The immunosuppressive effects of nicotine during human mixed lymphocyte reaction

Cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes and their ligands on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1, B7.1, B7.2 and CD40, production of interferon (IFN)-γ and IL-12 and proliferation of lymphocytes during human mixed lymphocyte reaction. Nicotine is known to inhibit the production of pro-inflammatory cytokines from macrophages through the stimulation of nicotinic acetylcholine receptor α7 subunit. In the present study, we examined the effect of increasing concentrations ranging from 0.1 to 100 μM of nicotine on the expression of ICAM-1, B7.1, B7.2 and CD40, production of IFN-γ and IL-12 and proliferation of lymphocytes during mixed lymphocyte reaction treated with IL-18 at 100 ng/ml for 48 h. Nicotine inhibited the expression of adhesion molecules, cytokine production and lymphocyte proliferation. The IC50 values of nicotine for inhibition of the IL-18-enhanced ICAM-1 expression, IFN-γ production and proliferation were 1, 1 and 2 μM, respectively. A non-selective and a selective antagonist for nicotinic acetylcholine receptor α7 subunit, mecamylamine and α-bungarotoxin abolished the effects of nicotine. The actions of nicotine might depend on stimulation of nicotinic acetylcholine receptor α7 subunit. Nicotine induced prostaglandin E₂ production during mixed lymphocyte reaction. The inhibitors of cyclooxygenase (COX)-2 and protein kinase A (PKA) at 100 μM inhibited the actions of nicotine, suggesting that the endogenous prostaglandin E₂ might be, at least, partially involved the actions of nicotine.     

Chotosan enhances macrophage colony-stimulating factor mRNA expression in the ischemic rat brain and C6Bu-1 glioma cells

Macrophage colony stimulating factor (M-CSF) is a cytokine which has been recently reported to have a neuroprotective effect on ischemic rat brain. In this study, we investigated the effect of chotosan, an oriental medicine, which has been clinically demonstrated to be effective for the treatment of vascular dementia, on M-CSF gene expression in rats with permanent occlusion of bilateral common carotid arteries (P2VO) in vivo and in a C6Bu-1 glioma cell line in vitro. The expression level of M-CSF mRNA in the cerebral cortices of P2VO rats was significantly higher than that in the cerebral cortices of sham-operated animals. Repeated treatment of P2VO rats with chotosan (75 mg/kg per day) for 4 d after P2VO significantly increased the expression level of M-CSF mRNA in the cortex but it had no effect on the expression of beta-actin, granulocyte colony stimulating factor (G-CSF), granulocyte/macrophage colony stimulating factor (GM-CSF) mRNAs. Moreover, the present in vitro studies revealed that chotosan treatment (10-100 mug/ml) of C6Bu-1 glioma cells dose-dependently enhanced M-CSF mRNA expression without affecting the expression of G-CSF, GM-CSF, and inducible nitric oxide synthase mRNAs. The effect of chotosan was reversed by Ro 31-8220 (1 muM), a selective protein kinase C (PKC) inhibitor, but not by H-89 (10 muM), a selective protein kinase A (PKA) inhibitor. These findings suggest that the upregulatory effect of chotosan on M-CSF mRNA expression involves PKC and may play an important role in the anti-vascular dementia action of this formula.     

Rituximab was effective on refractory thrombotic thrombocytopenic purpura but induced a flare of hemophagocytic syndrome in a patient with systemic lupus erythematosus

We report the case of a patient with systemic lupus erythematosus (SLE) who first revealed hemophagocytic syndrome (HPS), which was treated successfully with glucocorticoid and intravenous cyclophosphamide. The patient then demonstrated refractory thrombotic thrombocytopenic purpura (TTP) with normal a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-13 activity that responded well to rituximab. After rituximab treatment, the patient showed a flare of HPS that was controlled by additional intravenous cyclophosphamide treatment. This case showed that TTP with normal ADAMTS-13 activity is B-cell dependent and indicated that B-cell depletion might exacerbate some autoimmune conditions in SLE.     

