Protective effects of the melanocortin analog NDP-α-MSH in rats undergoing cardiac arrest

We previously reported that melanocortins afford cardioprotection in conditions of experimental myocardial ischemia/reperfusion, with involvement of the janus kinases (JAK), extracellular signal-regulated kinases (ERK) and signal transducers and activators of transcription (STAT) signalings. We investigated the influence of the melanocortin analog [Nle(4), D-Phe(7)]α-melanocyte-stimulating hormone (NDP-α-MSH) on short-term detrimental responses to cardiac arrest (CA) induced in rats by intravenous (i.v.) administration of potassium chloride, followed by cardiopulmonary resuscitation (CPR) plus epinephrine treatment. In CA/CPR rats i.v. treated with epinephrine (0.1mg/kg) and returned to spontaneous circulation (48%) we recorded low values of mean arterial pressure (MAP) and heart rate (HR), alteration of hemogasanalysis parameters, left ventricle low expression of the cardioprotective transcription factors pJAK2 and pTyr-STAT3 (JAK-dependent), increased oxidative stress, up-regulation of the inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and down-regulation of the anti-inflammatory cytokine IL-10, as assessed at 1h and 3h after CPR. On the other hand, i.v. treatment during CPR with epinephrine plus NDP-α-MSH (340μg/kg) almost completely restored the basal conditions of MAP and HR, reversed metabolic acidosis, induced left ventricle up-regulation of pJAK2, pTyr-STAT3 and IL-10, attenuated oxidative stress, down-regulated TNF-α and IL-6 levels, and improved survival rate by 81%. CA/CPR plus epinephrine alone or in combination with NDP-α-MSH did not affect left ventricle pSer-STAT3 (ERK1/2-dependent) and pERK1/2 levels. These results indicate that melanocortins improve return to spontaneous circulation, reverse metabolic acidosis, and inhibit heart oxidative stress and inflammatory cascade triggered by CA/CPR, likely via activation of the JAK/STAT signaling pathway

Mechanisms of Hydrogen Sulfide against the Progression of Severe Alzheimer’s Disease in Transgenic Mice at Different Ages

Abstract Backgroud: Alzheimer disease is an age-related severe neurodegenerative pathology. The level of the third endogenous gas, hydrogen sulfide (H2S), is decreased in the brain of Alzheimer’s disease (AD) patients compared with the brain of the age-matched normal individuals; also, plasma H2S levels are negatively correlated with the severity of AD. Recently, we have demonstrated that systemic H2S injections are neuroprotective in an early phase of preclinical AD. Objectives: This study focuses on the possible neuroprotection of a chronic treatment with an H2S donor and sulfurous water (rich of H2S) in a severe transgenic 3×Tg-AD mice model. Method: 3×Tg-AD mice at 2 different ages (6 and 12 months) were daily treated intraperitoneally with an H2S donor and sulfurous water (rich of H2S) for 3 months consecutively. We investigated the cognitive ability, brain morphological alterations, amyloid/tau cascade, excitotoxic, inflammatory and apoptotic responses. Results: Three months of treatments with H2S significantly protected against impairment in learning and memory in a severe 3×Tg-AD mice model, at both ages studied, and reduced the size of Amyloid β plaques with preservation of the morphological picture. This neuroprotection appeared mainly in the cortex and hippocampus, associated with reduction in activity of c-jun N-terminal kinases, extracellular signal-regulated kinases and p38, which have an established role not only in the phosphorylation of tau protein but also in the inflammatory and excitotoxic response. Conclusion: Our findings indicate that appropriate treatments with various sources of H2S, might represent an innovative approach to counteract early and severe AD progression in humans

Effetto della terapia con analoghi della somatostatina o con un antagonista del recettore del GH sul metabolismo glucidico nei pazienti con acromegalia: risultati di uno studio prospettico.

