemious muscle was poorly ameliorated. In hind limb muscles of treated mice, the active form was detected by HPLC in the low therapeutic concentration range. In vitro exposure to 100 microM BN 82270 led to higher active form in diaphragm than in EDL muscle. This is the first demonstration that this class of chimeric compounds, dually targeting pathology-related events, exerts beneficial effects in muscular dystrophy. The drug/prodrug system may require posology adjustment to produce wider beneficial effects on all muscle types.
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http://dx.doi.org/10.1016/j.nmd.2006.01.013DOI Listing
April 2006

Fiber type-related changes in rat skeletal muscle calcium homeostasis during aging and restoration by growth hormone.

Neurobiol Dis 2006 Feb 8;21(2):372-80. Epub 2005 Sep 8.

Division of Pharmacology, Department of Pharmaco-Biology, Faculty of Pharmacy, University of Bari, Bari I-70125, Italy.

The mechanisms by which aging induces muscle impairment are not well understood yet. We studied the impact of aging on Ca2+ homeostasis in the slow-twitch soleus and the fast-twitch extensor digitorum longus (EDL) muscles of aged rats by using the fura-2 fluorescent probe. In both muscles aging increases the resting cytosolic calcium concentration ([Ca2+]i). This effect was independent on calcium influx since a reduced resting permeability of sarcolemma to divalent cations was observed in aged muscles likely due to a reduced activity of leak channels. Importantly the effects of aging on resting [Ca2+]i, fiber diameter, mechanical threshold and sarcolemmal resting conductances were less pronounced in the soleus muscle, suggesting that muscle impairment may be less dependent on [Ca2+]i in the slow-twitch muscle. The treatment of aged rats with growth hormone restored the resting [Ca2+]i toward adult values in both muscles. Thus, an increase of resting [Ca2+]i may contribute to muscle weakness associated with aging and may be considered for developing new therapeutic strategies in the elderly.
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http://dx.doi.org/10.1016/j.nbd.2005.07.012DOI Listing
February 2006

Enhanced osteoclastogenesis in women after natural delivery.

Biochem Biophys Res Commun 2005 Aug;334(2):487-90

Department of Human Anatomy and Histology, University of Bari, Italy.

In the pre-expulsive and expulsive phases of labor, oxytocin and several other osteoclastogenic mediators, such as prostaglandins and IL-6, are secreted in high concentrations. This study was undertaken to assess whether the peripheral blood obtained from healthy women after vaginal delivery contains a larger pool of osteoclast precursors compared with age- and gender-matched controls. Our results clearly show that the number and size of osteoclasts generated in vitro from osteoclast precursors isolated from women after delivery are significantly larger than those from controls. This finding can account for the decrease in bone mass that is often observed during the breastfeeding period and the concomitant release of high quantities of calcium in the milk. Further investigations are required to establish whether analysis of blood osteoclast precursors can be predictive of changes in bone remodeling in this setting.
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http://dx.doi.org/10.1016/j.bbrc.2005.06.126DOI Listing
August 2005

Recovery of the soleus muscle after short- and long-term disuse induced by hindlimb unloading: effects on the electrical properties and myosin heavy chain profile.

Neurobiol Dis 2005 Mar;18(2):356-65

Unit of Pharmacology, Department of Pharmaco-Biology, Faculty of Pharmacy, University of Bari, Bari, I-70125 Italy.

The hindlimb unloading (HU) rat is a model of muscle disuse characterized by atrophy and slow-to-fast phenotype transition of the postural muscles, such as the soleus. We previously found that the resting sarcolemmal chloride conductance (gCl) that is typically lower in slow-twitch myofibers than in fast ones increased in soleus fibers following 1 to 3 weeks of HU in accord with the slow-to-fast transition of myosin heavy chain (MHC) isoforms. Nevertheless, the gCl already raised after a 3-day HU, whereas no change in MHC expression was detected. The present work evaluates the ability of soleus muscle to recover on return to normal load after a short (3 days) or long (2 weeks) disuse period. The changes observed after a 2-week HU were slowly reversible, since 3-4 weeks of reloading were needed to completely recover gCl, fiber diameter, MHC expression pattern, as well as the mechanical threshold Rheobase, an index of calcium homeostasis. After 3-day HU, the gCl increased homogeneously in most of the soleus muscle fibers and gCl recovery was rapidly completed after 4-day reloading. These results suggest different induction mechanisms for gCl augmentation after the short and long HU periods, as well as a possible role for gCl in the slow muscle adaptation to disuse.
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http://dx.doi.org/10.1016/j.nbd.2004.09.016DOI Listing
March 2005

A multidisciplinary evaluation of the effectiveness of cyclosporine a in dystrophic mdx mice.

Am J Pathol 2005 Feb;166(2):477-89

Sezione di Farmacologia, Dipartimento Farmacobiologico, Facoltà di Farmacia, Università degli Studi di Bari, Via Orabona 4, Campus, 70125 Bari, Italy.

