Model difference in the effect of cilostazol on the development of experimental pulmonary hypertension in rats.

BACKGROUND: Preventing pulmonary vascular remodeling is a key strategy for pulmonary hypertension (PH). Causes of PH include pulmonary vasoconstriction and inflammation. This study aimed to determine whether cilostazol (CLZ), a phosphodiesterase-3 inhibitor, prevents monocrotaline (MCT)- and chronic hypoxia (CH)-induced PH development in rats. METHODS: Fifty-one male Sprague-Dawley rats were fed rat chow with (0.3% CLZ) or without CLZ for 21 days after a single injection of MCT (60 mg/kg) or saline. Forty-eight rats were fed rat chow with and without CLZ for 14 days under ambient or hypobaric (air at 380 mmHg) CH exposure. The mean pulmonary artery pressure (mPAP), the right ventricle weight-to-left ventricle + septum weight ratio (RV/LV + S), percentages of muscularized peripheral pulmonary arteries (%Muscularization) and medial wall thickness of small muscular arteries (%MWT) were assessed. Levels of the endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (peNOS), AKT, pAKT and IκB proteins in lung tissue were measured using Western blotting. Monocyte chemotactic protein (MCP)-1 mRNA in lung tissue was also assessed. RESULTS: mPAP [35.1 ± 1.7 mmHg (MCT) (n = 9) vs. 16.6 ± 0.7 (control) (n = 9) (P < 0.05); 29.1 ± 1.5 mmHg (CH) (n = 10) vs. 17.5 ± 0.5 (control) (n = 10) (P < 0.05)], RV/LV + S [0.40 ± 0.01 (MCT) (n = 18) vs. 0.24 ± 0.01 (control) (n = 10) (P < 0.05); 0.41 ± 0.03 (CH) (n = 13) vs. 0.27 ± 0.06 (control) (n = 10) (P < 0.05)], and %Muscularization and %MWT were increased by MCT injection and CH exposure. CLZ significantly attenuated these changes in the MCT model [mPAP 25.1 ± 1.1 mmHg (n = 11) (P < 0.05), RV/LV + S 0.30 ± 0.01 (n = 14) (P < 0.05)]. In contrast, these CLZ effects were not observed in the CH model. Lung eNOS protein expression was unchanged in the MCT model and increased in the CH model. Lung protein expression of AKT, phosphorylated AKT, and IκB was downregulated by MCT, which was attenuated by CLZ; the CH model did not change these proteins. Lung MCP-1 mRNA levels were increased in MCT rats but not CH rats. CONCLUSIONS: We found model differences in the effect of CLZ on PH development. CLZ might exert a preventive effect on PH development in an inflammatory PH model but not in a vascular structural change model of PH preceded by vasoconstriction. Thus, the preventive effect of CLZ on PH development might depend on the PH etiology.

Sarpogrelate hydrochloride, a serotonin 5HT2A receptor antagonist, ameliorates the development of chronic hypoxic pulmonary hypertension in rats.

PURPOSE: The purpose of the present study was to determine if sarpogrelate hydrochloride (SPG), a serotonin 5HT2A receptor antagonist, prevented the development of chronic hypoxia-induced pulmonary hypertension (PH) and hypertensive pulmonary vascular remodeling. METHODS: Forty-one male Sprague-Dawley rats were exposed to hypobaric hypoxia (380 mmHg, 10 % oxygen) or room air and administered 50 mg/kg SPG or vehicle by gavage once daily from day -2 to day 14. The mean pulmonary artery pressure (PAP) and right ventricular hypertrophy (RVH) were measured. Hypertensive pulmonary vascular remodelings were assessed morphometrically by light microscopy. Serotonin-induced contraction was determined in isolated pulmonary artery rings from 24 rats. In another set of rats, Western blotting, real-time polymerase chain reaction and immunofluorescent staining (n = 9) for lung tissue were performed. RESULTS: Chronic hypoxia induced a rise in mean PAP and RVH, increased the percentage of muscularized arteries in peripheral pulmonary arteries and medial wall thickness in small muscular arteries, and potentiated serotonin-induced contraction, each of which was significantly (p < 0.05) ameliorated by SPG. Chronic hypoxia significantly increased the expression of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (peNOS) protein levels, cyclic guanosine monophosphate, and matrix metalloproteinase-13 (MMP-13) mRNA levels in whole lung tissues. SPG increased peNOS expression in the immunofluorescent staining of peripheral pulmonary arteries from chronic hypoxic rats and decreased the MMP-13 mRNA in lung tissue in chronic hypoxic rats. CONCLUSIONS: The administration of SPG ameliorated the development of chronic hypoxic PH and hypertensive pulmonary vascular changes.

