Pretreatment serum monocyte chemoattractant protein-1 as a predictor of long-term outcome by ustekinumab in patients with Crohn's disease.

BACKGROUND AND AIMS: Ustekinumab has been proven to be effective for treatment of patients with Crohn's disease; however, 30-40% of patients have been reported to lose clinical response within 2 years. We aimed to evaluate the efficacy of ustekinumab and identify predictors of short-term and long-term efficacy in Crohn's disease. METHODS: Patients with Crohn's disease receiving their first ustekinumab infusion in our hospital between June 2017 and September 2020 were prospectively enrolled. Concentrations of serum cytokines and chemokines were measured using a multiplex bead array assay. RESULTS: Fifty-nine Crohn's disease patients were enrolled in this study. Among 34 clinically active patients, 38.2% achieved a clinical response at week 8. None of the assayed factors were associated with short-term clinical response. Cumulative persistence rates of ustekinumab were 77.6% at 1 year and 58.9% at 2 years. Univariate Cox regression analysis revealed that Harvey-Bradshaw Index scores at baseline, concomitant immunomodulator treatment, and concentrations of interferon gamma-induced protein-10, monocyte chemoattractant protein-1 (MCP-1), and interleukin (IL)-1RA, IL-4, IL-6, and IL-8 were significantly associated with loss of efficacy. Multivariate Cox regression analysis found that biologic naïve status (hazard ratio [HR]: 0.1191, 95% confidence interval [CI]: 0.02458-0.5774) and MCP-1 concentrations (HR: 1.038, 95% CI: 1.015-1.062) were significantly and associated with loss of sustained efficacy for ustekinumab treatment. CONCLUSIONS: Our findings suggest that pretreatment serum MCP-1 analysis, combined with a history of biologic use, could be a novel biomarker for predicting the long-term efficacy of ustekinumab in patients with Crohn's disease.

[Current real-world treatments for Japanese patients with eosinophilic esophagitis].

A total of 306 patients with eosinophilic esophagitis (EoE) were analyzed at our department. Proton pump inhibitors or potassium-competitive acid blockers were used as the first-line treatment in 286 (93.5%) patients. Fifty-five (18.0%) patients received topical steroid swallowing therapy. During 17.7-month mean follow-up, 46.4% of the patients were followed-up with no medications, 37.3% of the patients received maintenance or on-demand therapy using acid-suppressive drugs, and 9.8% of the patients received maintenance therapy with steroid swallowing. The majority of patients with EoE were treated using a therapeutic strategy similar to that used for gastroesophageal reflux disease. However, some patients were refractory to the treatment. Current real-world treatment strategies for Japanese patients with EoE are clarified.

Successful Eradication of Helicobacter pylori Could Prevent Metachronous Gastric Cancer: A Propensity Matching Analysis.

BACKGROUND AND AIM: Helicobacter pylori is the leading cause of gastric cancer, but it is still uncertain whether eradicating H. pylori in early gastric cancer (EGC) patients who underwent endoscopic resection can prevent metachronous gastric cancer (MGC). This study aimed to investigate the effect of H. pylori eradication to prevent MGC after endoscopic submucosal dissection (ESD). METHODS: In this propensity-matched retrospective observational study, 770 patients with EGC who received ESD were enrolled. The outcome was the incidence of MGC; this was compared between the persistent and eradicated groups. RESULTS: MGC was detected in 27 patients (7.8%) during a median period of 39.0 months (range 26.0-64.0). After propensity matching, 126 pairs of patients in each group were analyzed. The 5-year cumulative incidence rates of MGC were 13.2 and 3.9% in the persistent and eradicated groups, respectively (p= 0.021, log-rank test). On multivariate analysis, H. pylori eradication prevented MGC significantly (hazard ratio [HR] 0.32; p = 0.029). The results remained robust after inverse probability of treatment weighting analysis (HR 0.30; p = 0.020). CONCLUSIONS: Successful H. pylori eradication could prevent MGC after ESD for EGC.

