Modified furosemide responsiveness index and biomarkers for AKI progression and prognosis: a prospective observational study.

BACKGROUND: Modified furosemide responsiveness index (mFRI) is a novel biomarker for assessing diuretic response and AKI progression in patients with early AKI. However, the comparative predictive performance of mFRI and novel renal biomarkers for adverse renal outcomes remains unclear. In a single-center prospective study, we aimed to evaluate the discriminatory abilities of mFRI and other novel renal biomarkers in predicting AKI progression and prognosis in patients with initial mild and moderate AKI (KDIGO stage 1 to 2). RESULTS: Patients with initial mild and moderate AKI within 48 h following cardiac surgery were included in this study. The mFRI, renal biomarkers (including serum or urinary neutrophil gelatinase-associated lipocalin [sNGAL or uNGAL], serum cystatin C, urinary N-acetyl-beta-D-glycosaminidase [uNAG], urinary albumin-to-creatinine ratio) and cytokines (TNF, IL-1ß, IL-2R, IL-6, IL-8, and IL-10) were measured at AKI diagnosis. The mFRI was calculated for each patient, which was defined as 2-hour urine output divided by furosemide dose and body weight. Of 1013 included patients, 154 (15.2%) experienced AKI progression, with 59 (5.8%) progressing to stage 3 and 33 (3.3%) meeting the composite outcome of hospital mortality or receipt of renal replacement therapy (RRT). The mFRI showed non-inferiority or potential superiority to renal biomarkers and cytokines in predicting AKI progression (area under the curve [AUC] 0.80, 95% confidence interval [CI] 0.77-0.82), progression to stage 3 (AUC 0.87, 95% CI 0.85-0.89), and composite outcome of death and receipt of RRT (AUC 0.85, 95% CI 0.82-0.87). Furthermore, the combination of a functional biomarker (mFRI) and a urinary injury biomarker (uNAG or uNGAL) resulted in a significant improvement in the prediction of adverse renal outcomes than either individual biomarker (all P < 0.05). Moreover, incorporating these panels into clinical model significantly enhanced its predictive capacity for adverse renal outcomes, as demonstrated by the C index, integrated discrimination improvement, and net reclassification improvement (all P < 0.05). CONCLUSIONS: As a rapid, cost-effective and easily accessible biomarker, mFRI, exhibited superior or comparable predictive capabilities for AKI progression and prognosis compared to renal biomarkers in cardiac surgical patients with mild to moderate AKI. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04962412. Registered July 15, 2021, https://clinicaltrials.gov/ct2/show/NCT04962412?cond=NCT04962412&draw=2&rank=1 .

ß-Hydroxybutyrate upregulates FGF21 expression through inhibition of histone deacetylases in hepatocytes.

Fibroblast growth factor 21 (FGF21) is secreted by hepatocytes as a peptide hormone to regulate glucose and lipid metabolism. FGF21 promotes hepatic ketogenesis and increases ketone body utilization in starvation. Histones are the target molecules of nutrients in regulating hepatic metabolic homeostasis. However, the effect of ketone bodies on FGF21 expression and the involvement of histones in it is not clear yet. The present study observed the effects of ß-hydroxybutyrate (ß-OHB), the main physiological ketone body, on FGF21 expression in human hepatoma HepG2 cells in vitro and in mice in vivo, and the role of histone deacetylases (HDACs) in ß-OHB-regulated FGF21 expression was investigated. The results showed that ß-OHB significantly upregulated FGF21 gene expression and increased FGF21 protein levels while it inhibited HDACs' activity in HepG2 cells. HDACs' inhibition by entinostat upregulated FGF21 expression and eliminated ß-OHB-stimulated FGF21 expression in HepG2 cells. Intraperitoneal injections of ß-OHB in mice resulted in the elevation of serum ß-OHB and the inhibition of hepatic HDACs' activity. Meanwhile, hepatic FGF21 expression and serum FGF21 levels were significantly increased in ß-OHB-treated mice compared with the control. It is suggested that ß-OHB upregulates FGF21 expression through inhibition of HDACs' activity in hepatocytes.

α-Lipoic acid up-regulates gene expression but reduces protein levels of fibroblast growth factor 21 in HepG2 cells.

