Doxycycline-Induced Changes in Circulating MMP or TIMP2 Levels Are Not Associated with Skeletal-Related Event-Free or Overall Survival in Patients with Bone Metastases from Breast Cancer.

Doxycycline is often used as a promoter of inducible gene expression in preclinical models; however, it can also have direct effects on tumor growth and survival. This is due in part to its ability to inhibit cell invasion and regulate matrix metalloproteinase (MMP) expression. Given that doxycycline is also osteotropic, a clinical study to assess its effects on modulation of tumor progression or prevention of skeletal-related events (SRE) in patients with bone metastases from breast cancer (the Achilles trial) was undertaken. Patients received 100 mg of oral doxycycline twice daily for 12 weeks, with serum obtained at baseline and 4, 8 and 12 weeks post-initiation of doxycycline treatment. Exploratory analysis of the effects of doxycycline on circulating levels of MMP or tissue inhibitor of matrix metalloproteinase 2 (TIMP2) was performed in enrolled patients. Statistically significant associations were observed between MMP2, MMP9 and TIMP2 at baseline with significant associations maintained between absolute levels and changes in levels of MMP2 and TIMP2 at weeks 4-12 post initiation of doxycycline. Treatment with doxycycline generally resulted in decreases in MMP2 and MMP9 levels with concurrent upregulation of TIMP2 at 12 weeks post-initiation of doxycycline treatment. Despite this, we observed no association with the levels of any of these factors with either SRE-free or overall survival in this patient cohort. In summary, despite observing hypothesized effects of doxycycline administration on surrogate markers of its anti-tumor activity, measures of circulating levels of these biomarkers were not prognostic in this patient population.

A Randomized Trial Comparing 3- versus 4-Monthly Cardiac Monitoring in Patients Receiving Trastuzumab-Based Chemotherapy for Early Breast Cancer.

PURPOSE: The optimal frequency for cardiac monitoring of left ventricular ejection fraction (LVEF) in patients receiving trastuzumab-based therapy for early breast cancer (EBC) is unknown. We conducted a randomized controlled trial comparing 3- versus 4-monthly cardiac monitoring. PATIENTS AND METHOD: Patients scheduled to receive trastuzumab-containing cancer therapy for EBC with normal (>53%) baseline LVEF were randomized to undergo LVEF assessments every 3 or 4 months. The primary outcome was the change in LVEF from baseline. Secondary outcomes included the rate of cardiac dysfunction (defined as a decrease in the LVEF of ≥10 percentage points, to a value <53%), delays in or discontinuation of trastuzumab therapy, and cardiology referral. RESULTS: Of the 200 eligible and enrolled patients, 100 (50%) were randomized to 3-monthly and 100 (50%) to 4-monthly cardiac monitoring. Of these patients, 98 and 97 respectively underwent at least one cardiac scan. The estimated mean difference in LVEF from baseline was -0.94% (one-sided 95% lower bound: -2.14), which exceeded the pre-defined non-inferiority margin of -4%. There were also no significant differences between the two study arms for any of the secondary endpoints. The rate of detection of cardiac dysfunction was 16.3% (16/98) and 12.4% (12/97) in the 3- and 4-monthly arms, respectively (95% CI: 4.0 [-5.9, 13.8]). CONCLUSIONS: Cardiac monitoring every 4 months was deemed non-inferior to that every 3 months in patients with HER2-positive EBC being treated with trastuzumab-based therapy. Given its costs and inconvenience, cardiac monitoring every 4 months should be considered standard practice. Registration: NCT02696707, 18 February 2016.

A prospective multi-centre, randomized study comparing the addition of tapering dexamethasone to other standard of care therapies for taxane-associated pain syndrome (TAPS) in breast cancer patients.