Effect of thrombomodulin on the development of monocrotaline-induced pulmonary hypertension.

PURPOSE: The purpose of the present study was to investigate whether thrombomodulin (TM) prevents the development of pulmonary hypertension (PH) in monocrotaline (MCT)-injected rats. METHODS: Human recombinant TM (3 mg/kg/2 days) or saline were given to MCT-injected male Sprague-Dawley rats for 19 (n = 14) or 29 (n = 11) days. Control rats (n = 6) were run for 19 days. The mean pulmonary artery pressure (mPAP), right ventricular hypertrophy (RVH), percentages of muscularized peripheral arteries (%muscularization), and medial wall thickness of small muscular arteries (%MWT) were measured. To determine inflammatory and coagulation responses, broncho-alveolar lavage fluid (BALF) was analyzed in another set of rats (n = 29). Western blotting for endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (peNOS) in the lung tissue was performed in separate rats (n = 13). Survival was determined in 60 rats. RESULTS: MCT increased mPAP, RVH, %muscularization, and %MWT. TM treatment significantly reduced mPAP, %muscularization, and %MWT in peripheral arteries with an external diameter of 50-100 µm in 19 days after MCT injection, but the effect was lost after 29 days. MCT increased the levels of tumor necrosis factor alpha, monocyte chemoattractant protein-1, and thrombin-antithrombin complex in BALF. Expression of eNOS increased in MCT rats, while peNOS decreased. The relative amount of peNOS to total eNOS increased in MCT/TM rats compared to MCT/Vehicle rats. A Kaplan-Meier survival curve showed no difference with and without TM. CONCLUSION: Although the administration of TM might slightly delay the progression of MCT-induced PH, the physiological significance for treatment is limited, since the survival rate was not improved.

Day zero ambulation under modified femoral nerve block after minimally invasive surgery for total knee arthroplasty: preliminary report.

Ambulation in the early postoperative period of total knee arthroplasty is crucial, in order to avoid complications and obtain preferable outcomes. Although a femoral nerve block can provide enough postoperative analgesia after total knee arthroplasty, falling, or other accidents due to motor paresis, are potentially adverse events in patients who have received a conventional femoral nerve block. We devised a modified femoral nerve block to spare voluntary knee extension ability, and clinically applied it to patients who received total knee arthroplasty under minimally invasive surgery. In our new-approach nerve blockade technique, the main targets of the sensory nerves are the saphenous nerves which branch out from the femoral nerve trunk. All the patients rated pain at bed rest between 0 and 3 on a numerical rating scale 3 h after the operation. In addition, the rectus femoris muscle was not affected at all, and the surgically invaded vastus medialis oblique muscle was completely anesthetized. Patients were able to not only actively raise their extremities with their knee in extension, but also to flex the knee in the air without pain or aggravation. On day 0, the patients were able to walk around, with the leg that had been operated upon not giving way. Our anesthetic approach can provide better pain relief than a conventional femoral nerve block, while the patients achieve ambulation on the day of the procedure, following minimally invasive knee surgery.

Technical communication: anatomy and clinical implications of ultrasound-guided selective femoral nerve block.

