A Pilot Study on the Efficacy of a Diabetic Diet Containing the Rare Sugar D-Allulose in Patients with Type 2 Diabetes Mellitus: A Prospective, Randomized, Single-Blind, Crossover Study

High sugar consumption increases the risk of diabetes, obesity, and cardiovascular diseases. Regarding the diet of patients with diabetes, artificial sweeteners are considered a safe alternative to sugar; however, there is also a risk that artificial sweeteners exacerbate glucose metabolism. D-allulose (C-3 isomer of d-fructose), which is a rare sugar, has been reported to have antidiabetic and antiobesity effects. In this study, the efficacy of a diabetic diet containing D-allulose was investigated in patients with type 2 diabetes using an intermittently scanned continuous glucose monitoring system (isCGM). This study was a validated, prospective, single-blind, randomized, crossover comparative study. Comparison of peak postprandial blood glucose (PPG) levels after consumption of a standard diabetic diet and a diabetic diet containing 8.5 g of D-allulose was the primary endpoint. A D-allulose-containing diabetic diet improved PPG levels in type two diabetes patients compared with a strictly energy-controlled diabetic diet. The results also showed a protective effect on endogenous pancreatic insulin secretory capacity owing to reduced insulin requirement. In patients with type two diabetes mellitus, diabetic diets containing 8.5 g D-allulose were effective in improving PPG levels.

Knowledge of diabetes and the practice of diabetes self-management during Ramadan fasting among patients with type 2 diabetes in Malaysia

BACKGROUND AND AIMS

To assess the level of diabetes knowledge and its association with diabetes self-management practices during Ramadan fasting among patients with type 2 diabetes (T2D).

METHODS

A cross-sectional study was conducted involving a sample of Malaysian patients with T2D. Patients aged 18 years and above, and attending an outpatient diabetic unit of a government hospital were recruited between February and April 2021. A self-administered questionnaire was utilized to assess diabetes knowledge and diabetes self-management practices.

RESULTS

A total of 306 participants completed the questionnaire. Most of them were females (54.2%) and above 55 years old (75.1%). Resultantly, knowledge of diabetes was considered average among 52% of the participants. Only 9.5% of them avoided the consumption of sweet foods during iftar. Practicing late suhoor (p = 0.012) and self-monitoring of blood glucose (SMBG) (p = 0.026) during Ramadan were significantly associated with a better diabetes knowledge score. Education level (p = 0.000), working status (p = 0.030), and monthly income (p = 0.000) were significantly associated with participants' knowledge level of diabetes. A higher proportion (72.2%) of the participants completed fasting for a month during Ramadan 2020. Meanwhile, hypoglycemia was the main reason (38.8%) for incomplete fasting.

CONCLUSIONS

These findings reflect the need to improve patients' knowledge of diabetes and diabetes self-management practices, especially during Ramadan. Such objectives could be achieved by considering the associated factors identified in this study.

A pilot study on the effect of D-allulose on postprandial glucose levels in patients with type 2 diabetes mellitus during Ramadan fasting

BACKGROUND

During Ramadan fasting, postprandial hyperglycemia is commonly observed after iftar (break of fast at sunset) meal. D-allulose is a rare sugar and is reported to have several health benefits, including the suppression of increase in postprandial glucose levels. This study investigates whether D-allulose (a C-3 epimer of D-fructose) improves the postprandial glucose in patients with type 2 diabetes mellitus (T2DM) during Ramadan.

METHODS

This was a pilot, prospective single-arm study design that was conducted for 10 consecutive days; 5 days of control and 5 days of consumption. The primary outcome was postprandial peak glucose levels. During the consumption period, 8.5 g of D-allulose was consumed by the participants before iftar meal. Postprandial glucose was measured using a continuous glucose monitoring system.

RESULTS

A total of 12 participants completed the study. Significant lower (p < 0.01) postprandial glucose values and the glucose incremental area under the curve (iAUC) were observed from 0 to 180 min during the consumption period compared to the control period. The consumption period demonstrated significantly higher percentages of time in which glucose values were found in the target range (p = 0.0032), and when the glucose levels above the target range were reduced (p = 0.0015).

CONCLUSIONS

The supplementation with D-allulose has the potential to improve postprandial hyperglycemia in patients with T2DM after iftar during Ramadan. Further studies are needed to confirm these findings. Trial registration ClinicalTrials.gov NCT05071950. Retrospectively registered, 8 October 2021.

Effects of 2-Methoxyestradiol, a Main Metabolite of Estradiol on Hepatic ABCA1 Expression in HepG2 Cells

ATP-binding cassette transporter A1 (ABCA1) is a key regulator of lipid efflux, and the absence of ABCA1 induces hepatic lipid accumulation, which is one of the major causes of fatty liver. 2-Methoxyestradiol (2-ME₂) has been demonstrated to protect against fatty liver. In this study, we investigated the effects of 2-ME₂ on the hepatic lipid content and ABCA1 expression. We found that 2-ME₂ dose-dependently increased ABCA1 expression, and therefore, the lipid content was significantly decreased in HepG2 cells. 2-ME₂ enhanced the ABCA1 promoter activity; however, this effect was reduced after the inhibition of the PI3K pathway. The overexpression of Akt or p110 induced ABCA1 promoter activity, while dominant-negative Akt diminished the ability of 2-ME₂ on ABCA1 promoter activity. Further, 2-ME₂ stimulated the rapid phosphorylation of Akt and FoxO1 and reduced the nuclear accumulation of FoxO1. Chromatin immunoprecipitation confirmed that FoxO1 bonded to the ABCA1 promoter region. The binding was reduced by 2-ME₂, which facilitated ABCA1 gene transcription. Furthermore, mutating FoxO1-binding sites in the ABCA1 promoter region or treatment with FoxO1-specific siRNA disrupted the effect of 2-ME₂ on ABCA1 expression. All of our results demonstrated that 2-ME₂ might upregulate ABCA1 expression via the PI3K/Akt/FoxO1 pathway, which thus reduces the lipid content in hepatocytes.

