Early alveolar epithelial cell necrosis is a potential driver of COVID-19-induced acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) with COVID-19 is aggravated by hyperinflammatory responses even after the peak of the viral load has passed; however, its underlying mechanisms remain unclear. In the present study, analysis of the alveolar tissue injury markers and epithelial cell death markers in patients with COVID-19 revealed that COVID-19-induced ARDS was characterized by alveolar epithelial necrosis at an early disease stage. Serum levels of HMGB-1, one of the DAMPs released from necrotic cells, were also significantly elevated in these patients. Further analysis using a mouse model mimicking COVID-19-induced ARDS showed that the alveolar epithelial cell necrosis involved two forms of programmed necrosis, namely necroptosis, and pyroptosis. Finally, the neutralization of HMGB-1 attenuated alveolar tissue injury in the mouse model. Collectively, necrosis, including necroptosis and pyroptosis, is the predominant form of alveolar epithelial cell death at an early disease stage and subsequent release of DAMPs is a potential driver of COVID-19-induced ARDS.

The U-shaped association of serum iron level with disease severity in adult hospitalized patients with COVID-19

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that leads to severe respiratory failure (RF). It is known that host exposure to viral infection triggers an iron-lowering response to mitigate pathogenic load and tissue damage. However, the association between host iron-lowering response and COVID-19 severity is not clear. This two-center observational study of 136 adult hospitalized COVID-19 patients analyzed the association between disease severity and initial serum iron, total iron-binding capacity (TIBC), and transferrin saturation (TSAT) levels. Serum iron levels were significantly lower in patients with mild RF than in the non-RF group; however, there were no significant differences in iron levels between the non-RF and severe RF groups, depicting a U-shaped association between serum iron levels and disease severity. TIBC levels decreased significantly with increasing severity; consequently, TSAT was significantly higher in patients with severe RF than in other patients. Multivariate analysis including only patients with RF adjusted for age and sex demonstrated that higher serum iron and TSAT levels were independently associated with the development of severe RF, indicating that inadequate response to lower serum iron might be an exacerbating factor for COVID-19.

A mayfly’s rapid transition toward unisexual populations

Sexual reproduction is overwhelmingly the most common reproductive mode among Metazoans, although it has been secondarily lost in some organisms. Ephoron shigae is a geographically parthenogenetic mayfly. Here, we provide details of the frequency of bisexual and parthenogenetic strains of E. shigae together with data on their sex ratios in the Abukuma-gawa River and one of its downstream tributaries, the Surikami-gawa River, in Japan. In a previous study in the 1990s, bisexual populations were observed in both rivers. The present study clearly shows that sex ratios have since changed to be almost entirely unisexual within the downstream area of the Abukuma-gawa River and the Surikami-gawa River. Our genetic analyses also show that these females are of a parthenogenetic strain, and that the original bisexual strains were overwhelmed within a period of <20 years. However, it was recently observed that many males and females of the bisexual strains continue to inhabit upstream areas of the Abukuma-gawa River. Therefore, we suggest that the parthenogenetic strains have increased in abundance primarily downstream. We show that a drastic change has occurred over a short period, involving the replacement of one strain and a corresponding change in reproductive mode along a riverine environment.

Enhancement of glycolysis by inhibition of oxygen-sensing prolyl hydroxylases protects alveolar epithelial cells from acute lung injury

Cellular bioenergetic failure caused by mitochondrial dysfunction is a key process of alveolar epithelial injury during acute respiratory distress syndrome (ARDS). Prolyl hydroxylases (PHDs) act as cellular oxygen sensors, and their inhibition activates hypoxia-inducible factor (HIF), resulting in enhanced cellular glycolytic activity, which could compensate for impaired mitochondrial function and protect alveolar epithelial cells from ARDS. Here, we evaluated the effects of pharmacological PHD inhibition with dimethyloxalylglycine (DMOG) on alveolar epithelial cell injury using in vitro and in vivo ARDS models. We established an in vitro model of alveolar epithelial injury mimicking ARDS by adding isolated neutrophils and LPS to cultured MLE12 alveolar epithelial cells. DMOG treatment protected MLE12 cells from neutrophil-LPS-induced ATP decline and cell death. Knockdown of HIF-1α or inhibition of glycolysis abolished the protective effect of DMOG, suggesting that it was exerted by HIF-1-dependent enhancement of glycolysis. Additionally, intratracheal DMOG administration to mice protected the alveolar epithelial barrier and improved arterial oxygenation, preventing ATP decline during LPS-induced lung injury. In summary, enhancement of glycolysis by PHD inhibition is a potential therapeutic approach for ARDS, protecting alveolar epithelial cells from bioenergetic failure and cell death.- Tojo, K., Tamada, N., Nagamine, Y., Yazawa, T., Ota, S., Goto, T. Enhancement of glycolysis by inhibition of oxygen-sensing prolyl hydroxylases protects alveolar epithelial cells from acute lung injury. FASEB J. 32, 2258-2268 (2018). www.fasebj.org.