Association of carotid atherosclerosis with genetic polymorphisms of the klotho gene in patients with hypertension

Aim: Previous studies suggest that klotho gene polymorphisms may be associated with atherosclerosis, but did not assess the relationship between klotho gene polymorphisms and atherosclerosis parameters such as carotid artery intima‐media thickness (IMT). Here, we studied whether klotho single nucleotide polymorphisms (SNP) were associated with carotid atherosclerosis. Methods: All subjects were Japanese. Eight‐hundred and fifty‐three patients with hypertension (465 men and 388 women) in the outpatient clinic and 1783 subjects from the general population (821 men and 962 women) attending health check‐ups were analyzed in the present study. We measured mean IMT of the common carotid artery to evaluate carotid atherosclerosis. Four single nucleotide polymorphisms (SNP) (rs7323281; intron1, rs5644481; exon4, rs3752472; exon3, rs650439; intron4) of klotho were selected as representative SNP in haplotype blocks. Results: Multivariate logistic regression analysis adjusted by confounding factors showed a significant association of rs650439 with carotid atherosclerosis in hypertensive patients (TT vs TA vs AA, P < 0.01; TT + TA vs AA, P < 0.01). By ancova considering confounding factors, rs650439 was also significantly associated with mean IMT (TT + TA vs AA, P = 0.04) in the hypertensive population. However, there was no significant association between klotho SNP and carotid IMT in the general population. Compared to the general population, the subject group with hypertensive patients clearly had more atherosclerosis risk factors. Conclusion: Only in hypertensive patients was klotho rs650439 strongly associated with mean IMT thickening of the common carotid artery. Therefore, klotho SNP (rs650439) may influence on the progression of carotid atherosclerosis in patients with hypertension. Geriatr Gerontol Int 2010 ; 10: 311–318.     

Deficits in auditory P50 inhibition in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is considered to involve abnormalities in inhibitory processes including gating systems. Auditory P50 inhibition, which is assessed by using a paired auditory stimulus paradigm to record P50 mid-latency evoked potential, is assumed to reflect sensory gating. In the present study, we investigated auditory P50 inhibition in subjects with OCD, and examined the relationship between P50 and clinical variables or neuropsychological performance. Twenty-six subjects with OCD and 26 age- and sex-matched healthy controls received P50 recording and neuropsychological tests. In the OCD subjects, we also evaluated clinical features including OC symptoms and subtypes of the disorder. P50 T/C ratios were significantly higher in OCD subjects than in control subjects (t=2.9, df=50, p=0.006). Compared to the controls, the OCD subjects performed significantly worse on the Symbol Digit Modalities Test (SDMT) and the Trail Making Test (TMT). There were no correlations between P50 T/C ratios and clinical variables or the results of neuropsychological tests. Our findings suggest that sensory gating deficits may be involved in the pathophysiology of OCD in a different way from clinical symptoms and executive attention dysfunction.     

Antihyperglycemic effects of ASP8497 in streptozotocin-nicotinamide induced diabetic rats: comparison with other dipeptidyl peptidase-IV inhibitors

(2S,4S)-4-Fluoro-1-({[4-methyl-1-(methylsulfonyl)piperidin-4-yl]amino}acetyl)pyrrolidine-2-carbonitrile monofumarate (ASP8497) is a novel dipeptidyl peptidase (DPP)-IV inhibitor. In this study, we investigated the antidiabetic potency, mechanism, and duration of action of ASP8497 both in vitro and in vivo, and compared it with the DPP-IV inhibitors vildagliptin, sitagliptin, and saxagliptin. ASP8497 inhibited rat plasma DPP-IV activity in vitro with an IC₅₀ value of 2.96 nmol/l, while those for vildagliptin, sitagliptin, and saxagliptin were 2.12,8.98, and 2.00 nmol/l, respectively. In rats that had streptozotocin-nicotinamide-induced, mildly diabetes, oral administration of ASP8497 dose-dependently and sustainably inhibited plasma DPP-IV activity. In addition, ASP8497 dose-dependently and significantly improved glucose tolerance with a concomitant increase in plasma glucagon-like peptide 1 (GLP-1) and insulin levels at both 0.5 h and 8 h after dosing. The order of both potency and duration of action for plasma DPP-IV inhibition and glucose tolerance improvement was as follows: saxagliptin > ASP8497 = vildagliptin = sitagliptin. These results suggest that ASP8497 exerts a potent and long-acting DPP-IV inhibitory effect and improves glucose tolerance through glucose-dependent insulinotropic action via elevation of the GLP-1 level in streptozotocin-nicotinamide-induced mildly diabetic rats. This compound is expected to be useful as a therapeutic agent for impaired glucose tolerance and type 2 diabetes.     