PURPOSE: Taxane-associated pain syndrome (TAPS) is common with docetaxel and is characterised by myalgias and arthralgias starting 2-3 days after treatment and can last for up to 7 days. Anecdotal evidence suggests that corticosteroids can reduce TAPS. This multicentre, randomized trial evaluated the effect of additional tapering dexamethasone on TAPS. METHODS: 130 breast cancer patients commencing docetaxel were randomized to dexamethasone premedication (8 mg/twice daily for 3 days) or dexamethasone premedication followed by tapering dexamethasone (4 mg/daily for 2 days followed by 2 mg/daily for 2 days). The primary endpoint was absolute change in FACT-Taxane questionnaire during the first chemotherapy cycle. Secondary endpoints: proportion of patients with clinically significant TAPS, QoL, pain and toxicity. RESULTS: 110/130 patients had complete data included in the primary analysis. The fall in FACT-Taxane scores was lower in the experimental group on day 5 (p = 0.05), but not on day 7 (p = 0.21). There was no difference in FACT-Taxane scores over the entire study duration (p = 0.59). Fewer patients in the experimental arm reported TAPS on day 5 (30 vs. 47%). There was a borderline significant attenuation of impairment of QoL with experimental treatment on day 5 (p = 0.06), but not day 7 (p = 0.53). Tapered schedule was associated with more dyspepsia and insomnia. CONCLUSION: A tapering schedule of dexamethasone was associated with a brief reduction in docetaxel-associated symptoms which was observed only during dexamethasone exposure and did not persist after discontinuation of the drug. TRIAL REGISTRATION: ClinicalTrials.gov NCT03348696.

Feasibility outcomes of a randomised, multicentre, pilot trial comparing standard 6-monthly dosing of adjuvant zoledronate with a single one-time dose in patients with early stage breast cancer.

BACKGROUND: Adjuvant zoledronate is widely used in patients with early stage breast cancer (EBC), but its optimal duration and dosing interval is still unknown. While a single-dose of zoledronate can improve bone density for many years, a proper evaluation of its effects on breast cancer-related outcomes would require a large trial. In this pilot study we evaluated the feasibility of performing such a trial. METHODS: Eligible patients with EBC were randomised to receive either one dose of zoledronate or 7 doses (6-monthly dosing for 3 years). Feasibility was assessed by a combination of primary outcomes including: activation of at least 6 Ontario sites within a year, active participation (i.e. approaching eligible patients for study participation) of at least half of the medical oncologists, and enrolment of at least 100 patients across all sites within 9 months of the sixth site being activated. RESULTS: All 6 sites were activated within 1 year and of 47 medical oncologists, 27 (57%) approached patients. Between November 2018 and April 2020, 211 eligible patients were randomised, 106 (50.2%) to a single dose of zoledronate and 105 (49.8%) to 6-monthly dosing. Baseline characteristics of randomised patients included; median age 59 (range 36-88), ER and/or PR positive (85%), Her2 positive (23%), menopausal status (premenopausal [19%], perimenopausal [6.7%] and postmenopausal [74%]) and 74% received neo/adjuvant chemotherapy. CONCLUSIONS: All study feasibility endpoints were met in this trial comparing alternative schedules for adjuvant zoledronate. We will now seek funding for performing a larger efficacy trial.Trial registration: NCT03664687.

Use of Preoperative Magnetic Resonance Imaging for Breast Cancer: A Canadian Population-Based Study.