Inhibition of Prolyl Hydroxylase Attenuates Fas Ligand-Induced Apoptosis and Lung Injury in Mice

Alveolar epithelial injury and increased alveolar permeability are hallmarks of acute respiratory distress syndrome. Apoptosis of lung epithelial cells via the Fas/Fas ligand (FasL) pathway plays a critical role in alveolar epithelial injury. Activation of hypoxia-inducible factor (HIF)-1 by inhibition of prolyl hydroxylase domain proteins (PHDs) is a possible therapeutic approach to attenuate apoptosis and organ injury. Here, we investigated whether treatment with dimethyloxalylglycine (DMOG), an inhibitor of PHDs, could attenuate Fas/FasL-dependent apoptosis in lung epithelial cells and lung injury. DMOG increased HIF-1α protein expression in vitro in MLE-12 cells, a murine alveolar epithelial cell line. Treatment of MLE-12 cells with DMOG significantly suppressed cell surface expression of Fas and attenuated FasL-induced caspase-3 activation and apoptotic cell death. Inhibition of the HIF-1 pathway by echinomycin or small interfering RNA transfection abolished these antiapoptotic effects of DMOG. Moreover, intraperitoneal injection of DMOG in mice increased HIF-1α expression and decreased Fas expression in lung tissues. DMOG treatment significantly attenuated caspase-3 activation, apoptotic cell death in lung tissue, and the increase in alveolar permeability in mice instilled intratracheally with FasL. In addition, inflammatory responses and histopathological changes were also significantly attenuated by DMOG treatment. In conclusion, inhibition of PHDs protects lung epithelial cells from Fas/FasL-dependent apoptosis through HIF-1 activation and attenuates lung injury in mice.

Adrenaline aggravates lung injury caused by liver ischemia-reperfusion and high-tidal-volume ventilation in rats

BACKGROUND

We often administer adrenaline to improve hypotension of patients undergoing systemic inflammation that is not treated with volume resuscitation. The effects of adrenaline on injured lungs during shock status have not been elucidated. We previously demonstrated that hepatic ischemia-reperfusion followed by high-tidal-volume ventilation-induced systemic inflammation, hypotension, and lung injury in rats. Using this animal model, we investigated the effects of adrenaline on lung injury and hemodynamics.

METHODS

Anesthetized rats were ventilated and underwent hepatic inflow interruption for 15 min twice. After the second liver ischemia-reperfusion, the tidal volume was increased to 24 ml · kg(-1) body weight from 6 ml · kg(-1), and 12 rats in each group were observed for 360 min after reperfusion with or without continuous intravenous adrenaline administration. Extra fluid was administered according to the decline in the arterial blood pressure.

RESULTS

Adrenaline administration significantly reduced the volume of intravenous resuscitation fluid. The wet-to-dry weight ratio of the lungs was higher (7.53 ± 0.37 vs. 4.63 ± 0.35, P < 0.001), the partial oxygen pressure in arterial blood was lower (213 ± 48 vs. 411 ± 33, P = 0.004), and the tumor necrosis factor-α concentration in bronchoalveolar lavage (BAL) fluid was higher (10(2.64) ± 10(0.22) vs. 10(1.91) ± 10(0.27), P = 0.015), with adrenaline. Histopathological examinations revealed marked exudation in the alveolar spaces in rats receiving adrenaline.

CONCLUSIONS

Continuous administration of adrenaline partially prevented a rapid decline in blood pressure but deteriorated lung injury in a rat model of liver ischemia-reperfusion with high-tidal-volume ventilation. A possibility that adrenaline administration aggravate ventilator-induced lung injury during systemic inflammation should be considered.

Atelectasis causes alveolar hypoxia-induced inflammation during uneven mechanical ventilation in rats

BACKGROUND

Patients with acute respiratory distress syndrome receiving mechanical ventilation show inhomogeneous lung aeration. Atelectasis during uneven mechanical ventilation leads to alveolar hypoxia and could therefore result in lung inflammation and injury. We aimed to elucidate whether and how atelectasis causes alveolar hypoxia-induced inflammation during uneven mechanical ventilation in an open-chest differential-ventilation rat model.

METHODS

We first investigated inflammatory and histological changes in the bilateral lungs of unilaterally ventilated rats, in which the right lung was atelectatic and the left lung was ventilated with high tidal volume (HTV). In the next series, we investigated the effects of normal tidal volume (NTV) ventilation of the right lungs with 60 % O2 or 100 % N2 during HTV ventilation of the left lungs. Then, proinflammatory cytokine secretions were quantified from murine lung epithelial (MLE15) and murine alveolar macrophage (MH-S) cells cultured under a hypoxic condition (5 % O2) mimicking atelectasis. Further, activities of nuclear factor (NF)-κB and hypoxia-inducible factor (HIF)-1 were assessed in the nonventilated atelectatic lung and MLE15 cells cultured under the hypoxic condition. Finally, effects of NF-κB inhibition and HIF-1α knockdown on the cytokine secretions from MLE15 cells cultured under the hypoxic condition were assessed.

RESULTS

The nonventilated atelectatic lungs showed inflammatory responses and minimal histological changes comparable to those of the HTV-ventilated lungs. NTV ventilation with 60 % O2 attenuated the increase in chemokine (C-X-C motif) ligand (CXCL)-1 secretion and neutrophil accumulation observed in the atelectatic lungs, but that with 100 % N2 did not. MLE15 cells cultured with tumor necrosis factor (TNF)-α under the hypoxic condition showed increased CXCL-1 secretion. NF-κB and HIF-1α were activated in the nonventilated atelectatic lungs and MLE15 cells cultured under the hypoxic condition. NF-κB inhibition abolished the hypoxia-induced increase in CXCL-1 secretion from MLE15 cells, while HIF-1α knockdown augmented it.

CONCLUSIONS

Atelectasis causes alveolar hypoxia-induced inflammatory responses including NF-κB-dependent CXCL-1 secretion from lung epithelial cells. HIF-1 activation in lung epithelial cells is an anti-inflammatory response to alveolar hypoxia in atelectatic lungs.