In this study we evaluated the anatomic basis and clinical findings of ultrasound-guided femoral nerve block performed close to the distal apex of the femoral triangle. Cadaver studies were conducted in 9 thighs of fresh bodies within 24 hours postmortem. In all cases, during injection of 10 mL of blue dye, the skin proximal to the injection site was compressed to prevent the proximal flow. In the first thigh, from the area just distal to the inguinal ligament, an epidural catheter was advanced distally beneath the fascia iliaca over the femoral nerve. In the remaining cases, 10 mL of blue dye was injected into the femoral nerve at the level of the proximal adductor canal and dye spread was evaluated after local dissection. The clinical study was conducted in 20 patients with severe varus deformities. Ten milliliters of 0.75% ropivacaine was injected as in the cadaveric series. The femoral nerve was successfully dyed in all cases of the cadaver study, whereas the muscular branch to the sartorius muscle and quadriceps muscle, with the exception of the vastus medialis muscle, evaded dyeing. All 20 patients with varus knee deformities reported analgesia; none of them experienced motor block. We conclude that local anesthetic injection at the site where the superficial femoral artery has passed beneath the medial border of the sartorius muscle (8 to 12 cm distal to the inguinal crease), combined with efforts taken to prevent proximal flow may anesthetize the sensation of the anterior-to medial aspect of the knee and motor branch of the vastus medialis muscle, without blocking the sartorius or quadriceps muscles.

[Two cases of diaphragmatic surgery in children under artificial pneumothorax].

We reported two cases of thoracoscopic diaphragm repair in children. The first case was a 6-day old neonate undergoing thoracoscopic repair of congenital diaphragmatic hernia under general anesthesia. During operation, CO2 was insufflated with a pressure of 4 cmH2O into the thoracic cavity. Although end-tidal CO2 increased to 90 mmHg, Sp(O2) and blood pressure were maintained within normal ranges. The second case was a 20-month-old infant undergoing thoracoscopic repair of diaphragmatic laxity. During operation, end-tidal CO2 increased to around 50 mmHg. Sp(O2) and blood pressure were normal. But during the procedure, insufflation pressure increased up to 10 cmH2O accidentally and arterial blood pressure curve disappeared. Insufflation pressure was corrected quickly and the arterial blood pressure recovered to normal within 10 seconds. The physiological changes of CO2 insufflation in thoracic cavity is similar to tension pneumothorax and we must take care to keep insufflation pressure under 4 cmH2O.

Intermittent pain in patients with chronic low back pain is associated with abnormalities in muscles and fascia.

We investigated the relationship between paravertebral muscles and perimuscular connective tissues of the thoracolumbar fascia region and the four types of pain in patients suffering from chronic low back pain. A total of 17 patients with chronic low back pain participated in this study. Ultrasound imaging method was used to measure the thickness and echogenicity of the paravertebral muscles and perimuscular connective tissues. The measurement site considered in this study was located lateral to the midpoint between L2-3 and L4-5 spines. In addition, age, gender, BMI, numerical rating scale and the short-form McGill pain questionnaire 2 (includes questions with respect to continuous pain, intermittent pain, neuropathic pain and affective descriptors) were used for assessment. Statistical analysis was performed using correlation analysis and multiple regression analysis. A significant association was observed between paravertebral muscle echogenicity at L2-3 and the numerical rating scale (r = 0.499), between paravertebral muscle echogenicity at L4-5 with numerical rating scale (r = 0.538) and intermittent pain (r = 0.594), and between perimuscular connective tissue thickness at L2-3 and numerical rating scale (r = 0.762). We observed that the factor influencing perimuscular connective tissue thickness at L2-3 and L4-5 was intermittent pain (ß = 0.513, ß = 0.597, respectively). It was also observed that some of the imaging findings were associated with age and BMI. In conclusion, we observed that paravertebral muscle echogenicity and perimuscular connective tissue thickness in patients with chronic low back pain were associated with pain, especially intermittent pain.

Effect of all-trans-retinoic acid on the development of chronic hypoxia-induced pulmonary hypertension.