IMPORTANCE: Contrary to practice guidelines, breast magnetic resonance imaging (MRI) is commonly used in the preoperative evaluation of women with breast cancer. While existing literature has found little benefit to MRI in most patients, potential downstream consequences associated with breast MRI are not well described. OBJECTIVE: To describe patterns of preoperative breast MRI utilization in a health care system with universal insurance and its association with downstream investigations and clinical outcomes. DESIGN, SETTING, AND PARTICIPANTS: This was a population-based retrospective cohort study using administrative heath care databases in Ontario, Canada (2012 population, 13.5 million) over 14 geographic regions were evaluated within the data set. Participants comprised 53 015 patients with primary operable breast cancer treated from 2003 to 2012. MAIN OUTCOMES AND MEASURES: Use of preoperative breast MRI by year, geographic region, and breast cancer stage. Postdiagnosis imaging, biopsy, and short-term surgical outcomes were also evaluated between those who did and did not receive MRI. RESULTS: Overall, 14.8% of patients (7824 of 53 015) had a preoperative MRI. During the 10-year study period, MRI use increased across all stages by 8-fold (from 3% to 24%; P < .001 for trend). Factors associated with MRI use were younger age, higher socioeconomic status, higher Charlson comorbidity score, surgery performed in a teaching hospital, and fewer years of surgeon experience. Multivariate analyses showed that preoperative breast MRI was associated with higher likelihood of the following: postdiagnosis breast imaging (odds ratio [OR], 2.09; 95% CI, 1.92-2.28), postdiagnosis breast biopsies (OR, 1.74; 95% CI, 1.57-1.93), postdiagnosis imaging to assess for distant metastatic disease (OR, 1.51; 95% CI, 1.42-1.61), mastectomy (OR, 1.73; 95% CI, 1.62-1.85), contralateral prophylactic mastectomy (OR, 1.48; 95% CI, 1.23-1.77), and a greater than 30-day wait to surgery (OR, 2.52; 95% CI, 2.36-2.70) (all ORs are adjusted). CONCLUSIONS AND RELEVANCE: Preoperative breast MRI use has increased substantially in routine clinical practice and is associated with a significant increase in ancillary investigations, wait time to surgery, mastectomies, and contralateral prophylactic mastectomies.

Treatment choices for patients with invasive lobular breast cancer: a doctor survey.

RATIONALE, AIMS AND OBJECTIVES: Invasive lobular breast cancer (ILC) has distinct features that present challenges for management. We surveyed doctors regarding management approaches, opinions on quality of evidence supporting their practice, and future research needs. METHODS: An online questionnaire was developed and circulated to breast cancer surgical, radiation and medical oncologists. RESULTS: The questionnaire was completed by 88/428 doctors (20.6%); 22/56 (39.3%) surgeons, 21/64 (32.8%) radiation oncologists and 45/308 (14.6%) medical oncologists. The majority (65%) of surgeons were comfortable treating ILC patients using the same surgical management as patients with invasive ductal cancers (IDC). Furthermore, 25% would perform a similar surgery but would obtain larger gross margins. There was equipoise for radiation oncologists regarding whether or not ILC was an independent risk factor for local-regional recurrence after either breast-conserving surgery or mastectomy. Of those radiation oncologists who believe ILC is an independent risk factor for recurrence after mastectomy, 44.4% would offer radiation in the absence of usual indications. Medical oncologists approached systemic therapy for ILC patients similarly to those with comparable IDCs. Areas identified as most controversial and requiring future research were preoperative magnetic resonance imaging, radiotherapy post-mastectomy and the responsiveness of ILC to adjuvant chemotherapy compared with endocrine therapy. CONCLUSIONS: There is a variation in doctors' beliefs, management and opinions regarding the quality of evidence for the management of ILC. Clinical trials specifically assessing the management of ILC are required to guide clinical practice.

Imaging for distant metastases in women with early-stage breast cancer: a population-based cohort study.

BACKGROUND: Practice guidelines recommend that imaging to detect metastatic disease not be performed in the majority of patients with early-stage breast cancer who are asymptomatic. We aimed to determine whether practice patterns in Ontario conform with these recommendations. METHODS: We used provincial registry data to identify a population-based cohort of Ontario women in whom early-stage, operable breast cancer was diagnosed between 2007 and 2012. We then determined whether imaging of the skeleton, thorax, and abdomen or pelvis had been performed within 3 months of tissue diagnosis. We calculated rates of confirmatory imaging of the same body site. RESULTS: Of 26,547 patients with early-stage disease, 22,811 (85.9%) had at least one imaging test, and a total of 83,249 imaging tests were performed (mean of 3.7 imaging tests per patient imaged). Among patients with pathologic stage I and II disease, imaging was performed in 79.6% (10,921/13,724) and 92.7% (11,882/12,823) of cases, respectively. Of all imaging tests, 19,784 (23.8%) were classified as confirmatory investigations. Imaging was more likely for patients who were younger, had greater comorbidity, had tumours of higher grade or stage or had undergone preoperative breast ultrasonography, mastectomy or surgery in the community setting. INTERPRETATION: Despite recommendations from multiple international guidelines, most Ontario women with early-stage breast cancer underwent imaging to detect distant metastases. Inappropriate imaging in asymptomatic patients with early-stage disease is costly and may lead to harm. The use of population datasets will allow investigators to evaluate whether or not strategies to implement practice guidelines lead to meaningful and sustained change in physician practice.