Unexpected monophyletic origin of Ephoron shigae unisexual reproduction strains and their rapid expansion across Japan

The burrowing polymitarcyid mayfly Ephoron shigae is distributed across Japan, Korea, northeast China and far east Russia. Some populations are bisexual, and others are unisexual, i.e. geographically parthenogenetic throughout Japan. In general, parthenogenetic organisms are often found in harsh environments, such as at high latitudes and altitudes, in xeric as opposed to mesic conditions, in isolated habitats such as islands and island-like areas, and at the peripheral regions of the taxon's range. In E. shigae, however, the distributions of bisexual and unisexual populations overlap broadly in their respective geographical ranges. In the analysis of mitochondrial 16S rRNA and COI, we revealed that unisexual populations were of monophyletic origin and recently differentiated somewhere in western Japan. In the nuclear DNA EFI-α analysis, parthenogenetic strains had two genotypes, i.e. the heterozygous genotype of E1/E3 and the homozygous genotype of E1/E1 or E3/E3, while specimens of bisexual lineage had 20 genotypes. These results are consistent with an automixis mode of reproduction for the parthenogenetic strains, and also support the monophyletic origin of the parthenogenetic strains. Furthermore, there would be no gene flow between the specimens of the bisexual lineage and those of the parthenogenetic strain.

A pilot study of tele-anaesthesia by virtual private network between an island hospital and a mainland hospital in Japan

We studied the use of tele-anaesthesia between Sado General Hospital (SGH) located on Sado Island and Yokohama City University Hospital (YCUH) located in mainland Japan. The two sites were connected via a virtual private network (VPN). We investigated the relationship between the bandwidth of the VPN and both the frame rate and the delay time of the tele-anaesthesia monitoring system. The tool used for communication between the two hospitals was free videoconferencing software (FaceTime), which can be used over Wi-Fi connections. We also investigated the accuracy of the commands given during teleanaesthesia: any commands from the anaesthetist at the YCUH that were not carried out for any reason, were recorded in the anaesthetic records at the SGH. The original frame rate and data rate at the SGH were 5 fps and approximately 18 Mbit/s, respectively. The frame rate at the transmission speeds of 1, 5 and 20 Mbit/s was 0.6, 1.6 and 5.0 fps, respectively. The corresponding delay time was 12.2, 4.9 and 0.7 s. Twenty-five adult patients were enrolled in the study and tele-anaesthesia was performed. The total duration of anaesthesia was 37 hours. All 888 anaesthetic commands were completed. There were 7 FaceTime disconnections, which lasted for 10 min altogether. Because no commands needed to be given during the FaceTime disconnection, the telephone was not used. The anaesthesia assistance system might form part of the solution to medical resource shortages.

Edaravone prevents lung injury induced by hepatic ischemia-reperfusion

BACKGROUND

Lung injury is a major clinical concern after hepatic ischemia-reperfusion (I/R), due to the production of reactive oxygen species in the reperfused liver. We investigated the efficacy of edaravone, a potent free-radical scavenger, for attenuating lung injury after hepatic I/R.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were assigned to sham + normal saline (NS), I/R + NS, or I/R + edaravone group. Rats in the I/R groups were subjected to 90 min of partial hepatic I/R. Five minutes before reperfusion, 3 mg/kg edaravone was administered to the I/R + edaravone group. After 6 h of reperfusion, we evaluated lung histopathology and wet-to-dry ratio. We also measured malondialdehyde (MDA), an indicator of oxidative stress, in the liver and the lung, as well as cytokine messenger RNA expressions in the reperfused liver and plasma cytokine concentrations.

RESULTS

Histopathology revealed lung damages after 6 h reperfusion of partial ischemic liver. Moreover, a significant increase in lung wet-to-dry ratio was observed. MDA concentration increased in the reperfused liver, but not in the lungs. Edaravone administration attenuated the lung injury and the increase of MDA in the reperfused liver. Edaravone also suppressed the reperfusion-induced increase of interleukin-6 messenger RNA expressions in the liver and plasma interleukin-6 concentrations.

CONCLUSIONS

Edaravone administration before reperfusion of the ischemic liver attenuates oxidative stress in the reperfused liver and the subsequent lung injury. Edaravone may be beneficial for preventing lung injury induced by hepatic I/R.

Role of nerve growth factor-tyrosine kinase receptor A signaling in paclitaxel-induced peripheral neuropathy in rats

The mechanisms underlying paclitaxel-induced peripheral neuropathy remain unknown. Nerve growth factor (NGF) is a representative neurotrophic factor that maintains neuronal function, promotes survival, and mediates neuropathic pain. We investigated expression levels of NGF and its receptors in the dorsal root ganglia (DRG) and spinal dorsal horn (DH) following paclitaxel treatment. Intraperitoneal (I.P.) administration of paclitaxel induced significant mechanical hypersensitivity and cold allodynia in rats, significantly increased the expression of NGF and its receptor tyrosine kinase receptor A (trkA) in the DRG, and increased NGF expression in the DH. In contrast, paclitaxel treatment did not alter the mRNA levels of NGF or its receptors in the DRG, DH, sciatic nerve, or hindpaw skin. Moreover, expression of NEDD4-2, a negative regulator of trkA, was significantly increased in the DRG of paclitaxel-treated rats. Intrathecal (I.T.) administration of the tyrosine kinase receptor inhibitor k252a significantly alleviated mechanical hypersensitivity in paclitaxel-treated rats. Our results suggest that NGF-trkA signaling is involved in mechanical allodynia in paclitaxel-induced neuropathy.