Fibroblast growth factor 21 (FGF21) is a metabolism-regulating hepatokine, and its expression is finely controlled by the nutrients and cellular stressors. α-Lipoic acid (ALA) regulates fuel metabolism as a nutrient, but it also arouses mitochondrial and endoplasmic reticulum (ER) stress as well as oxidative stress in hepatocytes. However, the role of cellular stress in ALA-regulated FGF21 expression has not been demonstrated as yet. The present study found that ALA up-regulated FGF21 gene expression while it reduced FGF21 protein levels in HepG2 cells, which was accompanied by mitochondrial damage that was shown by ATP reduction and ROS elevation. ALA led to mitochondrial stress and ER stress as shown by the increased expression of HSP60, ATF6 and ATF4. Inhibition of ER stress by 4-PBA significantly attenuated ALA-stimulated FGF21 gene expression while it did not influence the reduction of FGF21 protein levels. H2 O2 -induced oxidative stress reduced FGF21 protein levels in HepG2 cells, and anti-oxidation by Tempol blocked ALA-induced reduction of FGF21 proteins. In conclusion, ALA up-regulates FGF21 gene expression through the stimulation of mitochondrial and ER stress while it reduces FGF21 protein levels through the induction of oxidative stress in HepG2 cells. Further studies are needed to demonstrate the in vivo effect of ALA on hepatic FGF21 expression.

Pyruvate Upregulates Hepatic FGF21 Expression by Activating PDE and Inhibiting cAMP-Epac-CREB Signaling Pathway.

Fibroblast growth factor 21 (FGF21) functions as a polypeptide hormone to regulate glucose and lipid metabolism, and its expression is regulated by cellular metabolic stress. Pyruvate is an important intermediate metabolite that acts as a key hub for cellular fuel metabolism. However, the effect of pyruvate on hepatic FGF21 expression and secretion remains unknown. Herein, we examined the gene expression and protein levels of FGF21 in human hepatoma HepG2 cells and mouse AML12 hepatocytes in vitro, as well as in mice in vivo. In HepG2 and AML12 cells, pyruvate at concentrations above 0.1 mM significantly increased FGF21 expression and secretion. The increase in cellular cAMP levels by adenylyl cyclase activation, phosphodiesterase (PDE) inhibition and 8-Bromo-cAMP administration significantly restrained pyruvate-stimulated FGF21 expression. Pyruvate significantly increased PDE activities, reduced cAMP levels and decreased CREB phosphorylation. The inhibition of exchange protein directed activated by cAMP (Epac) and cAMP response element binding protein (CREB) upregulated FGF21 expression, upon which pyruvate no longer increased FGF21 expression. The increase in plasma pyruvate levels in mice induced by the intraperitoneal injection of pyruvate significantly increased FGF21 gene expression and PDE activity with a reduction in cAMP levels and CREB phosphorylation in the mouse liver compared with the control. In conclusion, pyruvate activates PDEs to reduce cAMP and then inhibits the cAMP-Epac-CREB signaling pathway to upregulate FGF21 expression in hepatocytes.

Comparison of the Curative Efficacy of Hemivertebra Resection via the Posterior Approach Assisted With Unilateral and Bilateral Internal Fixation in the Treatment of Congenital Scoliosis.

Objective: This study aimed to compare the curative efficacy of hemivertebra resection via the posterior approach assisted with unilateral and bilateral internal fixation in the treatment of congenital scoliosis (CS). Methods: In this study, 29 children (15 males and 14 females), who underwent hemivertebra resection via the posterior approach and received internal fixation from November 2005 to September 2018, were analyzed retrospectively. The age of these patients ranged from 0.9 to 15 years, with an average of 3.8 years. The follow-up duration ranged from 2 to 12.3 years, with an average of 5.7 years. The patients in group A received unilateral internal fixation, and those in group B received bilateral internal fixation. The operation duration, bleeding volume, and complications during the operation, as well as the Cobb angles of scoliosis and kyphosis before and after the operation and at the last follow-up, were compared between the two groups. Results: In group A, the operation duration was 207.4 ± 54.5 min, and the bleeding volume was 215.3 ± 75.4 ml; in group B, the operation duration was 249.5 ± 51.0 min, and the bleeding volume was 291.3 ± 115.6 ml (P < 0.05). The Cobb angles of segmental scoliosis, segmental kyphosis, cephalic compensatory curve, and caudal compensatory curve were significantly improved in the two groups after operation and at the last follow-up (P < 0.05). The post-operative correction rate of the scoliosis Cobb angle was 67.2% in group A and 79.5% in group B; and the difference was statistically significant (P < 0.05). At the last follow-up, the correction rate of the scoliosis Cobb angle was 72.7% in group A and 76.2% in group B (P > 0.05). After the operation and at the last follow-up, the correction rates of kyphosis were 83.1 and 79.6% in group A and 71.8 and 65.5% in group B (P > 0.05). Conclusion: Hemivertebra resection via posterior approach with unilateral internal fixation can also achieve the effect of bilateral internal fixation in the treatment of CS. It is able to preserve a certain degree of contralateral spinal growth potential and is a feasible method.