BACKGROUND: An earlier study showed that all-trans-retinoic acid (ATRA) prevents the development of monocrotalin-induced pulmonary hypertension (PH). The purpose of the present study was to determine the effect of ATRA on another model of chronic hypoxia-induced PH. METHODS AND RESULTS: Male Sprague-Dawley rats were given 30 mg/kg ATRA or vehicle only by gavage once daily for 14 days during hypobaric hypoxic exposure. Chronic hypoxic exposure induced PH, right ventricular hypertrophy (RVH), and hypertensive pulmonary vascular changes. Quantitative morphometry of the pulmonary arteries showed that ATRA treatment significantly reduced the percentage of muscularized arteries in peripheral pulmonary arteries only with an external diameter between 15 and 50 microm. ATRA treatment also significantly reduced the medial wall thickness in small muscular arteries only with an external diameter between 50 and 100 microm. Unfortunately, these reductions did not accompany the lowering of pulmonary artery pressure nor decrease in RVH. Chronic hypoxia-induced PH rats with ATRA had a loss in body weight. Chronic hypoxia increased the expression of endothelial nitric oxide synthase in the lung on western blotting and immunohistochemistry, in which ATRA treatment had no effect. CONCLUSIONS: The administration of ATRA might not have a therapeutic role in preventing the development of chronic hypoxia-induced PH, because of body weight loss and the subtle preventable effects of vascular changes.

Colforsin-induced vasodilation in chronic hypoxic pulmonary hypertension in rats.

PURPOSE: Colforsin, a water-soluble forskolin derivative, directly activates adenylate cyclase and thereby increases the 3',5'-cyclic adenosine monophosphate (cAMP) level in vascular smooth muscle cells. In this study, we investigated the vasodilatory action of colforsin on structurally remodeled pulmonary arteries from rats with pulmonary hypertension (PH). METHODS: A total of 32 rats were subjected to hypobaric hypoxia (380 mmHg, 10% oxygen) for 10 days to induce chronic hypoxic PH, while 39 rats were kept in room air. Changes in isometric force were recorded in endothelium-intact (+E) and -denuded (-E) pulmonary arteries from the PH and control (non-PH) rats. RESULTS: Colforsin-induced vasodilation was impaired in both +E and -E arteries from PH rats compared with their respective controls. Endothelial removal did not influence colforsin-induced vasodilation in the arteries from control rats, but attenuated it in arteries from PH rats. The inhibition of nitric oxide (NO) synthase did not influence colforsin-induced vasodilation in +E arteries from controls, but attenuated it in +E arteries from PH rats, shifting its concentration-response curve closer to that of -E arteries from PH rats. Vasodilation induced by 8-bromo-cAMP (a cell-permeable cAMP analog) was also impaired in -E arteries from PH rats, but not in +E arteries from PH rats, compared with their respective controls. CONCLUSIONS: cAMP-mediated vasodilatory responses without beta-adrenergic receptor activation are impaired in structurally remodeled pulmonary arteries from PH rats. In these arteries, endothelial cells presumably play a compensatory role against the impaired cAMP-mediated vasodilatory response by releasing NO (and thereby attenuating the impairment). The results suggest that colforsin could be effective in the treatment of PH.

Virtual reality as a non-pharmacologic analgesic for fasciotomy wound infections in acute compartment syndrome: a case report.

BACKGROUND: Fasciotomy is a life-saving procedure to treat acute compartment syndrome, a surgical emergency. As fasciotomy dramatically improves wound pain, it should be performed as soon as possible. Moreover, delays in the use of fasciotomy can increase the rate of wound infections. Once the fasciotomy wound is infected, pain control is achieved via the long-term use of opioids or anti-inflammatory analgesics. However, the administration of high doses of opioids may cause complications, such as respiratory depression, over-sedation, and constipation. Therefore, treatment methods other than narcotic administration should be established to better manage the pain caused by fasciotomy wound infections. Virtual reality has recently been introduced in analgesic therapy as a replacement, or complement, to conventional pharmacological treatments. Its use has been extensively studied in the pain management of patients with burns. An increasing number of painful conditions are being successfully treated with virtual reality. Here, we report a case of acute compartment syndrome complicated by fasciotomy wound infection. CASE PRESENTATION: A 40-year-old Japanese man suffering from acute compartment syndrome of his leg due to a car accident trauma was treated with a fasciotomy to decompress intra-compartmental pressure and restore tissue perfusion, and admitted to an intensive care unit. Unfortunately, as the open fasciotomy wound was complicated by infection, he complained of hyperalgesia and severe pain during wound debridement. He was therefore given acetaminophen and high-dose intravenous patient-controlled analgesic fentanyl (35 µg/kg per day) to reduce the pain. Despite these efforts, the pain was poorly controlled and opioid-induced side effects such as respiratory depression were observed. An immersive virtual reality analgesic therapy aimed at distraction and relaxation was used and effectively alleviated the pain. Three sessions of virtual reality analgesic therapy over 2 days produced sustainable analgesic effects, which led to a 25-75% dose reduction in fentanyl administration and the concomitant alleviation of respiratory depression. CONCLUSIONS: This case suggests the feasibility of virtual reality analgesic therapy for pain management of fasciotomy wound complications in acute compartment syndromes. Virtual reality represents a treatment option that would reduce analgesic consumption and eliminate opioid-induced respiratory depression to treat fasciotomy wound infection.

