TPA-treated Group Research Articles

Use of Tissue Plasminogen Activator in Abdominal Abscesses in Children-A Single-Center Randomized Control Trial.

To establish the efficacy of once-per-day intracavitary tissue plasminogen activator (tPA) in the treatment of pediatric intra-abdominal abscesses. A single-center prospective, double-blinded, randomized controlled trial of the use of intracavitary tPA in abdominal abscesses in children. Patients were randomized to either tPA-treatment or saline-treatment groups. Primary outcome was drainage catheter dwell (hours). Secondary outcomes were length of hospital stay, times to discharge, clinical and sonographic resolution, and adverse events (AEs). Twenty-eight children were randomized to either group (n = 14 each). Demographics between groups were not significantly different (age P = .28; weight P = .40; gender P = .44). There were significantly more abscesses in the tPA-treated group (P = .03). Abscesses were secondary to perforated appendicitis (n = 25) or postappendectomy (n = 3). Thirty-four abscesses were drained, 4 aspirated, 3 neither drained/aspirated. There was no significant difference in number of drains (P = .14), drain size (P = .19), primary outcome (P = .077), or secondary outcomes found. No procedural or intervention drug-related AEs occurred. No patient in the saline-treated group required to be switched/treated with tPA. No significant difference in the length of catheter dwell time, procedure time to discharge, or time to resolution was found. Intracavitary tPA was not associated with morbidity or mortality. The results neither support nor negate routine use of tPA in the drainage of intra-abdominal abscess in children. It is possible that a multicentre study with a larger number of patients may answer this question more definitively.

Triplet chemotherapy vs doublet chemotherapy plus bevacizumab in metastatic, recurrent, and persistent cervical cancer

Objective: The effectiveness of paclitaxel-cisplatin-ifosfamide triplet regimen (TIP) was reported to be superior to that of paclitaxel-cisplatin doublet. However, the efficacy of paclitaxel-cisplatin-bevacizumab triplet (TPA) and TIP has not been compared. Here, we compared the efficacy and safety of TIP and TPA in patients with metastatic, recurrent, or persistent cervical cancer.Methods: We retrospectively reviewed the medical records of patients with recurrent, persistent, or metastatic cervical cancer who were at the Samsung Medical Center, Seoul, Korea between January 2005 and September 2018. Of the 161 patients included in the study, 92 had received TIP and 71 had received TPA. For the study, we compared the response rates, progression-free survival (PFS), overall survival (OS), and safety in the 2 treatment groups.Results: The response rates of patients who received TIP and TPA were comparable (64.1% vs 73.2%, P = 0.239). Histology (squamous vs nonsquamous) was the only prognostic factor that affected the response to therapy (odds ratio, 0.259; 95% confidence interval [CI], 0.119-0.562; P = 0.001). The PFS after TIP and TPA treatment was similar: 12.0 months (95%CI, 10.26-13.74) vs 11.5 months (95%CI, 10.18-12.83), respectively. In a Cox proportional hazard model, objective response to therapies was the only independent prognostic factor for both PFS and OS. However, different types of therapy (TIP vs TPA) did not affect the oncological outcomes for either PFS or OS. Although hematologic toxicity was significantly higher in the TIP-treated group than in the TPA-treated group, both regimens were safe and well-tolerated.Conclusions: The effectiveness and safety of TIP was comparable to TPA in terms of response rates, survival, and adverse effects. TIP could be an effective alternative in the treatment of cervical cancer when TPA is contraindicated or unaffordable.

Mechanism of Telapristone Acetate (CDB4124) on Progesterone Receptor Action in Breast Cancer Cells