Production of insulin-like growth factor-II in hepatocellular carcinoma with recurrent hypoglycemia: a case report.

A 35-year-old woman, who was an HBV carrier, complained of fever for 2 weeks, and thus, she was admitted in our hospital. Both serum AFP and PIVKA-II levels were abnormally high, and an abdominal enhanced CT revealed the presence of multiple masses in both lobes of the liver. She was diagnosed with hepatocellular carcinoma (T4, N0, M0, and Vp4) and was treated with transcatheter arterial infusion chemotherapy. On the 4th day of her illness, her serum glucose level was 26mg/dl. Glucose infusion and intravenous hyperalimentation were not effective, and she experienced repeated hypoglycemic attacks. Based on the low levels of both insulin (0.4µU/ml) and insulin-like growth factor (IGF)-I (14ng/ml), we made a diagnosis of non-islet cell tumor hypoglycemia associated with hepatocellular carcinoma. The patient was orally administered prednisolone at a dose of 20mg/day. On the 49th day of illness, the hepatocellular carcinoma ruptured, and 2 days later, she died because of hemorrhage shock. Postmortem immunohistochemical staining for IGF-II was positive in the tumor cells of the liver. Furthermore, Western immunoblotting revealed the presence of high-molecular-weight form of IGF-II in the serum of the patient.

Metabolomics reveal 1-palmitoyl lysophosphatidylcholine production by peroxisome proliferator-activated receptor α.

PPARα is well known as a master regulator of lipid metabolism. PPARα activation enhances fatty acid oxidation and decreases the levels of circulating and cellular lipids in obese diabetic patients. Although PPARα target genes are widely known, little is known about the alteration of plasma and liver metabolites during PPARα activation. Here, we report that metabolome analysis-implicated upregulation of many plasma lysoGP species during bezafibrate (PPARα agonist) treatment. In particular, 1-palmitoyl lysophosphatidylcholine [LPC(16:0)] is increased by bezafibrate treatment in both plasma and liver. In mouse primary hepatocytes, the secretion of LPC(16:0) increased on PPARα activation, and this effect was attenuated by PPARα antagonist treatment. We demonstrated that Pla2g7 gene expression levels in the murine hepatocytes were increased by PPARα activation, and the secretion of LPC(16:0) was suppressed by Pla2g7 siRNA treatment. Interestingly, LPC(16:0) activates PPARα and induces the expression of PPARα target genes in hepatocytes. Furthermore, we showed that LPC(16:0) has the ability to recover glucose uptake in adipocytes induced insulin resistance. These results reveal that LPC(16:0) is induced by PPARα activation in hepatocytes; LPC(16:0) contributes to the upregulation of PPARα target genes in hepatocytes and the recovery of glucose uptake in insulin-resistant adipocytes.

Role of AMPK and PPARγ1 in exercise-induced lipoprotein lipase in skeletal muscle.

Exercise can effectively ameliorate type 2 diabetes and insulin resistance. Here we show that the mRNA levels of one of peroxisome proliferator-activated receptor (PPAR) family members, PPARγ1, and genes related to energy metabolism, including PPARγ coactivator-1 protein-1α (PGC-1α) and lipoprotein lipase (LPL), increased in the gastrocnemius muscle of habitual exercise-trained mice. When mice were intraperitoneally administered an AMP-activated protein kinase (AMPK) activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), the mRNA levels of the aforementioned three genes increased in gastrocnemius muscle. AICAR treatment to C2C12 differentiated myotubes also increased PPARγ1 mRNA levels, but not PPARα and -δ mRNA levels, concomitant with increased PGC-1α mRNA levels. An AMPK inhibitor, compound C, blocked these AICAR effects. AICAR treatment increased the half-life of PPARγ1 mRNA nearly threefold (4-12 h) by activating AMPK. When C2C12 myoblast cells infected with a PPARγ1 expression lentivirus were differentiated into myotubes, PPARγ1 overexpression dramatically increased LPL mRNA levels more than 40-fold. In contrast, when PPARγ1 expression was suppressed in C2C12 myotubes, LPL mRNA levels were significantly reduced, and the effect of AICAR on increased LPL gene expression was almost completely blocked. These results indicated that PPARγ1 was intimately involved in LPL gene expression in skeletal muscle and the AMPK-PPARγ1 pathway may play a role in exercise-induced LPL expression. Thus, we identified a novel critical role for PPARγ1 in response to AMPK activation for controlling the expression of a subset of genes associated with metabolic regulation in skeletal muscle.