Evaluating the feasibility of performing window of opportunity trials in breast cancer.

BACKGROUND: The waiting period to surgery represents a valuable "window of opportunity" to evaluate novel therapeutic strategies. Interventional studies performed during this period require significant multidisciplinary collaboration to overcome logistical hurdles. We undertook a one-year prospective window of opportunity study to assess feasibility. METHODS: Eligible newly diagnosed postmenopausal, estrogen receptor positive breast cancer patients awaiting primary surgery received anastrozole daily until surgery. Feasibility was assessed by (a) the proportion of patients who consented and (b) completed the study. Comparison of pre- and poststudy Ki67 labelling index and cleaved caspase 3 scores (CC3) was performed. RESULTS: 22/131 (16.8%) patients were confirmed eligible and 20/22 (91%) patients completed the study. 19/20 (95%) patients agreed to undergo optional additional tissue biopsies. The mean duration of anastrozole use was 24.7 (15-44) days. There were a statistically significant decline in mean Ki67 indices of 48.8% (p < 0.001) and a trend towards significance in the decline of CC3 (p = 0.17) when comparing pre- with posttreatment values. CONCLUSION: window of opportunity trials in breast cancer are a feasible way of assessing the biologic efficacy of different therapies in the presurgical setting. The majority of eligible women were willing to participate including undergoing additional tissue biopsies.

Imaging for metastatic disease in patients with newly diagnosed breast cancer: are doctor's perceptions in keeping with the guidelines?

RATIONALE, AIMS AND OBJECTIVES: Despite multiple guidelines advocating against routine radiological evaluation for metastases in women with early stage breast cancer, imaging is still frequently overused. The objective of this study was to assess doctor's views on imaging guidelines, and an attempt to establish why personal and local clinical practice patterns regarding imaging may differ from current guidelines. METHODS: Canadian doctors who treat breast cancer were invited by email to complete an online survey developed by members of the research team. RESULTS: Responses were received from 173 physicians (26% response rate). Most (82%) indicated awareness of at least one published imaging guideline. Sixty per cent indicated that they had read the recommendations of the 2012 American Society of Clinical Oncology 'Top 5' list for choosing wisely in oncology imaging and, of those, 81% agreed with it. However, most indicated that this recommendation has not influenced them to order less imaging. Over 95% of doctors identified suspicious history, physical examination findings and inflammatory breast cancer as important factors for performing imaging. The majority did not feel that patient demand, fear of litigation or ease of access to imaging influenced their ordering for imaging. CONCLUSIONS: The majority of breast cancer doctors are aware of and generally agree that guidelines pertaining to staging imaging for early breast cancer are reflective of evidence. Despite this, adherence is variable and factors such as local practice patterns and disease biology may play a role. Alternative strategies, beyond simply publishing recommendations, are therefore required if there is to be a sustained change in doctor behaviour.

Are Physicians Choosing Wisely When Imaging for Distant Metastases in Women With Operable Breast Cancer?