Progesterone is a steroid hormone that plays an important role in the breast. Progesterone exerts its action through binding to progesterone receptor (PR), a transcription factor. Deregulation of the progesterone signaling pathway is implicated in the formation, development, and progression of breast cancer. Next-generation selective progesterone receptor modulators (SPRMs) have potent antiprogestin activity and are selective for PR, reducing the off-target effects on other nuclear receptors. To date, there is limited information on how the newer generation of SPRMs, specifically telapristone acetate (TPA), affect PR function at the molecular level. In this study, T47D breast cancer cells were used to investigate the molecular mechanism by which TPA antagonizes PR action. Global profiling of the PR cistrome and interactome was done with chromatin immunoprecipitation sequencing (ChIP-seq) and rapid immunoprecipitation mass spectrometry. Validation studies were done on key genes and interactions. Our results demonstrate that treatment with the progestin (R5020) alone resulted in robust PR recruitment to the chromatin, and addition of TPA reduced PR recruitment globally. TPA significantly changed coregulator recruitment to PR compared with R5020. Upon conservative analysis, three proteins (TRPS1, LASP1, and AP1G1) were identified in the R5020+TPA-treated group. Silencing TRPS1 with small interfering RNA increased PR occupancy to the known PR regulatory regions and attenuated the inhibition of gene expression after TPA treatment. TRPS1 silencing alleviated the inhibition of proliferation by TPA. In conclusion, TPA decreases PR occupancy on chromatin and recruits coregulators such as TRPS1 to the PR complex, thereby regulating PR target gene expression and associated cellular responses.

12-O-tetradecanoylphorbol-13-acetate activates hair follicle melanocytes for hair pigmentation via Wnt/β-catenin signaling

Melanocyte stem cells (McSCs) undergo cyclical activation and quiescence together with hair follicle stem cells (HFSCs). This process is strictly controlled by the autonomous and extrinsic signaling environment. However, the modulation of factors important for the activation of McSCs for hair pigmentation remains unclear. 12-O-tetradecanoylphorbol-13-acetate (TPA) mimics vital signaling pathways involved in melanocyte growth and melanogenesis in vitro. To investigate whether TPA regulates quiescent McSCs for hair pigmentation, we topically smeared TPA on 7-week-old mouse dorsal skin and found that TPA stimulated hair growth and hair matrix pigmentation. These changes were associated with a significant increase in the number of hair bulb melanocytes. Moreover, in the TPA-treated group, hair bulge McSCs and hair bulb melanoblasts actively proliferated. At the molecular level, nuclear β-catenin, a key factor of Wnt/β-catenin signaling, was highly synthesized in melanocytes and keratinocytes in TPA-induced hair bulbs. Inhibition of Wnt/β-catenin signaling by injecting Dickkopf1 plasmids into TPA-treated skin decreased hair matrix pigmentation and inhibited the proliferation and differentiation of McSCs. Our findings suggest that the topical application of TPA stimulates the proliferation and differentiation of McSCs and their progeny for hair matrix pigmentation by activating Wnt/β-catenin signaling. This might provide a useful experimental model for the study of signals controlling the activation of McSCs.

Thrombolytic protocol minimizes ischemic-type biliary complications in liver transplantation from donation after circulatory death donors.

Liver transplantation (LT) with donation after circulatory death (DCD) donors has been associated with a high rate of ischemic-type biliary strictures (ITBSs) and inferior graft survival. To investigate the impact of an intraoperative tissue plasminogen activator (tPA) on outcomes following DCD LT, we conducted a retrospective analysis of DCD LT at the Toronto General Hospital (TGH) and the Ochsner Medical Center (OMC). Between 2009 and 2013, 85 DCD LTs were performed with an intraoperative tPA injection (n = 30 at TGH, n = 55 at OMC), and they were compared with 33 DCD LTs without a tPA. Donor and recipient characteristics were similar in the 2 groups. There was no significant difference in the intraoperative packed red blood cell transfusion requirement (3.2 ± 3.4 versus 3.1 ± 2.3 U, P = 0.74). Overall, biliary strictures occurred less commonly in the tPA-treated group (16.5% versus 33.3%, P = 0.07) with a much lower rate of diffuse intrahepatic strictures (3.5% versus 21.2%, P = 0.005). After 1 and 3 years, the tPA group versus the non-tPA group had superior patient survival (97.6% versus 87.0% and 92.7% versus 79.7%, P = 0.016) and graft survival (96.4% versus 69.7% and 90.2% versus 63.6%, P < 0.001). In conclusion, a tPA injection into the hepatic artery during DCD LT reduces ITBSs and improves graft and patient survival without increasing the risk for bleeding.

