Lafutidine, a histamine H2 receptor antagonist with mucosal protective properties, attenuates 5-fluorouracil-induced intestinal mucositis in mice through activation of extrinsic primary afferent neurons

Intestinal mucositis accompanied by severe diarrhea is one of the most common side effects during cancer chemotherapy. Lafutidine, a histamine H2 receptor antagonist with mucosal protective properties via sensory afferent neurons, is used for the treatment of upper gastrointestinal diseases. The present study investigated the effects of lafutidine on 5-fluorouracil (5-FU)-induced intestinal mucositis induced in mice. Male C57BL/6 wild-type (WT), sensory deafferented mice, and transient receptor potential vanilloid subfamily 1 knockout (TRPV1KO) mice were used. Animals were administered 5-FU once daily, while lafutidine and famotidine were administered twice daily for 6 days. Repeated administration of 5-FU caused severe intestinal mucositis, characterized by shortening of villi and destruction of crypts and was accompanied by diarrhea and body weight loss. Daily administration of lafutidine reduced the severity of intestinal mucositis, diarrhea and body weight loss in a dose-dependent manner, while famotidine had no effect on intestinal mucositis. The preventive effects of lafutidine were completely abolished in sensory deafferented and TRPV1-KO mice. Lafutidine significantly suppressed 5-FU-increased MPO activity and inflammatory cytokine expression on day 6, but not apoptosis induction in intestinal crypts on day 1. Lafutidine induced Alcian Blue and PAS-positive mucus production in the small intestine. These findings suggest that lafutidine attenuates 5-FU-induced intestinal mucositis, most likely by increasing mucus production via activation of sensory afferent neurons. Furthermore, intact TRPV1 signaling is essential for the activation of sensory afferent neurons induced by lafutidine. Therefore, lafutidine is more useful than other common antacids for the treatment of intestinal mucositis during cancer chemotherapy.

Suppression of infliximab antibody levels by azathioprine in patients with rheumatoid arthritis

In rheumatoid arthritis (RA) treatment, the concomitant use of methotrexate has been shown to reduce the incidence of antibodies to infliximab (ATI), on the other hand, it is unclear whether azathioprine can reduce ATI production. We enrolled a total of 10 Japanese adult patients with RA who were treated with infliximab concomitantly with methotrexate or azathioprine. Serum concentrations of infliximab and ATI of these patients were measured. The mean serum infliximab concentrations was 1.6±1.3 μg/ml in patients with methotrexate and 1.0±0.5 μg/ml in patients with azathioprine. Serum ATI concentrations were below the limit of quantitation in 4 of 5 patients in each group. The results from the present study suggest that azathioprine suppresses ATI production.

Proteinuria selectivity index as a prognostic biomarker in lupus nephritis

Objectives The selectivity index has been proposed in predicting the response to immunosuppressive therapy in nephrotic syndrome and other primary kidney disorders. The aim of this study was to elucidate the predictive value of the selectivity index for the treatment response and renal outcome in patients with lupus nephritis. Methods Forty-four patients with lupus nephritis with selectivity index available at the time of renal biopsy were divided into two groups according to the cut-off value of the selectivity index determined by a receiver operating characteristics curve to differentiate treatment responders from non-responders. The baseline characteristics, overall response rate and renal functional outcome were studied retrospectively, and compared between the two groups. Prognostic factors for achieving remission were identified. Results The cut-off value of the selectivity index was 0.167. The low selectivity index (<0.167) and the high selectivity index (≥0.167) group included 24 and 20 patients, respectively. The overall response rate was significantly higher (88% vs. 50%, P = 0.007) and the rate of progression to end-stage renal disease was lower in the low selectivity index group (0% vs. 15%, P = 0.049). More patients in the high selectivity index group had chronic lesions on renal biopsy ( P = 0.002). The selectivity index was the prognostic factor for achieving overall response based on a multivariate analysis ( P = 0.020). Conclusions A selectivity index ≥0.167 was a strong predictor for a poor treatment response and the presence of chronic lesions on renal biopsy. Further exploration with a larger cohort and longer follow-up period is warranted.