Antiproliferative and anti-inflammatory effects of fractionated crude lectins from boiled kidney beans (Phaseolus vulgaris).

In this study, we investigated the biological profile of lectins isolated from raw and boiled Japanese red Kintoki beans (red kidney beans [RKB]; Phaseolus vulgaris). Lectins in beans showing agglutination activity were retained after heating. Raw and boiled RKB lectins were fractionated using carboxymethyl- and diethylaminoethyl-Sepharose, respectively. Boiled RKB lectins were evaluated for carbohydrate specificity as well as cytokine-inducing and antiproliferative activities against cancer cells and compared with raw RKB lectins. Raw RKB lectins showed specificity for thyroglobulin and fetuin, whereas boiled lectins showed specificity for N-acetylneuraminic acid. Raw RKB lectins showed low resistance to proteases and tolerated temperatures greater than 80°C for 5 min. Notably, lectins from raw and boiled beans showed antiproliferative activity against five types of cancer cells B16, LM8, HeLa, HepG2, and Colo 679. In particular, lectins from raw beans exhibited a significantly stronger activity than those from boiled beans. Anti-inflammatory effects were notably observed in crude extracts from raw and boiled beans. Specifically, lectins fractionated from boiled beans markedly inhibited the expression of tumor necrosis factor-α and interleukin-6. Overall, our results showed that RKB lectins from boiled beans exert anti-inflammatory and anticancer effects and could be developed as potential chemopreventive agents. PRACTICAL APPLICATION: Japanese red kidney beans (RKB) are cultivated in numerous parts of the temperate zone and consumed in many countries. Lectins from boiled beans exhibited anticancer activity, similar to lectins from raw beans. Additionally, crude and fractionated lectins from boiled beans showed anti-inflammatory activity. Thus, boiled RKB lectins have the potential to be used as a bioactive protein for medical research and could be developed as anticancer agents.

DHA attenuates postprandial hyperlipidemia via activating PPARα in intestinal epithelial cells.

It is known that peroxisome proliferator-activated receptor (PPAR)α, whose activation reduces hyperlipidemia, is highly expressed in intestinal epithelial cells. Docosahexaenoic acid (DHA) could improve postprandial hyperlipidemia, however, its relationship with intestinal PPARα activation is not revealed. In this study, we investigated whether DHA can affect postprandial hyperlipidemia by activating intestinal PPARα using Caco-2 cells and C57BL/6 mice. The genes involved in fatty acid (FA) oxidation and oxygen consumption rate were increased, and the secretion of triacylglyceride (TG) and apolipoprotein B (apoB) was decreased in DHA-treated Caco-2 cells. Additionally, intestinal FA oxidation was induced, and TG and apoB secretion from intestinal epithelial cells was reduced, resulting in the attenuation of plasma TG and apoB levels after oral administration of olive oil in DHA-rich oil-fed mice compared with controls. However, no increase in genes involved in FA oxidation was observed in the liver. Furthermore, the effects of DHA on intestinal lipid secretion and postprandial hyperlipidemia were abolished in PPARα knockout mice. In conclusion, the present work suggests that DHA can inhibit the secretion of TG from intestinal epithelial cells via PPARα activation, which attenuates postprandial hyperlipidemia.

Up-regulation of endothelial nitric oxide synthase (eNOS), silent mating type information regulation 2 homologue 1 (SIRT1) and autophagy-related genes by repeated treatments with resveratrol in human umbilical vein endothelial cells.