Naturally Occurring Phenolic Acids Modulate TPA-induced Activation of EGFR, AP-1, and STATs in Mouse Epidermis

Epidermal growth factor receptor (EGFR) plays an important role in epithelial carcinogenesis and appears to be involved in STATs activation. In this study we investigated the possible interference of naturally occurring phenolic acids with EGFR, activator protein-1 (AP-1), and signal transducers and activators of transcription (STATs) pathways activated by topical application of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Balb/c mice epidermis. Pretreatment with tannic or chlorogenic acid resulted in a significant decrease in the phosphorylation of EGFR Y-1068 and Y-1173 tyrosine residues, which was accompanied by reduced activation of AP-1. Tannic acid decreased also the c-Jun AP-1 subunit level and binding to TPA response element (TRE) (3- and 2-fold in comparison with TPA-treated group respectively). Simultaneous reduction of JNK activity might be responsible for reduced activation of AP-1. In contrast to these more complex phenolics, protocatechuic acid increased the activity of JNK and was also the most efficient inhibitor of STATs activation. These results indicate that naturally occurring phenolic acids, by decreasing EGFR, AP-1, and STATs activation, may modulate other elements both upstream and downstream in these pathways and thus inhibit the tumor development. Although more complex phenolics affect mainly the EGFR/AP-1 pathway, STATs seem to be the most important targets for simple compounds, such as protocatechuic acid.

Stroke : Highlights of Selected Articles

<i>Stroke</i> : Highlights of Selected Articles

Abstract 3443: No Exacerbation of Perihematomal Edema or Ventricular Volume with Intraventricular Tissue Plasminogen Activator in Patients with Spontaneous Intraventricular Hemorrhage

Introduction: In severe spontaneous intraventricular hemorrhage (IVH), intraventricular (IVR) administration of tissue plasminogen activator (tPA) results in more rapid clearing of blood from the ventricles than with external ventricular drainage (EVD) alone. However, experimental studies suggest tPA may be neurotoxic in compromised brain tissue and may exacerbate perihematomal edema. Methods: We used computerized volumetrics to assess change in intracerebral hemorrhage (ICH), IVH, ventricular and peri-ICH edema (PHE) volumes at 2-5 (T1) and 5-9 (T2) days following diagnostic CT scans (T0) of 20 patients (10 tPA treated; 10 controls) with IVH requiring EVD. Control patients from a hospital database treated with EVD alone were matched by IVH and ICH volume to tPA-treated patients. Treated patients came from two multicenter trials involving 100 patients with IVH, and spontaneous ICH volume &lt;30cc and received a median of 4 doses (range 1-8) of tPA. Results: There were no significant differences between matched pairs in terms of age, admission Glasgow Coma Score, Graeb IVH score, PHE volume, total ventricular volume, or ICH volume. Median IVH volume was larger in the tPA-treated group (26.2 cc iqr10.2 vs. 23.1 cc iqr9.2; P=0.02). IVR tPA resulted in more rapid clearance of IVH as determined by T2-T0 decrease in Graeb score and median IVH volume (tPA: -18.7 (10.8) cc; control:-7.6 (3.2) cc; P=0.005). Ratios of PHE to ICH volume were non-significantly higher in control vs. tPA treated patients at T1 and T2 [control:tPA = 0.82:0.77 (T1);P=0.44 and 0.64:0.56 (T2);P=0.48]. Total ventricular volume was significantly larger in the control group at T2 (median: 41.7 (36.9) cc vs. tPA: 24.5 (11.9) cc; P=0.02) and cumulative median cerebrospinal fluid drainage was non-significantly higher (control: 1079 (463) cc vs. tPA: 639 (428) cc; P=0.08). Ventriculitis was more frequent in the control group (4 vs. 2 episodes; P=0.08) as was shunt dependence (4 vs. 0 cases; P=0.04). Conclusions: For case matched large IVH with small ICH volume, IVR tPA enhances lysis of intraventricular blood clots, accelerates resolution of post-hemorrhagic hydrocephalus and has no significant impact on perihematomal edema.