Prolonged nitric oxide inhalation fails to regress hypoxic vascular remodeling in rat lung.

STUDY OBJECTIVE: The purpose of present study was to investigate whether long-term nitric oxide (NO) inhalation during the recovery in air might improve the regression of chronic hypoxic pulmonary hypertension (PH) and vascular changes. MATERIALS AND METHODS: The rats were exposed to 10 ppm of NO in air for 10 days (n = 12) and 30 days (n = 4), or 40 ppm of NO in air for 10 days (n = 6) and 30 days (n = 12) following 10 days of hypobaric hypoxia (380 mm Hg, 10% oxygen). For each NO group, air control rats following hypoxic exposure were studied at the same time (n = 13, 11, 9, and 11, respectively). Normal air rats (n = 6) without hypoxic exposure and rats (n = 7) following 10 days of hypoxic exposure were used as normal and chronic hypoxic control groups, respectively. Muscularization of normally nonmuscular peripheral arteries and medial hypertrophy of normally muscular arteries were assessed by light microscopy. An additional 16 rats were used to investigate the recovery of pulmonary artery pressure with (n = 8) and without NO inhalation (n = 8) after 10 days of hypobaric hypoxia. RESULTS: Long-term hypoxia-induced PH, right ventricular hypertrophy (RVH), and hypertensive pulmonary vascular changes, each of which regressed partly after recovery in room air. There were no differences among rats with and without NO during each recovery period in RVH, medial wall thickness of muscular artery, and the percentages of muscularized arteries at the alveolar wall and duct levels. Continuous inhaled 40 ppm NO decreased pulmonary artery pressure from 40.1 +/- 1.1 to 29.9 +/- 3.8 mm Hg (mean +/- SE) [n = 8], which was not different in the rats without NO inhalation (n = 8). Urine nitrate level was higher in rats that had inhaled NO. CONCLUSION: Continuous NO inhalation showed no effect on regression of pulmonary vascular remodeling in chronic hypoxic PH after returning to room air.

Thrombomodulin protects against lung damage created by high level of oxygen with large tidal volume mechanical ventilation in rats.

BACKGROUND: Ventilator-induced lung injury (VILI) is associated with inflammatory responses in the lung. Thrombomodulin (TM), a component of the coagulation system, has anticoagulant and anti-inflammatory effects. We hypothesized that the administration of recombinant human soluble TM (rhsTM) would block the development of lung injury. METHODS: Lung injury was induced by high tidal volume ventilation for 2 h with 100% oxygen in rats. Rats were ventilated with a tidal volume of 35 ml/kg with pretreatment via a subcutaneous injection of 3 mg/kg rhsTM (HV (high tidal volume)/TM) or saline (HV/SAL) 12 h before mechanical ventilation. Rats ventilated with a tidal volume of 6 ml/kg under 100% oxygen with rhsTM (LV (low tidal volume)/TM) or saline (LV/SAL) were used as controls. Lung protein permeability was determined by Evans blue dye (EBD) extravasation. RESULTS: Lung injury was successfully induced in the HV/SAL group compared with the LV/SAL group, as shown by the significant decrease in arterial oxygen pressure (PaO2), increased protein permeability, and increase in mean pulmonary artery pressure (mPAP) and ratio of mean pulmonary artery pressure to mean artery pressure (Pp/Ps). Treatment of rats with lung injury with rhsTM (HV/TM) significantly attenuated the decrease in PaO2 and the increase in both mPAP and Pp/Ps, which was associated with a decrease in the lung protein permeability. Lung tissue mRNA expressions of interleukin (IL)-1α, IL-1ß, IL-6, tumor necrosis factor-α, and macrophage inflammatory protein (MIP)-2 were significantly higher in HV than in LV rats. Rats with VILI treated with rhsTM (HV/TM) had significantly lower mRNA expressions of IL-1α, IL-1ß, IL-6, and MIP-2 than those expressions in HV/SAL rats. CONCLUSIONS: Administration of rhsTM may prevent the development of lung injury created by high level of oxygen with large tidal volume mechanical ventilation, which has concomitant decrease in proinflammatory cytokine and chemokine expression in the lung.

