Current status of delirium assessment tools in the intensive care unit: a prospective multicenter observational survey.

Delirium is a critical challenge in the intensive care unit (ICU) or high care unit (HCU) setting and is associated with poor outcomes. There is not much literature on how many patients in this setting are assessed for delirium and what tools are used. This study investigated the status of delirium assessment tools of patients in the ICU/HCU. We conducted a multicenter prospective observational study among 20 institutions. Data for patients who were admitted to and discharged from the ICU/HCU during a 1-month study period were collected from each institution using a survey sheet. The primary outcome was the usage rate of delirium assessment tools on an institution- and patient-basis. Secondary outcomes were the delirium prevalence assessed by each institution's assessment tool, comparison of delirium prevalence between delirium assessment tools, delirium prevalence at the end of ICH/HCU stay, and the relationship between potential factors related to delirium and the development of delirium. Result showed that 95% of institutions used the Intensive Care Delirium Screening Checklist (ICDSC) or the Confusion Assessment Method for the ICU (CAM-ICU) to assess delirium in their ICU/HCU, and the remaining one used another assessment scale. The usage rate (at least once during the ICU/HCU stay) of the ICDSC and the CAM-ICU among individual patients were 64.5% and 25.1%, and only 8.2% of enrolled patients were not assessed by any delirium assessment tool. The prevalence of delirium during ICU/HCU stay was 17.9%, and the prevalence of delirium at the end of the ICU/HCU stay was 5.9%. In conclusion, all institutions used delirium assessment tools in the ICU/HCU, and most patients received delirium assessment. The prevalence of delirium was 17.9%, and two-thirds of patients had recovered at discharge from ICU/HCU.Trial registration number: UMIN000037834.

Therapeutic effect of carbon monoxide-releasing molecule-3 on acute lung injury after hemorrhagic shock and resuscitation.

Hemorrhagic shock and resuscitation (HSR) induces a pulmonary inflammatory response and frequently causes acute lung injury. Carbon monoxide-releasing molecule-3 (CORM-3) has been reported to liberate and deliver CO under physiological conditions, which exerts organ-protective effects during systemic insults. The present study aimed to determine whether the administration of CORM-3 following HSR exerts a therapeutic effect against HSR-induced lung injury without any detrimental effects on oxygenation and hemodynamics. To induce hemorrhagic shock, rats were bled to a mean arterial blood pressure of 30 mmHg for 45 min and then resuscitated with the shed blood. CORM-3 or a vehicle was intravenously administered immediately following the completion of resuscitation. The rats were divided into four groups, including sham, HSR, HSR/CORM-3 and HSR/inactive CORM-3 groups. Arterial blood gas parameters and vital signs were recorded during HSR. The histopathological changes to the lungs were evaluated using a lung injury score, while pulmonary edema was evaluated on the basis of the protein concentration in bronchoalveolar lavage fluid and the lung wet/dry ratio. We also investigated the pulmonary expression levels of inflammatory mediators and apoptotic markers such as cleaved caspase-3 and transferase-mediated dUTP-fluorescein isothiocyanate nick-end labeling (TUNEL) staining. Although HSR caused significant lung histopathological damage and pulmonary edema, CORM-3 significantly ameliorated this damage. CORM-3 also attenuated the HSR-induced upregulation of tumor necrosis factor-α, inducible nitric oxide synthase and interleukin-1ß genes, and the expression of interleukin-1ß and macrophage inflammatory protein-2. In addition, the expression of interleukin-10, an anti-inflammatory cytokine, was inversely enhanced by CORM-3, which also reduced the number of TUNEL-positive cells and the expression of cleaved caspase-3 following HSR. Although CORM-3 was administered during the acute phase of HSR, it did not exert any influence on arterial blood gas analysis data and vital signs during HSR. Therefore, treatment with CORM-3 ameliorated HSR-induced lung injury, at least partially, through anti-inflammatory and anti-apoptotic effects, without any detrimental effects on oxygenation and hemodynamics.