THR-18, a 18-mer peptide derived from PAI-1, is neuroprotective and improves thrombolysis by tPA in rat stroke models

Objective: The thrombolytic treatment of stroke is limited by a narrow therapeutic time window and is associated with significant adverse side effects. To improve this situation, the modulation of tissue-type plasminogen activator (tPA) activity by a synthetic plasminogen activator inhibitor-1-derived 18-mer peptide (THR-18) was examined in two models of stroke in rats.Methods: In the first model (thromboembolic), stroke was induced by intra-carotid injection of micro-clots to rats, and tPA (6 mg/kg) was intravenously infused for 30 minutes with or without THR-18 (1 mg/kg) at 4 hours post-induction. In the second model [transient middle cerebral artery occlusion (tMCAO)], stroke was induced for 2 hours by a transient mechanical occlusion. tPA and/or THR-18 (0·02, 0·1, and 1 mg/kg) were intravenously infused for 60 minutes at the time of reperfusion.Results: In the thromboembolic model, cerebral blood flow, measured before and up to 5·5 hours post-induction, revealed that tPA administration caused reperfusion of flow at 30 minutes post-infusion. Later on, an additional increase in reperfusion was seen in the tPA+THR-18 group, and not with tPA alone. In both models, the frequency of intracranial hemorrhage in the tPA-treated group was found to be significantly higher than the control, and this tPA effect was attenuated by THR-18. In the thromboembolic study, infarct size and brain edema were similar in the control and tPA-treated rats. However, the combination of tPA and THR-18 caused a statistically significant reduction in both parameters (infarct size 17·8 versus 25·0%, brain edema 5 versus 8%, tPA+THR-18 versus control, respectively). In the tMCAO mechanical model, infarct size and brain edema were both increased by tPA treatment as compared to the control group, and this increase was markedly diminished by THR-18 co-administration. Neurobehavioral assessment of the tMCAO animals performed at 72 hours post-stroke induction revealed significant improvements (P<0·05-0·01) in neuroscores in all groups of animals treated with peptide-tPA, as compared to the tPA monotherapy group. A significant (P<0·05) improvement in the neurological outcome was also seen in the THR-18 monoterapy group, as compared to the control animals, thus demonstrating a clear neuroprotective effect by the peptide on its own.Discussion: The results support the use of THR-18 together with tPA in the thrombolytic therapy of stroke, in order to achieve better patency, less tPA-induced damage, and possibly a widening of tPA therapeutic time window.

Albumin ameliorates tissue plasminogen activator-mediated blood–brain barrier permeability and ischemic brain injury in rats

Objective: Tissue plasminogen activator (tPA) may aggravate ischemic neuronal damage after focal cerebral ischemia and increase blood–brain barrier permeability. Human serum albumin has neuroprotective effects on ischemic stroke. However, whether albumin can attenuate the deleterious effects of tPA is yet unknown.Methods: In the present study, we attempted to determine the effects of albumin on cerebral injury and blood–brain barrier disruption induced by middle cerebral artery occlusion for 2 hours followed by 24 hours of reperfusion and tPA.Results: We found that infarct volume in rats which received saline and tPA was 35.6 ± 3.8% (mean ± SEM) and 50.9 ± 4.5%, respectively. There was significant difference between the two groups (p<0.01). The infarct volume in rats that received tPA with albumin was significantly decreased to 29.2 ± 3.3% (p<0.05), compared with tPA-only-treated group. Combination therapy using tPA with albumin also improved neurological deficits and reduced brain edema significantly (p<0.05). Relative to tPA-treated group, rats that received combination therapy using tPA with albumin had significantly reduced blood–brain barrier permeability, evaluated by quantitation of Evans blue leakage (p<0.05).Conclusion: In acute ischemic stroke, combination therapy using tPA with albumin can attenuate the deleterious effects of tPA.

Effect of radiofrequency radiation exposure on mouse skin tumorigenesis initiated by 7,12-dimethybenz[α]anthracene

Purpose: Although radiofrequency (RF) radiation is not considered mutagenic, it has been suggested as a promoter of tumorigenesis. To study if RF radiation has a tumor promoting effect, we exposed mice with skin tumorigenesis initiated by 7,12-dimethybenz[α]anthracene (DMBA) to RF radiation.Materials and methods: Eighty male ICR mice were subjected to a single DMBA application (100 μg/100 μl acetone/mouse) on shaved dorsal skin at the age of 7 weeks. After one week, the mice were randomized into four equal groups of 20 mice each: i.e., sham-, 849 MHz-, 1,763 MHz-exposed, and 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated groups. The RF exposure was conducted at a whole body average specific absorption rate (SAR) of 0.4 W/Kg, for 2 cycles of 45 min exposure with a 15 min interval each day, 5 days a week for 19 weeks. The TPA-treated group served as a positive control for skin tumorigenesis and were administered TPA (4 μg/100 μl acetone/mouse) twice weekly without RF exposure.Results: All mice were examined weekly at a macroscopic level. No skin tumors were observed in any groups except in the TPA-treated positive control group. TPA is known tumor promoter in DMBA-induced skin carcinogenesis and tumor incidence in the TPA treated group was 95%. At week 20 after DMBA initiation, skin tissues were analyzed immunohistochemically using anti-proliferating cell nuclear antigen (PCNA) antibody. No differences were observed by pathological examination or by PCNA staining between the sham- and the RF-exposed groups. The expression of cyclin D1 and c-fos were detected only in the tumorous skin tissues of the TPA-treated group.Conclusion: No evidence was found that RF radiation serves as a tumor promoter for skin tumors. Our data suggests that 849 MHz and 1,763 MHz RF radiations, similar to those emitted from mobile phones, do not have any promoting effect on skin tumor development in DMBA-initiated mice.

