Fluoropyrimidine type, patient age, tumour sidedness and mutation status as determinants of benefit in patients with metastatic colorectal cancer treated with EGFR monoclonal antibodies: individual patient data pooled analysis of randomised trials from the ARCAD database.

BACKGROUND: KRAS mutations in metastatic colorectal cancer (mCRC) are used as predictive biomarkers to select therapy with EGFR monoclonal antibodies (mAbs). Other factors may be significant determinants of benefit. METHODS: Individual patient data from randomised trials with a head-to-head comparison between EGFR mAb versus no EGFR mAb (chemotherapy alone or best supportive care) in mCRC, across all lines of therapy, were pooled. Overall survival (OS) and progression-free survival (PFS) were compared between groups. Treatment effects within the predefined KRAS biomarker subsets were estimated by adjusted hazard ratio (HRadj) and 95% confidence interval (CI). EGFR mAb efficacy was measured within the KRAS wild-type subgroup according to BRAF and NRAS mutation status. In both KRAS wild-type and mutant subgroups, additional factors that could impact EGFR mAb efficacy were explored including the type of chemotherapy, line of therapy, age, sex, tumour sidedness and site of metastasis. RESULTS: 5675 patients from 8 studies were included, all with known mCRC KRAS mutation status. OS (HRadj 0.90, 95% CI 0.84-0.98, p = 0.01) and PFS benefit (HRadj 0.73, 95% CI 0.68-0.79, p < 0.001) from EGFR mAbs was observed in the KRAS wild-type group. PFS benefit was seen in patients treated with fluorouracil (HRadj 0.75, 95% CI 0.68-0.82) but not with capecitabine-containing regimens (HRadj 1.04, 95% CI 0.86-1.26) (pinteraction = 0.002). Sidedness also interacted with EGFR mAb efficacy, with survival benefit restricted to left-sided disease (pinteraction = 0.038). PFS benefits differed according to age, with benefits greater in those under 70 (pinteraction = 0.001). The survival benefit was not demonstrated in those patients with mutations found in the KRAS, NRAS or BRAF genes. The presence of liver metastases interacted with EGFR mAb efficacy in patients with KRAS mutant mCRC (pinteraction = 0.004). CONCLUSION: The benefit provided by EGFR mAbs in KRAS WT mCRC is associated with left-sided primary tumour location, younger patient age and absence of NRAS or BRAF mutations. Survival benefit is observed with fluorouracil but not capecitabine. Exploratory results support further research in KRAS mutant mCRC without liver metastases.

Germline polymorphisms as biomarkers of tumor response in colorectal cancer patients treated with anti-EGFR monoclonal antibodies: a systematic review and meta-analysis.

Studies of germline polymorphisms as predictors of tumor response to anti-epidermal growth factor receptor (EGFR) monoclonal antibody agents in metastatic colorectal cancer have reported inconsistent results. We performed a systematic review of studies from 1990 to September 2015, followed by random-effects meta-analyses for polymorphisms examined in at least three studies. Of 87 studies, 40 passed the criteria for systematic review and 23 for meta-analysis. The polymorphisms suitable for meta-analysis were CCND1 (rs17852153), COX2 (rs20417), EGF (rs4444903), EGFR (rs712829, rs11543848, 3'UTR CA repeat), FCGR2A (rs1801274), FCGR3A (rs396991), IL8 (rs4073), KRAS (rs61764370) and VEGFA (rs3025039). Meta-analysis yielded nominal significance (at α=0.05) for rs4444903 and rs11543848, but showed no significant results after multiple testing correction; this was unchanged by sensitivity analyses to address subgroups, funnel-plot asymmetries, and study quality. This highlights a tendency for lack of replication in the face of initial positive results, and possibly the unsuitability of relying on tumor response as a surrogate marker in this setting.

Diurnal blood pressure and urine production in acute spinal cord injury compared with controls.

