Efficacy and safety of dupilumab in Japanese adults with moderate-to-severe atopic dermatitis: a subanalysis of three clinical trials.

BACKGROUND: Dupilumab, a human monoclonal antibody, blocks the shared receptor unit for interleukin-4 and interleukin-13. International phase II and III studies have evaluated the efficacy and safety of dupilumab in adults with moderate-to-severe atopic dermatitis (AD), but the effects of dupilumab in Japanese patients have not been reported. OBJECTIVES: To evaluate the efficacy and safety of dupilumab in Japanese patients with moderate-to-severe AD. METHODS: We analysed the efficacy and safety of dupilumab in the Japanese cohorts of a 16-week, phase IIb dose-finding trial (AD-1021; NCT01859988); a 16-week, phase III, placebo-controlled monotherapy trial (LIBERTY AD SOLO 1; NCT02277743) and a 52-week, phase III, placebo-controlled study of dupilumab with topical corticosteroids (LIBERTY AD CHRONOS; NCT02260986). RESULTS: Twenty-seven, 106 and 117 Japanese patients were enrolled in AD-1021, SOLO 1 and CHRONOS, respectively. Baseline disease severity was numerically higher in the Japanese cohort than in the overall study population. Generally, dupilumab significantly improved signs and symptoms of AD, including pruritus and patient quality of life, compared with placebo in the Japanese cohort, consistent with the overall study population. The combined safety profile of dupilumab in the Japanese cohort was similar to that in the total study populations; dupilumab was associated with an increased incidence of injection-site reactions and conjunctivitis compared with placebo. Dupilumab was associated with rapid reduction in thymus and activation-regulated chemokine and gradual IgE reductions. CONCLUSIONS: Dupilumab alone or with topical corticosteroids improved signs and symptoms of AD, had an acceptable safety profile, and suppressed biomarkers of type 2 inflammation compared with placebo in Japanese adult patients with moderate-to-severe AD. What's already known about this topic? Differences in atopic dermatitis (AD) pathology have been reported between Asian and Western populations, in which distinct helper T-cell activation profiles have been observed. International clinical studies in adults with moderate-to-severe AD have evaluated the efficacy and safety of dupilumab, which blocks interleukin-4 and interleukin-13, key molecules in type 2 inflammation. The effects of dupilumab in Japanese patients specifically have not yet been reported. What does this study add? Dupilumab alone or with topical corticosteroids improved signs and symptoms of AD and had an acceptable safety profile compared with placebo in Japanese patients with moderate-to-severe AD. The effects were comparable with those observed in the overall study population. Reported immunological differences in AD pathology in Asian patients may be secondary to type 2 immune activation.

Effect of nutrient intake on intramuscular glucose metabolism during the early growth stage in cross-bred steers (Japanese Black male × Holstein female).

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism-related genes in skeletal muscle of cross-bred cattle. From 1.5 to 5 months of age, group H (n=7) animals were intensively fed a high-protein and low-fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n=7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high-nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real-time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3-kinase (PI-3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin-independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin-dependently mediated glucose uptake in LT of cattle.

Droplet splashing by a slingshot mechanism.

When a drop impacts onto a liquid pool, it ejects a thin horizontal sheet of liquid, which emerges from the neck region connecting the two liquid masses. The leading section of this ejecta bends down to meet the pool liquid. When the sheet touches the pool, at an "elbow," it ruptures and sends off microdroplets by a slingshot mechanism, driven by surface tension. High-speed imaging of the splashing droplets suggests the liquid sheet is of submicron thickness, as thin as 300 nm. Experiments in partial vacuum show that air resistance plays the primary role in bending the sheet. We identify a parameter regime where this slingshot occurs and also present a simple model for the sheet evolution, capable of reproducing the overall shape.

A bright and long-pulse illumination for ultrahigh-speed microscopy of living specimens.