HDL promotes adiponectin gene expression via the CAMKK/CAMKIV pathway

Adiponectin (APN) is an adipokine that protects against diabetes and atherosclerosis. High-density lipoprotein (HDL) mediates reverse cholesterol transport, which also protects against atherosclerosis. In this process, the human homolog of the B class type I scavenger receptor (SR-BI/CLA-1) facilitates the cellular uptake of cholesterol from HDL. The level of circulating APN is positively correlated with the serum level of HDL-cholesterol. In this study, we investigated whether HDL stimulates the gene expression of APN through the Ca2+/calmodulin (CaM)-dependent protein kinase IV (CaMKIV) cascade. APN expression was examined using real-time PCR and western blot analysis in 3T3-L1 cells incubated with HDL. CaMKIV activity was assessed by the detection of activation loop phosphorylation (at Thr196 residue), and the effect of the constitutively active form, CaMKIVc, on APN promoter activity was investigated. Our results showed that HDL stimulated APN gene expression via hSR-BI/CLA-1. Furthermore, we explored the signaling pathways by which HDL stimulated APN expression in 3T3-L1 cells. The stimulation of APN gene expression by HDL appears to be mediated by CaMKK, as STO-609, a specific inhibitor of CaMKK2, prevents this effect. We revealed that CaMKIVc increased APN gene transcriptional activity, and the CaMKIV-dominant negative mutant blocked the effect of HDL on APN promoter activity. Finally, knockdown of hSR-BI/CLA-1 also canceled the effect of HDL on APN gene expression. These results suggest that HDL has an important role to improve the function of adipocytes by activating hSR-BI/CLA-1, and CaMKK/CaMKIV pathway is conceivable as one of the signaling pathways of this activation mechanism.

Oxidized LDL Downregulates ABCA1 Expression via MEK/ERK/LXR Pathway in INS-1 Cells

Impaired insulin secretion is one of the main causes of type 2 diabetes. Cholesterol accumulation-induced lipotoxicity contributes to impaired insulin secretion in pancreatic beta cells. However, the detailed mechanism in this process remains unclear. In this study, we proved that oxidized low-density lipoprotein (OxLDL) reduced insulin content, decreased PDX-1 expression, and impaired glucose-stimulated insulin secretion (GSIS) in INS-1 cells, which were rescued by addition of high-density lipoprotein (HDL). OxLDL receptors and cholesterol content were increased by OxLDL. Consistently, OxLDL suppressed cholesterol transporter ABCA1 expression and transcription in a dose-dependent and time-dependent manner. Inhibition of MEK by its specific inhibitor, PD98059, altered the effect of OxLDL on ABCA1 transcription and activation of ERK. Next, chromatin immunoprecipitation assay demonstrated that liver X receptor (LXR) could directly bind to ABCA1 promoter and this binding was inhibited by OxLDL. Furthermore, OxLDL decreased the nuclear LXR expression, which was prevented by HDL. LXR-enhanced ABCA1 transcription was suppressed by OxLDL, and the effect was cancelled by mutation of the LXR-binding sites. In summary, our study shows that OxLDL down-regulates ABCA1 expression by MEK/ERK/LXR pathway, leading to cholesterol accumulation in INS-1 cells, which may result in impaired insulin synthesis and GSIS.

Treatment with 2-methoxyestradiol increases endothelial nitric oxide synthase activity via scavenger receptor class BI in human umbilical vein endothelial cells

Concentrations of 2-methoxyestradiol (2ME2), a principal metabolite of estradiol, are significantly lower in women with severe preeclampsia. Nitric oxide (NO) released by endothelial nitric oxide synthase (eNOS) plays an important role in regulating cardiovascular homeostasis. Importantly, high-density lipoprotein (HDL) stimulates eNOS activity via endothelial human scavenger receptor class B type I (hSR-BI/CLA-1). Here, we aimed to determine the effect of 2ME2 on hSR-BI/CLA-1 expression in human umbilical vein endothelial cells (HUVECs). hSR-BI/CLA-1 expression was measured by real-time PCR, western blotting and reporter gene assays; eNOS activity was assessed by the measurement of eNOS phosphorylation. Both the mRNA and protein concentrations of hSR-BI/CLA-1 were significantly increased by 2ME2 in HUVECs. 2ME2 also dose-dependently increased the transcriptional activity of the hSR-BI/CLA-1 promoter. The effect of 2ME2 treatment on the promoter activity of hSR-BI/CLA-1 was abrogated by treatment with LY294002, a specific inhibitor of phosphatidylinositol 3-kinase, as was the increase in HDL-induced eNOS activation. Notably, constitutively active Akt increased the activity of the hSR-BI/CLA-1 promoter, whereas dominant-negative Akt abolished the effect of 2ME2 treatment on hSR-BI/CLA-1 promoter activity. The nuclear Sp1 protein concentration was significantly increased by exposure to 2ME2 and Sp1 overexpression increased the promoter activity of the hSR-BI/CLA gene. Furthermore, knockdown of Sp1 inhibited the effect of 2ME2 treatment on hSR-BI/CLA-1 protein expression. These results indicate that 2ME2 treatment increases HDL-dependent eNOS phosphorylation by upregulating endothelial hSR-BI/CLA-1 expression, suggesting that 2ME2 has a potential therapeutic value in the treatment of preeclampsia.