[A Case of Well Leg Compartment Syndrome after Robot-assisted Laparoscopic Prostatectomy].

We report a case of well leg compartment syndrome (WLCS) in both legs after robot-assisted laparoscopic prostatectomy (RALP). A 65-year-old man underwent surgery for prostate cancer. He was placed in the lithotomy position and both his legs were protected with elastic stockings and intermittent pneumatic com- pression to prevent deep vein thrombosis during sur- gery. After surgery, he complained of pain in both calves. Movement and sensory disorder along with swelling were found in both legs. Computed tomogra- phy of the legs showed damage to the soleus and gas- trocnemius muscles of both legs. The creatinine phos- phokinase level had increased to 10,560 IU · l⁻¹. The patient was diagnosed with WLCS in both legs and underwent conservative treatment. Symptoms in both legs started to improve from the next day. The right leg swelling receded within 10 days, while the left leg swelling receded 67 days after surgery. WLCS in the legs after RALP is a rare but severe complication requiring early diagnosis and intervention. To prevent WLCS, it is important that we recognize this disease as a potential complication after RALP.

[Delayed emergence from general anesthesia in a dementia patient with Lewy bodies].

A 73-year-old man (164cm height 51 kg body weight) with a history of Parkinson's disease and dementia was scheduled for a cervical lymph node biopsy under general anesthesia. We induced anesthesia with thiamylal and fentanyl, and maintained with sevoflurane and remifentanil without any incident. The patient did not emerge from anesthesia after the surgery. He developed coma and did not respond to painful stimuli. However, his breathing was spontaneous with stable hemodynamics. Although naloxone was given, he was still comatose. His clinical neurological findings showed no organic abnormalities. Forty minutes after the surgery, he suddenly woke up and followed instructions. We learned that previously he had been diagnosed with dementia with Lewy bodies.

Spontaneous intraocular hemorrhage in rats during postnatal ocular development.

To study spontaneous intraocular hemorrhage in rats during postnatal ocular development and to elucidate the underlying mechanism, postnatal ocular development in the albino Wistar Hannover (WH) and Sprague-Dawley (SpD) and pigmented Long-Evans (LE) strains was analyzed. Pups (n = 2 to 5) from each strain were euthanized daily on postnatal days (PND) 0 through 21 and their eyes examined macroscopically and histologically; similar analyses were performed in 26 to 39 additional WH pups daily from PND 7 to 14. At necropsy, ring-shaped red regions and red spots were present in the eyes of WH and SpD rats. These lesions were attributed histologically to hemorrhage of the tunica vasculosa lentis or of the retina, choroid, and hyaloid artery, respectively. Similar intraocular hemorrhages occurred in LE rats, although the macroscopic alterations found in WH and SpD rats were not present in this strain. Among the 3 strains evaluated, the incidence of the intraocular hemorrhage was highest in WH rats. We here showed that intraocular hemorrhage occurs spontaneously during normal ocular development in rats regardless of the strain; however, the region, degree, and incidence of intraocular hemorrhage differ among strains. Hemorrhage in the tunica vasculosa lentis and hyaloid artery may result from the leakage of erythrocytes from the temporary vasculature of these tissues during regression. The mechanisms underlying hemorrhage in the retina and choroid remain unclear. To our knowledge, this report is the first to describe the spontaneous intraocular hemorrhage that occurs during postnatal ocular development in rats.

[Three cases of perioperative anaphylaxis identified by using skin-prick tests].