Ultrahigh-speed microscopy of living specimens requires ultrabright illumination. Moreover, the duration of illumination should be sufficiently long, on the order of at least several tens of milliseconds, in order to investigate the dynamic state of living specimens. However, specimens are exposed to a high risk of damage by the intense illumination. The brightness and pulse duration of illumination have to be continuously controlled for use in the ultrahigh-speed microscopy of living specimens. Commercial or laboratory-made illumination systems do not satisfy the abovementioned requirements. In this paper, the development of a bright and long-pulse illumination system for ultrahigh-speed microscopy of living specimens is presented. A xenon flashlamp with an arc length of 1.5 mm has been used as the light source. The electrical power supply consists of a voltage-regulated circuit, a capacitor bank, and a control circuit including an insulated-gate bipolar transistor as a gating device, which provides a large rectangular current pulse with the duration in the range to the order of several tens of milliseconds. The brightness, pulse duration, and repetition rate can be easily and continuously controlled. The illumination developed in the present study is installed in an inverted fluorescence microscope equipped with a high-speed camera in order to evaluate the performance as an illumination source. A fluorescent image of the living spermatozoa of a mouse obtained at a frame rate of 8 kHz shows good contrast. Such an image cannot be obtained using a commercial illumination system.

Stick-slip substructure in rapid tape peeling.

The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 µm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼ 100 m/s, which promotes the sound, so characteristic of this phenomenon.

A torque removal study on the primary stability of orthodontic titanium screw mini-implants in the cortical bone of dog femurs.

The aim of this study was to biomechanically evaluate the primary stability of pure titanium orthodontic mini-implants, inserted into pre-drilled cavities of differing diameters. Mini-implants (1.2 mm diameter) were placed into 1.0 mm and 1.2 mm diameter cavities prepared in the mid-region of the bilateral hind leg femurs of anesthetized beagles. Removal torque strengths were measured immediately, 1, 3, 6, 9 and 12 weeks post-insertion of the implant. For mini-implants placed into 1-mm cavities, removal torque values decrease over the first 6 weeks (p<0.01), after which values remained static. Average values obtained immediately, 1, 3 and 6 weeks post-insertion were 10.98, 8.83, 7.20 and 5.12 Ncm, respectively . Immediately post-insertion, removal torque values of mini-implants placed in a 1.2-mm cavity, were 11-fold lower than those placed in 1.0-mm cavities, which then demonstrated a significant increase in strength from 3 weeks (1.35 Ncm) to 6 weeks (5.17 Ncm) post-insertion (p<0.01). Measurements 6, 9 and 12 weeks post-insertion were similar to those in the 1.0-mm cavity. Initial stability of titanium mini-implants is considered necessary for immediate and early use in orthodontics, and an implant without this initial stability should be replaced or isolated until it develops the appropriate stability supported by osseointegration.

[Postoperative penicillin-resistant streptococcus pneumonia in lung cancer patient].

A 78-year-old man underwent a left lower sleeve lobectomy and lymph node dissection for lung cancer. His postoperative course had been uneventful until postoperative day (POD) 3, but severe dyspnea occurred suddenly and the chest X-p showed infiltration shadow on POD 3. Streptococcus pneumonia antigen in the urine was elevated, suggesting pneumonia caused by Streptococcus pneumonia. The patient was treated with double dose of imipenem/cilastatin sodium and supported with a mechanical ventilator in an intensive care unit. Although the patient recovered from penicillin resistant Streptococcus pneumonia, he was suffered from Klebsiella sepsis and expired on the POD 26.

Three-dimensional observation of connective tissue of bovine masseter muscle under concentrate- and roughage-fed conditions by using immunohistochemical/confocal laser-scanning microscopic methods.

We investigated changes in connective tissue components of masseter (MA) muscle in Japanese black heifers (n= 6) in concentrate- and roughage-fed groups (groups C and R, respectively). Body weight, at slaughter, of experimental heifers in group C (272.3 +/- 22.3 kg) was higher (P < 0.05) than that of group R (213.8 +/- 27.5 kg). However, muscle weight and myofiber diameter (superficial and deep layers) of MA muscle did not differ between groups C and R. In contrast, total mastication duration of group R was longer (P < 0.05) than that of group C. MA muscle of groups C and R was composed only of type I myofiber. Using immunohistochemical/confocal laser-scanning microscopy, type I collagen was observed mainly in perimysium, and type V and VI collagen were observed in perimysium and endomysium of both groups. Type IV collagen and laminin were observed only in the endomysium in both groups. However, type III collagen and fibronectin were strongly apparent in the perimysium and endomysium in group R. Connective tissue components in the perimysium of groups C and R were observed to form plate-shaped layers. On the other hand, honeycomb-shaped connective tissue components were seen in the endomysium-surrounded muscle fibers. In particular, fibronectin was strongly observed in the perimysium and endomysium in group R. These results indicate that there are different developmental changes among connective tissue components in MA muscle in response to mastication. The immunohistochemical/confocal laser-scanning microscopic method is useful to investigate the structural relationship among connective tissue components in skeletal muscle.