Resveratrol, a polyphenolic phytoalexin found in red wine and various plants, has been reported to up-regulate the expression of endothelial NO synthase (eNOS) in human umbilical vein endothelial cells (HUVEC). However, this effect was neither long term in nature nor physiologically relevant at the concentration of resveratrol studied. In the present study, we investigated the effects of repeated treatments with a lower concentration of resveratrol on the expression of genes in HUVEC. The expression levels of eNOS and silent mating type information regulation 2 homologue 1 (SIRT1) were up-regulated in HUVEC by repeated treatments with 1 µM-resveratrol for 6 d, but not with fenofibrate. Moreover, resveratrol treatment increased the expression of autophagy-regulated genes such as γ-aminobutyric acid A receptor-associated protein (GABARAP), microtubule-associated protein 1 light chain 3B (LC3B) and autophagy-related protein 3 (ATG3), the radical scavenger activity-related metallothionein-1X (MT1X) gene and the anti-inflammatory activity-related annexin A2 (ANXA) gene. In addition, resveratrol treatment down-regulated the expression of the cell-cycle checkpoint control RAD9 homologue B (RAD9B) gene. These results indicate the beneficial effects of resveratrol on the cardiovascular system.

Inflammation-induced nitric oxide suppresses PPARα expression and function via downregulation of Sp1 transcriptional activity in adipocytes.

The activation of peroxisome proliferator-activated receptor alpha (PPARα), a ligand-dependent transcription factor that regulates lipid oxidation-related genes, has been employed to treat hyperlipidemia. Emerging evidence indicates that Ppara gene expression decreases in adipose tissue under obese conditions; however, the underlying molecular mechanisms remain elusive. Here, we demonstrate that nitric oxide (NO) suppresses Ppara expression by regulating its promoter activity via suppression of specificity protein 1 (Sp1) transcriptional activity in adipocytes. NO derived from lipopolysaccharide (LPS) -activated macrophages or a NO donor (NOR5) treatment, suppressed Ppara mRNA expression in 10T1/2 adipocytes. In addition, Ppara transcript levels were reduced in the white adipose tissue (WAT) in both acute and chronic inflammation mouse models; however, such suppressive effects were attenuated via a nitric oxide synthase 2 (NOS2) inhibitor. Endoplasmic reticulum (ER) stress inhibitors attenuated the NO-induced repressive effects on Ppara gene expression in 10T1/2 adipocytes. Promoter mutagenesis and chromatin immunoprecipitation assays revealed that NO decreased the Sp1 occupancy in the proximal promoter regions of the Ppara gene, which might partially result from the reduced Sp1 expression levels by NO. This study delineated the molecular mechanism that modulates Ppara gene transcription upon NO stimulation in white adipocytes, suggesting a possible mechanism for the transcriptional downregulation of Ppara in WAT under obese conditions.

Neutrophil-to-lymphocyte ratio may predict clinical relapse in ulcerative colitis patients with mucosal healing.

Endoscopic mucosal healing (MH) is an important treatment goal for patients with ulcerative colitis (UC). The neutrophil-to-lymphocyte ratio (NLR) reflects systemic inflammation and has been reported to be a useful predictive marker for UC. This study aimed to evaluate the clinical utility of the NLR for predicting clinical relapse in UC patients with MH. We retrospectively enrolled patients with UC who underwent colonoscopy at the Osaka City University Hospital between January 2010 and December 2010, whose Mayo Endoscopic Subscore was 0 or 1. The correlation between the incidence of relapse and demographic factors, including the NLR, was analyzed. We included 129 patients in the present study. The median NLR at the time of endoscopy was 1.98, and differences in the high NLR group and the low NLR group were compared. During a median follow-up period of 46.4 months, 58 patients (45.0%) experienced relapse. The cumulative relapse-free rate was significantly higher in the low NLR group than in the high NLR group (P = 0.03, log-rank test). Multivariate analysis identified high NLR as an independent prognostic factor for clinical relapse (hazard ratio, 1.74; 95% confidence interval, 1.02-2.98; P = 0.04). NLR is a novel and useful predictor of clinical relapse in UC patients with MH, and it can potentially be a strong indicator to determine the appropriate treatment strategy and decision-making in clinical practice.

