Labor Analgesia Initiation With Dural Puncture Epidural Versus Conventional Epidural Techniques: A Randomized Biased-Coin Sequential Allocation Trial to Determine the Effective Dose for 90% of Patients of Bupivacaine.

BACKGROUND: The dural puncture epidural (DPE) technique has a faster onset, better sacral spread, and improved bilateral coverage when compared to the conventional epidural (EPL) technique. Whether these qualities translate into a lower bupivacaine dose to provide initial analgesia is unknown. We sought to determine the effective dose of bupivacaine to achieve initial (first 30 minutes) labor analgesia in 90% of patients (ED90) with the DPE and EPL techniques, using a biased-coin, sequential allocation method. METHODS: A total of 100 women of mixed parity with term, singleton gestation at ≤5 cm dilation with no major comorbidities were randomized to receive a DPE or an EPL technique. An experienced anesthesiologist performed these techniques and administered an allocated dose of plain bupivacaine diluted with isotonic sterile 0.9% saline to a total volume of 20 mL via the EPL catheter. Bupivacaine doses for each subject were determined by the response of the previous subject, using a biased-coin sequential allocation method, with success defined by a numeric rating scale (NRS) < 3 at 30 minutes. Outcome assessments were performed by an investigator blinded to the technique and bupivacaine dose. Sensory and motor blockade and maternal or fetal side effects were recorded every 5 minutes for the first 30 minutes. The ED90 of bupivacaine with each technique was estimated using centered isotonic regression. RESULTS: A total of 95 women were included in the final analysis. The ED90 of bupivacaine was estimated at 29.30 mg (90% confidence interval [CI], 28.55-31.56) with a DPE technique and 45.25 mg (90% CI, 42.80-52.03) with an EPL technique. CONCLUSIONS: Using a biased-coin, sequential allocation method, the DPE technique requires less bupivacaine to achieve effective initial analgesia (ED90) when compared to the EPL technique.

Pyridoxamine scavenges protein carbonyls and inhibits protein aggregation in oxidative stress-induced human HepG2 hepatocytes.

Introduction of carbonyl groups into amino acid residues is a hallmark for oxidative damage to proteins by reactive oxygen species (ROS). Protein carbonylation can have deleterious effects on cell function and viability, since it is generally unrepairable by cells and can lead to protein dysfunction and to the production of potentially harmful protein aggregates. Meanwhile, pyridoxamine (PM) is known to scavenge various toxic carbonyl species derived from either glucose or lipid degradation through nucleophilic addition. PM is also demonstrated to catalyze non-enzymatic transamination reactions between amino and α-keto acids. Here, we found that PM scavenges protein carbonyls in oxidized BSA with concomitant generation of pyridoxal and recovers oxidized lysozyme activity. Moreover, we demonstrated that the treatment of H2O2-exposed HepG2 hepatocytes with PM significantly reduced levels of cellular carbonylated proteins and aggregated proteins, and also improved cell survival rate. Our results suggest that PM may have potential efficacy in ameliorating ROS-mediated cellular dysfunction.

Palmitate induces insulin resistance in human HepG2 hepatocytes by enhancing ubiquitination and proteasomal degradation of key insulin signaling molecules.

Obesity-associated insulin resistance is a major pathogenesis of type 2 diabetes mellitus and is characterized by defects in insulin signaling. High concentrations of plasma free fatty acids (FFAs) are involved in the etiology of obesity-associated insulin resistance. However, the detailed mechanism by which FFAs contribute to the development of insulin resistance is not yet fully understood. We investigated the molecular basis of insulin resistance elicited by FFAs using the human hepatocyte cell line HepG2. Among major human FFAs, palmitate markedly inhibited insulin-stimulated phosphorylation of key insulin signaling molecules such as insulin receptor, insulin receptor substrate-1, and Akt, indicating that palmitate is the principal inducer of insulin resistance. We revealed that palmitate facilitates ubiquitination of the key insulin signaling molecules, and subsequently elicits their proteasomal degradation. Furthermore, we demonstrated that inhibition of ubiquitination by the ubiquitin-activating enzyme E1 inhibitor PYR41 significantly prevents palmitate-inducible insulin resistance but not by the proteasome inhibitor MG132, implying that ubiquitinated signaling molecules may be dysfunctional. In conclusion, inhibition of ubiquitination of the key insulin signaling molecules may be a potential strategy for preventing and treating obesity-associated insulin resistance.