STUDY DESIGN: This is a prospective observational study. OBJECTIVES: The objective of this study was to determine time-dependent changes in diurnal blood pressure (BP) and urine production in acute spinal cord injury (SCI). SETTING: This study was conducted in a specialist, state-based spinal cord service in Victoria, Australia. METHODS: Consenting patients admitted consecutively with acute SCI were compared with patients confined to bed rest while awaiting surgery and with mobilising able-bodied controls. Participants underwent ambulatory BP monitoring (ABPM), measurement of diurnal urine production and rated orthostatic symptoms over 1 year. Participants with night:day systolic BP (SBP) <90% were classified as dippers, 90-100% as non-dippers and >100% as reverse dippers. RESULTS: Participants comprised tetraplegics (n=47, 40.0±17.3 years), paraplegics (n=35, 34.4±13.9 years), immobilised (n=18, 30.9±11.3 years) and mobilising (n=44, 33.1±13.5 years) controls. At baseline, 24-h BP was significantly lower in tetraplegics (111.8±1.9/62.1±1.1 mm Hg) but not in paraplegics (116.7± 1.4/66.0±1.1 mm Hg), compared with controls (117.1 ±1.3/69.1±1.1 mm Hg), adjusting for gender. This difference was not observed at 1 year. The average night:day SBP in mobilising controls was 86.1±0.7%, differing from paraplegics (94.0±1.5%, P<0.001) and tetraplegics (101.5±1.5%, P<0.001). Urine production in tetraplegics and paraplegics did not fall at night compared with the day. Abnormal diurnal BP and orthostatic symptoms in tetraplegics persisted throughout the study. Nocturnal hypertension was observed in 27% (n=9) of tetraplegics, of whom only 2 had day hypertension. All mobilising controls with nocturnal hypertension (n=6, 14%) had day hypertension. CONCLUSION: People with SCI have a high prevalence of isolated nocturnal hypertension, reverse dipping, orthostatic intolerance and nocturnal polyuria. Cardiovascular risk management and assessment of orthostatic symptoms should include ABPM.

Significance of baseline and change in quality of life scores in predicting clinical outcomes in an international phase III trial of advanced pancreatic cancer: NCIC CTG PA.3.

BACKGROUND: There is insufficient information regarding the prognostic significance of baseline and change in quality of life (QoL) scores on overall survival (OS) in advanced pancreatic cancer. METHODS: QoL was assessed prospectively using the EORTC QLQ-C30 as part of the PA.3 trial of gemcitabine + erlotinib (G + E) vs. gemcitabine + placebo (G + P). Relevant variables and QoL scores at baseline and change at 8 weeks were analyzed by Cox stepwise regression to determine predictors of OS. RESULTS: 222 of 285 patients (pts) treated with G + E and 220 of 284 pts treated with G + P completed baseline QoL assessments. In a multivariable Cox analysis combining all pts, better QoL physical functioning (PF) score independently predicted longer OS (HR 0.86; CI: 0.80-0.93), as did non-white race (HR 0.64; CI: 0.44-0.95), PS 0-1 (HR 0.65; CI: 0.50-0.85), locally advanced disease (HR 0.55; CI: 0.43-0.71) and G + E (HR 0.78; CI: 0.64-0.96). Improvement in physical function at week 8 also predicted for improved survival (HR 0.89; CI: 0.81-0.97 for 10 point increase in score, p = 0.02). CONCLUSION: In addition to clinical variables, patient reported QoL scores at baseline and change from baseline to week 8 added incremental predictive information regarding survival for advanced pancreatic cancer patients.

Estimation of drug cost avoidance and pathology cost avoidance through participation in NCIC Clinical Trials Group phase III clinical trials in Canada.

BACKGROUND: Cost avoidance occurs when, because of provision of a drug therapy [drug cost avoidance (dca)] or a pathology test [pathology cost avoidance (pca)] during trial participation, health care payers need not pay for standard treatments or testing. The aim of our study was to estimate the total dca and pca for Canadian patients enrolled in relevant phase iii trials conducted by the ncic Clinical Trials Group. METHODS: Phase iii trials that had completed accrual and resulted in dca or pca were identified. The pca was calculated based on the number of patients screened and the test cost. The dca was estimated based on patients randomized, the protocol dosing regimen, drug cost, median dose intensity, and median duration of therapy. Costs are presented in Canadian dollars. No adjustment was made for inflation. RESULTS: From 1999 to 2011, 4 trials (1479 patients) resulted in pca and 17 trials (3195 patients) resulted in dca. The total pca was estimated at $4,194,849, which included testing for KRAS ($141,058), microsatellite instability ($18,600), and 21-gene recurrence score ($4,035,191). The total dca was estimated at $27,952,512, of which targeted therapy constituted 43% (five trials). The combined pca and dca was $32,147,361. CONCLUSIONS: Over the study period, trials conducted by the ncic Clinical Trials Group resulted in total cost avoidance (pca and dca) of approximately $7,518 per patient. Although not all trials lead to cost avoidance, such savings should be taken account when the financial impact of conducting clinical research is being considered.