L’acromegalia è una rara sindrome, la cui incidenza complessiva è di 3,3 casi/milione/anno, sostenuta nella maggior parte dei pazienti da un adenoma ipofisario GH secernente [1-3]. L’acromegalia è gravata da un significativo aumento della mortalità dovuto alla maggiore prevalenza di complicanze cardio e cerebrovascolari, respiratorie, neoplastiche e metaboliche [8]. Tra le complicanze metaboliche, quelle a carico del metabolismo glucidico, presenti nel 30-40% dei pazienti acromegalici, rivestono un ruolo particolarmente importante perché possono contribuire ad aumentare il rischio vascolare di questi pazienti. L’acromegalia è caratterizzata da un eccesso di GH che ha un azione contro insulare, ma anche da un eccesso di IGF1,che ha un azione insulino simile. Le complicanze sistemiche dell’acromegalia possono regredire o migliorare in seguito alla cura dell’acromegalia mediante intervento neurochirurgico di adenomectomia. Tuttavia, la terapia chirurgica risulta efficace nel 50% dei pazienti, per cui i pazienti con persistenza di malattia devono essere sottoposti a trattamenti aggiuntivi tra cui terapia medica che comprende gli analoghi della somatostatina (SMSa) e antagonisti del recettore del GH: pegvisomant (PEG). Gli analoghi della somatostatina riducono la secrezione di GH dell’adenoma ipofisario ma anche la secrezione d’insulina pancreatica andando quindi a modificare il metabolismo glucidico. I pochi dati disponibili in letteratura suggeriscono che il pegvisomant potrebbe migliorare la sensibilità insulinica [41,48,64,65]. Una recente meta-analisi ha rivelato che gli effetti della somatostatina sul metabolismo glucidico sono limitati; tuttavia i risultati sono estremamente variabili quando vengono paragonati i singoli studi. Non è quindi completamente determinato l’effetto delle terapie mediche dell’acromegalia sul metabolismo glucidico. DISEGNO E SCOPO DELLO STUDIO Il nostro studio si è proposto di analizzare in una coorte di 62 pazienti acromegalici l’effetto di SMSa, SMSa associata a PEG (SMSa+PEG) o PEG sul metabolismo glucidico. Si tratta di uno studio storico prospettico dove abbiamo valutato il metabolismo del glucosio al momento della diagnosi di acromegalia e durante il follow up. Inizialmente il metabolismo glucidico è stato valutato al momento della diagnosi e durante terapia con i soli SMSa. Nel gruppo di pazienti con acromegalia non controllata con i soli SMSa è stato aggiunto PEG e dopo controllo dell’attività di malattia sono stati sospesi gli SMSa ed è stato continuato il solo PEG. Il metabolismo glucidico è stato quindi valutato sia durante la terapia combinata SMS+PEG che durante il solo PEG. I parametri utilizzati sono stati: glicemia e insulinemia, sia a digiuno che dopo prova da carico orale di glucosio, la sensibilità dell’insulina (QUICK-I) e la resistenza dell’insulina (HOMA2-IR). RISULTATI Parametri a digiuno La terapia con SMSa si associava ad un aumento della glicemia plasmatica a digiuno rispetto al basale (Δbasale-SMSa: -10.84 ± 1.47, P<0.001),soprattutto nel sottogruppo di pazienti con acromegalia non controllata, suggerendo un ruolo del controllo di malattia sui livelli di glicemia plasmatica a digiuno (Δbasale- SMSaCONTR vs Δbasale- SMSa NON-CONTRP 0.0127). La terapia combinata con SMSa+PEG si associava ad una riduzione della glicemia plasmatica a digiuno rispetto ai SMSa (comparando con SMSa NON-CONTR) che si riduce ulteriormente quando veniva sospesa la terapia con SMSa). In accordo con i dati della glicemia plasmatica a digiuno, il trattamento con SMSa si associava ad un limitato, ma significativo, aumento dei livelli di HbA1c rispetto al basale sia in monoterapia sia nel trattamento in combinata; dove abbiamo osservato un piccolo ma significativo aumento dei livelli di HbA1c dopo l’interruzione degli SMSa (ΔSMSa-PEG-PEG=0.37±0.07 P=0.0004). Come atteso, il valore medio dell’insulina era superiore nella valutazione basale; la terapia con SMSa ha ridotto i livelli d’insulina, soprattutto nei pazienti con raggiungimento del controllo di malattia (tabella 3.4). L’aggiunta del pegvisomant agli SMSa nei soggetti con malattia é stata associata ad un ulteriore riduzione dei livelli di insulina a digiuno (P=0.0253) senza differenze rispetto ai pazienti controllati con SMSa, così come quelli che hanno continuato la terapia con solo pegvisomant. HOMA2-IR era >2,5 in 9 pazienti al basale, indicando una condizione di insulinoresistenza. Il trattamento con SMSa e PEG si associava ad una riduzione dell’HOMA2-IR indipendentemente dal controllo di malattia. QUICK-Index è un parametro che valuta la sensibilità all’insulina e nel nostro studio è risultato ridotto nell’acromegalia attiva. Il controllo di malattia con SMSa, SMSa-PEG e PEG si è associato ad un piccolo ma significativo aumento delQUICK-Index. OGTT La somministrazione con SMSa si associava ad un netto aumento nei livelli di glucosio sia al basale durante OGTT sia al 120’ (Δbasale- SMSa= -42.93 e durante la totalità dei momenti temporali esaminati (AUCGLU).Senza differenze in relazione al controllo di malattia. L’aggiunta del PEG ai soggetti non controllati con gli SMSa si associava ad un miglioramento nei parametri del glucosio che, di fatto, ha raggiunto una significatività statistica quanto gli SMSa sono stati interrotti ed è stato continuato il solo PEG P=0.0021). Prevalenza di alterazioni del glucosio durante i diversi trattamenti La prevalenza di alterazioni del metabolismo glucidico varia durante i diversi trattamenti. Il trattamento con SMSa si associava ad una prevalenza di alterazioni più alta rispetto al gruppo basale e al gruppo PEG. Analizzando in particolare solo i diciotto pazienti valutati sia in trattamento combinato SMSa+PEG che con solo PEG e andando a comparare i due gruppi, si è notata una minore frequenza di normale tolleranza al glucosio (NGT) nel gruppo SMSa+PEG rispetto al gruppo con solo PEG (7 vs 11). Inoltre nello stesso gruppo l’alterata tolleranza al glucosio (IFG) risultava lievemente superiore rispetto al gruppo con solo PEG (1 vs 0) cosi come per il diabete mellito (DM)( 2 vs 0) mentre per quanto riguarda l’alterata glicemia a digiuno (IGT) il rapporto tra i gruppi non mostrava differenze (7 vs: 7). . CONCLUSIONI La terapia medica dell’acromegalia sia con SMSa che con PEG determina un miglioramento della sensibilità all’insulina, probabilmente per la riduzione nei livelli di GH (azione del SMSa) o della sua azione (azione del PEG) e quindi per una minore azione contro insulare. Tuttavia la terapia con SMSa determina un aumento della glicemia e dell’emoglobina glicata che non si verifica con il PEG. Queste variazioni non sono legate alla differente efficacia dei due farmaci nel controllare l’attività dell’acromegalia perché si riscontrano nei pazienti con normali valori di IGF1 suggerendo che l’effetto sia legato alle diverse proprietà delle molecole. La diversa scelta terapeutica ha un impatto anche sulla prevalenza delle alterazioni cliniche del metabolismo glucidico che sono risultate più frequenti nei pazienti in terapia con SMSa. In conclusione, la scelta nella terapia medica dell’acromegalia deve tenere in considerazione anche gli effetti che i farmaci impiegati hanno sul metabolismo glucidico.