Anthocyanin- and hydrolyzable tannin-rich pomegranate fruit extract modulates MAPK and NF-kappaB pathways and inhibits skin tumorigenesis in CD-1 mice.

Chemoprevention has come of age as an effective cancer control modality; however, the search for novel agent(s) for the armamentarium of cancer chemoprevention continues. We argue that agents capable of intervening at more than one critical pathway in the carcinogenesis process will have greater advantage over other single-target agents. Pomegranate fruit extract (PFE) derived from the tree Punica granatum possesses strong antioxidant and antiinflammatory properties. Pomegranate fruit was extracted with acetone and analyzed based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and found to contain anthocyanins, ellagitannins and hydrolyzable tannins. We evaluated whether PFE possesses antitumor-promoting effects. We first determined the effect of topical application of PFE to CD-1 mice against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced conventional markers and other novel markers of skin tumor promotion. We found that topical application of PFE (2 mg/mouse) 30 min prior to TPA (3.2 nmole/mouse) application on mouse skin afforded significant inhibition, in a time-dependent manner, against TPA-mediated increase in skin edema and hyperplasia, epidermal ornithine decarboxylase (ODC) activity and protein expression of ODC and cyclooxygenase-2. We also found that topical application of PFE resulted in inhibition of TPA-induced phosphorylation of ERK1/2, p38 and JNK1/2, as well as activation of NF-kappaB and IKKalpha and phosphorylation and degradation of IkappaBalpha. We next assessed the effect of skin application of PFE on TPA-induced skin tumor promotion in 7,12-dimethylbenz(a)anthracene-initiated CD-1 mouse. The animals pretreated with PFE showed substantially reduced tumor incidence and lower tumor body burden when assessed as total number of tumors per group, percent of mice with tumors and number of tumors per animal as compared to animals that did not receive PFE. In TPA-treated group, 100% of the mice developed tumors at 16 weeks on test, whereas at this time in PFE-treated group, only 30% mice exhibited tumors. Skin application of PFE prior to TPA application also resulted in a significant delay in latency period from 9 to 14 weeks and afforded protection when tumor data were considered in terms of tumor incidence and tumor multiplicity. The results of our study provide clear evidence that PFE possesses antiskin-tumor-promoting effects in CD-1 mouse. Because PFE is capable of inhibiting conventional as well as novel biomarkers of TPA-induced tumor promotion, it may possess chemopreventive activity in a wide range of tumor models. Thus, an in-depth study to define active agent(s) in PFE capable of affording antitumor-promoting effect is warranted.

Lupeol modulates NF-kappaB and PI3K/Akt pathways and inhibits skin cancer in CD-1 mice.