PURPOSE: In 2012, the American Society of Clinical Oncology (ASCO) published its inaugural Top Five recommendations for "choosing wisely" in oncology. One recommendation was to avoid imaging for metastatic disease in asymptomatic patients with early-stage breast cancer. We assessed whether local practice is in keeping with provincial practice guidelines and whether publication of the ASCO recommendations had any significant impact on this. METHODS: A retrospective review of staging imaging for distant metastases was performed in patients with primary operable (early-stage) breast cancer seen at a large Canadian academic cancer center. RESULTS: A total of 200 patient medical records were reviewed: 100 patients from 2011 (pre-ASCO Top Five), and 100 after September 2012 (post-ASCO Top Five). Baseline patient and tumor characteristics were similar in both groups. Overall, 169 patients (84.5%) underwent at least one imaging test (mean, 3.6 tests per imaged patient); 154 patients (77.0%) underwent imaging that was not in keeping with the spirit of the local guideline recommendations. The frequency of imaging did not change after publication of the ASCO recommendations. Furthermore, imaging to clarify indeterminate initial imaging was required in 51 (30.2%) of 169 patients. None of the confirmatory imaging results ultimately revealed metastatic disease. CONCLUSION: Despite the presence of local imaging guidelines, patients with early-stage breast cancer still undergo imaging for distant metastases. There was no reduction in imaging after publication of the ASCO Top Five recommendations. Broader knowledge translation strategies beyond publication are needed if recommendations are to be implemented into routine clinical practice.

Patient perceptions and expectations regarding imaging for metastatic disease in early stage breast cancer.

PURPOSE: The probability of detecting radiologically evident metastatic disease in asymptomatic women with newly diagnosed operable breast cancer is low. Despite the recommendations of most practice guidelines imaging is still frequently performed. Relatively little is known about what patients believe is important when it comes to radiologic staging. METHODS: Patients with early stage breast cancer who had completed their definitive breast surgery were surveyed about their personal experiences, perceptions, and expectations on the issue of perioperative imaging for distant metastatic disease. RESULTS: Over a 3 month period, 245 women with primary operable breast cancer completed the questionnaire (87.0% response rate) and 80.8% indicated having had at least one imaging test for distant metastatic disease. These were either of the thorax (72.2%), abdomen (55.9%) or skeleton (65.3%) with a total of 701 imaging tests (average of 3.5 tests per patient imaged) performed. Overall, 57.1% indicated that they would want imaging done if the chance of detecting metastases was ≤10%. Although 80.0% of patients indicated that, "doing whatever their doctor recommended" was important to them, 70.4% also noted that they would be uncomfortable if their physician did not order imaging, even if this was in keeping with practice guidelines. CONCLUSIONS: Most patients with early stage breast cancer recall having imaging tests for distant metastases. Given the choice, most would prefer having imaging performed, even if this is not in line with current guidelines. If patient expectations are, in part, driving excessive imaging, new strategies addressing this are required.

Pharmacotherapy of bone metastases in breast cancer patients--an update.

INTRODUCTION: Bone metastases in breast cancer patients are a common clinical problem and pose a threat to the quality of life of such patients. Multiple randomized trials have demonstrated the benefit of both bisphosphonates and denosumab in reducing the incidence and delaying the onset of skeletal related events (SREs) in breast cancer patients with bone metastases. AREAS COVERED: We review the current literature on the use of bisphosphonates and denosumab along with strategies to maximize benefit and minimize risk of these agents. We also review potential future targets. EXPERT OPINION: Despite the potent osteoclast inhibiting effects of the bone-targeted agents in current clinical use, we have likely maximized their ability to inhibit SREs and must in turn focus on minimizing their potential toxicity. The future will likely involve more novel treatment strategies as well as the development of new agents. The current 'one size fits all' approach for the management of breast cancer bone metastases will be replaced by 'tailored' treatment for each individual patient as we usher in the era of 'personalized medicine.' In addition, new bone-targeted agents (e.g., sclerostin inhibitors) and combinations will continue to be explored, as will the evaluation of the bone-targeting properties of more conventional non-osteoclast targeting therapies.

Definition and consequences of locally advanced breast cancer.

PURPOSE OF REVIEW: Locally advanced breast cancer (LABC) represents the most advanced stage breast cancer that is still potentially curable with surgery, radiation, and systemic therapy. The purpose of this review is to discuss LABC in the context of modern practice with a focus on its definition and potential consequences. RECENT FINDINGS: There is no one encompassing definition for this disease, but in general cancers of the breast are considered to be locally advanced if they are large and/or have infiltrated into adjacent tissues (the overlying skin or underlying muscles) and/or are found to have extensive locoregional lymph node involvement. It is not surprising, therefore, that LABC can cause significant morbidity and mortality. SUMMARY: Recent advances in our understanding of the biology of breast cancer have made it clear that LABC does not represent a single clinical entity but rather a heterogeneous group of breast tumors that share a common theme of extensive locoregional spread without overt evidence of distant metastatic disease. Despite advances in breast cancer screening and treatment LABC remains a significant global healthcare issue.