We encountered three cases of perioperative anaphylaxis identified by using skin-prick tests. [Case 1] A 43-year-old woman was scheduled to undergo elective laparoscopic subtotal gastrectomy under general anesthesia for gastric tumor. However, the procedure was cancelled because of anaphylaxis that was noted at the beginning of the surgery. We performed a skin-prick test and observed a positive reaction with ro- curonium. [Case 2] A 79-year-old man underwent laparoscopic colon resection under general anesthesia for colon cancer. Anaphylaxis was noted at the end of surgery. We performed a skin-prick test and observed a positive reaction with sugammadex. [Case 3] A 44-year-old woman underwent myomectomy under general anesthesia for a uterine fibroid. Anaphylaxis was noted approximately 10 minutes after the beginning of surgery. We performed a skin-prick test and noted a positive reaction with latex. It is difficult to identify the reason for anaphylaxis during surgery under general anesthesia because various agents may be responsible for the anaphylactic reaction. Anaphylaxis during surgery is a rare but life-threatening event and it is important to identify the causative agent for anaphylaxis.

Ligand-independent androgen receptor antagonism caused by the newly developed pesticide pyrifluquinazon (PFQ).

Androgen receptor (AR) is an essential component to activate AR dependent gene transcriptions. Despite wide acceptance of pharmacological controls on transcriptional pathway depending on competitive inhibitions of ligand binding, only a few examples, AR antagonism via ligand-independent mechanisms, have been recognized. Pyrifluquinazon(PFQ), a newly developed pesticide, induced representative AR antagonism against rats in in vivo and in vitro. Intriguingly, this AR antagonism was not based on inhibition of ligand binding. Instead, the evidence suggested that the AR antagonism was induced as a consequence of decline of cellular AR protein level. This study demonstrated that AR N-terminal region could be an essential element for a ligand-independent mechanism underling the AR antagonism by PFQ. Our findings should provide a novel insight into the regulation of AR-mediated transcription.

EET agonist prevents adiposity and vascular dysfunction in rats fed a high fat diet via a decrease in Bach 1 and an increase in HO-1 levels.

Recent reports have shown interplay between EETs (epoxides) and the heme oxygenase (HO) system in attenuating adipogenesis in cell culture models; prompting an examination of the effectiveness of EET agonist on obesity and associated cardio-metabolic dysfunction. Patho-physiological effects of an EET agonist (NUDSA) were contrasted in the absence and in the presence of stannous mesoporphyrin (an HO inhibitor) in SD rats fed a high fat (58%, HF) for 16 weeks. Animals on HF diet exhibited enhanced oxidative stress, increased levels of inflammatory cytokines and decreased levels of adiponectin along with reduced vascular and adipose tissue levels of EETs, HO-1; as compared to control rats (11% dietary fat). Treatment with NUDSA not only reversed serum adiponectin and vascular and adipose tissue levels of EETs and HO-1, but also, decreased blood pressure, subcutaneous and visceral fat content and serum TNFα and IL-6 levels in rats on HF diet. Aortic endothelial function, peNOS expression and adipose tissue markers of energy homeostasis i.e. pAMPK, Sirt1 and FAS, impaired in rats fed a HF diet, were restored in animals treated with this EET agonist. That NUDSA enhanced HO-1 expression, was accompanied by increase in p-GSK-3ß and pAKT levels along with attenuation of adipose tissue levels of Bach 1--the transcriptional suppresser of HO-1 expression. Prevention of these beneficial effects of NUDSA, in animals on HF diet and concurrently exposed to NUDSA and SnMP, supports the role of EET-HO interaction in mediating such effects. Taken together, our findings suggest that the EETs stimulate HO-1 expression via suppression of Bach 1 and interplay of these two systems affords vascular and metabolic protection in diet induced obesity.

High-fat diet exacerbates renal dysfunction in SHR: reversal by induction of HO-1-adiponectin axis.