Morbidity associated with cesarean delivery in the United States: is placenta accreta an increasingly important contributor?

OBJECTIVE: The purpose of this study was to examine cesarean delivery morbidity and its predictors in the United States. STUDY DESIGN: We used 2000-2011 Nationwide Inpatient Sample data to identify cesarean deliveries and records with 12 potential cesarean delivery complications, including placenta accreta. We estimated cesarean delivery morbidity rates and rate changes from 2000-2011, and fitted Poisson regression models to assess the relative incidence of morbidity among repeat vs primary cesarean deliveries and explore its predictors. RESULTS: From 2000-2011, 76 in 1000 cesarean deliveries (97 in 1000 primary and 48 in 1000 repeat cesarean deliveries) were accompanied by ≥1 of 12 complications. The unadjusted composite cesarean delivery morbidity rate increased by 3.6% only among women with a primary cesarean delivery (P < .001); the unadjusted rate of placenta accreta increased by 30.8% only among women with a repeat cesarean deliveries (P = .025). The adjusted rate of overall composite cesarean delivery morbidity decreased by 1% annually from 2000-2011 (P < .001). Compared with women with a primary cesarean delivery, those women who underwent a repeat cesarean delivery were one-half as likely (incidence rate ratio, 0.50; 95% CI, 0.49-0.50) to experience a complication, but 2.13 (95% CI, 1.98-2.29) times more likely to have a placenta accreta diagnosis. Both cesarean delivery morbidity and placenta accreta were positively associated with age >30 years, non-Hispanic black race/ethnicity, the presence of a chronic medical condition, and delivery in urban, teaching, or larger hospitals. CONCLUSION: Overall, cesarean delivery morbidity declined modestly from 2000-2011, but placenta accreta became an increasingly important contributor to repeat cesarean delivery morbidity. Clinicians should maintain a high index of suspicion for abnormal placentation and make adequate preparations for patients who need cesarean deliveries.

Opioid abuse and dependence during pregnancy: temporal trends and obstetrical outcomes.

BACKGROUND: The authors investigated nationwide trends in opioid abuse or dependence during pregnancy and assessed the impact on maternal and obstetrical outcomes in the United States. METHODS: Hospitalizations for delivery were extracted from the Nationwide Inpatient Sample from 1998 to 2011. Temporal trends were assessed and logistic regression was used to examine the associations between maternal opioid abuse or dependence and obstetrical outcomes adjusting for relevant confounders. RESULTS: The prevalence of opioid abuse or dependence during pregnancy increased from 0.17% (1998) to 0.39% (2011) for an increase of 127%. Deliveries associated with maternal opioid abuse or dependence compared with those without opioid abuse or dependence were associated with an increased odds of maternal death during hospitalization (adjusted odds ratio [aOR], 4.6; 95% CI, 1.8 to 12.1, crude incidence 0.03 vs. 0.006%), cardiac arrest (aOR, 3.6; 95% CI, 1.4 to 9.1; 0.04 vs. 0.01%), intrauterine growth restriction (aOR, 2.7; 95% CI, 2.4 to 2.9; 6.8 vs. 2.1%), placental abruption (aOR, 2.4; 95% CI, 2.1 to 2.6; 3.8 vs. 1.1%), length of stay more than 7 days (aOR, 2.2; 95% CI, 2.0 to 2.5; 3.0 vs. 1.2%), preterm labor (aOR, 2.1; 95% CI, 2.0 to 2.3; 17.3 vs. 7.4%), oligohydramnios (aOR, 1.7; 95% CI, 1.6 to 1.9; 4.5 vs. 2.8%), transfusion (aOR, 1.7; 95% CI, 1.5 to 1.9; 2.0 vs. 1.0%), stillbirth (aOR, 1.5; 95% CI, 1.3 to 1.8; 1.2 vs. 0.6%), premature rupture of membranes (aOR, 1.4; 95% CI, 1.3 to 1.6; 5.7 vs. 3.8%), and cesarean delivery (aOR, 1.2; 95% CI, 1.1 to 1.3; 36.3 vs. 33.1%). CONCLUSIONS: Opioid abuse or dependence during pregnancy is associated with considerable obstetrical morbidity and mortality, and its prevalence is dramatically increasing in the United States. Identifying preventive strategies and therapeutic interventions in pregnant women who abuse drugs are important priorities for clinicians and scientists.