Persistent release of IL-1s from skin is associated with systemic cardio-vascular disease, emaciation and systemic amyloidosis: the potential of anti-IL-1 therapy for systemic inflammatory diseases.

The skin is an immune organ that contains innate and acquired immune systems and thus is able to respond to exogenous stimuli producing large amount of proinflammatory cytokines including IL-1 and IL-1 family members. The role of the epidermal IL-1 is not limited to initiation of local inflammatory responses, but also to induction of systemic inflammation. However, association of persistent release of IL-1 family members from severe skin inflammatory diseases such as psoriasis, epidermolysis bullosa, atopic dermatitis, blistering diseases and desmoglein-1 deficiency syndrome with diseases in systemic organs have not been so far assessed. Here, we showed the occurrence of severe systemic cardiovascular diseases and metabolic abnormalities including aberrant vascular wall remodeling with aortic stenosis, cardiomegaly, impaired limb and tail circulation, fatty tissue loss and systemic amyloid deposition in multiple organs with liver and kidney dysfunction in mouse models with severe dermatitis caused by persistent release of IL-1s from the skin. These morbid conditions were ameliorated by simultaneous administration of anti-IL-1α and IL-1ß antibodies. These findings may explain the morbid association of arteriosclerosis, heart involvement, amyloidosis and cachexia in severe systemic skin diseases and systemic autoinflammatory diseases, and support the value of anti-IL-1 therapy for systemic inflammatory diseases.

A novel inhibitor of inducible nitric oxide synthase, ONO-1714, does not ameliorate hypoxia-induced pulmonary hypertension in rats.

A recent study showed that long-term administration of the inducible nitric oxide synthase (iNOS) inhibitor L-NIL reduced the development of pulmonary hypertension. The purpose of the present study was to identify the effect of an another iNOS inhibitor, ONO-1714, on the development of pulmonary hypertensive vascular changes in chronic hypoxic pulmonary hypertension in rats. ONO-1714 was administered to rats exposed to hypobaric hypoxia (air at 380 mmHg) for 10 days. Muscularization of normally nonmuscular peripheral arteries and medial hypertrophy of normally muscular arteries were assessed by light microscopy. iNOS mRNA and protein levels of the lung were assessed in normal and hypoxic rats. Chronic hypoxia induced pulmonary hypertension, right ventricular hypertrophy, and hypertensive pulmonary vascular changes. Although an acute single injection of ONO-1714 induced a significant increase in mean pulmonary artery pressure in chronic hypoxic pulmonary hypertensive rats, the increase was slight and transient. There were no significant differences among rats with and without long-term administration of ONO-1714 in pulmonary artery pressure, right ventricular hypertrophy, medial wall thickness of muscular arteries, and the percentage of muscularized arteries at the alveolar wall and duct levels. Although there was a significantly increased expression of iNOS as assessed with the reverse-transcription polymerase chain reaction in rats that were exposed to 10 days of hypobaric hypoxia, we could not detect a significant level of iNOS protein by Western blotting. ONO-1714 does not have a therapeutic role in preventing the development of chronic hypoxic pulmonary hypertension.