Chronic inflammation is a secondary reaction of Duchenne muscular dystrophy and may contribute to disease progression. To examine whether immunosuppressant therapies could benefit dystrophic patients, we analyzed the effects of cyclosporine A (CsA) on a dystrophic mouse model. Mdx mice were treated with 10 mg/kg of CsA for 4 to 8 weeks throughout a period of exercise on treadmill, a protocol that worsens the dystrophic condition. The CsA treatment fully prevented the 60% drop of forelimb strength induced by exercise. A significant amelioration (P < 0.05) was observed in histological profile of CsA-treated gastrocnemius muscle with reductions of nonmuscle area (20%), centronucleated fibers (12%), and degenerating area (50%) compared to untreated exercised mdx mice. Consequently, the percentage of normal fibers increased from 26 to 35% in CsA-treated mice. Decreases in creatine kinase and markers of fibrosis were also observed. By electrophysiological recordings ex vivo, we found that CsA counteracted the decrease in chloride conductance (gCl), a functional index of degeneration in diaphragm and extensor digitorum longus muscle fibers. However, electrophysiology and fura-2 calcium imaging did not show any amelioration of calcium homeostasis in extensor digitorum longus muscle fibers. No significant effect was observed on utrophin levels in diaphragm muscle. Our data show that the CsA treatment significantly normalized many functional, histological, and biochemical endpoints by acting on events that are independent or downstream of calcium homeostasis. The beneficial effect of CsA may involve different targets, reinforcing the usefulness of immunosuppressant drugs in muscular dystrophy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1602333PMC
http://dx.doi.org/10.1016/S0002-9440(10)62270-5DOI Listing
February 2005

The alteration of calcium homeostasis in adult dystrophic mdx muscle fibers is worsened by a chronic exercise in vivo.

Neurobiol Dis 2004 Nov;17(2):144-54

Unit of Pharmacology, Department of Pharmacobiology, Faculty of Pharmacy, University of Bari, Bari, Italy.

Chronic exercise in vivo aggravates dystrophy in mdx mice. Calcium homeostasis was evaluated ex vivo by micro-spectrofluorometry on tendon-to-tendon dissected extensor digitorum longus (EDL) muscle fibers. Resting cytosolic calcium ([Ca2+]i) and sarcolemmal permeability through Gd3+ -sensitive mechanosensitive calcium (MsCa) channel were significantly higher in mdx vs. wild-type fibers. The exercise further enhanced [Ca2+]i in mdx fibers and increased sarcolemmal permeability by activating nifedipine-sensitive leak calcium channels. The two genotypes did not differ in caffeine sensitivity and in the excitation-calcium release (ECaR) coupling mechanism by K+ depolarization. The exercise produced a similar adaptation of activation curve of ECaR and of sensitivity to caffeine. However, the inactivation of ECaR of mdx fibers did not adapt to exercise. No fiber phenotype transition occurred in exercised muscle. We provide the first evidence that an in vivo exercise worsens the impaired calcium homeostasis of dystrophic fibers, supporting the role of enhanced calcium entrance in dystrophic progression.
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http://dx.doi.org/10.1016/j.nbd.2004.06.002DOI Listing
November 2004

Taurine and skeletal muscle disorders.

Neurochem Res 2004 Jan;29(1):135-42

Unit of Pharmacology, Department of Pharmacobiology, University of Bari, Italy.

Taurine is abundantly present in skeletal muscle. We give evidence that this amino acid exerts both short-term and long-term actions in the control of ion channel function and calcium homeostasis in striated fibers. Short-term actions can be estimated as the ability of this amino acid to acutely modulate both ion channel gating and the function of the structures involved in calcium handling. Long-term effects can be disclosed in situations of tissue taurine depletion and are likely related to the ability of the intracellular taurine to control transducing pathways as well as homeostatic and osmotic equilibrium in the tissue. The two activities are strictly linked because the intracellular level of taurine modulates the sensitivity of skeletal muscle to the exogenous application of taurine. Myopathies in which ion channels are directly or indirectly involved, as well as inherited or acquired pathologies characterized by metabolic alterations and change in calcium homeostasis, are often correlated with change in muscle taurine concentration and consequently with an enhanced therapeutic activity of this amino acid. We discuss both in vivo and in vitro evidence that taurine, through its ability to control sarcolemmal excitability and muscle contractility, can prove beneficial effects in many muscle dysfunctions.
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http://dx.doi.org/10.1023/b:nere.0000010442.89826.9cDOI Listing
January 2004

Enhanced dystrophic progression in mdx mice by exercise and beneficial effects of taurine and insulin-like growth factor-1.

J Pharmacol Exp Ther 2003 Jan;304(1):453-63

Department of Pharmacobiology, Unit of Pharmacology, University of Bari, Bari, Italy.

A preclinical screening for prompt-to-use drugs that are safer than steroids and beneficial in Duchenne muscular dystrophy was performed. Compounds able to reduce calcium-induced degeneration (taurine or creatine 10% in chow) or to stimulate regeneration [insulin-like growth factor-1 (IGF-1); 50 or 500 microg/kg s.c.] were administered for 4 to 8 weeks to mdx mice undergoing chronic exercise on a treadmill, a protocol to worsen dystrophy progression. alpha-Methyl-prednisolone (PDN; 1 mg/kg) was used as positive control. The effects were evaluated in vivo on forelimb strength and in vitro electrophysiologically on the macroscopic chloride conductance (gCl), an index of degeneration-regeneration events in mdx muscles, and on the mechanical threshold, a calcium-sensitive index of excitation-contraction coupling. The exercise produced a significant weakness and an impairment of gCl, by further decreasing the already low value of degenerating diaphragm (DIA) and fully hampering the increase of gCl typical of regenerating extensor digitorum longus (EDL) mdx muscle. The already negative voltage threshold for contraction of mdx EDL was also slightly worsened. Taurine > creatine > IGF-1 counteracted the exercise-induced weakness. The amelioration of gCl was drug- and muscle-specific: taurine was effective in EDL, but not in DIA muscle; IGF-1 and PDN were fully restorative in both muscles, whereas creatine was ineffective. An acute effect of IGF-1 on gCl was observed in vitro in untreated, but not in IGF-1-treated exercised mdx muscles. Taurine > PDN > IGF-1, but not creatine, significantly ameliorated the negative threshold voltage values of the EDL fibers. The results predict a potential benefit of taurine and IGF-1 for treating human dystrophy.
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http://dx.doi.org/10.1124/jpet.102.041343DOI Listing
January 2003