Annarita Toscano

Neuroprotective effects of acetyl-L-carnitine on neuropathic pain and apoptosis: A role for the nicotinic receptor

Several pathologies related to nervous tissue alterations are characterized by a chronic pain syndrome defined by persistent or paroxysmal pain independent or dependent on a stimulus. Pathophysiological mechanisms related to neuropathic disease are associated with mitochondrial dysfunctions that lead to an activation of the apoptotic cascade. In a model of peripheral neuropathy obtained by the loose ligation of the rat sciatic nerve, acetyl‐L‐Carnitine (ALCAR; 100 mg/kg intraperitoneally [i.p.] twice daily for 14 days) was able to reduce hyperalgesia and apoptosis. In the present study, different mechanisms for the analgesic and the antineuropathic effect of ALCAR are described. The muscarinic blocker atropine (5 mg/kg i.p.) injected simultaneously with ALCAR did not antagonize the ALCAR antihyperalgesic effect on the paw‐pressure test but significantly reduced the analgesic effect of ALCAR. Conversely, the antineuropathic effect of ALCAR was prevented by cotreatment with the nicotinic antagonist mecamylamine (2 mg/kg i.p. twice daily for 14 days). A pharmacological silencing of the nicotinic receptors significantly reduced the X‐linked inhibitor of apoptosis protein–related protective effect of ALCAR on the apoptosis induced by ligation of the sciatic nerve. Taken together, these data highlight the relevance of nicotinic modulation in neuropathy treatment.

The -670G>A polymorphism in the FAS gene promoter region influences the susceptibility to systemic sclerosis

Objective: To evaluate the role of the single-nucleotide polymorphism (SNP) at position −670 in the FAS gene promoter (FAS−670G>A) in influencing the susceptibility, clinical features and severity of systemic sclerosis (SSc). Methods: 350 white Italian SSc patients (259 with limited cutaneous SSc (lcSSc) and 91 with diffuse cutaneous SSc (dcSSc)) and 232 healthy individuals were studied. Patients were assessed for the presence of autoantibodies (anticentromere, anti-topoisomerase I (anti-Scl-70) antibodies), interstitial lung disease (ILD), pulmonary arterial hypertension and scleroderma renal crisis. FAS−670G>A SNP was genotyped by PCR restriction fragment length polymorphism assay. Serum levels of soluble FAS (sFAS) were analysed by ELISA. Results: A significant difference in FAS−670 genotype distribution was observed between SSc patients and healthy individuals (p = 0.001). The frequency of the FAS−670A allele was significantly greater in SSc than in controls (p = 0.001). No significant difference in genotype distribution and allele frequencies was observed between lcSSc and dcSSc, although a greater frequency of the FAS−670A allele was found in dcSSc. The FAS−670AA genotype significantly influenced the predisposition to SSc (OR 1.97, 95% CI 1.35 to 2.88, p = 0.001) and to both lcSSc (OR 1.84, 95% CI 1.23 to 2.75, p = 0.003) and dcSSc (OR 2.37, 95% CI 1.41 to 3.99, p = 0.001). FAS−670A allele frequency was greater, although not significantly, in anti-Scl-70 antibody-positive dcSSc and ILD dcSSc. sFAS was significantly higher in patients and controls carrying the FAS−670AA genotype compared with those carrying the FAS−670GG genotype (p = 0.003 in SSc, p = 0.004 in controls). Conclusion: The FAS−670A allele is significantly associated with susceptibility to SSc, suggesting a role for a genetic control of apoptosis in the pathogenesis of the disease.

The neuropathy-protective agent acetyl-l-carnitine activates protein kinase C-γ and MAPKs in a rat model of neuropathic pain