Diversity, composition and potential roles of sedimentary microbial communities in different coastal substrates around subtropical Okinawa Island, Japan.

BACKGROUND: Marine benthic prokaryotic communities play crucial roles in material recycling within coastal environments, including coral reefs. Coastal sedimentary microbiomes are particularly important as potential reservoirs of symbiotic, beneficial, and pathogenic bacteria in coral reef environments, and therefore presumably play a core role in local ecosystem functioning. However, there is a lack of studies comparing different environments with multiple sites on the island scale, particularly studies focusing on prokaryotic communities, as previous investigations have focused mainly on a single site or on specific environmental conditions. In our study, we collected coastal sediments from seven sites around Okinawa Island, Japan, including three different benthic types; sandy bottoms, seagrass meadows, and hard substratum with living scleractinian corals. We then used metabarcoding to identify prokaryotic compositions and estimate enzymes encoded by genes to infer their functions. RESULTS: The results showed that the three substrata had significantly different prokaryotic compositions. Seagrass meadow sites exhibited significantly higher prokaryotic alpha-diversity compared to sandy bottom sites. ANCOM analysis revealed that multiple bacterial orders were differentially abundant within each substratum. At coral reef sites, putative disease- and thermal stress-related opportunistic bacteria such as Rhodobacterales, Verrucomicrobiales, and Cytophagales were comparatively abundant, while seagrass meadow sites abundantly harbored Desulfobacterales, Steroidobacterales and Chromatiales, which are common bacterial orders in seagrass meadows. According to our gene-coded enzyme analyses the numbers of differentially abundant enzymes were highest in coral reef sites. Notably, superoxide dismutase, an important enzyme for anti-oxidative stress in coral tissue, was abundant at coral sites. Our results provide a list of prokaryotes to look into in each substrate, and further emphasize the importance of considering the microbiome, especially when focusing on environmental conservation. CONCLUSION: Our findings prove that prokaryotic metabarcoding is capable of capturing compositional differences and the diversity of microbial communities in three different environments. Furthermore, several taxa were suggested to be differentially more abundant in specific environments, and gene-coded enzymic compositions also showed possible differences in ecological functions. Further study, in combination with field observations and temporal sampling, is key to achieving a better understanding of the interactions between the local microbiome and the surrounding benthic community.

Acute pain and analgesic requirement after vaginal childbirth with and without neuraxial labor analgesia-Retrospective cohort study.