Long-term quality of life after laparoscopy-assisted distal gastrectomy for gastric cancer.

BACKGROUND: Laparoscopy-assisted distal gastrectomy (LAG) is gaining acceptance for treating early gastric cancer. However, the long-term quality of life after LAG for gastric cancer is unknown. This study compared the long-term quality of life after LAG versus open distal gastrectomy (ODG) for early gastric cancer. METHOD: This study included 53 patients who underwent LAG and 37 patients who underwent ODG for treatment of early gastric cancer. Quality of life was evaluated on the basis of a 22-item questionnaire that addressed food tolerance and mental and physical conditions, scored on a scale of 1-3. RESULTS: The mean follow-up periods after LAG and ODG were 99.3 and 97.0 months, respectively. Although the majority of patients who had undergone LAG were consuming a normal diet and had weight loss of less than 5 kg, all 22 items and the total score of the LAG group were comparable to those of the ODG group. However, the incidence of postoperative intestinal obstruction was significantly lower in the LAG group than in the ODG group (1% vs. 13%, p < 0.05). CONCLUSIONS: LAG is equivalent to ODG with respect to long-term quality of life and is associated with a reduced incidence of postoperative intestinal obstruction.

Identification of the high-risk group for metastasis of gastric cancer cases by vascular endothelial growth factor receptor-1 overexpression in peripheral blood.

Identification of an isolated tumour cell with metastatic ability is important for predicting the recurrence and prognosis of gastric cancer. A biological marker for evaluating the metastatic ability of gastric cancer cells has not yet been identified. We assessed vascular endothelial growth factor receptor-1 mRNA expression by quantitative real-time reverse transcriptase-polymerase chain reaction. Vascular endothelial growth factor receptor-1 mRNA in peripheral blood was more highly expressed in perioperative metastasis-positive and postoperative recurrence cases than in normal control cases, early cancer cases and nonmetastatic advanced cancer cases. The peripheral blood vascular endothelial growth factor receptor-1 mRNA-positive group was associated with advanced clinical stage, deep invasion beyond the muscularis propria, lymphatic involvement, vascular involvement, lymph node metastasis, positive peritoneal lavage cytology, preoperative metastasis and postoperative recurrence. Flow cytometry analysis disclosed that vascular endothelial growth factor receptor-1 expressing cells in the peripheral blood were more abundant in cancer cases with metastases than in cases without metastases. Our data suggest that the amount of positive cells may provide information on the clinical features of gastric cancer, especially in regard to gastric cancer metastasis.

Laparoscopic sentinel node navigation achieved by infrared ray electronic endoscopy system in patients with gastric cancer.

BACKGROUND: The sentinel node (SN) concept has attracted considerable attention recently for the treatment of patients with early gastric cancer (EGC). This study evaluated the feasibility of laparoscopic SN navigation achieved by means of an infrared ray electronic endoscopy (IREE) system with indocyanine green (ICG) injection in patients with EGC. METHODS: Laparoscopic SN navigation was performed for 16 patients with preoperatively diagnosed EGC. After identification of SNs, routine laparoscopically assisted distal gastrectomy with lymphadenectomy was performed. Lymph nodes were examined histologically for metastasis by hematoxylin and eosin staining on one section of each node. RESULTS: One or more SNs and lymphatic basins were detected in all 16 patients. The average number of SNs detected was 2.9. Lymph node metastasis was found in 2 of the 16 patients (13%). In one of these two patients, lymph node metastasis was found in SNs. In the other patient, metastasis was found in a non-SN rather than a SN, but in the same lymphatic basin. The accuracy of this detection method was 94%, and there was one false-negative case. No adverse events occurred after injection of ICG. CONCLUSION: Laparoscopic SN navigation by means of IREE combined with ICG injection is feasible for patients undergoing laparoscopic surgery for EGC.

Extranodal metastasis is an indicator of poor prognosis in patients with gastric carcinoma.