High-dietary fat intake is a major risk factor for development of metabolic and cardiovascular-renal dysfunction including obesity, coronary artery disease, hypertension, and chronic renal failure. We examined the effect of a high-fat diet on renal function and morphology in spontaneously hypertensive rats (SHR), a phenotype designed to mimic metabolic syndrome. High-fat diet induced increase (P < 0.05) in blood pressure, body weight, and renal lipid deposition in these rats. This increase in body weight was accompanied by elevations (P < 0.05) of blood glucose and low-density lipoprotein (LDL) levels, a decrease (P < 0.05) in adiponectin and increases (P < 0.05) in plasma monocyte chemotactic protein-1 (MCP-1) along with renal macrophage infiltration. These pathophysiological perturbations were attenuated (P < 0.05) by heme oxygenase-1 (HO-1) induction by treatment with cobalt protoporphyrin (CoPP). Further effects of CoPP included increased (P < 0.05) renal expression of adiponectin along with enhancement (P < 0.05) of pAKT, pAMPK, and p-eNOS in SHRs fed a high-fat diet. Prevention of such beneficial effects of CoPP by the concurrent administration of the heme-HO inhibitor stannous mesoporphyrin (SnMP) corroborates the role of HO system in mediating such effects. Taken together, our results demonstrate that high-fat diet induces a metabolic syndrome-like phenotype in hypertensive rats, which is amenable to rescue by increases in HO-1- and adiponectin-dependent pathways.

Lentiviral-human heme oxygenase targeting endothelium improved vascular function in angiotensin II animal model of hypertension.

We examined the hypothesis that vascular and renal dysfunction caused by angiotensin II (Ang II) through increased levels of blood pressure, inflammatory cytokines, and oxidative stress in Sprague-Dawley rats can be prevented by lentiviral-mediated delivery of endothelial heme oxygenase (HO)-1. We targeted the vascular endothelium using a lentiviral construct expressing human HO-1 under the control of the endothelium-specific promoter VE-cadherin (VECAD-HO-1) and examined the effect of long-term human HO-1 expression on blood pressure in Ang II-mediated increases in blood pressure and oxidant stress. A bolus injection of VECAD-HO-1 into the renal artery resulted in expression of human HO-1 for up to 6-9 weeks. Sprague-Dawley rats were implanted with Ang II minipumps and treated with lentivirus carrying either the HO-1 or green fluorescent protein. Renal tissue from VECAD-HO-1-transduced rats expresses human HO-1 mRNA and proteins without an effect on endogenous HO-1. Infusion of Ang II increased blood pressure (p < 0.001) but decreased vascular relaxation in response to acetylcholine, endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (peNOS) levels, and renal and plasma levels of adiponectin (p < 0.05); in contrast, plasma tumor necrosis factor-α and monocyte chemoattractant protein-1 levels increased. Ang II-treated animals had higher levels of superoxide anion and inducible nitric oxide synthase and increased urinary protein and plasma creatinine levels. Lentiviral transduction with the VECAD-HO-1 construct attenuated the increase in blood pressure (p < 0.05), improved vascular relaxation, increased plasma adiponectin, and prevented the elevation in urinary protein and plasma creatinine in Ang II-treated rats. Endothelial-specific expression of HO-1 also reduced oxidative stress and levels of inflammatory cytokines resulting in increased expression of the anti-apoptotic proteins phosphorylated AKT, phosphorylated AMP-activated protein kinase, peNOS, and eNOS. Collectively, these findings demonstrate that endothelial-specific increases in HO-1 expression attenuate Ang II hypertension and the associated vascular dysfunction that is associated with increases in adiponectin and peNOS and reductions in oxidative stress and levels of inflammatory cytokines.

CYP4A2-induced hypertension is 20-hydroxyeicosatetraenoic acid- and angiotensin II-dependent.