Candidate plasticity gene 16 and jun dimerization protein 2 are involved in the suppression of insulin gene expression in rat pancreatic INS-1 β-cells

Chronic hyperglycemia causes pancreatic β-cell dysfunction, impaired insulin secretion and the suppression of insulin gene expression. This phenomenon is referred to as glucotoxicity, and is a critical component of the pathogenesis of type 2 diabetes. We previously reported that the expression of candidate plasticity gene 16 (CPG16) was higher in rat pancreatic INS-1 β-cells under glucotoxic conditions and CPG16 suppressed insulin promoter activity. However, the molecular mechanisms of the CPG16-mediated suppression of insulin gene expression are unclear. In this study, we found that CPG16 directly bound and phosphorylated jun dimerization protein 2 (JDP2), an AP-1 family transcription factor. CPG16 co-localized with JDP2 in the nucleus of INS-1 cells. JDP2 bound to the G1 element of the insulin promoter and up-regulated promoter activity. Finally, CPG16 suppressed the up-regulation of insulin promoter activity by JDP2 in a kinase activity-dependent manner. These results suggest that CPG16 suppresses insulin promoter activity by phosphorylating JDP2.

Successful Therapy Using Pasireotide Long-acting Release for Cushing's Disease Merged with Biochemical Acromegaly

It is quite rare that Cushing's disease shows acromegaly, and no pharmacotherapy has yet been discussed. A 21-year-old woman was diagnosed with Cushing's disease and underwent trans-sphenoidal surgery. Five years later, she was diagnosed with recurrent Cushing's disease and biochemical acromegaly because of elevated levels of serum growth hormone (GH), plasma insulin-like growth factor-1, plasma adrenocorticotropic hormone (ACTH), and the 24-hour urinary excretion of free cortisol. After treatment initiation with pasireotide-long-acting release (LAR), both the ACTH and GH declined. Our case is the first to show the efficacy of pasireotide-LAR in controlling both Cushing's disease and acromegaly.

AGEs inhibit scavenger receptor class B type I gene expression via Smad1 in HUVECs

Vascular complications are the main cause of morbidity and mortality in diabetic patients, and advanced glycation end products (AGEs) play a critical role in promoting diabetic vascular dysfunction. The human homolog of scavenger receptor class B type I (SR-BI), CD36, and LIMPII analog-1 (hSR-BI/CLA-1) facilitates the cellular uptake of cholesterol from HDL. In endothelial cells, HDL activates endothelial nitric oxide synthase (eNOS) via hSR-BI/CLA-1. In this study, we elucidated the effects of AGEs on hSR-BI/CLA-1 expression in human umbilical vein endothelial cells (HUVECs). HSR-BI/CLA-1 expression was examined by real-time PCR, western blot analysis, and reporter gene assay in HUVECs incubated with AGEs. eNOS activity was assessed by detecting the phosphorylation (Ser 1179) of eNOS. Our results showed that AGEs decreased the endogenous expression of hSR-BI/CLA-1. AGEs also inhibited the activity of the hSR-BI/CLA-1 promoter and its mRNA expression via receptor RAGE. We identified the binding site for Smad1 on the hSR-BI/CLA-1 promoter: Smad1 bound to its promoter. AGE treatment stimulated the transcriptional activity of Smad1, and mutation of the Smad1 binding site inhibited the effect of AGEs on the hSR-BI/CLA-1 promoter. HDL-treatment enhanced the phosphorylation of eNOS at Ser 1179, but pretreatment with AGEs inhibited the phosphorylation of eNOS Ser 1179. These results suggested that AGEs downregulate the expression of the endothelial hSR-BI/CLA-1 via the Smad1 pathway, which may be a therapeutic target for diabetic endothelial dysfunction.

Ectopic Cortisol-producing Adrenocortical Adenoma Detected by 131I-6β-iodomethyl-norcholesterol Scintigraphy

A 50-year-old man was referred to our department for overt Cushing's syndrome (CS). His plasma cortisol concentrations were 314 μg/L, and his urinary cortisol concentrations were 431 μg/day. The plasma adrenocorticotropic hormone (ACTH) concentration was below the detectable limit. Computed tomography revealed atrophy of both adrenal glands and the presence of a left pararenal tumor. 131I-6β-iodomethyl-norcholesterol scintigraphy showed an intense uptake by the left pararenal tumor. These findings suggested that the left pararenal tumor was ectopic cortisol-producing adrenocortical adenoma. This case serves as a reminder that 131I-6β-iodomethyl-norcholesterol scintigraphy is an effective method for diagnosing ACTH-independent CS in which no adrenal tumor has been found.

Role of ATP-binding cassette transporter A1 in suppressing lipid accumulation by glucagon-like peptide-1 agonist in hepatocytes

Objective

Adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) influences hepatic cholesterol transportation. Accumulation of hepatic cholesterol leads to fatty liver disease, which is improved by glucagon-like peptide 1 (GLP-1) in diabetes. Therefore, we analyzed the molecular mechanism in the regulation of hepatic ABCA1 by GLP-1 analogue exendin-4.

Methods

Hepatic ABCA1 expression and transcription were checked by western blotting, real-time polymerase chain reaction (PCR), and luciferase assay in HepG2 cells. Chromatin immunoprecipitation (ChIP) and site-directed mutagenesis were employed to determine transcriptional regulation of the ABCA1 gene. Prolactin regulatory element-binding (PREB)-transgenic mice were generated to access the effect of exendin-4 on improving lipid accumulation caused by a high-fat diet (HFD).