Treatment for locally advanced breast cancer: a global challenge, personalized medicine or both?

In this special issue of Current Opinion in Supportive and Palliative Care, we are delighted to bring together key, internationally recognized experts in the field of breast cancer care for a special issue on locally advanced breast cancer (LABC). To place this disease in context, we have deliberately tried to keep the chapter headings pertinent to the real world issues facing both patients and their healthcare providers.

Third-line chemotherapy in small-cell lung cancer: an international analysis.

INTRODUCTION: Small-cell lung cancer is an aggressive disease for which the mainstay of treatment is chemotherapy. Despite good initial responses most patients will relapse. Some will receive second-line therapy with clinical benefit, but for third-line chemotherapy there is little evidence to guide treatment decisions and the benefits of treatment are unknown. This study investigated the treatment of SCLC in the third-line setting. PATIENTS AND METHODS: An international, multicenter retrospective analysis of patients who received at least 3 lines of chemotherapy for their SCLC was performed. RESULTS: From 2000 to 2010, 120 patients were identified from 5 centers: median age 61, 40% (n = 72) limited stage, and 79% (n = 95) Eastern Cooperative Oncology Group performance status of 0 to 1. Only 22% of these patients received 3 distinct lines of chemotherapy. The remainder were rechallenged with a chemotherapy regimen used at least once previously. Six percent received platinum-based chemotherapy in all 3 lines. In third-line, response rate was 18% and median overall survival was 4.7 months. Factors associated with longer survival included normal baseline LDH levels and response to second-line chemotherapy. On multivariate analysis only normal baseline LDH retained statistical significance. Thirty-five patients went on to receive chemotherapy beyond the third line. CONCLUSION: Few SCLC patients receive 3 chemotherapy lines. Most patients were rechallenged with a similar regimen at least once. Response and survival in the third-line setting are modest. Lack of response to second-line chemotherapy and elevated baseline LDH level might predict lack of benefit from third-line treatment. This data set does not include patients receiving fewer lines for comparison.

Bone-Targeted Agents for the Management of Breast Cancer Patients with Bone Metastases.

Despite advances in adjuvant therapy for breast cancer, bone remains the most common site of recurrence. The goal of therapy for these patients is palliative and focused on maximizing the duration and quality of their life, while concurrently minimizing any disease or treatment-related complications. Bone metastases predispose patients to reduced survival, pain, impaired quality of life and the development of skeletal-related events. With an increased understanding of the pathophysiology of bone metastasis, effective treatments for their management have evolved and are now in widespread clinical use. This article will discuss the pathogenesis of bone metastases and review the key clinical evidence for the efficacy and safety of currently available systemic bone-targeted therapies in breast cancer patients with an emphasis on bisphosphonates and the receptor activator of nuclear factor kappa B ligand (RANKL) inhibitors. We will also discuss novel strategies and therapies currently in development.

Angiotensin converting enzyme-regulated, noncholinergic sympathoadrenal catecholamine release mediates the cardiovascular actions of human 'new pressor protein' related to coagulation beta-factor XIIa.