Chemoprevention has become an effective cancer control modality; however, the search for novel agent(s) for the armamentarium of cancer chemoprevention continues. We argue that agents capable for inhibition of promotion stage of tumorigenesis with the ability to intervene at several critical pathways in the tumorigenesis process will have greater advantage over other single-target agents. Lupeol, a triterpene, is the principal constituent of common fruit plants such as olive, mango, fig and medicinal herbs that have been used to treat skin aliments. Lupeol has been reported to possess a wide range of medicinal properties that include strong antioxidant, antimutagenic, anti-inflammatory and antiarthritic effects. In the present study, we show that Lupeol possesses antitumor-promoting effects in a mouse skin tumorigenesis model. We first determined the effect of topical application of Lupeol to CD-1 mouse against 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced conventional markers and other novel markers of skin tumor promotion. We found that topical application of Lupeol (1-2 mg/mouse) 30 min prior to TPA (3.2 nmol/mouse) application onto the skin of CD-1 mice afforded significant inhibition, in a time- and dose-dependent manner, against TPA-mediated increase in (i) skin edema and hyperplasia, (ii) epidermal ornithine decarboxylase (ODC) activity, and (iii) protein expression of ODC, cyclo-oxygenase-2 and nitric oxide synthase. As of the role of nuclear factor kappa B (NF-kappaB) and phosphatidyl inositol 3-kinase (PI3K)/Akt signaling in tumor promotion, we next determined the effect of topical application of Lupeol to mouse skin against these signaling pathways. We found that Lupeol treatment to mouse skin resulted in the inhibition of TPA-induced (i) activation of PI3K, (ii) phosphorylation of Akt at Thr(308), (iii) activation of NF-kappaB and IKKalpha, and (iv) degradation and phosphorylation of IkappaBalpha. The animals pretreated with Lupeol showed significantly reduced tumor incidence, lower tumor body burden and a significant delay in the latency period for tumor appearance. At the termination of the experiment at 28 weeks, 100% of the animals in TPA-treated group exhibited seven to eight tumors/mouse, whereas only 53% of the mice receiving Lupeol prior to TPA treatment exhibited one to three tumors/mouse. These results for the first time provide evidence that Lupeol possesses antiskin tumor-promoting effects in CD-1 mouse and inhibits conventional as well as novel biomarkers of tumor promotion. We suggest that Lupeol is an attractive antitumor-promoting agent that must be evaluated in tumor models other than skin carcinogenesis.

Extension of ischemic therapeutic time window by a free radical scavenger, Edaravone, reperfused with tPA in rat brain

3-methyl-1-phenyl-2-pyrazolin-5-one (Edaravone) is a free radical scavenger. We tested the hypothesis that combination treatment of Edaravone and recombinant tissue plasminogen activator (tPA) extends the therapeutic time window. Male Wistar rats were subjected to 1.5-, 3.0- or 4.5-hour middle cerebral artery (MCA) occlusion (MCAO) by a nylon thread. Animals were randomly divided into four groups. The Sham group rats were operated without MCAO and drug injection. In the Vehicle-treated group the same volume of saline was given every 1.5 hours from just after MCAO to just before reperfusion. In the Vehicle + tPA-treated group saline injection was given as above and tPA (5 mg/kg, i.v.) was given once just after reperfusion. Edaravone+tPA-treated group: Edaravone (3 mg/kg, i.v.) was given every 1.5 hours instead of saline and tPA injection as above. Survival rate, infarct size and evidence of apoptosis and hemorrhage were examined in the animals. Combining administration of Edaravone+tPAsignificantly increased survival rate after 3 hours of transient MCAO, and reduced infarct volume after 1.5 hours of transient MCAO compared with the vehicle or vehicle+tPAgroups. In Edaravone+tPA-treated group, the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) and 4-hydroxynonenal (4-HNE) positive cells were reduced at 16 hours after 3 hours of transient MCAO, but not in advanced glycation end products (AGEs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Hemorrhage rate and the area decreased in the Edaravone+tPA-treated group. The combination therapy of Edaravone+tPA increased survival rate, and reduced the infarct volume and hemorrhage with reduction of lipid peroxidation. Therefore, Edaravone combination is expected to extend the therapeutic time window of tPA in the clinical situation.

Fibrinolysis therapy achieved with tissue plasminogen activator and aspiration of the liquefied clot after experimental intracerebral hemorrhage: rapid reduction in hematoma volume but intensification of delayed edema formation.