Defect structures in nematic liquid crystals around charged particles

We numerically study the orientation deformations in nematic liquid crystals around charged particles. We set up a Ginzburg-Landau theory with inhomogeneous electric field. If the dielectric anisotropy epsilon 1 is positive, Saturn-ring defects are formed around the particles. For epsilon 1< 0 , novel "ansa" defects appear, which are disclination lines with their ends on the particle surface. We find unique defect structures around two charged particles. To lower the free energy, oppositely charged particle pairs tend to be aligned in the parallel direction for epsilon 1> 0 and in the perpendicular plane for epsilon 1< 0 with respect to the background director. For identically charged pairs the preferred directions for epsilon 1> 0 and epsilon 1< 0 are exchanged. We also examine competition between the charge-induced anchoring and the short-range anchoring. If the short-range anchoring is sufficiently strong, it can be effective in the vicinity of the surface, while the director orientation is governed by the long-range electrostatic interaction far from the surface.

Mutations of carnitine palmitoyltransferase II (CPT II) in Japanese patients with CPT II deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency is an inherited disorder involving beta-oxidation of long-chain fatty acids. CPT II deficiency is a wide-spectrum disorder that includes a lethal neonatal form, an infantile form, and an adult-onset form. However, the ethnic characteristics and the relationship between genotype and clinical manifestation are not well understood. We investigated three non-consanguineous Japanese patients with CPT II deficiency and examined cell lines from 4 unrelated patients and 50 healthy donors. The CPT 2 gene was typed by direct DNA sequencing of polymerase chain reaction-amplified gene products. Case 1 (infantile form) was heterozygous for a phenylalanine to tyrosine substitution at position 383 (p.F383Y) and a novel valine to leucine substitution at 605 (p.V605L). Cases 2, 4, and 5 (infantile form) and case 3 (adult-onset form) were heterozygous for a single mutation at F383Y. Case 6 (adult-onset form) was compound heterozygous at the CPT 2 locus, with deletion of cytosine and thymine at residue 408, resulting in a stop signal at 420 (p.Y408fsX420), and an arginine to cysteine substitution at position 631 (p.R631C). Case 7 (adult-onset form) was homozygous for the p.F383Y mutation. In conclusion, we identified p.F383Y mutations in six of seven patients with CPT II deficiency and two novel variants of the coding gene: p.Y408fsX420 and p.V605L. These mutations differ from those in Caucasian patients, who commonly harbor p.S113L, p.P50H, and p.Q413fsX449 mutations; therefore, our data and those of other Japanese groups suggest that the p.F383Y mutation is significant in Japanese patients with CPT II deficiency.

Ghrelin prevents development of diabetes at adult age in streptozotocin-treated newborn rats

AIMS/HYPOTHESIS

Ghrelin, a stomach-derived hormone, functions in multiple biological processes, including glucose metabolism and cellular differentiation and proliferation. In this study, we examined whether early treatment with ghrelin can regenerate beta cells of the pancreas in an animal model of diabetes mellitus, the n0-STZ model, in which neonatal rats are injected with streptozotocin (STZ) at birth.

METHODS

Following administration of ghrelin to n0-STZ rats from postnatal days 2 to 8, we examined beta cell mass, mRNA expression levels of insulin and of pancreatic and duodenal homeobox 1 (Pdx1) gene, and pancreatic morphology on days 21 and 70. In addition, we investigated the effects of ghrelin on beta cell replication.

RESULTS

By day 21, ghrelin treatment increased pancreatic expression of insulin and Pdx1 mRNA in n0-STZ rats. The number of replicating cells was also significantly increased in the ghrelin-treated n0-STZ model. At day 70, n0-STZ rats exhibited hyperglycaemia, despite slight increases in plasma insulin levels. Ghrelin treatment resulted in the improvement of plasma glucose levels, which were associated with normal plasma insulin levels. Pancreatic insulin mRNA and protein levels were significantly increased in ghrelin-treated n0-STZ model animals.

CONCLUSIONS/INTERPRETATION

These findings suggest that ghrelin promotes regeneration of beta cells in STZ-treated newborn rats. Thus, early administration of ghrelin may help prevent the development of diabetes in disease-prone subjects after beta cell destruction.

Skin Metabolism in Transdermal Therapeutic Systems

Skin has at least two barriers with protective functions: the stratum corneum physical barrier and a biochemical barrier in the epidermis and dermis. Numerous chemical and physical enhancers exist for transdermal therapeutic systems; some cause irritation, and possibly influence enzyme deactivation. Knowledge of enzymatic skin reactions is important for developing safe and efficacious transdermal systems for treatment not only of skin diseases but also for systemic application. This paper overviews the effects of (a) chemical enhancers and additives, (b) drug structure, and (c) physical enhancement on skin metabolism.

Pharmacokinetic model for in vivo/in vitro correlation of intravitreal drug delivery

A pharmacokinetic model of intravitreal drug delivery has been developed for describing the elimination and distribution of ocular drugs in the posterior segments of the eye. The model, based on Fick's second law of diffusion, assumes the cylindrical vitreous body with three major pathways for elimination: the posterior aqueous chamber, the retina/choroids/sclera (RCS) membrane and the lens posterior capsule. The model parameters such as the diffusion coefficient and the partition coefficient of the drug in the vitreous body and its surrounding tissues, the posterior lens capsule and the retina/choroids/sclera membrane, can be determined from in vitro membrane penetration experiments using respective rabbit tissues. The time course of in vivo mean concentration of the drug in the rabbit vitreous body following intravitreal drug delivery well agreed with the profile calculated from the present pharmacokinetic model for both membrane-controlled polymeric devices and biodegradable rod-matrix systems. The pharmacokinetic model suggests that the major route of elimination of drug molecules released from the vitreous implant is through the posterior aqueous humor because of the absence of a barrier membrane. However, the elimination through the RCS membrane cannot be overlooked because of the large diffusion area of the RCS membrane. The vitreous body concentration of the drug released from biodegradable vitreous implants can be predicted from the in vivo release rate-time profile by the present pharmacokinetic model.