Results

Exendin-4 stimulated hepatic ABCA1 expression and transcription via the Ca²⁺/calmodulin (CaM)-dependent protein kinase kinase/CaM-dependent protein kinase IV (CaMKK/CaMKIV) pathway, whereas GLP-1 receptor antagonist exendin9-39 cancelled this effect. Therefore, exendin-4 decreased hepatic lipid content. ChIP showed that PREB could directly bind to the ABCA1 promoter, which was enhanced by exendin-4. Moreover, PREB stimulated ABCA1 promoter activity, and mutation of PREB-binding site in ABCA1 promoter cancelled exendin-4-enhanced ABCA1 promoter activity. Silencing of PREB attenuated the effect of exendin-4 and induced hepatic cholesterol accumulation. Blockade of CaMKK by STO-609 or siRNA cancelled the upregulation of ABCA1 and PREB induced by exendin-4. In vivo, exendin-4 or overexpression of PREB increased hepatic ABCA1 expression and decreased hepatic lipid accumulation and high plasma cholesterol caused by a HFD.

Conclusions

Our data shows that exendin-4 stimulates hepatic ABCA1 expression and decreases lipid accumulation by the CaMKK/CaMKIV/PREB pathway, suggesting that ABCA1 and PREB might be the therapeutic targets in fatty liver disease.

•

The GLP-1R agonist exendin-4 suppressed lipid accumulation by upregulating ABCA1 expression in hepatocytes.

•

Exendin-4 regulated the expression and transcription of hepatic ABCA1 via the CaMKK/CaMKIV/PREB pathway.

•

Overexpression of PREB or exendin-4 protected mouse liver from fatty liver by upregulation of ABCA1.

Bilateral Adrenocortical Adenomas along with Virilization and Cushing's Syndrome

We herein present the case of a 27-year-old woman with clinical and biochemical features of virilism. Imaging studies revealed the presence of a bilateral adrenal tumor. Although the secretion of androgens was remarkable, the autonomous production of cortisol was also evident because of a loss of circadian rhythm and the absence of cortisol suppression by dexamethasone. The surgical excision of both adrenal tumors was performed, and the histological examination showed no malignancy. We also report the successful pregnancy and delivery of the patient who showed evolving adrenocortical insufficiency along with virilization and Cushing's syndrome and who continued to receive glucocorticoid replacement therapy during pregnancy.

IGF1 suppresses cholesterol accumulation in the liver of growth hormone-deficient mice via the activation of ABCA1

Recently, several clinical studies have suggested that adult growth hormone (GH) deficiency that also has low concentration of IGF1 is associated with an increased prevalence of fatty liver (FL). ATP-binding cassette transporter A1 (ABCA1) is a pivotal regulator of lipid efflux from cells to apolipoproteins and plays an important role on formation of FL. In this study, we determined the effects of IGF1 on ABCA1 expression in GH-deficient mice to clarify its effects on FL. Western blotting, real-time PCR, and a luciferase assay were employed to examine the effect of IGF1. The binding of FoxO1 to the ABCA1 promoter was assessed by chromatin immunoprecipitation (ChIP) assay. Cholesterol accumulation was analyzed by Oil Red O stain and cholesterol content measurement. We confirmed that IGF1 upregulated the ABCA1 expression. The activity of a reporter construct containing the ABCA1 promoter was induced by IGF1, and this effect was blocked by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K). Constitutively active Akt stimulated the ABCA1 promoter activity, and a dominant-negative mutant of Akt or mutagenesis of the FoxO1 response element abolished the effect of IGF1. A ChIP assay indicated that FoxO1 mediated IGF1 transcriptional activity by directly binding to the ABCA1 promoter region. For in vivo experiments, we used an inhibitor for the GH receptor (Pegvisomant) to reduce the IGF1 level. A high-fat diet induced FL in mice (C57BL/6J) given Pegvisomant treatment. IGF1 treatment stimulated ABCA1 expression to improve cholesterol accumulation in these mice. These results show that the PI3K/Akt/FoxO1 pathway contributes to the regulation of ABCA1 expression in response to IGF1 stimulation that suppressed FL in GH-deficient mice.

Effect of TNF-α on the expression of ABCA1 in pancreatic β-cells

ATP-binding cassette transporter A1 (ABCA1), a 254-kD membrane protein, is a key regulator of lipid efflux from cells to apolipoproteins. ABCA1 in pancreatic β-cells influences insulin secretion and cholesterol homeostasis. Tumor necrosis factor (TNF)-α is a pleiotropic cytokine that elicits a wide spectrum of physiological events, including cell proliferation, differentiation, and apoptosis, and is also known to decrease glucose-dependent insulin secretion in pancreatic islets. In the present study, we examined the role of TNF-α on ABCA1 expression in rat pancreatic islets and INS-1 cells. ABCA1 protein levels decreased in response to rising concentrations of TNF-α in pancreatic islets. Real-time polymerase chain reaction analysis showed a significant decrease in ABCA1 mRNA expression. In parallel with its effect on endogenous ABCA1 mRNA levels, TNF-α suppressed the activity of a reporter construct containing the ABCA1 promoter. This effect was abrogated by BIRB796, but not by SB203580 or PD98095. The constitutively active form of p38 mitogen-activated protein kinase (MAPK) γ suppressed ABCA1 promoter activity but not p38-MAPK (α, β), while a dominant-negative mutant of p38-MAPK γ blocked the effect of TNF-α on ABCA1 promoter activity. BIRB796 inhibited the increased cholesterol ester content induced by TNF-α. However, BIRB796 had no effect on the decreased insulin content nor ABCA1 suppression caused by TNF-α in INS-1 cells. In summary, TNF-α suppressed the expression of endogenous ABCA1 in pancreatic islets and INS-1 cells. These findings raise the possibility that TNF-α may affect insulin secretion by controlling ABCA1 expression.