Fibrinolysis therapy accomplished using tissue plasminogen activator (tPA) and aspiration is considered to be a viable alternative to microsurgery and medical therapy for the treatment of deep-seated spontaneous intracerebral hematomas (SICHs). Tissue plasminogen activator is a mediator of thrombin- and ischemia-related delayed edema. Because both thrombin release and ischemia occur after SICH, the authors planned to investigate the effect of fibrinolytic therapy on hematoma and delayed edema volume. A spherical hematoma was created in the frontal white matter of 18 pigs. In the tPA-treated group (nine pigs), a mean of 1.55 ml tPA was injected into the clot and the resulting liquefied blood was aspirated. Magnetic resonance (MR) imaging was performed on Days 0 (after surgery), 4, and 10, and the volumes of hematoma and edema were determined. In the animals not treated with tPA (untreated group; nine pigs), the volume of hematoma dropped from 1.43+/-0.42 ml on Day 0 to 0.85+/-0.28 ml on Day 10. In the tPA-treated group, the volume of hematoma was reduced from 1.51 +/- 0.28 ml on Day 0 to 0.52 +/- 0.39 ml on Day 10. In comparison with the untreated group, the reduction in hematoma volume was significantly accelerated (p = 0.02). In the untreated group, perihematomal edema increased from 0.32 +/- 0.61 ml to 1.73 +/- 0.73 ml on Day 4, before dropping to 1.17 +/- 0.92 ml on Day 10. In the tPA-treated group, the volume of the edema increased from 0.09 +/- 0.21 ml on Day 0 to 1.93 +/- 0.79 ml on Day 4, and further to 3.34 +/- 3.21 ml on Day 10. The increase in edema volume was significantly more pronounced in the tPA-treated group (p = 0.04). Despite a significantly accelerated reduction in hematoma volume, the development of delayed perifocal edema was intensified by fibrinolytic therapy, which is probably related to the function of tPA as a mediator of edema formation after thrombin release and ischemia. Further experimental and clinical investigations are required to establish the future role of fibrinolysis in the management of SICH.

Metalloproteinase inhibition reduces thrombolytic (tissue plasminogen activator)-induced hemorrhage after thromboembolic stroke.

A potentially dangerous side effect associated with tissue plasminogen activator (tPA) use is cerebral hemorrhage. We have focused on developing drugs that could be administered with tPA to reduce the rate of hemorrhage. Since recent studies suggest that various matrix metalloproteinases (MMPs) are important in tumor necrosis factor-alpha production and membrane and vessel remodeling after ischemia, we investigated whether MMP inhibition affected the rate of hemorrhage and infarct production in the absence or presence of tPA treatment. We occluded the middle cerebral artery of New Zealand White rabbits with radiolabeled blood clots. Five minutes after embolization, we administered either the MMP inhibitor BB-94 (30 mg/kg SC) or its vehicle. Additional groups received BB-94 or vehicle in combination with tPA, administered 60 minutes after embolization (3.3 mg/kg tPA). After 48 hours, the rabbits were killed and brains were removed, immersion fixed for 1 week in 4% paraformaldehyde, and then cut into 5-mm coronal sections that were examined for the presence of hemorrhage, infarcts, and recanalization. Hemorrhage after embolic stroke was detected in 24% of the control group. tPA induced macroscopically visible hemorrhage in 77% of the tPA-treated group. The rabbits treated with BB-94 had an 18% incidence of hemorrhage (P:>0.05 compared with control). However, when the combination of BB-94 and tPA was administered to rabbits, there was only a 41% incidence of hemorrhage (compared with 77% in the tPA group; P:<0. 05). Both tPA and BB-94/tPA were similarly effective at lysing clots, at 49% and 35% (P:<0.05), respectively, compared with the 5% rate of lysis in the control group. There was a trend for a reduction in the number of infarcts, but it did not reach statistical significance. Our data suggest that MMP inhibition attenuates mechanisms involved in tPA-induced hemorrhage. This novel form of combination therapy may show promise as a treatment strategy for acute stroke.

Abstracts of literature

Abstracts of literature

Effects of unilateral intrathecal administrations of low dose tissue-type plasminogen activator on clot lysis, vasospasm and brain phospholipid hydroperoxidation in a primate model of bilateral subarachnoid hemorrhage

In order to clarify the effect of clot lysis by recombinant tissue-type plasminogen activator (tPA) on the brain lipid peroxidationl we measured phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) levels in a primate model of subarachnoid hemorrhage (SA H). Monkeys were assigned into two groups; a tPA-treated group receiving intrathecal injections of 0.02 mg tPAI and a placebo-treated group receiving saline. The tPA or placebo was injected into the right side of the basal cistern every 8 h for 6 days following bilateral SAH induction. The tPA cleared the right side clots (p < 0.0007)1 but not the left side clots. The degree of vasospasm in the right middle cerebral artery and the rCBF decrease in the right parietal cortex were significantly attenuated in the tPA group (p < 0.05). In the placebo groupi more severe vasospasm and marked rCBF reduction were noted in comparison with those in the tPA group. PCOOH levels in the parietal cortex were significantly higher in the placebo group than in the tPA group (p < 0.05). There were no significant changes in brain PEOOH levels. These results may explain the limitations for clinical application of unilateral intrathecal administration of tPA. [Neural Res 1998; 20: 625–631]