NDP-\u3b1-MSH induces intense neurogenesis and cognitive recovery in Alzheimer transgenic mice through activation of melanocortin MC4 receptors

Melanocortins exert neuroprotection in a variety of experimental neurodegenerative disorders, including Alzheimer's disease (AD). Further, in previous research we showed that these endogenous peptides stimulate neurogenesis in an acute neurodegenerative disorder such as ischemic stroke. In the present research, we investigated the potential neurogenic effect of melanocortins in AD using APPSwe transgenic mice (Tg2576). To this purpose, 24week-old animals were prepared for 5-bromo-2'-deoxyuridine (BrdU) labeling of proliferating cells on days 1-11 of the study. Treatment of Tg2576 mice with nanomolar doses of the melanocortin analog [Nle(4),D-Phe(7)]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH), administered once daily from day 1 to 50, improved brain histology and cognitive functions relative to saline-treated Tg2576 animals. No signs of toxicity were observed. Immunohistochemical examination of the hippocampus at the end of the study (day 50) showed that NDP-\u3b1-MSH-treated Tg2576 mice had a greater number of BrdU immunoreactive cells colocalized with NeuN (an indicator of mature neurons) and Zif268 (an indicator of functionally integrated neurons) in the dentate gyrus, relative to saline-treated Tg2576 animals; no newly formed astrocytes were found. Animal pretreatment with selective melanocortin MC4 receptor antagonist HS024 before each NDP-\u3b1-MSH administration prevented all the beneficial effects of the peptide. The present data indicate that MC4 receptor stimulation by a melanocortin prevents cognitive decline in experimental AD, this effect being associated not only with neuroprotection but also with an intense neurogenesis. MC4 receptor agonists could be innovative and safe candidates to counteract AD progression in humans