BACKGROUND: Few data are available on the intensity of pain that women experience during the first five days after vaginal childbirth. Moreover, it is unknown if the use of neuraxial labor analgesia has any impact on the level of postpartum pain. METHODS: We performed a retrospective cohort study based on chart review of all women who delivered vaginally at an urban teaching hospital between April 2017 and April 2019. The primary outcome was the area under the curve of pain score on numeric rating scale (NRS) documented in electronic medical records for five days postpartum (NRS-AUC5days). Secondary outcomes included peak NRS score, doses of oral and intravenous analgesics consumed during the first five days postpartum, and relevant obstetric outcomes. Logistic regression was used to examine the associations between the use of neuraxial labor analgesia and pain-related outcomes adjusting for potential confounders. RESULTS: During the study period, 778 women (38.6%) underwent vaginal delivery with neuraxial analgesia and 1240 women (61.4%) delivered without neuraxial analgesia. Median (Interquartile range) of NRS-AUC5days was 0.17 (0.12-0.24) among women who received neuraxial analgesia and 0.13 (0.08-0.19) among women who did not (p<0.001). Women who received neuraxial analgesia were more likely to require the first- and second-line analgesics postpartum than women who did not: diclofenac (87.9% vs. 73.0%, p< 0.001, respectively); acetaminophen (40.7% vs. 21.0%, p< 0.001, respectively). The use of neuraxial labor analgesia was independently associated with increased odds of having NRS-AUC5days in the highest 20 percentile (adjusted odds ratio [aOR] 2.03; 95% confidence interval [CI] 1.55-2.65), having peak NRS ≥ 4 (aOR 1.54; 95% CI 1.25-1.91) and developing hemorrhoids during the postpartum hospitalization (aOR 2.13; 95% CI 1.41-3.21) after adjusting for relevant confounders. CONCLUSION: Although women who used neuraxial labor analgesia had slightly higher pain scores and increased analgesic requirement during postpartum hospitalization, pain after vaginal childbirth was overall mild. The small elevation in the pain burden in neuraxial group does not seem to be clinically relevant and should not influence women's choice to receive labor analgesia.

Physical and psychological recovery after vaginal childbirth with and without epidural analgesia: A prospective cohort study.

BACKGROUND: Enhanced recovery is the gold standard in modern perioperative management, including that for cesarean deliveries. However, qualitative and quantitative data on the physical and psychological recovery of women after vaginal childbirth are limited. Whether neuraxial labor analgesia influences postpartum recovery is unknown. METHODS: Primiparous women anticipating a vaginal childbirth between January 2020 and May 2021 were enrolled. Women with major comorbidities or postpartum complications and those who underwent a cesarean delivery were excluded. Daily step count was measured using a wrist-worn activity tracker (FitbitTM Inspire HR) for 120 hours after vaginal childbirth. Subjective fatigue levels and health-related quality of life were assessed using the Multidimensional Fatigue Inventory (MFI) and EuroQol 5 Dimension 5 Level (EQ-5D-5L), respectively, at the 3rd trimester antenatal visit, on postpartum day 1 and 3, and at the one-month postpartum visit. Rest and dynamic pain scores and the location of pain were documented by participants during postpartum hospitalization. RESULTS: Among 300 women who were enrolled antenatally, 95 and 116 had a vaginal delivery without (NCB group) and with (EPL group) epidural analgesia, respectively. The median number of steps per 24 hours increased daily in both groups, and no significant difference was detected between the groups. Postpartum pain was mild overall, with median rest and dynamic pain scores being less than 4 and similar between the groups. MFI and EQ-5D-5L scores were the worst on postpartum day 1 in both groups and gradually improved to antepartum level by the one-month postpartum visit. Higher MFI score on postpartum day 1, but not the use of epidural analgesia, was associated with lower odds of achieving adequate postpartum ambulation (defined as >3500 steps between 48 and 72 hours postpartum). CONCLUSION: The use of epidural analgesia was not associated with worse recovery outcomes during postpartum hospitalization. TRIAL REGISTRATION: UMIN-CTR, #UMIN000039343, registered on January 31, 2020.

Pyrroloquinoline quinone, a novel protein tyrosine phosphatase 1B inhibitor, activates insulin signaling in C2C12 myotubes and improves impaired glucose tolerance in diabetic KK-A(y) mice.