The impact of COVID-19 on Japanese patients with eosinophilic gastrointestinal disorders during the vaccination era.

Background: Eosinophilic gastrointestinal disorders (EGIDs) are chronic allergic diseases categorized as eosinophilic esophagitis (EoE) and non-EoE EGIDs. Few studies regarding the association between EGIDs and coronavirus disease 2019 (COVID-19) have been reported. Although most Japanese individuals received the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine, the incidence of COVID-19 remained high in 2022. This study examines the incidence of COVID-19 in patients with EGIDs during the vaccination era. Methods: Patients with EGIDs who visited our department between October and December 2022 were enrolled in the study. The incidence and severity of COVID-19 prior to October 1, 2022 were determined. Patients who reported having COVID-19 also reported their hospitalization history, intensive care unit admissions, and EGID flares. The number of SARS-CoV-2 vaccinations received and treatment for EGIDs were obtained from the patients' medical records. Results: Of 111 patients with EGIDs (65 with EoE and 46 with non-EoE EGIDs) included in this study, 31 (28%) patients reported having COVID-19, including 14 (22%) with EoE and 17 (37%) with non-EoE EGIDs. Fifty-nine (84%) patients received two or more vaccinations, and 11 (16%) patients received no vaccinations. COVID-19 was mild in all but one patient who had moderate symptoms. COVID-19 was not associated with EGID flares. EGID treatments and an unvaccinated status were not associated with an increased risk of COVID-19. Conclusion: COVID-19 was mild in patients with EGIDs and not associated with EGIDs flares during the vaccination era. There was a relatively high incidence of COVID-19 among patients with non-EoE EGIDs.

Impact of the COVID-19 Pandemic on the Lifestyle and Psychosocial Behavior of Patients with Inflammatory Bowel Diseases: A Narrative Review.

The coronavirus disease (COVID-19) pandemic has had a considerable impact on the global healthcare system and potentially the clinical course of patients with inflammatory bowel disease (IBD). Although IBD is a chronic disease, its therapy (except steroid therapy) does not increase the risk of contracting or aggravating COVID-19. However, the clinical course of patients is significantly influenced by environmental factors. Social restrictions due to the pandemic or the fear of contracting the virus have influenced lifestyle and psychosocial behaviors that may worsen the clinical course of patients with IBD. This narrative literature review summarizes the current evidence on the impact of the COVID-19 pandemic on the lifestyle and psychosocial behaviors of patients with IBD. The COVID-19 pandemic negatively affected the lifestyle and psychosocial behaviors of patients with IBD. Furthermore, patients with IBD failed to maintain medication adherence, thus affecting the clinical course of their condition.

Hepatic phosphatidylcholine catabolism driven by PNPLA7 and PNPLA8 supplies endogenous choline to replenish the methionine cycle with methyl groups.

Choline supplies methyl groups for regeneration of methionine and the methyl donor S-adenosylmethionine in the liver. Here, we report that the catabolism of membrane phosphatidylcholine (PC) into water-soluble glycerophosphocholine (GPC) by the phospholipase/lysophospholipase PNPLA8-PNPLA7 axis enables endogenous choline stored in hepatic PC to be utilized in methyl metabolism. PNPLA7-deficient mice show marked decreases in hepatic GPC, choline, and several metabolites related to the methionine cycle, accompanied by various signs of methionine insufficiency, including growth retardation, hypoglycemia, hypolipidemia, increased energy consumption, reduced adiposity, increased fibroblast growth factor 21 (FGF21), and an altered histone/DNA methylation landscape. Moreover, PNPLA8-deficient mice recapitulate most of these phenotypes. In contrast to wild-type mice fed a methionine/choline-deficient diet, both knockout strains display decreased hepatic triglyceride, likely via reductions of lipogenesis and GPC-derived glycerol flux. Collectively, our findings highlight the biological importance of phospholipid catabolism driven by PNPLA8/PNPLA7 in methyl group flux and triglyceride synthesis in the liver.