BACKGROUND: Human 'new pressor protein' (NPP), related to coagulation beta-factor XIIa (beta-FXIIa), potently releases sympathoadrenal catecholamines in bioassay rats, with concurrent elevation of systolic and diastolic blood pressure (SBP/DBP) and heart rate (HR). Elevated plasma NPP/beta-FXIIa levels in hypertensive anephric pediatric patients on hemodialysis associated with fluid status and blood pressure changes were previously reported, suggesting that NPP/beta-FXIIa contributed to their hypertension. OBJECTIVE: To investigate the mechanism of action of NPP/beta-FXIIa. METHODS: Hemodynamic and sympathoadrenal responses to NPP (20 microL plasma equivalent/rat) or coagulation beta-FXIIa (300 ng/kg intravenously) were measured in rats treated with pentolinium (ganglion blockade [+GB]) and/or captopril (+CAP; angiotensin converting enzyme [ACE] inhibition). RESULTS: In controls not receiving GB or CAP (-GB-CAP), NPP/beta-FXIIa raised plasma epinephrine (E) sixfold, SBP/DBP by 14/8 mmHg and HR by 15 beats/min. With blockade of the cholinergic pathway to the sympathoadrenal system (+GB), basal E, norepinephrine (NE), SBP, DBP and HR all dropped. However NPP/beta-FXIIa remained capable of raising E 20-fold, NE fourfold, SBP/DBP by 27/11 mmHg and HR by 20 beats/min, suggesting that it acted through a 'noncholinergic' mechanism. With +CAP alone, NPP/beta-FXIIa raised plasma E 18-fold, NE threefold, SBP/ DBP by 29/8 mmHg and HR by 73 beats/min, implicating an ACE-regulated 'peptidergic' mechanism. Combining +GB with +CAP potentiated NPP/beta-FXIIa actions further by raising E 50-fold, NE sevenfold, SBP/DBP by 55/20 mmHg and HR by 87 beats/min, strengthening the efficacy of this alternate pathway. CONCLUSIONS: The cardiovascular effects of NPP/beta-FXIIa are considerably mediated by a noncholinergic (peptidergic) ACE-regulated mechanism for sympathoadrenal catecholamine release that is enhanced by +GB and/or +CAP. Under inflammatory procoagulant conditions, endogenously produced NPP/beta-FXIIa may interfere with the antihypertensive effects of ACE inhibition therapy.

Human coagulation factor XII-related "new pressor protein": role of PACAP in its cardiovascular and sympathoadrenal effects.

OBJECTIVE: To investigate the role of pituitary adenylate cyclase-activating polypeptide (PACAP)-38 and -27 as possible mediators of the actions of "new pressor protein" (NPP), which is related to coagulation factor XIIa, on blood pressure (systolic and diastolic blood pressure) and heart rate, and on the release of adrenal medullary catecholamines. METHODS: Adult male Wistar bioassay rats (n=8 to 18 per group) were anesthetized with inactin (100 mg/kg intraperitoneally), ganglion-blocked with pentolinium (19.2 mg/kg subcutaneously) and treated with captopril (2.5 mg/kg intravenously). Human NPP was injected at 20 L plasma equivalent per approximately 300 g of rat intravenously, and both PACAPs were injected at 10 g/kg intravenously. The systolic and diastolic blood pressure and heart rate responses to all of these agonists were determined using a MacLab/8 system. Arterial plasma adrenaline and noradrenaline were determined by high performance liquid chromatography with fluorimetric detection. Responses to NPP, the PACAPs and a specific PACAP antagonist were compared to assess the PACAPs as potential mediators of the cardiovascular effects of NPP. RESULTS: PACAP-38 mimicked the effects of NPP on systolic and diastolic blood pressure and heart rate more closely than did PACAP-27. Generally, NPP raised diastolic blood pressure and heart rate, and especially plasma adrenaline and noradrenaline, more impressively in degree and duration than that achieved by the PACAPs. The antagonism of PACAP receptors (PAC-1) significantly reduced the cardiovascular effects of NPP by 30% to 50%. CONCLUSIONS: PACAP-38, especially, may qualify as a potential mediator of the cardiovascular and sympathoadrenal effects of NPP but incomplete inhibition of NPP activity by PAC-1 receptor antagonism and the observed differences all suggest that PACAP is not the only peptide involved. Such peptidic mediation of the effects of NPP may explain the potentiation of NPP by captopril and why NPP remains effective after cholinergic blockade. These data suggest that PACAP is involved in a novel axis between NPP, cardiac function and blood pressure that resists angiotensin-converting enzyme inhibition. Any endogenous production of NPP could raise clinically relevant issues pertaining to therapy with ACE inhibitors.