Locus coeruleus and dopaminergic consolidation of everyday memory

The retention of episodic-like memory is enhanced, in humans and animals, when something novel happens shortly before or after encoding. Using an everyday memory task in mice, we sought the neurons mediating this dopamine-dependent novelty effect, previously thought to originate exclusively from the tyrosine-hydroxylase-expressing (TH+) neurons in the ventral tegmental area. Here we report that neuronal firing in the locus coeruleus is especially sensitive to environmental novelty, locus coeruleus TH+ neurons project more profusely than ventral tegmental area TH+ neurons to the hippocampus, optogenetic activation of locus coeruleus TH+ neurons mimics the novelty effect, and this novelty-associated memory enhancement is unaffected by ventral tegmental area inactivation. Surprisingly, two effects of locus coeruleus TH+ photoactivation are sensitive to hippocampal D1/D5 receptor blockade and resistant to adrenoceptor blockade: memory enhancement and long-lasting potentiation of synaptic transmission in CA1 ex vivo. Thus, locus coeruleus TH+ neurons can mediate post-encoding memory enhancement in a manner consistent with possible co-release of dopamine in the hippocampus.

The Relationship between Psychotropic Drug Use and Suicidal Behavior in Japan: Japanese Adverse Drug Event Report

Introduction: Very few studies have explored the adverse effect of psychotropic drugs worldwide. Methods: This study analyzed 1 813 suicide-related drug reports involving 553 patients collected from the Japanese National Adverse Drug Report Database between October 2001 and January 2012 to investigate psychotropic drugs associated with completed suicide vs. other suicide-related behaviors, including ideation and self-injury. The drugs investigated included antidepressants, antipsychotics, benzodiazepines, non-benzodiazepine hypnotic agents, noradrenergic and specific serotonergic antidepressants, selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, and other drugs. Results: These reports referenced 300 (54.2%) individuals who completed suicide. Adjusting for age, sex, and drugs used, the multivariate model revealed that participants who took antipsychotics were 1.70 times (95% CI, 1.11-2.61) more likely to complete suicide compared with those who did not. All other drugs became non-significant. Compared with those who took only one medication, those prescribed more than 4 drugs were more likely to complete suicide (OR 4.44, 95% CI, 2.40-8.20). Discussion: Antipsychotic drugs and polypharmacy may be regarded as predictors of completed suicide.

Successful treatment of cold agglutinin disease with anti-CD20 antibody (rituximab) in a patient with systemic lupus erythematosus

Cold agglutinin disease (CAD) is a rare cause of anaemia in patients with systemic lupus erythematosus (SLE). CAD is usually refractory to glucocorticosteroid, and other immunosuppressive and/or cytotoxic therapies. We report the case of a 55-years old woman with SLE and CAD that did not respond to high-dose methylprednisolone, cyclosporin A, and double filtration plasma pheresis. Because several recent case reports and studies have indicated promising results of rituximab treatment for CAD and for SLE, rituximab was given weekly at 375 mg/m2in two doses. The rituximab was well tolerated, and there were no adverse effects. The hemolysis and SLE improved markedly, and the patient remained disease free eight months later. This is the first report of successful rituximab treatment of CAD in a patient with SLE. We conclude that rituximab is worth trying in such patients if they fail to respond to conventional treatment.

Na(+) /Ca(2+) exchanger-heterozygote knockout mice display increased relaxation in gastric fundus and accelerated gastric transit in vivo

BACKGROUND

For the contraction and relaxation of gastric smooth muscles to occur, the intracellular Ca(2+) concentration must be increased and decreased, respectively. The Na(+) /Ca(2+) exchanger (NCX) is a plasma membrane transporter that is involved in regulating intracellular Ca(2+) concentrations.

METHODS

To determine the role of NCX in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced relaxations in the circular muscles of the gastric fundus in NCX1 and NCX2 heterozygote knockout mice (HET).

KEY RESULTS

The myenteric plexus layers and the longitudinal and circular muscle layers in the gastric fundus of wild-type mice (WT) were strongly immunoreactive to NCX1 and NCX2. EFS induced a transient relaxation that was apparent during the stimulus and a sustained relaxation that persisted after the end of the stimulus. The amplitudes of EFS-induced transient relaxation and sustained relaxation were greater in NCX1 HET and NCX2 HET than in WT. When an inhibitor of nitric oxide synthase was added following the EFS, neither NCX1 HET nor NCX2 HET exhibited transient relaxation, similar to WT. Furthermore, when a PACAP antagonist was added following the EFS, sustained relaxation in NCX1 HET and NCX2 HET was not observed, similar to WT. Next, we examined the effect of NCX heterozygous deficiency on relaxation in response to NO and PACAP in smooth muscles. The magnitude of NOR-1- and PACAP-induced relaxations in NCX1 HET and NCX2 HET was similar to that of WT.

CONCLUSIONS & INFERENCES

In this study, we demonstrate that NCX1 and NCX2 expressed in neurons regulate the motility in the gastric fundus.