We have shown previously that increased vascular endothelial expression of CYP4A2 leads to 20-hydroxyeicosatetraenoic (20-HETE)-dependent hypertension. The renin-angiotensin system is a key regulator of blood pressure. In this study, we examined possible interactions between 20-HETE and the renin-angiotensin system. In normotensive (110±3 mm Hg) Sprague-Dawley rats transduced with a lentivirus expressing the CYP4A2 cDNA under the control of an endothelial-specific promoter (VECAD-4A2), systolic blood pressure increased rapidly, reaching 139±1, 145±3, and 150±2 mm Hg at 3, 5, and 10 days after transduction; blood pressure remained elevated, thereafter, with maximum levels of 163±3 mm Hg. Treatment with lisinopril, losartan, or the 20-HETE antagonist 20-hydroxyeicosa-6(Z), 15(Z)-dienoic acid decreased blood pressure to control values, but blood pressure returned to its high levels after cessation of treatment. Endothelial-specific overexpression of CYP4A2 resulted in increased expression of vascular angiotensin-converting enzyme (ACE) and angiotensin II type 1 receptor and increased levels of plasma and tissue angiotensin II; all were attenuated by treatment with HET0016, an inhibitor of 20-HETE synthesis, or with 20-hydroxyeicosa-6(Z), 15(Z)-dienoic acid. In cultured endothelial cells, 20-HETE specifically and potently induced ACE expression without altering the expression of ACE2, angiotensinogen, or angiotensin II receptors. This is the first study to demonstrate that 20-HETE, a key constrictor eicosanoid in the microcirculation, induces ACE and angiotensin II type 1 receptor expression and increases angiotensin II levels, suggesting that the mechanisms by which 20-HETE promotes hypertension include activation of the renin-angiotensin system that is likely initiated at the level of ACE induction.

Protective effect of carbon monoxide inhalation on lung injury after hemorrhagic shock/resuscitation in rats.

BACKGROUND: Hemorrhagic shock and resuscitation (HSR) induces pulmonary inflammation that leads to acute lung injury. Carbon monoxide (CO), a by-product of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. The aim of this study was to examine the effects of CO inhalation at low concentration on lung injury induced by HSR in rats. METHODS: Rats were subjected to HSR by bleeding to achieve mean arterial pressure of 30 mm Hg for 60 minutes followed by resuscitation with shed blood and saline as needed to restore blood pressure. HSR animals were either maintained in room air or were exposed to CO at 250 ppm for 1 hour before and 3 hours after HSR. RESULTS: HSR caused an increase in the DNA binding activity of nuclear factor-kappaB and activator protein-1 in the lung followed by the up-regulation of pulmonary gene expression of tumor necrosis factor-alpha, inducible nitric oxide synthase, and interleukin (IL)-10. HSR also resulted in an increase in myeloperoxidase activity and wet weight to dry weight ratio in the lung, and more prominent histopathologic changes including congestion, edema, cellular infiltration, and hemorrhage. In contrast, CO inhalation significantly ameliorated these inflammatory events as judged by fewer histologic changes, less up-regulation of inflammatory mediators, and less activation of nuclear factor-kappaB and activator protein-1. Interestingly, the protective effects against lung injury afforded by CO were associated with further increases in mRNA expression of IL-10 in the lung. CONCLUSIONS: These findings suggest that inhaled CO at a low concentration ameliorated HSR-induced lung injury and attenuated inflammatory cascades by up-regulation of anti-inflammatory IL-10.

Role of heme oxygenase-1 in protection of the kidney after hemorrhagic shock.

Hemorrhagic shock followed by resuscitation (HSR) causes oxidative stress, which results in multiple organ damage. The kidney is one of the target organs of HSR-mediated oxidative tissue injury. Heme oxygenase (HO)-1, the rate-limiting enzyme in heme catabolism, is induced by oxidative stress; it protects against oxidative tissue injuries. The aim of the present study was to examine the role of renal HO-1 induction after HSR. Rats were subjected to hemorrhagic shock to achieve a mean arterial pressure of 30 mmHg for 60 min, followed by resuscitation with the shed blood. HSR resulted in a significant increase in functional HO-1 protein in the tubular epithelial cells of the kidney, whereas HSR resulted in only a slight increase in gene expression of tumor necrosis factor (TNF)-alpha and inducible nitric oxide synthase (iNOS), and in protein expression of activated caspase-3 solely in renal cells where HO-1 expression was absent. HSR also resulted in a significant increase in Bcl-2 gene expression. Pretreatment of HSR animals with tin-mesoporphyrin (0.5 micromol/kg), a specific competitive inhibitor of HO activity, resulted in a significant decrease in HO activity and exacerbated tissue inflammation and apoptotic cell death as judged by the marked increase in expression of TNF-alpha and iNOS, and in activated caspase-3-positive cells, and the significant reduction in Bcl-2 expression, respectively. These findings indicate that HO-1 induction is an adaptive response to HSR-induced oxidative stress and is essential for protecting tubular epithelial cells from oxidative damage through its anti-inflammatory and anti-apoptotic properties.