Recent advances in the study on resveratrol.

Appropriate long-term drinking of red wine is associated with a reduced risk for lifestyle-related diseases such as cardiovascular disease and cancer, making resveratrol, a constituent of grapes and various other plants, an attractive compound to be studied. Historically, resveratrol has been identified as a phytoalexin, antioxidant, cyclooxygenase (COX) inhibitor, peroxisome proliferator-activated receptor (PPAR) activator, endothelial nitric oxide synthase (eNOS) inducer, silent mating type information regulation 2 homolog 1 (SIRT1) activator, and more. Despite scepticism concerning the biological availability of resveratrol, a growing body of in vivo evidence indicates that resveratrol has protective effects in several stress and disease models. Here, we provide a review of the studies on resveratrol, especially with respect to COX, PPAR, and eNOS activities, and discuss its potential for promoting human health.

Analysis of autonomic function during natural defecation in patients with irritable bowel syndrome using real-time recording with a wearable device.

BACKGROUND: Autonomic dysfunction is a factor in irritable bowel syndrome (IBS). However, there are no reports of autonomic nervous system (ANS) activity during natural defecation in patients with IBS. We aimed to clarify the relationship between ANS activity and life events, such as defecation and abdominal symptoms, using real-time recording. METHODS: Six patients with IBS and 14 healthy controls were enrolled in this prospective multicenter study. ANS activity was recorded for 24 h using a T-shirt wearable device, and life events were recorded simultaneously in real time using a smartphone application software. Low frequency/high frequency (LF/HF) and HF calculated by power spectrum analysis were defined as activity indicators of the sympathetic and parasympathetic nerves, respectively. RESULTS: The means of LF/HF and HF in the period with positive symptoms were comparable between the groups; however, the sum of LF/HF, sum of ΔLF/HF, and the maximum variation in ΔLF/HF were significantly higher in the IBS group. In the IBS group, the sum of ΔLF/HF and LF/HF increased significantly from 2 min before defecation, and the sum of LF/HF remained significantly higher until 9 min after defecation. The sum of ΔLF/HF at 2 min before defecation was significantly positively correlated with the intensity of abdominal pain and diarrhea and constipation scores. In contrast, it was significantly negatively correlated with defecation satisfaction and health-related quality of life. CONCLUSIONS: In patients with IBS, sympathetic nerve activity was activated 2 min before defecation, which was correlated with abdominal symptoms and lower QOL.

Effect of the Coronavirus Disease 2019 Lockdown on Lifestyle Factors in Japanese Patients with Inflammatory Bowel Disease.

Objective To examine the effect of the coronavirus disease 2019 (COVID-19) lockdown on lifestyle factors and psychological stress in patients with inflammatory bowel disease (IBD). Methods A retrospective study was conducted on patients with IBD in Japan 2 months after the initiation of the first state of emergency (June 16 to August 21, 2020). A self-reported questionnaire was used to collect data, and lifestyle factors and psychological stress levels before and after the state of emergency were compared. Patients Patients with IBD who were followed up regularly at Osaka City University Hospital from June 16 to August 21, 2020, were included and were classified into elderly (≥65 years old) and non-elderly groups (<65 years old). Results The study sample comprised 451 responders (241, ulcerative colitis; 210, Crohn's disease; 0, COVID-19). The sleep duration increased, whereas the exercise, working, and walking durations decreased during the COVID-19 lockdown. The proportion of patients with psychological stress due to COVID-19, those with an inability to exercise, and those staying indoors increased significantly during COVID-19 lockdown. Lifestyle factors changed more markedly in non-elderly patients, those who were more stressed due to COVID-19, those with the inability to exercise, and those staying indoors during COVID-19 lockdown. Among elderly patients, no significant changes were identified in stress-causing factors. Conclusion The COVID-19 lockdown affected lifestyle factors and psychological stress in patients with IBD, particularly non-elderly patients. These findings may be helpful in suggesting favorable lifestyle changes for patients with IBD.