Selective peroxisome proliferator-activated receptor-α modulator K-877 regulates the expression of ATP-binding cassette transporter A1 in pancreatic beta cells

ATP-binding cassette transporter A1 (ABCA1) protein is a pivotal regulator of cholesterol and phospholipid efflux from cells to high-density lipoprotein (HDL) particles. Pancreatic ABCA1 functions in beta cell cholesterol homeostasis and affects insulin secretion. We investigated the effect of pemafibrate (K-877), a novel selective PPARα modulator (SPPARMα), on pancreatic ABCA1 expression. In vivo experiment, mice were divided into four treatment groups, namely, normal food plus placebo, high fat diet (HFD) plus placebo, normal food plus K-877 (0.3 mg/kg/day), or HFD plus K-877 (0.3 mg/kg/day), and treated for eight weeks. The results in vitro experiment indicate that K-877 treatment increased levels of ABCA1 mRNA, as well as protein, subsequently reduced the cellular cholesterol content in INS-1 cells. PPARα specific antagonist GW6471 attenuate K-877 induced ABCA1 expression in INS-1 cells. ABCA1 promoter activity increased with K-877 treatment at concentration 1 μM and 10 μM. Glucose-stimulated insulin secretion was ameliorated by K-877 treatment in INS-1 cells and isolated mouse islets. Although the expression of ABCA1 was reduced in mice with HFD treatment, both ABCA1 protein and mRNA levels were increased in mice with K-877 treatment. K-877 treatment improved glucose intolerance induced by HFD in mice. These findings raise the possibility that K-877 may affect insulin secretion by controlling ABCA1 expression in pancreatic beta cells.

Angiotensin II induces cholesterol accumulation and impairs insulin secretion by regulating ABCA1 in beta cells

In pancreatic β cells, ABCA1, a 254 kDa membrane protein, affects cholesterol homeostasis and insulin secretion. Angiotensin II, as the main effector of the renin-angiotensin system, decreases glucose-stimulated insulin secretion (GSIS). We examined the effect of angiotensin II on ABCA1 expression in primary pancreatic islets and INS-1 cells. Angiotensin II decreased ABCA1 protein and mRNA; angiotensin II type 1 receptor (AT1R) blockade rescued this ABCA1 repression. In parallel, angiotensin II suppressed the promoter activity of ABCA1, an effect that was abrogated by PD98095, a specific inhibitor of MAPK kinase (MEK). LXR enhanced ABCA1 promoter activity, and angiotensin II decreased the nuclear abundance of LXR protein. On a chromatin immunoprecipitation assay, LXR mediated the transcription of ABCA1 by directly binding to its promoter. Mutation of the LXR binding site on the ABCA1 promoter cancelled the effect of angiotensin II. Furthermore, angiotensin II induced cholesterol accumulation and impaired GSIS; inhibition of AT1R or MEK pathway reversed these effects. In summary, our study showed that angiotensin II suppressed ABCA1 expression in pancreatic islets and INS-1 cells, indicating that angiotensin II may influence GSIS by regulating ABCA1 expression. Additional research may address therapeutic needs in diseases such as diabetes mellitus.

Combination therapy of ipilimumab and nivolumab induced thyroid storm in a patient with Hashimoto's disease and diabetes mellitus: a case report

BACKGROUND

Recently, immune checkpoint inhibitors have widely been used for the management of advanced melanoma. However, high-grade immune-related adverse events can occur, particularly with combination immunotherapy. We report a case of a patient with melanoma who developed thyroid storm following treatment with ipilimumab and nivolumab.

CASE PRESENTATION

An 85-year-old Japanese man with a history of malignant melanoma presented to our department with severe thyrotoxicosis and poor blood glucose control. He was already being treated for Hashimoto's disease and type 2 diabetes mellitus before the treatment for the melanoma. During admission, laboratory investigations revealed the following thyroid functions: thyroid-stimulating hormone below sensitivity, free triiodothyronine 31.7 pg/ml, and thyroglobulin 48,000 IU/ml. Thyroid-stimulating hormone receptor antibody was negative, and a ^99mTc-labeled thyroid scan revealed a markedly decreased uptake. He was treated with beta-blocker, orally administered potassium iodine, a relatively low dose of prednisolone, and insulin injection therapy to control his blood glucose, resulting in an improvement in thyroid function and his symptoms.

CONCLUSION

It might be important to be aware of the possibility of thyroid storm induced by immune checkpoint inhibitors.

Blockade of the KATP channel Kir6.2 by memantine represents a novel mechanism relevant to Alzheimer's disease therapy

Here, we report a novel target of the drug memantine, ATP-sensitive K⁺ (K_ATP) channels, potentially relevant to memory improvement. We confirmed that memantine antagonizes memory impairment in Alzheimer's model APP23 mice. Memantine increased CaMKII activity in the APP23 mouse hippocampus, and memantine-induced enhancement of hippocampal long-term potentiation (LTP) and CaMKII activity was totally abolished by treatment with pinacidil, a specific opener of K_ATP channels. Memantine also inhibited Kir6.1 and Kir6.2 K_ATP channels and elevated intracellular Ca²⁺ concentrations in neuro2A cells overexpressing Kir6.1 or Kir6.2. Kir6.2 was preferentially expressed at postsynaptic regions of hippocampal neurons, whereas Kir6.1 was predominant in dendrites and cell bodies of pyramidal neurons. Finally, we confirmed that Kir6.2 mutant mice exhibit severe memory deficits and impaired hippocampal LTP, impairments that cannot be rescued by memantine administration. Altogether, our studies show that memantine modulates Kir6.2 activity, and that the Kir6.2 channel is a novel target for therapeutics to improve memory impairment in Alzheimer disease patients.