Epoxyeicosatrienoic acid agonist regulates human mesenchymal stem cell-derived adipocytes through activation of HO-1-pAKT signaling and a decrease in PPARγ.

Human mesenchymal stem cells (MSCs) expressed substantial levels of CYP2J2, a major CYP450 involved in epoxyeicosatrienoic acid (EET) formation. MSCs synthesized significant levels of EETs (65.8 ± 5.8 pg/mg protein) and dihydroxyeicosatrienoic acids (DHETs) (15.83 ± 1.62 pg/mg protein), suggesting the presence of soluble epoxide hydrolase (sEH). The addition of an sEH inhibitor to MSC culture decreased adipogenesis. EETs decreased MSC-derived adipocytes in a concentration-dependent manner, 8,9- and 14,15-EET having the maximum reductive effect on adipogenesis. We examined the effect of 12-(3-hexylureido)dodec-8(Z)-enoic acid, an EET agonist, on MSC-derived adipocytes and demonstrated an increased number of healthy small adipocytes, attenuated fatty acid synthase (FAS) levels (P < 0.01), and reduced PPARγ, C/EBPα, FAS, and lipid accumulation (P < 0.05). These effects were accompanied by increased levels of heme oxygenase (HO)-1 and adiponectin (P < 0.05), and increased glucose uptake (P < 0.05). Inhibition of HO activity or AKT by tin mesoporphyrin (SnMP) and LY2940002, respectively, reversed EET-induced inhibition of adipogenesis, suggesting that activation of the HO-1-adiponectin axis underlies EET effect in MSCs. These findings indicate that EETs decrease MSC-derived adipocyte stem cell differentiation by upregulation of HO-1-adiponectin-AKT signaling and play essential roles in the regulation of adipocyte differentiation by inhibiting PPARγ, C/EBPα, and FAS and in stem cell development. These novel observations highlight the seminal role of arachidonic acid metabolism in MSCs and suggest that an EET agonist may have potential therapeutic use in the treatment of dyslipidemia, diabetes, and the metabolic syndrome.

Epoxyeicosatrienoic acid agonist rescues the metabolic syndrome phenotype of HO-2-null mice.

Heme oxygenase (HO) and cytochrome P450 (P450)-derived epoxyeicosatrienoic acids (EETs) participate in vascular protection, and recent studies suggest these two systems are functionally linked. We examined the consequences of HO deficiency on P450-derived EETs with regard to body weight, adiposity, insulin resistance, blood pressure, and vascular function in HO-2-null mice. The HO-2-null mice were obese, displayed insulin resistance, and had high blood pressure. HO-2 deficiency was associated with decreases in cyp2c expression, EET levels, HO-1 expression, and HO activity and with an increase in superoxide production and an impairment in the relaxing response to acetylcholine. In addition, HO-2-null mice exhibited increases in serum levels of tumor necrosis factor (TNF)-alpha and macrophage chemoattractant protein (MCP)-1 and a decrease in serum adiponectin levels. Treatment of HO-2-null mice with a dual-activity EET agonist/soluble epoxide hydrolase inhibitor increased renal and vascular EET levels and HO-1 expression, lowered blood pressure, prevented body weight gain, increased insulin sensitivity, reduced subcutaneous and visceral fat, and decreased serum TNF-alpha and MCP-1, while increasing adiponectin and restoring the relaxing responses to acetylcholine. The decrease in cyp2c expression and EETs levels in HO-2-null mice underscores the importance of the HO system in the regulation of epoxygenase levels and suggests that protection against obesity-induced cardiovascular complications requires interplay between these two systems. A deficiency in one of these protective systems may contribute to the adverse manifestations associated with the clinical progression of the metabolic syndrome.