Melanocortins promote neurogenesis and counteract cognitive decline in a transgenic mouse model of moderate Alzheimer\u2019s disease

Alzheimer's disease (AD), both sporadic and genetic, is a chronic disorder characterized by activation of the amyloid/tau cascade in the hippocampus and isocortex. Besides neuroprotective approaches, also neurorestorative strategies for AD are under intensive investigations. [1] The melanocortin system consists of endogenous neuropeptides of the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) family, acting via five different metabotropic melanocortin receptor subtypes (MC1-MC5). Melanocortins also induce neuroprotection associated with long-lasting functional recovery and counteraction of cognitive decline, as found in acute experimental neurodegenerative conditions and more recently in a chronic neurodegenerative disease as AD. [2] Further, these endogenous peptides have been by us reported to stimulate neurogenesis in an acute neurodegenerative disorder as ischemic stroke. [3] Here we investigated the possible neuroprotective and neurogenic effect of melanocortins in AD with a medium level of severity by using 24 week-old (at the start of the study) APPSwe transgenic mice (Tg2576). METHODS: Tg2576 mice were treated (once daily on days 1-50) with a nanomolar dose of the melanocortin analog [Nle4,D-Phe7]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH). Animals were prepared for 5-bromo-2\u2019-deoxyuridine (BrdU) labeling of proliferating cells at days 1-11 of the study, and histological and immunohistochemical studies of the brain were performed for the assessment of neurogenesis. Further, the mouse ability to learn and recall was evaluated by means of the Morris water-maze test at the twenty-seventh week (starting 14 days after the first BrdU injection) and thirty-first week of age. Within 90 min the end of the last behavioural test (day 50 of the study; 31 week-old mice) animals were killed and the brains were removed and processed for histological examination. The whole hippocampi were dissected from brains of some animals to perform western blot analysis of the Zif268 protein (Zif268 protein is transiently expressed after synaptic activation). All values were analyzed by means of two-way repeated measures ANOVA (behavioral data) or one-way ANOVA (all other data), both followed by the Student-Newman-Keuls\u2019 test. A value of p < 0.05 was considered significant. RESULTS: Treatment of Tg2576 mice with the melanocortin analog [Nle4,D-Phe7]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH) reduced cerebral cortex/hippocampus level of A\u3b2 deposit (p < 0.001), increased hippocampus Zif268 expression (p <0.001), improved brain histological picture and cognitive functions (p <0.001), relative to saline-treated Tg2576 animals, and no signs of toxicity were recorded. Further, immunohistochemical examination of the hippocampus on day 50 (end of the study) showed, in the dentate gyrus of NDP-\u3b1-MSH-treated Tg2576 mice, a very elevated number of BrdU immunoreactive cells colocalized with NeuN (indicator of mature neurons) and Zif268 (indicator of functionally integrated neurons), in comparison with saline-treated Tg2576 animals (p <0.001); no newly formed astrocytes were found. Animal pretreatment (before each administration of NDP-\u3b1-MSH) with the selective melanocortin MC4 receptor antagonist HS024 prevented all favourable effects of NDP-\u3b1-MSH (p <0.001). CONCLUSIONS: Our data suggest that MC4 receptor-stimulating melanocortins are able to counteract cognitive decline in experimental AD not only by affording neuroprotection, but also by inducing intense neurogenesis. These agents could be candidates for an innovative and safe strategy to counteract AD progression in humans

Modulation of the JAK/ERK/STAT signaling in melanocortin-induced inhibition of local and systemic responses to myocardial ischemia/reperfusion