Insulin resistance is a pathological hallmark of type 2 diabetes mellitus and is characterized by defects in insulin signaling. Protein tyrosine phosphatase 1B (PTP1B) negatively regulates insulin signaling by tyrosine dephosphorylation of insulin receptor, and increased activity and expression of PTP1B is implicated in the pathogenesis of insulin resistance. Therefore, inhibition of PTP1B is anticipated to improve insulin resistance in type 2 diabetic subjects. Pyrroloquinoline quinone (PQQ), a redox cofactor for bacterial dehydrogenases, inhibits PTP1B to oxidatively modify the catalytic cysteine through its redox cycling activity. Here, we report that PQQ induces the ligand-independent activation of insulin signaling by inhibiting cellular PTP1B and enhances glucose uptake through the translocation of glucose transporter 4 in mouse C2C12 myotubes. Furthermore, we demonstrated that oral administration of PQQ improved impaired glucose tolerance in type 2 diabetic KK-A(y) mice. Our results strongly suggest that PQQ can be useful in anti-diabetic treatment for type 2 diabetic subjects.

Cloning and characterization of a gene cluster for hatomarubigin biosynthesis in Streptomyces sp. strain 2238-SVT4.

Streptomyces sp. strain 2238-SVT4 produces hatomarubigins A, B, C, and D, which belong to the angucycline family. Among them, hatomarubigin D has a unique dimeric structure with a methylene linkage. PCR using aromatase and cyclase gene-specific primers identified the hrb gene cluster for angucycline biosynthesis in Streptomyces sp. 2238-SVT4. The cluster consisted of 30 open reading frames, including those for the minimal polyketide synthase, ketoreductase, aromatase, cyclase, O-methyltransferase, oxidoreductase, and oxygenase genes. Expression of a part of the gene cluster containing hrbR1 to hrbX in Streptomyces lividans TK23 resulted in the production of hatomarubigins A, B, and C. Hatomarubigin D was obtained from the conversion of hatomarubigin C by a purified enzyme encoded by hrbY, among the remaining genes.

Phenethyl isothiocyanate activates leptin signaling and decreases food intake.

Obesity, a principal risk factor for the development of diabetes mellitus, heart disease, and hypertension, is a growing and serious health problem all over the world. Leptin is a weight-reducing hormone produced by adipose tissue, which decreases food intake via hypothalamic leptin receptors (Ob-Rb) and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Protein tyrosine phosphatase 1B (PTP1B) negatively regulates leptin signaling by dephosphorylating JAK2, and the increased activity of PTP1B is implicated in the pathogenesis of obesity. Hence, inhibition of PTP1B may help prevent and reduce obesity. In this study, we revealed that phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate in certain cruciferous vegetables, potently inhibits recombinant PTP1B by binding to the reactive cysteinyl thiol. Moreover, we found that PEITC causes the ligand-independent phosphorylation of Ob-Rb, JAK2, and STAT3 by inhibiting cellular PTP1B in differentiated human SH-SY5Y neuronal cells. PEITC treatment also induced nuclear accumulation of phosphorylated STAT3, resulting in enhanced anorexigenic POMC expression and suppressed orexigenic NPY/AGRP expression. We demonstrated that oral administration of PEITC to mice significantly reduces food intake, and stimulates hypothalamic leptin signaling. Our results suggest that PEITC might help prevent and improve obesity.

Piperine Promotes Glucose Uptake through ROS-Dependent Activation of the CAMKK/AMPK Signaling Pathway in Skeletal Muscle.