BACKGROUND: The aim of this study was to determine the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma. METHODS: The study included 1023 patients who underwent gastrectomy with lymphadenectomy for primary gastric carcinoma between January 1993 and December 1996. EM was defined as the presence of tumour cells in extramural soft tissue that was discontinuous with either the primary lesion or locoregional lymph nodes. RESULTS: EM was detected in 146 (14.3 per cent) of the 1023 patients and in 1060 (3.0 per cent) of the 35 811 nodules that were retrieved as 'lymph nodes' from adipose connective tissues. The incidence of EM was significantly higher in patients with tumours that were large (diameter 10 cm or more), infiltrative, deeply invading or undifferentiated and in those with lymph node, peritoneal or liver metastases, or lymphatic or vascular involvement. After curative operation overall survival was significantly worse for patients with EM than those without (P < 0.001). Multivariate analysis identified EM as an independent prognostic factor (hazard ratio 1.82 (95 per cent confidence interval 1.23 to 2.71); P = 0.003). CONCLUSION: EM is an independent prognostic factor and should therefore be included in the tumour node metastasis (TNM) staging system.

Increased expression of NAD(P)H oxidase subunits, NOX4 and p22phox, in the kidney of streptozotocin-induced diabetic rats and its reversibity by interventive insulin treatment.

AIM/HYPOTHESIS: An increased production of reactive oxygen species (ROS) could contribute to the development of diabetic nephropathy. NAD(P)H oxidase might be an important source of ROS production in kidney as reported in blood vessels. In this study, we show the increased expression of essential subunits of NAD(P)H oxidase, NOX4 and p22phox, in the kidney of diabetic rats. METHODS: The levels of mRNA of both NOX4 and p22phox were evaluated in kidney from streptozotocin-induced diabetic rats and age-matched control rats at 4 and 8 weeks after onset of diabetes by Northern blot analysis. The localization and expression levels of these components and 8-hydroxy-deoxyguanosine (8-OHdG), which is a marker of ROS-induced DNA damage, were also evaluated by immunostaining. RESULTS: The levels of both NOX4 and p22phox mRNA were increased in the kidney of diabetic rats as compared with control rats. Immunostaining analysis showed that the expression levels of NOX4 and p22phox were clearly increased in both distal tubular cells and glomeruli from diabetic rats. Both the localization and the expression levels of these components were in parallel with those of 8-OHdG. Interventive insulin treatment for 2 weeks completely restored the increased levels of these components in the diabetic kidney to control levels in parallel with those of 8-OHdG. CONCLUSIONS/INTERPRETATION: This study provides evidence that NAD(P)H oxidase subunits, NOX4 and p22phox, were increased in the kidney of diabetic rats. Thus, NAD(P)H-dependent overproduction of ROS could cause renal tissue damage in diabetes. This might contribute to the development of diabetic nephropathy.

A possible target of antioxidative therapy for diabetic vascular complications-vascular NAD(P)H oxidase.

A growing body of evidence has shown that oxidative stress may be involved in the development of vascular complications associated with diabetes. However, the molecular mechanism for increased reactive oxygen species (ROS) production in diabetes remains uncertain. Among various possible mechanisms, attention have increasingly been paid to NAD(P)H oxidase as the most important source of ROS production in vascular cells. High glucose level stimulates ROS production through protein kinase C (PKC)-dependent activation of vascular NAD(P)H oxidase. Furthermore, the expression of NAD(P)H oxidase components is increased in micro- and macrovascular tissues of diabetic animals in association with various functional disorders and histochemical abnormalities. These results suggest that vascular NAD(P)H oxidase-driven ROS production may contribute to the onset or development of diabetic micro- or macrovascular complications. In this point of view, the possible new strategy of antioxidative therapy for diabetic vascular complications is discussed in this review.

[Resected cases with primary lung cancer after preoperative high dose irradiation].

After greater than 60 gray (Gy) irradiation, we performed the pulmonary resection in the 18 primary lung cancer cases. The mean irradiation dose to the tumor was 68.2 (range 60-101) Gy, and the mean irradiation dose to the bronchial stump was 47.1 (range 0-82) Gy. Median time from end of irradiation to surgical resection was 136 (range 20-894) days. One partial resection, 9 single lobectomies, 3 double lobectomies, and 5 pneumonectomies were done. Mainly, we closed the bronchial stump by the automatic stapling device and additional hand suturing. The bronchial stump was covered in the 12 cases by the owner stalk thymus, the intercostals muscular flap, the omentum flap, and et al. The major postoperative complications due to preoperative irradiation were not seen. Bronchopleural fistulas did not occur. Pathologically, the wall of the submucosal capillary vessels were getting thick in the patients operated more than 3 months later after irradiation. In such cases with the decrease of the blood flow, the bronchial stump should be covered. The pulmonary resection after the high dose irradiation was considered to be tolerable.