Association of Graves' disease with Evans' syndrome in a patient with IgA nephropathy

A 20-year-old woman with IgA nephropathy was admitted to Jikei University Hospital for the treatment of rapid deterioration of renal function after receiving 131I-therapy against hyperthyroidism on October 23,1999, and hemodialysis was started. On admission, she was diagnosed as having Evans' syndrome in addition to known Graves' disease. Renal biopsy revealed end-stage renal damage, then, hemodialysis was maintained. Treatment for Evans' syndrome was also started and her general condition gradually improved. The present case implied that "Graves' disease" and "Evans' syndrome" could represent some of the manifestations of an underlying immunological disorder in the patient.

Coordinate regulation of endothelin and adrenomedullin secretion by oxidative stress in endothelial cells

To elucidate the significance of oxidative stress in the modulation of endothelial functions, we examined the effects of H(2)O(2) on the expression of two endothelium-derived vasoactive peptides, endothelin (ET) and adrenomedullin (Am), and their interaction. H(2)O(2) dose dependently suppressed ET secretion and ET-1 mRNA expression in bovine carotid endothelial cells (ECs). Menadion sodium bisulfate, a redox cycling drug, also decreased ET secretion in a dose-dependent manner. Catalase, a H(2)O(2) reductase, and dl-alpha-tocopherol (vitamin E) significantly inhibited H(2)O(2)-induced suppression of ET secretion. Downregulation of ET-1 mRNA under oxidative stress was regulated at the transcriptional level. In contrast, H(2)O(2) increased Am secretion (and its mRNA expression) accompanied by the augmentation of cAMP production. Am, as well as 8-bromo-cAMP and forskolin decreased ET secretion in a dose-dependent fashion. Furthermore, an anti-Am monoclonal antibody that we developed abolished H(2)O(2)-induced suppression of ET secretion at 6-24 h after the addition of H(2)O(2). H(2)O(2) increased the intracellular Ca(2+) concentration ([Ca(2+)](i)). Moreover, treatment with ionomycin, a Ca(2+) ionophore, and thapsigargin, an inhibitor of endoplasmic reticulum ATPase, decreased ET secretion dose dependently for 3 h. These results suggest that the production of ET was decreased via activation of the Am-cAMP pathway and by the elevation of [Ca(2+)](i) under oxidative stress. These findings elucidate the coordinate expression of two local vascular hormones, ET and Am, under oxidative stress, which may protect against vascular diseases.

An experimental approach to study the binding properties of vitamin E (alpha-tocopherol) during hairless mouse skin permeation

An experimental approach to study the binding properties of vitamin E has been developed. Total vitamin E solubility in the skin was determined by a partition study, followed by in vitro skin permeation studies with whole skin and stripped skin. The amount of freely diffusable vitamin E in the diffusion process was determined from the permeation profiles of whole skin and stripped skin by employing a bi-layer model. The concentrations of vitamin E in the stratum corneum and viable dermis were determined separately. By subtracting this amount from the total concentration of vitamin E in the skin, as determined by the solubility study, the amount of bound vitamin E was determined. After skin permeation reached a steady state, the donor solution was removed and the permeation study continued (desorption study). During the entire period of the desorption experiment, the amount of vitamin E in the receptor solution hardly increased and remained constant. After the desorption experiment, vitamin E still remaining in the skin was determined by extracting with tissue solubilizer, SOLABLE, and is considered as the amount of vitamin E strongly bound in the skin. The concentrations of bound vitamin E determined by permeation and desorption studies coincided relatively well. To further investigate skin binding of vitamin E, a differential scanning calorimetry study was performed. Vitamin E-treated stratum corneum showed phase transitions at 76 and 85 degrees C, associated with lipid transitions. The thermal transitions associated with the lipid transition suggested interactions of vitamin E with lipid components of the skin. During skin permeation, vitamin E forms a very strong reservoir in the skin tissue and this amount of vitamin E, about 30%, exists as a bound-form with the lipid components of the stratum corneum.

Positional dissociation between the genetic mutation responsible for pseudohypoparathyroidism type Ib and the associated methylation defect at exon A/B: evidence for a long-range regulatory element within the imprinted GNAS1 locus

Pseudohypoparathyroidism type Ib (PHP-Ib) is a paternally imprinted disorder which maps to a region on chromosome 20q13.3 that comprises GNAS1 at its telomeric boundary. Exon A/B of this gene was recently shown to display a loss of methylation in several PHP-Ib patients. In nine unrelated PHP-Ib kindreds, in whom haplotype analysis and mode of inheritance provided no evidence against linkage to this chromosomal region, we confirmed lack of exon A/B methylation for affected individuals, while unaffected carriers showed no epigenetic abnormality at this locus. However, affected individuals in one kindred (Y2) displayed additional methylation defects involving exons NESP55, AS and XL, and unaffected carriers in this family showed an abnormal methylation at exon NESP55, but not at other exons. Taken together, current evidence thus suggests that distinct mutations within or close to GNAS1 can lead to PHP-Ib and the associated epigenetic changes. To further delineate the telomeric boundary of the PHP-Ib locus, the previously reported kindred F, in which patient F-V/51 is recombinant within GNAS1, was investigated with several new markers and direct nucleotide sequence analysis. These studies revealed that F-V/51 remains recombinant at a single nucleotide polymorphism (SNP) located 1.2 kb upstream of XL. No heterozygous mutation was identified between exon XL and an SNP approximately 8 kb upstream of NESP55, where this affected individual becomes linked, suggesting that the genetic defect responsible for parathyroid hormone resistance in kindred F, and probably other PHP-Ib patients, is located >or=56 kb centromeric of the abnormally methylated exon A/B. A region upstream of the known coding exons of GNAS1 is therefore predicted to exert, presumably through imprinting of exon A/B, long-range effects on G(s)alpha expression.

