Fluorescence probes to detect lipid-derived radicals.

Lipids and their metabolites are easily oxidized in chain reactions initiated by lipid radicals, forming lipid peroxidation products that include the electrophiles 4-hydroxynonenal and malondialdehyde. These markers can bind cellular macromolecules, causing inflammation, apoptosis and other damage. Methods to detect and neutralize the initiating radicals would provide insights into disease mechanisms and new therapeutic approaches. We describe the first high-sensitivity, specific fluorescence probe for lipid radicals, 2,2,6-trimethyl-4-(4-nitrobenzo[1,2,5]oxadiazol-7-ylamino)-6-pentylpiperidine-1-oxyl (NBD-Pen). NBD-Pen directly detected lipid radicals in living cells by turn-on fluorescence. In a rat model of hepatic carcinoma induced by diethylnitrosamine (DEN), NBD-Pen detected lipid radical generation within 1 h of DEN administration. The lipid radical scavenging moiety of NBD-Pen decreased inflammation, apoptosis and oxidative stress markers at 24 h after DEN, and liver tumor development at 12 weeks. Thus, we have developed a novel fluorescence probe that provides imaging information about lipid radical generation and potential therapeutic benefits in vivo.

Detection and inhibition of lipid-derived radicals in low-density lipoprotein.

Oxidized low density lipoprotein (Ox-LDL) is implicated in a variety of oxidative diseases. To clarify the mechanisms involved and facilitate the investigation of therapeutics, we previously developed a detection method for lipid-derived radicals using the fluorescent probe 2,2,6-trimethyl-6-pentyl-4-(4-nitrobenzo[1,2,5]oxadiazol-7-ylamino)piperidine-1-oxyl (NBD-Pen). In this study, NBD-Pen was used to detect lipid-derived radicals in Ox-LDL from in vitro and in vivo samples using an iron overloaded mouse model. By following the timeline of lipid radical generation using this method, the iron overloaded mice could be successfully treated with the antioxidant Trolox, resulting in successful lowering of the plasma lipid peroxidation, aspartate transaminase and alanine transaminase levels. Furthermore, using a combination therapy of the chelating agent deferoxamine (DFX) and Trolox, liver injury and oxidative stress markers were also reduced in iron overloaded mice. The NBD-Pen method is highly sensitive as well as selective and is suitable for targeting minimally modified LDL compared with other existing methods.

Relationships between sarcopenia and household status and locomotive syndrome in a community-dwelling elderly women in Japan.

AIM: The aim of the present study was to identify factors associated with sarcopenia in community-dwelling elderly women in Japan. METHODS: A total of 186 women aged over 65 years attending preventive care classes were enrolled in the study. Muscle mass was assessed using bioelectrical impedance analysis. Sarcopenia was defined as low muscle mass and low muscle strength in accord with the consensus report of the Asian Working Group for Sarcopenia. Data regarding household status (living alone, with a spouse, or with children and/or grandchildren), calf circumference and the presence of locomotive syndrome were obtained, as well as dietary variety score, Tokyo Metropolitan Institute of Gerontology Index of Competence and Mini-Nutritional Assessment short form, and 10-item Eating Assessment Tool scores. RESULTS: Sarcopenia was identified in 21.0% of participants. Participants with sarcopenia were older, had a lower body mass index and calf circumference, and were more likely to have locomotive syndrome, and living with children and/or grandchildren. In multivariate analysis, age, body mass index <18.5 and locomotive syndrome were significantly associated with sarcopenia, as were associated living alone (OR 1.69, 95% CI 0.45-6.41), and living with children and/or grandchildren (OR 2.46, 95% CI 0.71-8.54) and dietary variety score ≥9 (OR 4.98, 95% CI 0.97-25.56). CONCLUSIONS: Age, body mass index, dietary variety score, locomotive syndrome and household status were associated with sarcopenia. Early interventions are required for older adults identified as having a higher risk of sarcopenia to prevent its adverse health consequences. Geriatr Gerontol Int 2017; 17: 54-60.

Aminophylline suppresses stress-induced visceral hypersensitivity and defecation in irritable bowel syndrome.

Pharmacological therapy for irritable bowel syndrome (IBS) has not been established. In order to find candidate drugs for IBS with diarrhea (IBS-D), we screened a compound library of drugs clinically used for their ability to prevent stress-induced defecation and visceral hypersensitivity in rats. We selected the bronchodilator aminophylline from this library. Using a specific inhibitor for each subtype of adenosine receptors (ARs) and phosphodiesterases (PDEs), we found that both A2BARs and PDE4 are probably mediated the inhibitory effect of aminophylline on wrap restraint stress (WRS)-induced defecation. Aminophylline suppressed maternal separation- and acetic acid administration-induced visceral hypersensitivity to colorectal distension (CRD), which was mediated by both A2AARs and A2BARs. We propose that aminophylline is a candidate drug for IBS-D because of its efficacy in both of stress-induced defecation and visceral hypersensitivity, as we observed here, and because it is clinically safe.

Ameliorative effect of chlorpromazine hydrochloride on visceral hypersensitivity in rats: possible involvement of 5-HT2A receptor.

BACKGROUND AND PURPOSE: Visceral hypersensitivity is responsible for pathogenesis of irritable bowel syndrome (IBS). Therefore, its prevention can help avoid abdominal pain and discomfort in IBS. To find candidate drugs for visceral hypersensitivity, we screened existing medicines for their ability to prevent visceral sensitivity induced by colorectal distension (CRD) in rats and identified chlorpromazine, a typical antipsychotic drug, as a candidate compound. In this study, we investigated the effect of chlorpromazine on visceral hypersensitivity. EXPERIMENTAL APPROACH: Visceral sensitivity (visceromotor response) was monitored by measuring the electrical activity of the abdominal external oblique muscle contraction in response to CRD using a barostat apparatus. Visceral hypersensitivity was induced by a colonic instillation of sodium butyrate or acetic acid in neonates. KEY RESULTS: Oral administration of chlorpromazine suppressed butyrate-induced visceral hypersensitivity to CRD. Interestingly, atypical antipsychotic drugs, quetiapine and risperidone, ameliorated butyrate-induced visceral hypersensitivity, whereas the typical antipsychotic drugs, haloperidol and sulpiride, did not. Pharmacological analysis using specific inhibitors showed that a selective 5-HT2A receptor antagonist, ketanserin, suppressed butyrate-induced visceral hypersensitivity, whereas a selective dopamine D2 receptor antagonist, L-741626, did not. Furthermore, the 5-HT2A receptor agonist AL-34662 stimulated visceral sensitivity to CRD in healthy control rats but not in butyrate-treated rats. These findings suggest that increased 5-HT levels in the colon contribute to the induction of visceral hypersensitivity. CONCLUSIONS AND IMPLICATIONS: Our results indicate that chlorpromazine ameliorates visceral hypersensitivity and that the 5-HT2A receptor is a potential therapeutic target for treating abdominal pain and discomfort in IBS.