Randomized phase I study of standard-fractionated or accelerated-hyperfractionated radiotherapy with concurrent cisplatin and vindesine for unresectable non-small cell lung cancer: a report of Japan Clinical Oncology Group Study (JCOG 9601).

BACKGROUND: We attempted dose escalation of standard-fractionated and accelerated-hyperfractionated radiotherapy combined with concurrent cisplatin and vindesine to improve local control and survival in unresectable non-small cell lung cancer. METHODS: Twenty-one patients were enrolled between June 1996 and August 1997. There were 19 males and two females and their median age was 65 years (range 45-74 years). Performance status was 0 in 10 cases and 1 in 11 cases. Disease stage was IIIA in three cases and IIIB in 18 cases. The cases were randomized to a standard-fractionated arm (n = 10) or an accelerated-hyperfractionated radiotherapy arm (n = 11) with two or three cycles of concomitant cisplatin 80 mg/m(2) on day 1 and vindesine 3 mg/m(2) on days 1 and 8 every 4 weeks in both arms. Dose escalation from 60 Gy/30 fractions/6 weeks to 70 Gy/35 fractions/7 weeks was planned in the standard-fractionated radiotherapy group and from 54 Gy/36 fractions/3.6 weeks to 60 Gy/40 fractions/4 weeks and then 66 Gy/44 fractions/4.4 weeks in the accelerated-hyperfractionated radiotherapy group. RESULTS: Grade 3 or 4 hematological toxicities were observed as follows: in the standard-fractionated/accelerated-hyperfractionated radiotherapy group, leukocytopenia 9/10, anemia 2/3 and thrombocytopenia 0/2. Grade 3 non-hematological toxicity consisted of esophagitis 0/3, increased serum total bilirubin 2/0 and hypoxia 0/1. Two patients died of radiation pneumonitis in the standard-fractionated radiotherapy group. Dose-limiting toxicity was observed in four of the 10 and seven of the 11 patients at initial dose level of standard-fractionated radiotherapy, 60 Gy/30 fractions/6 weeks, and of accelerated-hyperfractionated radiotherapy, 54 Gy/36 fractions/3.6 weeks, respectively. Thus, we failed to escalate the dose of radiotherapy in both arms. The overall response rate in the standard-fractionated group and the accelerated-hyperfractionated radiotherapy group was 70 and 73% and the 1-year survival rate was 70 and 64%, respectively. CONCLUSIONS: We concluded that these schedules of radiotherapy with concurrent cisplatin and vindesine were unacceptable for use in patients with unresectable non-small cell lung cancer. Further modifications of the schedule for radiotherapy and evaluation of combination with new chemotherapy are warranted.

Constitutive activation of Wnt/beta-catenin signaling pathway in migration-active melanoma cells: role of LEF-1 in melanoma with increased metastatic potential.

A constitutive complex of beta-catenin and LEF-1 has been detected in melanoma cell lines expressing either mutant beta-catenin or mutant APC (Rubinfeld et al., Science, 275, 1790-1792, 1997). However, it has been recently reported that beta-catenin mutations are rare in primary malignant melanoma, but its nuclear and/or cytoplasmic localization, a potential indicator of Wnt/beta-catenin pathway activation, is frequently observed in melanoma (Rimm et al., Am. J. Pathol., 154, 325-329, 1999). In human malignant melanoma, the appearance of the tumorigenic phase represents a capacity for metastasis and is the significant phenotypic step in disease progression. Cell motility in invasive melanoma is thought to play a crucial role in metastatic behavior. In this work, we sought to determine which transcription factor of the LEF/TCF family was preferentially involved in human melanoma from different stages of tumor progression. We show that LEF-1 mRNA expression is predominant in highly migrating cells from metastatic melanomas. These actively migrating melanoma cells showed nuclear and cytoplasmic accumulation of beta-catenin and active transcription from a reporter plasmid of the LEF/TCF binding site. These results may provide a new insight into the role of the Wnt/beta-catenin signaling pathway in the tumor progression of malignant melanoma.