SCOPE: The prevalence of type 2 diabetes mellitus (T2DM) is increasing yearly worldwide. Glycemic control is the basis for the treatment of T2DM, as it can prevent the progress of associated complications. Spices possess various health beneficial effects on humans. The aim of this study is to search for spices that can promote glucose uptake and to elucidate the underlying molecular mechanism(s). METHODS AND RESULTS: Among 24 spice extracts, the extracts from black pepper and white pepper significantly increase glucose uptake in L6 myotubes. Piperine is found to be the active compound in these extracts. Treatment of myotubes with piperine induces the translocation of glucose transporter 4 (GLUT4) to the plasma membrane by phosphorylation of AMP-activated protein kinase (AMPK). Piperine increases the intracellular Ca2+ level and reactive oxygen species (ROS) generation through transient receptor potential vanilloid channel 1 (TRPV1), followed by activation of Ca2+ /calmodulin-dependent protein kinase kinase-beta (CaMKKß) as the upstream events for AMPK phosphorylation. Furthermore, oral administration of piperine to Wistar rats at 0.01 and 0.1 mg kg-1 body weight decreases postprandial hyperglycemia accompanied by GLUT4 translocation and AMPK phosphorylation. CONCLUSION: Piperine in pepper prevents hyperglycemia by GLUT4 translocation through CaMKKß/AMPK signaling via TRPV1-dependent increase in the intracellular Ca2+ level and ROS generation.

Patterns of Opioid Prescription and Use After Cesarean Delivery.

OBJECTIVE: To define the amount of opioid analgesics prescribed and consumed after discharge after cesarean delivery. METHODS: We conducted a survey at six academic medical centers in the United States from September 2014 to March 2016. Women who had undergone a cesarean delivery were contacted by phone 2 weeks after discharge and participated in a structured interview about the opioid prescription they received on discharge and their oral opioid intake while at home. RESULTS: A total of 720 women were enrolled; of these, 615 (85.4%) filled an opioid prescription. The median number of dispensed opioid tablets was 40 (interquartile range 30-40), the median number consumed was 20 (interquartile range 8-30), and leftover was 15 (interquartile range 3-26). Of those with leftover opioids, 95.3% had not disposed of the excess medication at the time of the interview. There was an association between a larger number of tablets dispensed and the number consumed independent of patient characteristics. The amount of opioids dispensed did not correlate with patient satisfaction, pain control, or the need to refill the opioid prescription. CONCLUSION: The amount of opioid prescribed after cesarean delivery generally exceeds the amount consumed by a significant margin, leading to substantial amounts of leftover opioid medication. Lower opioid prescription correlates with lower consumption without a concomitant increase in pain scores or satisfaction.

Late Pregnancy ß Blocker Exposure and Risks of Neonatal Hypoglycemia and Bradycardia.

BACKGROUND AND OBJECTIVES: ß blockers are widely used in the treatment of hypertensive disorders during pregnancy. These medications cross the placenta and may cause physiologic changes in neonates exposed in utero. We sought to define the risks of neonatal hypoglycemia and bradycardia associated with maternal exposure to ß blockers at the time of delivery in a large, nationwide cohort of Medicaid beneficiaries. METHODS: We used a cohort of 2 292 116 completed pregnancies linked to liveborn infants of Medicaid-enrolled women from 2003 to 2007. We examined the risks of neonatal hypoglycemia and neonatal bradycardia associated with maternal exposure to ß blockers at the time of delivery. Propensity score matching was used to control for potential confounders including maternal demographics, obstetric and medical conditions, and exposure to other medications. RESULTS: There were 10 585 (0.5%) pregnancies exposed to ß blockers at the time of delivery. The risk of neonatal hypoglycemia was 4.3% in the ß blocker-exposed neonates versus 1.2% in the unexposed; the risk of neonatal bradycardia was 1.6% in the exposed versus 0.5% in the unexposed. After controlling for confounders, risk remained elevated for both neonatal hypoglycemia and bradycardia among exposed pregnancies versus unexposed (adjusted odds ratio, 1.68, 95% confidence interval, 1.50-1.89 and adjusted odds ratio, 1.29, 95% confidence interval, 1.07-1.55, respectively). CONCLUSION: Our findings suggest that neonates born to mothers exposed to ß blockers in late pregnancy, including labetalol, are at elevated risk for neonatal hypoglycemia and bradycardia.