The role of the inherited genetic background on the consequences of lithium-pilocarpine status epilepticus: study in Genetic Absence Epilepsy Rats from Strasbourg and Wistar audiogenic rats

The susceptibility of rats with genetically inherited epilepsy to the genesis and consequences of secondary temporal lobe epilepsy is unknown. Here, we induced lithium-pilocarpine status epilepticus (SE) in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) or in Wistar audiogenic sensitive (AS) rats. Wistar AS needed less pilocarpine than GAERS and Non-Epileptic Rats (NERs) to develop SE. Sixty six, 40 and 5% of Wistar AS, GAERS and NERs, respectively, died within 24 h after SE. In GAERS, SE prevented the occurrence of absence seizures for 5 days. Thereafter a limited number of absence seizures with low amplitude and short duration were recorded. Wistar AS developed limbic epilepsy within 9 days after SE while GAERS and NERs needed 36-39 days to develop spontaneous motor seizures. Neuronal loss consecutive to SE was similar in the three strains and particularly marked in limbic forebrain and parahippocampal cortices. In conclusion, the development of focal limbic epilepsy in GAERS largely impairs the expression of absence seizures. The genetic background underlying the expression of audiogenic seizures sensitizes strongly the rats to a further insult and compromises their survival.     

Effects of polyunsaturated fatty acids on calcium response and degranulation from RBL-2H3 cells

To investigate the biological activity of various polyunsaturated fatty acids (PUFAs) on the allergic reaction, we examined the effects of six PUFAs and two saturated fatty acids on calcium response and degranulation from rat basophilic leukemia (RBL-2H3) cells. Between 20 and 40 microM of six PUFAs (omega-6 series: arachidonic acid [AA, C20:4], gamma-linolenic acid [gamma-LN, C18:3] and linoleic acid [LA, C18:2]; omega-3 series: alpha-linolenic acids [alpha-LN, C18:3] and eicosapentaenoic acid [EPA, C20:5]; and omega-9 series: oleic acid [OLE, C18:1]), or two saturated fatty acids (stearic acid [STA, C18:0] and arachidic acid [AD, C20:0]) were used to examine the effects on calcium response and degranulation from RBL-2H3 cells. Calcium response was monitored using the fluorescent calcium indicator fura-2, while degranulation was monitored by measuring histamine release from the cells. Three omega-6 PUFAs (AA, alpha-LN and LA) dose-dependently increased the cytosolic free-calcium concentration and histamine release from RBL-2H3 cells. This phenomenon was specific to the omega-6 PUFAs, the omega-3 PUFAs (alpha-LA and EPA), omega-9 PUFA (OLE) and the saturated fatty acids (STA and AD) had no effect. The increase in the cytosolic free-calcium concentration caused by the omega-6 PUFAs depended on the existence of external calcium, cell viability and the cellular IP(3) levels remained unchanged throughout the experiment. These results suggest that omega-6 PUFAs work as direct mediators of calcium signaling pathways in RBL-2H3 cells.     

Autoimmune pancreatitis with extreme elevation of DUPAN-2

An 80-year-old woman was admitted to our hospital with complaints of jaundice and liver dysfunction. She was found to have a high titer of serum IgG4, positive rheumatoid factor and marked elevation of DUPAN-2 (11,148 U/ml). Computed tomography showed swelling of the pancreas, and endoscopic retrograde cholangiopancreatography revealed diffuse irregular narrowing of the main pancreatic duct, which are typical findings of autoimmune pancreatitis. There was no evidence of malignancy. Administration of 30 mg/day of prednisolone was started. Computed tomography showed significant regression in the size of the pancreas, and the stenosis of the main pancreatic duct was improved on ERCP. The serum level of DUPAN-2 was also markedly decreased after the treatment.