Nano-realgar suppresses lung cancer stem cell growth by repressing metabolic reprogramming.

BACKGROUND: Recent studies in cancer biology suggest that metabolic glucose reprogramming is a potential target for cancer treatment. However, little is known about drug intervention in the glucose metabolism of cancer stem cells (CSCs) and its related underlying mechanisms. METHODS: The crude realgar powder was Nano-grinded to meets the requirements of Nano-pharmaceutical preparations, and Nano-realgar solution (NRS) was prepared for subsequent experiments. Isolation and characterization of lung cancer stem cells (LCSCs) was performed by magnetic cell sorting (MACS) and immunocytochemistry, respectively. Cell viability and intracellular glucose concentration were detected by MTT assay and glucose oxidase (GOD) kit. Protein expressions related to metabolic reprogramming was detected by ELISA assay. Determination of the expression of HIF-1α and PI3K/Akt/mTOR pathways was carried out by RT-PCR and western blotting analysis. A subcutaneous tumor model in BALB/c-nu mice was successfully established to evaluate the effects of Nano-realgar on tumor growth and histological structure, and the expression of HIF-1α in tumor tissues was measured by immunofluorescence. RESULTS: Nano-realgar inhibits cell viability and induces glucose metabolism in LCSCs, and inhibits protein expression related to metabolic reprogramming in a time- and dose-dependent manner. Nano-realgar downregulated the expression of HIF-1α and PI3K/Akt/mTOR pathways in vitro and in vivo. Nano-realgar inhibits tumor growth and changes the histological structure of tumors through in vivo experiments and consequently inhibits the constitutive activation of HIF-1α signaling. CONCLUSIONS: These results reveal that Nano-realgar inhibits tumor growth in vitro and in vivo by repressing metabolic reprogramming. This inhibitory effect potentially related to the downregulation HIF-1α expression via PI3K/Akt/mTOR pathway.

GPR120 Regulates Pancreatic Polypeptide Secretion From Male Mouse Islets via PLC-Mediated Calcium Mobilization.

The free fatty acid receptor G protein-coupled receptor 120 (GPR120) is expressed in pancreatic islets, but its specific cell distribution and function have not been fully established. In this study, a GPR120-IRES-EGFP knockin (KI) mouse was generated to identify GPR120-expressing cells with enhanced green fluorescence proteins (EGFP). EGFP-positive cells collected from KI mouse islets by flow cytometry had a significantly higher expression of pancreatic polypeptide (PP) evidenced by reverse transcriptase (RT)-quantitative polymerase chain reaction (qPCR). Single-cell RT-PCR and immunocytochemical double staining also demonstrated the coexpression of GPR120 with PP in mouse islets. The GPR120-specific agonist TUG-891 significantly increased plasma PP levels in mice. TUG-891 significantly increased PP levels in islet medium in vitro, which was markedly attenuated by GPR120 small interfering RNA treatment. TUG-891-stimulated PP secretion in islets was fully blocked by pretreatment with YM-254890 (a Gq protein inhibitor), U73122 (a phospholipase C inhibitor), or thapsigargin (an inducer of endoplasmic reticulum Ca2+ depletion), respectively. TUG-891 triggered the increase in intracellular free Ca2+ concentrations ([Ca2+]i) in PP cells, which was also eliminated by YM-254890, U73122, or thapsigargin. GPR120 gene expression was significantly reduced in islets of high-fat diet (HFD)-induced obese mice. TUG-891-stimulated PP secretion was also significantly diminished in vivo and in vitro in HFD-induced obese mice compared with that in normal-chow diet control mice. In summary, this study demonstrated that GPR120 is expressed in mouse islet PP cells and GPR120 activation stimulated PP secretion via the Gq/PLC-Ca2+ signaling pathway in normal-chow diet mice but with diminished effects in HFD-induced obese mice.