Endothelial-specific CYP4A2 overexpression leads to renal injury and hypertension via increased production of 20-HETE.

We have previously reported that adenoviral-mediated delivery of cytochrome P-450 (CYP) 4A2, which catalyzes the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE), results in endothelial dysfunction and hypertension in Sprague-Dawley (SD) rats (Wang JS, Singh H, Zhang F, Ishizuka T, Deng H, Kemp R, Wolin MS, Hintze TH, Abraham NG, Nasjletti A, Laniado-Schwartzman M. Circ Res 98: 962-969, 2006). In this study, we targeted the vascular endothelium by using a lentivirus construct expressing CYP4A2 under the control of the endothelium-specific promoter VE-cadherin (VECAD-4A2) and examined the effect of long-term CYP4A2 overexpression on blood pressure and kidney function in SD rats. A bolus injection of VECAD-4A2 increased blood pressure (P < 0.001) by 26, 36, and 30 mmHg 10, 20, and 30 days postinjection, respectively. Arteries from VECAD-4A2-transduced rats produced increased levels of 20-HETE (P < 0.01), expressed lower levels of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (p-eNOS) (P < 0.05), generated higher levels of superoxide anion, and displayed decreased relaxing responsiveness to acetylcholine (P < 0.05). Proteinuria increased by twofold in VECAD-4A2-transduced rats compared with controls. Treatment of VECAD-4A2-transduced rats with HET0016, an inhibitor of 20-HETE biosynthesis, not only attenuated the increase in blood pressure (P < 0.05) but also improved vascular function (acetylcholine-induced relaxations) and reduced plasma creatinine and proteinuria. HET0016 treatment decreased oxidative stress and increased the phosphorylated state of key proteins that regulate endothelial function, including eNOS, AKT, and AMPK. Collectively, these findings demonstrate that augmentation of vascular endothelial 20-HETE levels results in hypertension, endothelial dysfunction, and renal injury, which is offset by HET0016 through a reduction in vascular 20-HETE coupled with a lessening of oxidative stress and the amplification of pAKT, pAMPK, and p-eNOS levels leading to normalization of endothelial responses.

Heme Oxygenase-1 is an Essential Cytoprotective Component in Oxidative Tissue Injury Induced by Hemorrhagic Shock.

Hemorrhagic shock causes oxidative stress that leads to tissue injuries in various organs including the lung, liver, kidney and intestine. Excess amounts of free heme released from destabilized hemoproteins under oxidative conditions might constitute a major threat because it can catalyze the formation of reactive oxygen species. Cells counteract this by rapidly inducing the rate-limiting enzyme in heme breakdown, heme oxygenase-1 (HO-1), which is a low-molecular-weight stress protein. The enzymatic HO-1 reaction removes heme. As such, endogenous HO-1 induction by hemorrhagic shock protects tissues from further degeneration by oxidant stimuli. In addition, prior pharmacological induction of HO-1 ameliorates oxidative tissue injuries induced by hemorrhagic shock. In contrast, the deletion of HO-1 expression, or the chemical inhibition of increased HO activity ablated the beneficial effect of HO-1 induction, and exacerbates tissue damage. Thus, HO-1 constitutes an essential cytoprotective component in hemorrhagic shock-induced oxidative tissue injures. This article reviews recent advances in understanding of the essential role of HO-1 in experimental models of hemorrhagic shock-induced oxidative tissue injuries with emphasis on the role of its induction in tissue defense.

Physiological significance of heme oxygenase in hypertension.