The gamma isoform of protein kinase C (PKCgamma) is an injury-activated intracellular modulator that boosts neuronal activity in algesic and neuroregenerative signalling pathways. Acetyl-L-carnitine (ALCAR), a physiological compound with role in bioenergetic functions, shows an antihyperalgesic effect and at the same time can exert neuroregenerative and neuroprotective effects. Aimed to explore the link between pain and neuroregeneration, the effect of ALCAR treatment (100 mg kg(-1) i.p. twice daily for 15 days) on PKCgamma and mitogen-activated protein kinases (MAPKs) expression has been evaluated in CCI (chronic constriction injury) rats. The sciatic nerve and the lumbar tract of the spinal cord were processed to evaluate the levels of the phosphorylated form of PKCgamma, ERK 1,2, SAP/JNK, p-38 and c-Jun; furthermore, the mRNA expression of the early genes c-Jun and c-Fos has been investigated. Fifteen days after injury, the analysis in the sciatic nerves highlighted a bilateral increase of the activated forms of PKCgamma, ERK 1,2 and SAP/JNK, whereas c-Jun showed an increase only ipsilaterally. ALCAR completely prevented mechanical hyperalgesia and provoked in the nerve a c-Jun increment only. In the lumbar tract of the spinal cord, higher levels of activated PKCgamma, ERK 1,2, p38, SAP/JNK and c-Jun proteins were detected in the ipsilateral side in respect of sham. ALCAR was able to stimulate this expression profile. At the transcriptional level c-Jun mRNA was increased in the ipsilateral side of spinal cord of CCI saline-treated rats, whereas c-Fos mRNA was unchanged. ALCAR had a stimulatory effect on both these early genes. These findings may represent a different approach in the study of the complex balance between pain and neuroregeneration and could constitute the basis for developing new disease modifying agents in the treatment of neuropathic pain.

Expression of vascular endothelial growth factor receptor types 1, 2 and 3 in placenta from pregnancies complicated by hypertensive disorders

The aim of the present study was to determine the expression of vascular endothelial growth factor (VEGF) family receptors (VEGFR) in placentas from pregnancies complicated by hypertensive disorders of different clinical severity. Placental tissue from women with gestational hypertension, pre-eclampsia, pre-eclampsia with haemolysis, elevated liver enzymes and low platelets (HELLP syndrome) and normotensive women, as a control group, was examined. Immunohistochemical techniques, reverse transcription-polymerase chain reaction and western blot were used to evaluate receptor expression. In cases with gestational hypertension, as well as in control cases, VEGFR-1 and VEGFR-3 immunoreactivity was detected in all placental components, whereas in placentas from the pre-eclampsia and pre-eclampsia with HELLP syndrome groups, VEGFR-1 and VEGFR-3 immunoreactivity was detected only in some portions of trophoblast and/or some vessels and/or clusters of stromal cells. In the control group, VEGFR-2 immunoreactivity was observed only in the vessels, whereas the hypertensive groups showed VEGF-2 immunoreactivity also in trophoblast and stromal cells. The mRNA levels of the three receptors in the group with gestational hypertension were higher with respect to those in the control group. Placentas from pregnancies with pre-eclampsia showed lowest mRNA expression levels, whereas placentas from women with pre-eclampsia plus HELLP syndrome showed higher mRNA expression levels with respect to the three other groups. Receptor protein levels were lower in pathological cases compared with levels in the control group. These findings demonstrate a dysregulation of placental expression of VEGF family receptors related to the degree of clinical severity of the hypertensive disorder.

Effect of impaired glucose tolerance during pregnancy on the expression of VEGF receptors in human placenta

The aim of the present study was to determine the expression of vascular endothelial growth factor (VEGF) receptors VEGFR-1, VEGFR-2 and VEGFR-3 in placentas from pregnancies complicated by altered glycaemia. Placentas from women with physiological pregnancies (Group 1), pregnancies complicated by minor degree of glucose intolerance (MDGI, Group 2) and by gestational diabetes mellitus (GDM) treated with insulin (Group 3) were collected. Immunohistochemistry, RT-PCR and western blot were employed to evaluate receptor expression. In the three study groups, VEGFR-1 immunoreactivity was detected in all the placental components. VEGFR-2 immunoreactivity was observed in the vessels of all the placentas from Groups 1 and 2, but only in some placentas of Group 3. VEGFR-3 reactivity was observed in all the components of Group 1; in Groups 2 and 3 reactivity was observed in some portions of the trophoblast or the whole trophoblast, and in the stroma. VEGFR-1 and VEGFR-2 mRNA levels in Groups 2 and 3 were significantly higher compared with Group 1, whereas those of VEGFR-3 were significantly lower. Receptor protein levels were significantly lower in Groups 2 and 3 compared with Group 1. These findings demonstrated dysregulation of expression of the three placental receptors, both in GDM and in MDGI.

Tacrolimus causes reduced GLI1 expression and phenotypic changes in the TE 354.T basal cell carcinoma cell line

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