Protective effects of GPR120 agonist-programmed macrophages on renal interstitial fibrosis in unilateral ureteral obstruction (UUO) rats.

Macrophages in the kidney play different roles in renal interstitial fibrosis (RIF) depending on their phenotypes. M2 phenotype macrophages are believed to protect the kidney against RIF. Free fatty acid receptor GPR120 is expressed in macrophages, and its activation induces macrophage transition to M2 phenotype. In this study, the effects of GPR120 agonist-programmed macrophages on RIF were investigated. The peritoneal macrophages collected from rats were incubated with GPR120 agonist TUG891 in vitro for 24 h, and then they were transplanted autologously to the kidney with ureteral obstruction by intrarenal injection for 7 days on the same day following unilateral ureteral obstruction (UUO) operation. RIF was identified by Masson trichrome histological staining, and the expression of RIF-related proteins was analyzed by immunohistochemistry and western blot. It was observed that TUG891-programmed macrophages up-regulated the expression of CD206 and arginase-1 while the expression of interleukin-6 and tumor necrosis factor-α were down-regulated. RIF in rats was significantly increased following UUO, which was markedly alleviated by TUG891-programmed macrophages but not untreated macrophages. TUG891-programmed macrophages inhibited the abnormal expression of TGF-ß1 and SMAD2. The abnormal expression of epithelial-mesenchymal transition (EMT)-related proteins including vimentin, α-SMA and ß-catenin was also significantly decreased in rats with transplantation of TUG891-programmed macrophages as compared to UUO rats. This study suggests that autologous administration of peritoneal macrophages programmed in vitro by GPR120 agonist to kidney has a protective effect against RIF following UUO.

Prognostic Value of MicroRNA-15a in Human Cancers: A Meta-Analysis and Bioinformatics.

BACKGROUND: Although several studies have proved the relationship between the prognostic value of miRNA-15a and different types of cancer, the result remains controversial. Thus, a meta-analysis was conducted to clarify the prognostic value of miRNA-15a expression level in human cancers. METHODS: We enrolled appropriate literature by searching the databases of PubMed, Embase, and Web of Science. Subsequently, we extracted HRs and their 95% CIs and calculated pooled results of miRNA-15a for overall survival (OS) and disease-free survival (DFS). Besides, subgroup analysis, sensitivity analysis, and publication bias were also revealed in this study. We also further validated this meta-analysis using the Kaplan-Meier plotter database. RESULT: 10 studies, including 1616 patients, were embraced in our meta-analysis. The result showed the lower expression of miRNA-15a significantly predicted adverse OS (HR=2.17, 95% CI: 1.41-3.34), but there is no significant association between the expressing level and DFS in cancer patient (HR=2.04, 95% CI: 0.60-6.88). Based on Kaplan-Meier plotter database, we found the same results in bladder Carcinoma, head-neck squamous cell carcinoma, liver hepatocellular carcinoma, lung squamous cell carcinoma, pancreatic ductal adenocarcinoma, rectum adenocarcinoma, stomach adenocarcinoma, and uterine corpus endometrial carcinoma, but opposite results were found in cervical squamous cell carcinoma and esophageal carcinoma. CONCLUSION: Low expressing levels of miRNA-15a indicated poor OS, while miRNA-15a can be used as a prediction biomarker in different cancer types.

Chinese expert consensus on echelons treatment of thoracic injury in modern warfare.

The emergency treatment of thoracic injuries varies of general conditions and modern warfare. However, there are no unified battlefield treatment guidelines for thoracic injuries in the Chinese People's Liberation Army (PLA). An expert consensus has been reached based on the epidemiology of thoracic injuries and the concept of battlefield treatment combined with the existing levels of military medical care in modern warfare. Since there are no differences in the specialized treatment for thoracic injuries between general conditions and modern warfare, first aid, emergency treatment, and early treatment of thoracic injuries are introduced separately in three levels in this consensus. At Level I facilities, tension pneumothorax and open pneumothorax are recommended for initial assessment during the first aid stage. Re-evaluation and further treatment for hemothorax, flail chest, and pericardial tamponade are recommended at Level II facilities. At Level III facilities, simple surgical operations such as emergency thoracotomy and debridement surgery for open pneumothorax are recommended. The grading standard for evidence evaluation and recommendation was used to reach this expert consensus.