Pyogenic Spondylitis Caused by Staphylococcus schleiferi in a Patient with Crohn's Disease.

Staphylococcus schleiferi has rarely been reported to cause pyogenic spondylitis. A 42-year-old man had been treated for Crohn's disease with immunosuppressive agents and home parenteral nutrition via a central vein (CV) port. The patient was admitted to our hospital, presenting with neck pain and a fever. A neurological examination showed slight weakness in his left-hand muscles, and he was diagnosed with pyogenic spondylitis of C6 and C7 vertebral bodies due to catheter-related blood stream infection caused by S. schleiferi. An early diagnosis by magnetic resonance imaging, CV port removal and antibiotic therapy targeting S. schleiferi improved his symptoms.

Citral, a component of lemongrass oil, activates PPARα and γ and suppresses COX-2 expression.

Lemongrass is a widely used herb as a food flavoring, as a perfume, and for its analgesic and anti-inflammatory purposes; however, the molecular mechanisms of these effects have not been elucidated. Previously, we identified carvacrol from the essential oil of thyme as a suppressor of cyclooxygenase (COX)-2, a key enzyme for prostaglandin synthesis, and also an activator of peroxisome proliferator-activated receptor (PPAR), a molecular target for "lifestyle-related" diseases. In this study, we evaluated the essential oil of lemongrass using our established assays for COX-2 and PPARs. We found that COX-2 promoter activity was suppressed by lemongrass oil in cell-based transfection assays, and we identified citral as a major component in the suppression of COX-2 expression and as an activator of PPARα and γ. PPARγ-dependent suppression of COX-2 promoter activity was observed in response to citral treatment. In human macrophage-like U937 cells, citral suppressed both LPS-induced COX-2 mRNA and protein expression, dose-dependently. Moreover, citral induced the mRNA expression of the PPARα-responsive carnitine palmitoyltransferase 1 gene and the PPARγ-responsive fatty acid binding protein 4 gene, suggesting that citral activates PPARα and γ, and regulates COX-2 expression. These results are important for understanding the anti-inflammatory and anti-lifestyle-related disease properties of lemongrass.

Farnesol, an isoprenoid, improves metabolic abnormalities in mice via both PPARα-dependent and -independent pathways.

Peroxisome proliferator-activated receptors (PPARs) control energy homeostasis. In this study, we showed that farnesol, a naturally occurring ligand of PPARs, could ameliorate metabolic diseases. Obese KK-Ay mice fed a high-fat diet (HFD) containing 0.5% farnesol showed significantly decreased serum glucose level, glucosuria incidence, and hepatic triglyceride contents. Farnesol-containing HFD upregulated the mRNA expressions of PPARα target genes involved in fatty acid oxidation in the liver. On the other hand, farnesol was not effective in upregulating the mRNA expressions of PPARγ target genes in white adipose tissues. Experiments using PPARα-deficient [(-/-)] mice revealed that the upregulation of fatty acid oxidation-related genes required PPARα function, but the suppression of hepatic triglyceride accumulation was partially PPARα-dependent. In hepatocytes isolated from the wild-type and PPARα (-/-) mice, farnesol suppressed triglyceride synthesis. In luciferase assay, farnesol activated both PPARα and the farnesoid X receptor (FXR) at similar concentrations. Moreover, farnesol increased the mRNA expression level of a small heterodimer partner known as one of the FXR target genes and decreased those of sterol regulatory element-binding protein-1c and fatty acid synthase in both the wild-type and PPARα (-/-) hepatocytes. These findings suggest that farnesol could improve metabolic abnormalities in mice via both PPARα-dependent and -independent pathways and that the activation of FXR by farnesol might contribute partially to the PPARα-independent hepatic triglyceride content-lowering effect. To our knowledge, this is the first study on the effect of the dual activators of PPARα and FXR on obesity-induced metabolic disorders.