The last decade has witnessed an explosion in the elucidation of the role that the heme oxygenase system plays in human physiology. This system encompasses not only the heme degradative pathway, including heme oxygenase and biliverdin reductase, but also the products of heme degradation, carbon monoxide, iron, and biliverdin/bilirubin. Their role in diabetes, inflammation, heart disease, hypertension, transplantation, and pulmonary disease are areas of burgeoning research. The research has focused not only on heme itself but also on its metabolic products as well as endogenous compounds involved in a vast number of genetic and metabolic processes that are affected when heme metabolism is perturbed. It should be noted, however, that although the use of carbon monoxide and biliverdin/bilirubin as therapeutic agents has been successful, these agents can be toxic at high levels in tissue, e.g., kernicterus. Care must be used to ensure that when these compounds are used as therapeutic agents their deleterious effects are minimized or avoided. On balance, however, the strategies to target heme oxygenase-1 as described in this review offer promising therapeutic approaches to clinicians for the effective management of hypertension and renal function. The approaches detailed may prove to be seminal in the development of a new therapeutic strategy to treat hypertension.

Prevention of hemorrhagic shock-induced intestinal tissue injury by glutamine via heme oxygenase-1 induction.

Hemorrhagic shock (HS) is an oxidative stress that causes intestinal tissue injury. Heme oxygenase 1 (HO-1) is induced by oxidative stress and is thought to play an important role in the protection of tissues from oxidative injury. We previously reported the ileum to be the most susceptible to HS-induced tissue injury site in the intestine because HO-1 induction is the lowest at this site. We also previously demonstrated that glutamine (GLN) significantly induced HO-1 in the lower intestinal tract. In the present study, we investigated whether GLN pretreatment improves HS-induced intestinal tissue injury in the ileum by HO-1 induction. Treatment of rats with GLN (0.75 g/kg, i.v.) markedly induced functional HO-1 protein in mucosal epithelial cells in the ileum. Glutamine treatment before HS (MAP of 30 mmHg for 60 min) significantly ameliorated HS-induced mucosal inflammation and apoptotic cell death in the ileum, as judged by significant decreases in gene expression of TNF-alpha, iNOS, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1, myeloperoxidase activity, the number of infiltrated neutrophils, DNA fragmentation by in situ oligo ligation assay, and activated caspase-3 expression, and by increases in gene expression of IL-10 and Bcl-2. In contrast, treatment with tin mesoporphyrin, a specific inhibitor of HO activity, abolished the beneficial effect of GLN pretreatment. These findings indicate that GLN pretreatment significantly ameliorated tissue injury in the ileum after HS by inducing HO-1. Glutamine treatment may thus protect mucosal cells from HS-induced oxidative damage via the anti-inflammatory and antiapoptotic properties of HO-1.

Site-specific induction of intestinal hypoxia-inducible factor-1α after hemorrhagic shock.

The intestine is a major target organ in hemorrhagic shock (HS)-induced tissue injury. Hypoxia-inducible factor (HIF)-1α is the primary transcription factor responsible for regulating cellular response to changes in oxygen tension. Since HS is an acute hypoxic insult, the present study examined changes in the gene expression of HIF-1α in various regions of the intestine, as well as the distribution of HIF-1α protein in the intestinal cells of a rat model of HS. Levels of HIF-1α mRNA were marginally detectable in the intestine of sham-operated control animals, but obviously induced following HS. Duodenal, jejunal and colonic levels of HIF-1α mRNA robustly increased and reached a maximum during the ischemic phase of HS, followed by a rapid decrease almost to control levels during the early phase of resuscitation. The induction of HIF-1α mRNA was maximal in the duodenum. In contrast to the duodenum, jejunum and colon, in the ileum the HIF-1α mRNA level did not increase after HS. Consistent with enhanced HIF-1α gene expression, HIF-1α protein was expressed in the mucosal cells of the duodenum, jejunum and colon, but not in the ileum following HS. These findings indicate that intestinal HIF-1α expression was up-regulated at both the transcriptional and protein level in a site-specific manner in this rat model of HS. Differential regulation of HIF-1α expression along the longitudinal axes of the intestine might be a determinant of the adaptive response to HS-induced intestinal damage.