Inhibitory effect of Hibiscus protocatechuic acid on tumor promotion in mouse skin

Hibiscus protocatechuic acid (PCA), a phenolic acid isolated from Hibiscus sabdariffa L., was evaluated for its ability to inhibit the 12- O-tetradecanoylphorbol-13-acetate (TPA)-induced promotion in skin tumors of female CD-1 mice. Topical application of PCA (5, 10 or 20 μmol) 5 min prior to TPA (15 nmol) treatment twice weekly for 20 weeks to mice which were initiated with benzo[ a]pyrene (B[ a]P) inhibited the incidence of tumors in mice to 81.3, 62.5 and 56.3%, respectively, while all mice in the TPA-treated group developed tumors. The average number of tumors in mice pretreated with PCA was 2–4 and that of mice treated only with TPA was 6.6. The protection effects of PCA were also presented by its significant suppression on the TPA-induced hyperplasia in the skin and edema of mouse ears by 65 and 73% at doses of 10 and 20 μmol, respectively. When it was applied to the dorsal surface of CD-1 mice before TPA application, PCA (5, 10 or 20 μmol) inhibited the induction of epidermal ornithine decarboxylase (ODC) activity by 5 nmol TPA and myeloperoxidase (MPO) activity by 6.5 nmol TPA. The same doses of PCA also reduced the formation of hydrogen peroxide in the mouse skin to an inhibition of 61, 84 and 89%, respectively, when compared with that of the TPA-treated group. These results indicate that PCA possesses potential as a cancer chemopreventive agent against tumor promotion.

Effects of tissue plasminogen activator and a comparison of early invasive and conservative strategies in unstable angina and non-Q-wave myocardial infarction. Results of the TIMI IIIB Trial. Thrombolysis in Myocardial Ischemia.

Although coronary thrombosis plays a critical role in the pathogenesis of unstable angina and non-Q-wave myocardial infarction (NQMI), the effects of thrombolytic therapy in these disorders is not clear. Also, the role of routine early coronary arteriography followed by revascularization has not been established. Patients (n = 1473) seen within 24 hours of ischemic chest discomfort at rest, considered to represent unstable angina or NQMI, were randomized using a 2 x 2 factorial design to compare (1) TPA versus placebo as initial therapy and (2) an early invasive strategy (early coronary arteriography followed by revascularization when the anatomy was suitable) versus an early conservative strategy (coronary arteriography followed by revascularization if initial medical therapy failed). All patients were treated with bed rest, anti-ischemic medications, aspirin, and heparin. The primary end point for the TPA-placebo comparison (death, myocardial infarction, or failure of initial therapy at 6 weeks) occurred in 54.2% of the TPA-treated patients and 55.5% of the placebo-treated patients (P = NS). Fatal and nonfatal myocardial infarction after randomization (reinfarction in NQMI patients) occurred more frequently in TPA-treated patients (7.4%) than in placebo-treated patients (4.9%, P = .04, Kaplan-Meier estimate). Four intracranial hemorrhages occurred in the TPA-treated group versus none in the placebo-treated group (P = .06). The end point for the comparison of the two strategies (death, myocardial infarction, or an unsatisfactory symptom-limited exercise stress test at 6 weeks) occurred in 18.1% of patients assigned to the early conservative strategy and 16.2% of patients assigned to the early invasive strategy (P = NS). In the latter, the average length of initial hospitalization, incidence of rehospitalization within 6 weeks, and days of rehospitalization all were significantly lower. In the overall trial, patients with unstable angina and NQMI were managed with low rates of mortality (2.4%) and myocardial infarction or reinfarction (6.3%) at the time of the 6-week visit. These results can be achieved using either an early conservative or early invasive strategy, the latter resulting in a reduced incidence of days of hospitalization and of rehospitalization and in the use of antianginal drugs. The addition of a thrombolytic agent is not beneficial and may be harmful.