Chinese expert consensus on echelons treatment of pelvic fractures in modern war.

The characteristics and treatment of pelvic fractures vary between general conditions and modern war. An expert consensus has been reached based on pelvic injury epidemiology and the concepts of battlefield treatment combined with the existing levels of military medical care in modern warfare. According to this consensus, first aid, emergency treatment and early treatment of pelvic fractures are introduced in three separate levels. In Level I facilities, simple triage and rapid treatment following the principles of advanced trauma life support are recommended to evaluate combat casualties during the first-aid stage. Re-evaluation, further immobilization and fixation, and hemostasis are recommended at Level II facilities. At Level III facilities, the main components of damage control surgery are recommended, including comprehensive hemostasis, a proper resuscitation strategy, the treatment of concurrent visceral and blood vessel damage, and battlefield intensive care. The grading standard for evidence evaluation and recommendation was used to reach this expert consensus.

Grifolic acid causes osteosarcoma cell death in vitro and in tumor-bearing mice.

Grifolic acid is a natural compound isolated from the fungus Albatrellus confluens. In the present study, we assessed the effects of grifolic acid on human osteosarcoma cells. We found that grifolic acid dose- and time-dependently induced cell death in the U-2 OS, MG-63, Saos-2, and 143B human osteosarcoma cell lines. Grifolic acid decreased osteosarcoma cell mitochondrial membrane potential, ATP production, and cellular NADH levels, but did not impact mitochondrial membrane potential in isolated mitochondria from human osteosarcoma cells. Intratumoral injection of grifolic acid also promoted tumor cell death and prolonged survival in nude mice bearing human osteosarcoma xenografts. Grifolic acid had no obvious toxicity in mice, with no histological changes in liver, kidney, lung, or heart, and no changes in blood cell counts or levels of plasma total protein, alanine aminotransferase, or aspartate aminotransferase. These results show that grifolic acid induces osteosarcoma cell death by inhibiting NADH generation and ATP production without obvious toxicity. Intratumoral injection of grifolic acid may be a promising anti-osteosarcoma therapeutic option in patients.

Transcutaneous vagus nerve stimulation for the treatment of depression: a study protocol for a double blinded randomized clinical trial.

BACKGROUND: Depressive disorders are the most common form of mental disorders in community and health care settings. Unfortunately, the treatment of Major Depressive Disorder (MDD) is far from satisfactory. Vagus nerve stimulation (VNS) is a relatively new and promising physical treatment for depressive disorders. One particularly appealing element of VNS is the long-term benefit in mood regulation. However, because this intervention involves surgery, perioperative risks, and potentially significant side effects, this treatment has been limited to those patients with treatment-resistant depression who have failed medication trials and exhausted established somatic treatments for major depression, due to intolerance or lack of response.This double-blinded randomized clinical trial aims to overcome these limitations by introducing a novel method of stimulating superficial branches of the vagus nerve on the ear to treat MDD. The rationale is that direct stimulation of the afferent nerve fibers on the ear area with afferent vagus nerve distribution should produce a similar effect as classic VNS in reducing depressive symptoms without the burden of surgical intervention. DESIGN: One hundred twenty cases (60 males) of volunteer patients with mild and moderate depression will be randomly divided into transcutaneous vagus nerve stimulation group (tVNS) and sham tVNS group. The treatment period lasts 4 months and all clinical and physiological measurements are acquired at the beginning and the end of the treatment period. DISCUSSION: This study has the potential to significantly extend the application of VNS treatment for MDD and other disorders (including epilepsy, bipolar disorder, and morbid obesity), resulting in direct benefit to the patients suffering from these highly prevalent disorders. In addition, the results of this double-blinded clinical trial will shed new light on our understanding of acupuncture point specificity, and development of methodologies in clinical trials of acupuncture treatment. TRIALS REGISTRATION: Clinical Trials. ChiCTR-TRC-11001201 http://www.chictr.org/cn/

Effects of GH secretagogues on contractility and Ca2+ homeostasis of isolated adult rat ventricular myocytes.