Calcium Channel Blocker Exposure in Late Pregnancy and the Risk of Neonatal Seizures.

OBJECTIVE: To assess whether maternal calcium channel blocker exposure during late pregnancy is independently associated with neonatal seizures after carefully controlling for confounding factors. METHODS: Data were derived from the Medicaid Analytic eXtract for the years 2000-2007 and included 2,529,636 completed pregnancies. We compared the risk of neonatal seizures among neonates who were born to women who took calcium channel blockers in the final month of pregnancy to the risk in neonates born to women who did not use calcium channel blockers. Confounding was addressed through the use of propensity score matching. RESULTS: A total of 22,908 (0.91%) pregnancies included exposure to calcium channel blockers during the final month of pregnancy. Neonatal seizures occurred in 53 (0.23%) neonates born to mothers exposed to calcium channel blockers and in 4,609 (0.18%) neonates of unexposed women (unadjusted odds ratio [OR] 1.26, 95% confidence interval [CI] 0.96-1.65). After accounting for confounders, there was no increase in risk of neonatal seizures associated with calcium channel blocker exposure (OR 0.95, 95% CI 0.70-1.30). This null finding was robust across multiple sensitivity analysis. CONCLUSION: In this large, carefully controlled, population-based cohort study, there was no significant increase in the risk of neonatal seizures in neonates attributable to maternal calcium channel blocker exposure in late pregnancy. The results suggest that calcium channel blockers can be used by obstetricians in late pregnancy without excess concern about this neonatal complication. LEVEL OF EVIDENCE: II.

Safranal, a novel protein tyrosine phosphatase 1B inhibitor, activates insulin signaling in C2C12 myotubes and improves glucose tolerance in diabetic KK-Ay mice.

SCOPE: Protein tyrosine phosphatase 1B (PTP1B) negatively regulates insulin signaling by tyrosine dephosphorylation of insulin receptor, and its increased activity and expression is implicated in the pathogenesis of insulin resistance. Hence, PTP1B inhibition is anticipated to improve insulin resistance in type 2 diabetic subjects. The aim of this study was to find a novel PTP1B inhibitor from medicinal food and to evaluate its antidiabetic effects. METHODS AND RESULTS: We found that saffron (Crocus sativus L.), which is used both as a spice and as a traditional medicine, potently inhibits PTP1B activity. Analyses of saffron extracts demonstrated that safranal, the saffron's aroma compound, is a principal PTP1B inhibitor, and induces a ligand-independent activation of insulin signaling in cultured myotubes. Our data implied that the molecular mechanism underlying the inactivation of PTP1B could be attributed to the covalent modification of the catalytic cysteinyl thiol by safranal through a Michael addition. Furthermore, safranal significantly enhanced glucose uptake through the translocation of glucose transporter 4. We also demonstrated that 2-wk oral administration of 20 mg/kg/day safranal improved impaired glucose tolerance in type 2 diabetic KK-A(y) mice. CONCLUSION: Our results strongly suggest the usefulness of safranal in antidiabetic treatment for type 2 diabetic subjects.

Functional analysis of hatomarubigin biosynthesis genes and production of a new hatomarubigin using a heterologous expression system.

The function of hatomarubigin biosynthesis genes was analyzed by heterologous expression of the hrb gene cluster. Streptomyces lividans carrying a gene cluster consisting of 25 genes (hrbR1-hrbX) with hrbY was found to produce all the known hatomarubigins including hatomarubigin D, which has a unique dimeric angucycline with a methylene linkage. Gene disruption was used in this heterologous expression system to analyze the function of hrbF, a gene with no homology to any known angucycline biosynthesis genes. A new metabolite was detected in the fermented broth of S. lividans expressing the hrb genes lacking hrbF and was designated hatomarubigin F. This compound was identified as 5-hydroxyhatomarubigin E by NMR spectroscopic analysis, suggesting that HrbF regulates the regiospecificity of oxygenation enzymes.