12-OH-17,18-Epoxyeicosatetraenoic acid alleviates eosinophilic airway inflammation in murine lungs

BACKGROUND

Asthma is characterized by airway inflammation and obstruction with eosinophil infiltration into the airway. Arachidonic acid, an omega-6 fatty acid, is metabolized into cysteinyl leukotriene with pro-inflammatory properties for allergic inflammation, whereas the omega-3 fatty acid eicosapentaenoic acid (EPA) and its downstream metabolites are known to have anti-inflammatory effects. In this study, we investigated the mechanism underlying the counter-regulatory roles of EPA in inflamed lungs.

METHODS

Male C57BL6 mice were sensitized and challenged by ovalbumin (OVA). After EPA treatment, we evaluated the cell count of Bronchoalveolar lavage fluid (BALF), mRNA expressions in the lungs by q-PCR, and the amounts of lipid mediators by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipidomics. We investigated the effect of the metabolite of EPA by in vivo and in vitro studies.

RESULTS

Eicosapentaenoic acid treatment reduced the accumulation of eosinophils in the airway and decreased mRNA expression of selected inflammatory mediators in the lung. Lipidomics clarified the metabolomic profile in the lungs. Among EPA-derived metabolites, 12-hydroxy-17,18-epoxyeicosatetraenoic acid (12-OH-17,18-EpETE) was identified as one of the major biosynthesized molecules; the production of this molecule was amplified by EPA administration and allergic inflammation. Intravenous administration of 12-OH-17,18-EpETE attenuated airway eosinophilic inflammation through downregulation of C-C chemokine motif 11 (CCL11) mRNA expression in the lungs. In vitro, this molecule also inhibited the release of CCL11 from human airway epithelial cells stimulated with interleukin-4.

CONCLUSION

These results demonstrated that EPA alleviated airway eosinophilic inflammation through its conversion into bioactive metabolites. Additionally, our results suggest that 12-OH-17,18-EpETE is a potential therapeutic target for the management of asthma.

Thyroid stimulating hormone stimulates the expression of glucose transporter 2 via its receptor in pancreatic β cell line, INS-1 cells

Thyroid stimulating hormone (TSH) stimulates the secretion of thyroid hormones by binding the TSH receptor (TSHR). TSHR is well-known to be expressed in thyroid tissue, excepting it, TSHR has also been expressed in many other tissues. In this study, we have examined the expression of TSHR in rat pancreatic islets and evaluated the role of TSH in regulating pancreas-specific gene expression. TSHR was confirmed to be expressed in rodent pancreatic islets and its cell line, INS-1 cells. TSH directly affected the glucose uptake in INS cells by up-regulating the expression of GLUT2, and furthermore this process was blocked by SB203580, the specific inhibitor of the p38 MAPK signaling pathway. Similarly, TSH stimulated GLUT2 promoter activity, while both a dominant-negative p38MAPK α isoform (p38MAPK α-DN) and the specific inhibitor for p38MAPK α abolished the stimulatory effect of TSH on GLUT2 promoter activity. Finally, INS-1 cells treated with TSH showed increased protein level of glucokinase and enhanced glucose-stimulated insulin secretion. Together, these results confirm that TSHR is expressed in INS-1 cells and rat pancreatic islets, and suggest that activation of the p38MAPK α might be required for TSH-induced GLUT2 gene transcription in pancreatic β cells.

Endocytosis following dopamine D2 receptor activation is critical for neuronal activity and dendritic spine formation via Rabex-5/PDGFRβ signaling in striatopallidal medium spiny neurons

Aberrant dopamine D₂ receptor (D₂R) activity is associated with neuropsychiatric disorders, making those receptors targets for antipsychotic drugs. Here, we report that novel signaling through the intracellularly localized D₂R long isoform (D_2LR) elicits extracellular signal-regulated kinase (ERK) activation and dendritic spine formation through Rabex-5/platelet-derived growth factor receptor-β (PDGFRβ)-mediated endocytosis in mouse striatum. We found that D_2LR directly binds to and activates Rabex-5, promoting early-endosome formation. Endosomes containing D_2LR and PDGFRβ are then transported to the Golgi apparatus, where those complexes trigger Gαi3-mediated ERK signaling. Loss of intracellular D_2LR-mediated ERK activation decreased neuronal activity and dendritic spine density in striatopallidal medium spiny neurons (MSNs). In addition, dendritic spine density in striatopallidal MSNs significantly increased following treatment of striatal slices from wild-type mice with quinpirole, a D₂R agonist, but those changes were lacking in D_2LR knockout mice. Moreover, intracellular D_2LR signaling mediated effects of a typical antipsychotic drug, haloperidol, in inducing catalepsy behavior. Taken together, intracellular D_2LR signaling through Rabex-5/PDGFRβ is critical for ERK activation, dendritic spine formation and neuronal activity in striatopallidal MSNs of mice.

Prolactin regulatory element-binding protein is involved in suppression of the adiponectin gene in vivo

PURPOSE

Prolactin regulatory element-binding protein (PREB), a member of the WD-repeat protein family, has been recognized as a transcriptional factor that regulates prolactin promoter activity in the anterior pituitary of rats. PREB is expressed not only in the pituitary but also in various other tissues, including the adipose tissue. Previous studies have shown that PREB acts as a transcriptional regulator and suppresses the expression of the adiponectin gene in cultured 3T3L1 preadipocytes. The aim of this study was to further examine the potential role of PREB in adipose tissue in vivo.