Differential growth regulation in human melanoma cell lines by TIMP-1 and TIMP-2.

We investigated the role of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in the growth regulation. Primary (PM-WK and KHm-4), recurrent primary (RPM-EP and RPM-MC), lymph node metastatic (MM-AN, MM-BP and MM-RU), and a visceral metastatic (MM-LH) melanoma cell lines were used. Reverse transcriptase-coupled polymerase chain reaction and Western blotting revealed that all expressed and produced TIMP-1 and TIMP-2 except for PM-WK, which neither expressed nor produced TIMP-1. TIMP-1 and TIMP-2 secretion levels were measured by enzyme-linked immunosorbent assay in supernatants of cells. We found that the TIMP-1 production level was correlated with the cell migration rate. Moreover, TIMP-1 enhanced the cell migration of PM-WK. The growth of the primary melanoma cell lines was stimulated by TIMP-1 and inhibited by TIMP-2. In contrast, the growth of the visceral metastatic melanoma cell line was stimulated by TIMP-2.

Myocardial and interstitial matrix metalloproteinase activity after acute myocardial infarction in pigs.

A structural event during the evolution of a myocardial infarction (MI) is left ventricular (LV) remodeling. The mechanisms that contribute to early changes in LV myocardial remodeling in the post-MI period remain poorly understood. Matrix metalloproteinases (MMPs) contribute to tissue remodeling in several disease states. Whether and to what degree MMP activation occurs within the myocardial interstitium after acute MI remains to be determined. Adult pigs (n = 15) were instrumented to measure regional myocardial function and interstitial MMP levels within regions served by the circumflex and left anterior descending arteries. Regional function was measured by sonomicrometry, and interstitial MMP levels were determined by selective microdialysis and zymography as well as by MMP interstitial fluorogenic activity. Measurements were performed at baseline and sequentially for up to 3 h after ligation of the obtuse marginals of the circumflex artery. Regional fractional shortening fell by over 50% in the MI region but remained unchanged in the remote region after coronary occlusion. Release of soluble MMPs, as revealed by zymographic activity of myocardial interstitial samples, increased by 2 h post-MI. The increased zymographic activity after MI was consistent with MMP-9. Myocardial interstitial MMP fluorogenic activity became detectable within the ischemic region as early as 10 min after coronary occlusion and significantly increased after 1 h post-MI. MMP fluorogenic activity remained unchanged from baseline values in the remote region. The present study demonstrated that myocardial MMP activation can occur within the MI region in the absence of reperfusion. These unique results suggest that MMP release and activation occurs within the ischemic myocardial interstitium in the early post-MI period.

Matrix metalloproteinase expression and activity in isolated myocytes after neurohormonal stimulation.

Changes in myocardial matrix metalloproteinase (MMP) activity and expression have been associated with left ventricular (LV) remodeling. A recent study demonstrated that LV myocytes synthesize and release MMPs, which suggests that LV myocytes may participate in myocardial remodeling. However, extracellular stimuli that may potentially influence LV myocyte MMP production remains to be defined. In the present study MMP activity and expression were measured in porcine LV myocyte preparations (10(5) total cells; n = 6) following incubation (6 h) with endothelin-1 (ET-1;50 pM), angiotensin II (ANG II; 1 microM), or the beta-receptor agonist isoproterenol (Iso; 10 nM). LV myocyte-conditioned media were then subjected to gelatin zymography and an MMP-2 antibody capture assay. MMP zymographic gelatinase activity and MMP-2 content were increased by over 40% in LV myocyte-conditioned media after incubation with ET-1 or ANG II (P < 0.05). Exposure to the phorbol ester phorbol 12-myristate 13-acetate (PMA; 50 ng/ml) resulted in a 30% increase in zymographic gelatinase activity and a 63% increase in MMP-2 content (P < 0.05), suggesting that protein kinase C activation may be an intracellular mechanism for MMP induction. With the use of a confocal microscopy, membrane type-1 MMP (MT1-MMP) was localized to porcine LV myocytes, and immunoblotting for MT1-MMP using LV myocyte extracts revealed that after exposure to Iso, ET-1, ANG II, or PMA (P < 0.05), MT1-MMP abundance increased over 50%. Thus stimulation of specific neurohormonal systems that are relevant to LV remodeling influences LV myocyte MMP synthesis and release.