Ghrelin and its synthetic analogue hexarelin are specific ligands of GH secretagogue receptor (GHS-R) and induce a variety of cardiovascular protective and cardiac positive inotropic effects. The signaling system underlying immediate effects of both GHSs in cardiomyocytes remains undefined. In the present study, we investigated the immediate effects of GHSs on isolated ventricular myocyte shortening, intracellular Ca(2+) ([Ca(2+)](i)) transients, and the L-type Ca(2+) current (I(Ca,L)). Putative intracellular signalling cascades were studied with specific receptor and signalling blockers. In fresh isolated adult Wistar rat ventricular myocytes, GHSs produced a positive inotropic effect in a concentration-dependent manner and increased the amplitude of [Ca(2+)](i) transients and the I(Ca,L). The positive inotropic response was abolished by the GHS-R1a antagonist [D-Lys(3)]-GH-releasing peptide-6 (10 microm). GHS-induced increase in the I(Ca,L) was abolished by [D-Lys(3)]-GH-releasing peptide-6 and protein kinase C inhibitor, chelerythrine chloride (5 microm), but not by protein kinase A inhibitor, KT 5720 (10 microm). We conclude that hexarelin and ghrelin increase the I(Ca,L), through GHS-R1a receptor and protein kinase C signalling cascade, which contribute to its direct positive inotropic effect on cardiomyocytes.

Cholesterol induces mitochondrial dysfunction and apoptosis in mouse pancreatic beta-cell line MIN6 cells.

Reduction of pancreatic ß-cell mass is a key element leading to type 2 diabetes. Obesity and overweight with high levels of lipids including cholesterol are tightly linked to type 2 diabetes. The direct impact of cholesterol on pancreatic ß-cells, however, has not been extensively studied. In this study, MIN6 mouse ß-cell line was used to test the effect of cholesterol on pancreatic ß-cell apoptosis over different doses and durations. It was found that cholesterol dose- and time-dependently induced cell death of MIN6 cells above 160 µM after 6 h treatment in vitro. Annexin-V staining revealed that cholesterol treatment significantly induced apoptosis in MIN6 cells. Cholesterol treatment resulted in the loss of the ability to retain Rhodamine 123, indicating mitochondrial damage in MIN6 cells. Cholesterol-induced cell apoptosis and mitochondrial damage were blocked by low-temperature condition. In addition, glutathione also protected MIN6 cells from cholesterol-induced cell death. It is concluded that high level of cholesterol induces cell apoptosis in MIN6 cells, which is in part due to mitochondrial dysfunction. We suggest that excessive uptake of cholesterol in ß-cells may contribute to ß-cell apoptosis and dysfunction and the deterioration of type 2 diabetes.

[Effects of lipid rafts on signal transmembrane transduction mediated by c-Met].

OBJECTIVE: To study the effects of lipid rafts on cell signal transmembrane transduction mediated by c-Met. METHODS: After HepG2Cells were treated with MbCD to disrupt the lipid rafts and were treated with artificial recombination hepatocyte growth factor to activate c-Met, the activities of PLCr1/PKC, PI3K/Akt and MAPK signaling pathways in HepG2 cells were analyzed using Western blot. RESULTS: (1) After disruption of lipid rafts with MbCD, phosphorylation of PLCr1 decreased by 35% (P = 0.022); the content of PLCr in the cytoplasm increased by 1.75 fold (P = 0.017); PLCr1 conjugated with membrane decreased by 30% (P = 0.037). (2) The content of PKB in the cytosol decreased by 38% (P = 0.028), and the phosphorylation level of PKB conjugated with membrane decreased by 14% (P = 0.041). At the same time, PDK translocation from cytosol to the plasma membrane and its activation were inhibited by treatment with MbCD. (3) Treatment with MbCD had no significant effect on ErK/MAPK, p38/MAPK and JNK/MAPK signaling pathways. CONCLUSION: Disruption of lipid rafts with MbCD inhibits the activation of PLCr1/PKC and PI3K/PKB signaling pathways by HGF/cMet, but has no effect on MAPK signaling pathway.

Linoleic acid induces Ca2+-induced inactivation of voltage-dependent Ca2+ currents in rat pancreatic beta-cells.