METHODS

Transgenic mice that overexpressing PREB (PREB transgenic mice) were generated. Insulin resistance was evaluated in PREB transgenic mice using glucose and insulin tolerance tests. Adiponectin expression in the adipose tissue was examined by western blot analysis and quantitative polymerase chain reaction (qPCR). The expression levels of stearoyl-CoA desaturase (Scd) and adiponectin receptor 2(ADIPOR2) were quantified by qPCR.

RESULTS

Glucose and insulin tolerance tests revealed insulin resistance in PREB transgenic mice. Serum adiponectin and leptin concentrations were decreased. Adiponectin gene expression was decreased in the adipose tissue, which was confirmed by the downregulation of the adiponectin-dependent hepatic Scd gene and upregulation of the ADIPOR2 gene in the liver of PREB transgenic mice. We also found that pioglitazone, an agonist for the peroxisome proliferator-activated receptor-r, improved the insulin resistance in the PREB transgenic mice after a 10-day feeding period.

CONCLUSIONS

These results demonstrated that PREB might contribute to the regulation of adiponectin gene expression in vivo.

Roles of lipoprotein receptors in the entry of hepatitis C virus

Infection by hepatitis C virus (HCV), a plus-stranded RNA virus that can cause cirrhosis and hepatocellular carcinoma, is one of the major health problems in the world. HCV infection is considered as a multi-step complex process and correlated with abnormal metabolism of lipoprotein. In addition, virus attacks hepatocytes by the initial attaching viral envelop glycoprotein E1/E2 to receptors of lipoproteins on host cells. With the development of HCV model system, mechanisms of HCV cell entry through lipoprotein uptake and its receptor have been extensively studied in detail. Here we summarize recent knowledge about the role of lipoprotein receptors, scavenger receptor class B type I and low-density lipoprotein receptor in the entry of HCV, providing a foundation of novel targeting therapeutic tools against HCV infection.

Difference in the effects of switching from candesartan to olmesartan or telmisartan to olmesartan in hypertensive patients with type 2 diabetes: the COTO study

Purpose

This open-label controlled study compared the therapeutic efficacy of three representative angiotensin II receptor blockers (ARBs) in hypertensive patients with type 2 diabetes attending a hospital outpatient clinic. The primary measure in this study was morning home blood pressure (BP).

Patients and methods

Two studies were done concurrently to investigate the effects of switching from two different ARBs to olmesartan. Patients prescribed candesartan (8 mg once daily in the morning) or telmisartan (40 mg once daily in the morning) for 16 weeks were switched to olmesartan (20 mg once daily in the morning) for 16 weeks. Then, they were switched back to candesartan (CO group) or telmisartan (TO group) for another 16 weeks.

Results

Data from all patients in the CO group (n=165) and the TO group (n=152) were analyzed. Clinic and morning home BP and urinary albumin levels showed a significant decrease from baseline at 16 weeks after switching to olmesartan in both the CO and the TO group (clinic BP, morning home diastolic BP, and urinary albumin, P<0.05; morning home systolic BP, P<0.01). In contrast, clinic BP, morning home BP, and urinary albumin were significantly increased again 16 weeks after switching back to candesartan or telmisartan (clinic BP, morning home diastolic BP, and urinary albumin, P<0.05; morning home systolic BP, P<0.01). No subjects experienced an adverse reaction that required withdrawal from the study. No adverse reactions attributable to the study drugs were observed.

Conclusion

Olmesartan is a promising ARB for BP control in hypertensive type 2 diabetics.

Increased plasma levels of high mobility group box 1 in patients with acute liver failure

BACKGROUND

High-mobility group box 1 (HMGB1) is a monocyte-derived late-acting inflammatory mediator, which is released in conditions such as shock, tissue injury and endotoxin-induced lethality. In this study, we determined the plasma and hepatic tissue levels of HMGB1 in patients with acute liver failure (ALF).

PATIENTS AND METHODS

We determined the plasma levels of HMGB1 and aspartate aminotransferase (AST) in 7 healthy volunteers (HVs), 40 patients with liver cirrhosis (LC), 37 patients with chronic hepatitis (CH), 18 patients with severe acute hepatitis (AH), and 14 patients with fulminant hepatitis (FH). The 14 patients with FH were divided into two subgroups depending upon the history of plasma exchange (PE) before their plasma sample collection. The hepatic levels of HMGB1 were measured in tissue samples from 3 patients with FH who underwent living-donor liver transplantation and from 3 healthy living donors. Hepatic tissue samples were also subjected to immunohistochemical examination for HMGB1.

RESULTS

The plasma levels of HMGB1 (ng/ml) were higher in patients with liver diseases, especially in FH patients with no history of PE, than in HVs (0.3 ± 0.3 in HVs, 4.0 ± 2.0 in LC, 5.2 ± 2.6 in CH, 8.6 ± 4.8 in severe AH, 7.8 ± 2.7 in FH with a history of PE, and 12.5 ± 2.6 in FH with no history of PE, p < 0.05 in each comparison). There was a strong and statistically significant relationship between the mean plasma HMGB1 level and the logarithm of the mean AST level (R = 0.900, p < 0.05). The hepatic tissue levels of HMGB1 (ng/mg tissue protein) were lower in patients with FH than in healthy donors (539 ± 116 in FH vs. 874 ± 81 in healthy donors, p < 0.05). Immunohistochemical staining for HMGB1 was strong and clear in the nuclei of hepatocytes in liver sections from healthy donors, but little staining in either nuclei or cytoplasm was evident in specimens from patients with FH.