The effects of sarpogrelate on cardiomyocyte hypertrophy

Sarpogrelate was developed as an antiplatelet agent antagonizing 5-hydroxytryptamine (5-HT) receptors. It had been reported that 5-HT receptors were expressed in cardiovascular system, and that sarpogrelate had antihypertrophic effects in vascular smooth muscle cells. Cardiac hypertrophy is a major problem in cardiac diseases, so the present study was designed to elucidate the effects of sarpogrelate on cardiac hypertrophy. Cultured rat cardiomyocytes (MCs) and cardiac nonmyocytes (NMCs) were prepared by Percoll gradient and adhesion method and MCs were incubated with (MCs/NMCs) or without NMCs. As an index of protein synthesis of MCs, [3H]-leucine uptake into MCs and MCs/NMCs was measured. Sarpogrelate decreased [3H]-leucine uptake into MCs (maximum 62.6+/-20.6% of control at 10(-4)M, p<0.05 vs. control). Sarpogrelate also significantly attenuated angiotensin-II- and endothelin-1-induced [3H]-leucine uptake. These results indicated that sarpogrelate might have antihypertrophic effects and could be a useful aid for cardiovascular disease.

Possible involvement of endothelin-1 in cardioprotective effects of benidipine

Benidipine hydrochloride has been developed as an antagonist for the L-type calcium channel and is used as an anti-hypertensive drug. But recent studies have reported that benidipine exerts not only antihypertensive actions but also anti-hypertrophic actions on cardiac muscles. Endothelin-1 (ET-1), one of the endogenous pathological humoral factors of cardiovascular diseases such as hypertension and heart failure, has a strong vasoconstrictive action and could induce hypertension and cardiac hypertrophy. So, it is a matter of great interest whether or not calcium antagonists can decrease cardiac hypertrophy induced by the pathological vasoactive substances such as ET-1. Thus, the present study was designed to elucidate the effects of benidipine on cardiac hypertrophy, and particularly on the interaction with ET-1, using neonatal rat cardiac myocytes (MCs) and cardiac non-myocytes (NMCs) culture systems. Cells were cultured with or without ET-1, benidipine, and nifedipine and the effects of calcium antagonists on cardiac hypertrophy were evaluated by incorporations of [3H]-leucine and [3H]-thymidine into MCs and/or NMCs. Benidipine significantly decreased the ET-1-induced increase of [3H]-leucine and [3H]-thymidine uptake into cardiac MCs and NMCs, whereas no significant effects of nifedipine were observed. Furthermore, benidipine (10(-8)M) attenuated ET-1 secretions from NMCs. In summary, benidipine at least partially decreased the cardiac hypertrophy induced by paracrine mechanisms through its attenuation of ET-1 secretions from NMCs. Benidipine could thus be a useful tool for preventing cardiac hypertrophy due to hypertension.

Characterization of bone morphogenetic protein-6 signaling pathways in osteoblast differentiation

Bone morphogenetic protein (BMP)-6 is a member of the transforming growth factor (TGF)-(β) superfamily, and is most similar to BMP-5, osteogenic protein (OP)-1/BMP-7, and OP-2/BMP-8. In the present study, we characterized the endogenous BMP-6 signaling pathway during osteoblast differentiation. BMP-6 strongly induced alkaline phosphatase (ALP) activity in cells of osteoblast lineage, including C2C12 cells, MC3T3-E1 cells, and ROB-C26 cells. The profile of binding of BMP-6 to type I and type II receptors was similar to that of OP-1/BMP-7 in C2C12 cells and MC3T3-E1 cells; BMP-6 strongly bound to activin receptor-like kinase (ALK)-2 (also termed ActR-I), together with type II receptors, i.e. BMP type II receptor (BMPR-II) and activin type II receptor (ActR-II). In addition, BMP-6 weakly bound to BMPR-IA (ALK-3), to which BMP-2 also bound. In contrast, binding of BMP-6 to BMPR-IB (ALK-6), and less efficiently to ALK-2 and BMPR-IA, together with BMPR-II was detected in ROB-C26 cells. Intracellular signalling was further studied using C2C12 and MC3T3-E1 cells. Among the receptor-regulated Smads activated by BMP receptors, BMP-6 strongly induced phosphorylation and nuclear accumulation of Smad5, and less efficiently those of Smad1. However, Smad8 was constitutively phosphorylated, and no further phosphorylation or nuclear accumulation of Smad8 by BMP-6 was observed. These findings indicate that in the process of differentiation to osteoblasts, BMP-6 binds to ALK-2 as well as other type I receptors, and transduces signals mainly through Smad5 and possibly through Smad1.

A pharmacokinetic model of intravitreal delivery of ganciclovir

A pharmacokinetic model of intravitreal drug delivery was developed for describing the elimination and distribution of ganciclovir in the eye following intravitreous polymeric delivery. The model was based on Fick's second law of diffusion and assumed a cylindrical vitreous body. The model parameters such as the diffusion coefficient and the partition coefficient of the drug in the vitreous body and its surrounding tissues were determined from in vitro experiments using rabbit tissues. The time course of in vivo mean concentration of ganciclovir in the rabbit vitreous body agreed well with the profile calculated from the present pharmacokinetic model for both membrane-controlled polymeric devices and biodegradable rod-matrix systems. The clinical vitreous concentration following implantation of the membrane-controlled delivery system was the same order of magnitude but approximately four times lower than that predicted from the present model. This may indicate the metabolism of ganciclovir and/or the facilitated transport across the retina/choroid membrane in the human eye.