Free fatty acids (FFAs) regulate insulin secretion in a complex pattern and induce pancreatic beta-cell dysfunction in type 2 diabetes. Voltage-dependent Ca2+ channels (VDCC) in beta-cells play a major role in regulating insulin secretion. The aim of present study is to clarify the action of the FFA, linoleic acid, on VDCC in beta-cells. The VDCC current in primary cultured rat beta-cells were recorded under nystatin-perforated whole-cell recording configuration. The VDCC was identified as high-voltage-gated Ca2+ channels due to there being no difference in current amplitude under holding potential between -70 and -40 mV. Linoleic acid (10 microM) significantly inhibited VDCC currents in beta-cells, an effect which was fully reversible upon washout. Methyl-linoleic acid, which does not activate G protein coupled receptor (GPR)40, neither did alter VDCC current in rat beta-cells nor did influence linoleic acid-induced inhibition of VDCC currents. Linoleic acid-induced inhibition of VDCC current was not blocked by preincubation of beta-cells with either the specific protein kinase A (PKA) inhibitor, H89, or the PKC inhibitor, chelerythrine. However, pretreatment of beta-cells with thapsigargin, which depletes intracellular Ca2+ stores, completely abolished linoleic acid-induced decrease in VDCC current. Measurement of intracellular Ca2+ concentration ([Ca2+](i)) illustrated that linoleic acid induced an increase in [Ca2+](i) and that thapsigargin pretreatment inhibited this increase. Methyl-linoleic acid neither did induce increase in [Ca2+](i) nor did it block linoleic acid-induced increase in [Ca2+](i). These results suggest that linoleic acid stimulates Ca2+ release from intracellular Ca2+ stores and inhibits VDCC currents in rat pancreatic beta-cells via Ca2+-induced inactivation of VDCC.

Isolation and characterization of a human intestinal bacterium, Eubacterium sp. ARC-2, capable of demethylating arctigenin, in the essential metabolic process to enterolactone.

Plant lignans, such as pinoresinol diglucoside, secoisolariciresinol diglucoside and arctiin, are metabolized to mammalian lignans, enterolactone or enterodiol, by human intestinal bacteria. Their metabolic processes include deglucosylation, ring cleavage, demethylation, dehydroxylation and oxidation. Here we isolated an intestinal bacterium capable of demethylating arctigenin, an aglycone of arctiin, to 2,3-bis(3,4-dihydroxybenzyl)butyrolactone (1) from human feces, and identified as an Eubacterium species (E. sp. ARC-2), which is similar to Eubacterium limosum on the basis of morphological and biochemical properties and 16S rRNA gene sequencing. By incubating with E. sp. ARC-2, arctigenin was converted to 1 through stepwise demethylation. Demethylation of arctigenin by E. sp. ARC-2 was tetrahydrofolate- and ATP-dependent, indicating that the reaction was catalyzed by methyltransferase. Moreover, E. sp. ARC-2 transformed secoisolariciresinol to 2,3-bis(3,4-dihydroxybenzyl)-1,4-butanediol by demethylation.

Contribution of adipocyte-derived factors to beta-cell dysfunction in diabetes.

In addition to serving as an energy reservoir, the adipocyte has been characterized as an endocrine cell, secreting many bioactive factors which influence energy homeostasis. Being overweight, with excessive adipose tissue, is considered to be part of the pathogenesis of type 2 diabetes. Insulin resistance and beta-cell dysfunction are two major pathophysiological changes seen in type 2 diabetes. In addition to inducing insulin resistance in insulin-responsive tissues, adipocyte-derived factors play an important role in the pathogenesis of beta-cell dysfunction. Leptin, free fatty acids, adiponectin, tumor necrosis factor-alpha and interleukin-6 are all produced and secreted by adipocytes, and may directly influence aspects of beta-cell function, including insulin synthesis and secretion, insulin cell survival and apoptosis. During the progression from normal weight to obesity and on to overt diabetes, the adipocyte-derived factors contribute to the occurrence and development of beta-cell dysfunction and type 2 diabetes.

Morphological observation of immunological alterations in the spleens from estrogen receptor deficient mice.

AIM: To evaluate some immunological parameters in the spleens from estrogen receptor(ER) deficient mice. METHODS: Immunohistochemistry and immunofluorescence analysis were used in the study. RESULTS: Multiple alterations were found in the spleens of ER deficient mice, especially in ERbeta deficient mice, such as increased expression of proinflammatory cytokines and inducible nitric oxide synthase, elevated number of proliferating splenocytes and increased IgM/IgG production. Moreover, The splenocytes lack of ERbeta were resistant towards estrogen's suppression on proliferation. The activation of nuclear factor (NF)-kappaB in ERbeta deficient spleens may account for the above hyperactivity. CONCLUSION: ER, especially ERbeta, plays a key role in mediating the modulation of immune response by estrogen. ERbeta disruption may increase the sensibility towards autoimmune diseases.