CONCLUSION

We confirmed that plasma HMGB1 levels were increased in patients with ALF. Based on a comparison between HMGB1 contents in normal and ALF livers, it is very likely that HMGB1 is released from injured liver tissue.

Time-course effects of St John's wort on the pharmacokinetics of cyclosporine in dogs: interactions between herbal extracts and drugs

To clarify the interaction between St John's wort (SJW) and cyclosporine (CsA) in dogs, the pharmacokinetics of CsA before and during the repeated administration of SJW were analyzed. In the SJW group, SJW (300 mg) was given orally to four dogs every 24 h for 14 days. A single dose of CsA (5 mg/kg) was given orally 7 days before and 7 and 14 days after the initiation of the repeated administration of SJW. In the Control group, a single dose of CsA (5 mg/kg) was given orally to four other dogs in accordance with that in the SJW group. Blood samples from both groups were collected, and whole-blood concentrations of CsA were determined using high-performance liquid chromatography with UV detection. The maximum whole-blood concentration and AUC(0-∞) of the SJW group were significantly lower and the CL(tot) /F and V(d) /F were significantly higher than those in the Control group 7 and 14 days after the initiation of repeated SJW. Thus, repeated administrations of SJW affect the pharmacokinetic profiles of CsA in dogs. Further studies are necessary to elucidate the mechanisms of interaction between SJW and CsA in dogs.

Prognostic relevance of the lymph node ratio in surgical patients with extrahepatic cholangiocarcinoma

AIM

Few studies have investigated the influence of the lymph node ratio (LNR), the ratio of the number of lymph nodes harboring metastatic cancer to the total number of lymph nodes removed, on the outcome after surgery for extrahepatic cholangiocarcinoma. This study was conducted to examine the prognostic impact of LNR in patients undergoing resection for extrahepatic cholangiocarcinoma.

PATIENTS AND METHODS

We retrospectively analyzed a total of 60 consecutive patients who underwent resection for extrahepatic cholangiocarcinoma. We focused on the LNR, which was classified as 0 in 34 patients, between 0 and 0.2 in 13 patients, and greater than 0.2 in 13 patients.

RESULTS

The overall five-year survival rates for patients with LNRs of 0, 0 to 0.2, and ≥0.2 were 44%, 10%, and 0%, respectively (p = 0.023). LNR was an independent predictive factor for estimated survival by both univariate (p = 0.016) and multivariate (p = 0.022) analyses including LNR, the sites of the primary tumors, and surgical margin as the variables. There were no statistically significant differences between patients who had less than 12 lymph nodes removed and those who had 12 or more lymph nodes removed (p = 0.484).

CONCLUSION

LNR was a powerful, independent predictor of estimated survival in patients undergoing surgical resection for extrahepatic cholangiocarcinoma. LNR should be considered when stratifying patients for future clinical trials.

Pharmacokinetics of nicorandil in dogs with mild mitral regurgitation

The aim of this study was to examine the pharmacokinetics of nicorandil, a hybrid of an adenosine triphosphate-sensitive potassium channel opener and a nitrate, and to estimate its clinical doses in dogs with mild mitral valve regurgitation (MR). Nicorandil (0.1, 0.3, and 1.0 mg/kg) was administered orally to normal dogs and those with experimentally-induced MR, and its plasma concentrations were analyzed using high-performance liquid chromatography. Plasma concentrations increased dose-dependently after the administration of nicorandil, and were not different between normal dogs and those with MR. Similar to the effective plasma values obtained in cardiac disease in humans, the findings of this pharmacokinetic study may indicate that a dose of 0.3-1.0 mg/kg has the same effectiveness in dogs with cardiac dysfunction.

Platelet-activating factor-induced synaptic facilitation is associated with increased calcium/calmodulin-dependent protein kinase II, protein kinase C and extracellular signal-regulated kinase activities in the rat hippocampal CA1 region

Platelet-activating factor (PAF) is an important inflammatory lipid mediator affecting neural plasticity. In the present study, we demonstrated how PAF affects synaptic efficacy through activation of protein kinases in the rat hippocampal CA1 region. In cultured hippocampal neurons, 10 to 1000 nM PAF stimulated autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) and phosphorylation of synapsin I and myristoylated alanine-rich protein kinase C substrate (MARCKS). In hippocampal CA1 slices, field excitatory postsynaptic potentials (fEPSPs) induced by stimulation of the Schaffer collateral/commissural pathways were significantly increased 10-50 min after exposure to 100 to 1000 nM PAF. Immunoblotting analysis showed that 100 nM PAF treatment for 10 or 50 min significantly and persistently increased CaMKII autophosphorylation in the hippocampal CA1 region. Increased protein kinase Calpha (PKCalpha) autophosphorylation was also seen at the same time point after PAF exposure. By contrast, extracellular signal-regulated kinase (ERK) phosphorylation was slightly but significantly increased at 10 min after PAF exposure. Consistent with increased CaMKII autophosphorylation, AMPA-type glutamate receptor subunit 1 (GluR1) (Ser-831) phosphorylation as a CaMKII postsynaptic substrate significantly increased after 10 or 50 min of treatment, whereas synapsin I (Ser-603) phosphorylation as a presynaptic substrate increased at 10 min in the hippocampal CA1 region. Phosphorylation of MARCKS (Ser-152/156) and NMDA receptor subunit 1 (NR1) (Ser-896) as PKCalpha substrates also significantly increased after 10 min but had not further increased by 50 min in the CA1 region. Increased of fEPSPs induced by PAF treatment completely and/or partly inhibited by KN93 and/or U0126 treatment. These results suggest that PAF induces synaptic facilitation through activation of CaMKII, PKC and ERK in the hippocampal CA1 region.