Effect of ultrasound application on skin metabolism of prednisolone 21-acetate

PURPOSE

The effect of ultrasound on skin penetration and metabolism of prednisolone (PN) and prednisolone 21-acetate (PNA) was investigated in the hairless mouse skin in vitro.

METHODS

The abdominal skin excised freshly was pretreated under different ultrasound intensities (4.32, 2.88, and 1.50 W/cm2) for 10, 30, and 60 min. The penetration/metabolism rate of PNA and its metabolite (PN) was then measured using a side-by-side diffusion cell.

RESULTS

The skin penetration of PN was enhanced by the ultrasound pretreatment. This enhancement was attributed to the decrease in the stratum corneum barrier capacity by ultrasound energy. The steady-state appearance rate of PN following the skin bioconversion of PNA decreased appreciably with increasing the product of the duration of pretreatment (Dp, min) and the intensity of ultrasound applied (Iu, W/cm2). When the product value was less than 40 W/cm2 . min, the steady-state appearance rate of the PN hardly increased in spite of the penetration enhancement of PNA.

CONCLUSIONS

These findings indicated a possible deactivation of the skin enzymes by ultrasound energy.

Urocortin, a newly identified corticotropin-releasing factor-related mammalian peptide, stimulates atrial natriuretic peptide and brain natriuretic peptide secretions from neonatal rat cardiomyocytes

The effect of urocortin (UCN), a recently characterized mammalian member of corticotropin-releasing factor (CRF)-related peptide and a putative endogenous ligand for CRF type 2 beta receptor in the regulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release, was investigated using cultured neonatal rat cardiomyocytes. Treatment with UCN (10(-10)-10(-6)M) resulted in significant increase in ANP and BNP secretions, and the effect of UCN on ANP and BNP secretions was more potent than that of CRF on an equimolar basis. The effect of UCN (10(-7)M) was completely blocked by alpha-helical CRF (9-41), a specific CRF type 2 receptor antagonist. The effect of UCN (10(-7)M) was not only blunted by cAMP-dependent protein kinase A (PKA) inhibitor, H-89 (10(-5)M), but also diltiazem (10(-7)M), a voltage-dependent Ca2+ channel blocker. Further, UCN stimulated cAMP production in cardiomyocytes. Also, UCN (10(-7)M) itself stimulated [3H]leucine uptake into neonatal rat cardiomyocytes and potentiated endothelin-1-induced increase of [3H]leucine uptake. These results suggest that activation of CRF type 2 receptor, especially type 2 beta receptor, with UCN induces ANP and BNP secretions, at least in part, via PKA pathway during cardiac hypertrophy.

Oxidative stress suppresses the endothelial secretion of endothelin

To address endothelial function on vascular walls exposed to oxidative stress, we investigated the effect of oxidative stress on the secretion of endothelin-1 (ET-1) from cultured bovine carotid artery endothelial cells (BAECs). Concentrations of ET-1 in the media were measured by a specific radioimmunoassay and ET-1 mRNA expression was estimated by Northern blot analysis. Treatment of BAECs with 0.5-2.0 mM H2O2 for 3 h suppressed both ET-1 secretion and ET-1 mRNA expression in a dose-dependent manner compared to control. Attenuation of ET-1 mRNA expression by H2O2 was revealed to take place at the transcriptional level. The addition of NG-nitro-L-arginine-methyl ester (L-NAME) 10 microns, a specific nitric oxide synthase inhibitor, had no effect on H2O2-induced suppression of ET-1 mRNA expression. Suppression of ET secretion under oxidative stress observed in the present study is proposed to be a compensatory mechanism of endothelial cells to inhibit vasoconstriction and proliferation during oxidative stress.

Lingual thyroid presenting as acquired hypothyroidism in the adulthood

There are numerous reported cases of lingual thyroid with an obvious prevalence in pediatric age. Such ectopic thyroid glands are probably quantitatively deficient and thyroid function may be low or at a low normal level. Apparently, most cases of ectopic thyroid tissue develop congenital hypothyroidism, the so-called cretinism. In this report, we describe a very rare adult male case of lingual thyroid who developed hypothyroidism in adulthood; the anomaly remained undiscovered, being without local common symptoms, and permitted a normal life.

[Delivery of macromolecular drugs to the vitreous and its peripheral tissues]

We evaluated the release behavior of FITC-dextran with an average molecular weight of 4,400(FD4), as a model peptide drug, from poly(DL-lactic acid) (PLA) implant. The drug level in the vitreous and its peripheral tissues were measured following the implantation in the rabbit vitreous. The release profile of FD4 from the PLA implant was biphasic; a fraction of the drug molecules incorporated in the polymer implant was swiftly released; then slowly or even negligibly for a certain period of time and finally complete bursting release probably due to bulk erosion of the polymer. The time-course of drug concentration in the vitreous and aqueous humor after implantation showed a constant level for 14 days and then parabola, where the highest concentration appeared around 28 days. The drug concentrations in the retina/ choroid was maintained a constant level for 28 days. After an injection of FD4 in the rabbit vitreous, the drug concentration in those tissues approximately decreased mono-exponentially. These findings suggest that the present implant could be a useful carrier for delivery of macromolecular drugs to the vitreous and its peripheral tissues.