The janus kinases (JAK), extracellular signal-regulated kinases (ERK) and signal transducers and activators of transcription (STAT) pathways have been shown to play a cardioprotective role. We previously gave evidence that melanocortins afford cardioprotection in conditions of myocardial ischemia/reperfusion. Here we aimed to investigate the influence of melanocortins on the JAK/ERK/STAT signaling in cardiac and systemic responses to prolonged myocardial ischemia/reperfusion. Ischemia was produced in rats by ligature of the left anterior descending coronary artery for 30 min. At the end of the 2-h reperfusion, western blot analysis of the cardioprotective transcription factors pJAK2, pERK1/2, pTyr-STAT3 and pSer-STAT3, the inflammatory mediator tumor necrosis factor-\u3b1 (TNF-\u3b1), the pro-apoptotic factors BAX and c-jun N-terminal kinases (pJNK), the anti-apoptotic protein Bcl-XL, as well as of the cardioprotective enzyme heme oxygenase-1 (HO-1), was performed in the left ventricle and spleen. Intravenous treatment, during coronary artery occlusion, with the melanocortin analogs [Nle4, D-Phe7]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH) and adrenocorticotropic hormone 1-24 [ACTH-(1-24)], induced a left ventricle up-regulation of pJAK2, pERK1/2 and pTyr-STAT3 (JAK-dependent), and a reduction in pJNK and TNF-\u3b1 levels; these effects of NDP-\u3b1-MSH and ACTH-(1-24) were associated with over-expression of the pro-survival proteins HO-1 and Bcl-XL, and marked decrease of the myocardial infarct size. Melanocortin treatment did not affect left ventricle pSer-STAT3 (ERK1/2-dependent) and BAX levels. In the spleen, NDP-\u3b1-MSH and ACTH-(1-24) induced similar effects on the expression of the above transcription factors/proteins, except for pERK1/2 (down-regulated) and HO-1 (unaffected). Blockade of JAK and ERK pathways with AG490 and U0126, respectively, abrogated the myocardial infarct size reduction by NDP-\u3b1-MSH. These results indicate that melanocortins inhibit local and systemic inflammatory and apoptotic cascades triggered by prolonged myocardial ischemia/reperfusion, with consequent reduction in myocardium infarct size, seemingly via activation of the JAK/STAT signaling and with modulation of an ERK (STAT unrelated) signaling pathway

NDP-α-MSH attenuates heart and liver responses to myocardial reperfusion via the vagus nerve and JAK/ERK/STAT signaling

Melanocortin peptides afford cardioprotection during myocardial ischemia/reperfusion via janus kinases (JAK), extracellular signal-regulated kinases (ERK) and signal transducers/activators of transcription (STAT) pathways. Here we investigated whether melanocortin-induced modulation of the JAK/ERK/STAT signaling occurs via the cholinergic anti-inflammatory pathway, focusing our study on cardiac and hepatic responses to prolonged myocardial ischemia/reperfusion. Ischemia was produced in rats by ligature of the left anterior descending coronary artery for 30min; effects of ischemia/reperfusion were evaluated using Western blot of heart and liver proteins. Intravenous treatment, during coronary artery occlusion, with the melanocortin analog (Nle(4), D-Phe(7))α-melanocyte-stimulating hormone (NDP-α-MSH) induced a left ventricle up-regulation of the cardioprotective transcription factors pJAK2, pERK1/2 and pTyr-STAT3 (JAK-dependent), and a reduction in the levels of the inflammatory mediators tumor necrosis factor-α (TNF-α) and pJNK (a transcription factor also involved in apoptosis), as assessed at the end of the 2-h reperfusion period. Further, these beneficial effects of NDP-α-MSH were associated with heart over-expression of the pro-survival proteins heme oxygenase-1 (HO-1) and Bcl-XL, and decrease of ventricular arrhythmias and infarct size. In the liver NDP-α-MSH induced a decrease in the pJAK2 and pTyr-STAT3 levels, and strongly reduced pERK1/2 expression. In the liver of ischemic rats NDP-α-MSH also blunted pJNK activity and TNF-α expression, and up-regulated Bcl-XL. Bilateral cervical vagotomy prevented all effects of NDP-α-MSH, both in the heart and liver. These results indicate that melanocortins inhibit heart and liver damage triggered by prolonged myocardial ischemia/reperfusion likely, as main mechanism, via the vagus nerve-mediated modulation of the JAK/STAT/ERK signaling pathways