Intravitreous delivery of dexamethasone sodium m-sulfobenzoate from poly(DL-lactic acid) implants

Biodegradable intravitreal rod-shaped implants containing dexamethasone sodium m-sulfobenzoate (DMSB) were prepared from blends of poly(DL-lactic acid) (PLA) with number-average molecular weight 2000 (PLA2000) and 4000 (PLA4000). The effect of the fraction of PLA2000 on the release of DMSB from the implant was investigated after implantation in the vitreous body of rabbit eyes. After the initial burst, the drug was released slowly from the blended PLA implants with a PLA2000 fraction of below 30 wt% in normal eyes within a period of 28 d. For the implants with a higher PLA2000 fraction of over 50 wt%, the drug was released following approximately first order kinetics. In the vitrectomized eyes, the release of DMSB from the PLA2000/PLA4000 (5/5) implant was 2.5 times more rapid than in normal eyes, and the clearance of drug was also appreciably accelerated as compared with that in normal eyes.

Polymer blend implant for ocular delivery of fluorometholone

Ocular implants containing fluorometholone (FLM) were prepared using blends of poly (DL-lactic acid) (PLA) and polyvinyl pyrrolidone (PVP). The effect of the fraction of PVP content on the release of FLM from the implant was investigated in vitro. The drug was released from the device by approximately following first order kinetics within the period of 40 d. The release rate gradually increased with an increase in the PVP content. The in vivo study after implantation in the anterior chamber of rabbit eyes indicated that the PLA-PVP implant showed a good correlation between the in vitro and in vivo release of FLM. The present polymer blend implant demonstrated a constant level of FLM in the aqueous humor for one month.

Characterization of skin permeation of vitamin C: theoretical analysis of penetration profiles and differential scanning calorimetry study

A mechanism for the relatively high permeability of vitamin C in relation to the change in the protein domain of the stratum corneum has been proposed. Firstly, the skin permeation characteristics of vitamin C (l-[1-14C]-ascorbic acid) using whole skin and stripped skin of the hairless mouse were investigated. By employing a double layer model, physicochemical properties such as diffusivity and solubility of vitamin C in each skin layer, stratum corneum and viable skin were determined. Then, the high skin permeation rate of vitamin C was characterized. A differential scanning calorimetry, (DSC), study was employed to investigate the effect of vitamin C on the stratum corneum, a major diffusion barrier for the skin transport of the compound. Vitamin C was found to permeate rapidly through the skin, in spite of its low lipophilicity. The diffusivity determined from the lag-time was approximately 1000 times higher in the stripped skin, compared with whole skin. There is a dramatic increase (10-fold) in the permeation rate in stripped skin indicating the major barrier presented by the stratum corneum to the skin permeation of vitamin C. The DSC profile showed four very distinctive transitions near 100, 128, 135 and 145 degrees C which are associated with protein transitions. Comparing normal skin, the peaks are sharpened and there are additional phase transitions above 90 degrees C. An increase in sharpness reflects an increase in the hydration state of the sample, as hydrogen bonds between H2) molecules and other hydrogen donating chemicals of skin components become major chemical bonds in hydrated samples. The higher permeation rate of vitamin C observed may be due to its enhancing effect on the hydration capacity of skin and solubilizing action on the protein domain of the stratum corneum.

Binding of prednisolone and its ester prodrugs in the skin

PURPOSE

Skin binding of prednisolone and its esters was investigated in the hairless mouse skin in vitro.

METHODS

The distribution of the amount of drugs bound in the skin was determined by a skin slicing technique. The model drugs used were prednisolone (PN, M.W. 360) and its esters, senesyonate (PN-C5, M.W. 442), geranate (PN-C10, M.W. 510), farnesylate (PN-C15, M.W. 578), and geranylgeranate (PN-C20, M.W. 646).

RESULTS

The distribution of bound drug was nonhomogeneous in the skin; the concentration of PN-C10 and PN-C15 in the skin increased gradually with the distance from the skin surface. The parent drug, PN, however, was hardly bound in the viable skin.

CONCLUSIONS

These findings suggest that the prodrugs of prednisolone may prolong the dermal retention of the parent drug and minimize to delivery into the systemic circulation of the prodrug and metabolite.

Unexplained increase in serum corticosteroid-binding globulin levels in a patient with chronic thyroiditis, pituitary adenoma and empty sella

Unexplained high serum corticosteroid-binding globulin (CBG) concentrations (mean +/- SD, 74.1 +/- 12.1 micrograms/dl; normal women, 32.5 +/- 5.6 micrograms/dl) were found in an unmarried women who was not pregnant or taking exogenous estrogens. She was also found to suffer from subclinical chronic thyroiditis, pituitary adenoma and empty sella. The increased serum CBG concentrations in this patient were not due to any of the factors known to increase CBG. Consistently high basal serum GH levels and unusual GH responses to GH-releasing factor (GRF) and L-dopa were also noted.

Stimulation by corticotropin-releasing factor of atrial natriuretic peptide and brain natriuretic peptide secretions from cultured neonatal rat cardiomyocytes

The new functional role of corticotropin-releasing factor (CRF) in the regulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release was investigated using cultured neonatal rat cardiomyocytes. Treatment with CRF (10(-10)-10(-6) M) resulted in dose- and time-dependent increase in ANP and BNP secretion, up to 2.5-fold and 1.8-fold above control values, respectively. The effect was significant at 6 hr and persisted for at least 36 hr. The effect of CRF (10(-7) M) was partially blocked by alpha-helical CRF(9-41) (10(-7) M), a specific CRF receptor antagonist. The effect of CRF (10(-7) M) was not only blunted by cAMP-dependent protein kinase A (PKA) inhibitor, H-89 (10(-5) M), but also by protein kinase C inhibitors, H-7 (50 microM) and Calphostin C (10(-6) M). H-7 (50 microM) and Calphostin C (10(-6) M) alone lowered basal ANP and BNP levels. Furthermore, CRF (10(-7) M) stimulates protein synthesis up to 1.2-fold. These results indicate that CRF stimulates ANP and BNP secretions through the CRF receptor and, at least in part, via PKA activation during cardiac hypertrophy.