Location of colon cancer (right-sided versus left-sided) as a prognostic factor and a predictor of benefit from cetuximab in NCIC CO.17.

BACKGROUND: Right- and left-sided colon cancers (RC, LC) differ with respect to biology, pathology and epidemiology. Previous data suggest a mortality difference between RC and LC. We examined if primary tumour side also predicts for outcome in chemotherapy refractory, metastatic colon cancer (MCC). We also compared RC versus LC as a predictor of efficacy of epidermal growth factor receptor (EGFR) inhibition with cetuximab. METHODS: Reanalyzing NCIC CO.17 trial (cetuximab versus best supportive care [BSC]), we coded the primary tumour side as RC (caecum to transverse colon) or LC (splenic flexure to rectosigmoid). The association between tumour side and baseline characteristics was assessed. Cox regression models determined factors affecting overall survival (OS) and progression free survival (PFS). RESULTS: Patients with RC (150/399) had more poorly differentiated, mutant KRAS, mutated PIK3CA and wild-type BRAF tumours, fewer liver and lung metastases, and shorter interval between diagnosis and study entry. Among BSC patients, tumour side was not prognostic for PFS (hazard ratios (HR) 1.07 [0.79-1.44], p = 0.67) or OS (HR 0.96 [0.70-1.31], p = 0.78). Among wild-type KRAS patients, those with LC had significantly improved PFS when treated with cetuximab compared to BSC (median 5.4 versus 1.8 months, HR 0.28 [0.18-0.45], p < 0.0001), whereas those with RC did not (median 1.9 versus 1.9 months, HR 0.73 [0.42-1.27], p = 0.26), [interaction p = 0.002]. CONCLUSION: In refractory MCC, tumour location within the colon is not prognostic, but is strongly predictive of PFS benefit from cetuximab therapy. Additional research is needed to understand the molecular differences between RC and LC and their interaction with EGFR inhibition.

A retrospective review of the ambulatory blood pressure patterns and diurnal urine production in subgroups of spinal cord injured patients.

STUDY DESIGN: Retrospective study. OBJECTIVES: To quantify diurnal blood pressure (BP) patterns and nocturnal hypertension and to measure diurnal urine production in spinal cord injury (SCI) patients with clinically significant disorders of BP control. SETTING: A specialist state-based spinal cord service in Victoria, Australia. METHODS: Medical records of patients with traumatic SCI who were referred to a specialist service for management of a BP disorder were examined. Ambulatory BP and nocturnal urine production were compared between groups of patients classified according to level, completeness and chronicity of SCI. Patients with night:day systolic BP <90% were classified as dippers, 90-100% as non-dippers and >100% as reversed dippers. RESULTS: Patients (44 tetraplegic, 10 paraplegic) were predominantly males (92.6%) aged 41±2.5 years (mean±s.e.m.). Referral was for orthostatic intolerance (n=37), autonomic dysreflexia (n=6), nocturnal polyuria (n=4), elevated BP (n=1) and peripheral oedema (n=1). The average BP was 111.1±1.4/65.0±1.2 mm Hg. In 56% of patients (n=30), BP at night was higher than during the day and another 37% (n=20) were non-dippers. Nocturnal hypertension was present in 31% (n=17) of the patients. In the tetraplegic patients, urine flow rate was greater during the night than day (121±9.5 ml h(-1) vs 89±8.2 ml h(-1), P=0.025). CONCLUSION: Ambulatory BP monitoring in patients with SCI and clinically significant BP disorders detected a high incidence of reversed dipping and nocturnal hypertension. We postulate elevated nocturnal BP may contribute to nocturnal diuresis that might cause relative volume depletion and thereby contribute to daytime orthostatic hypotension.

Epiregulin gene expression as a biomarker of benefit from cetuximab in the treatment of advanced colorectal cancer.

BACKGROUND: Anti-EGFR antibody, cetuximab, improves overall survival (OS) in K-ras wild-type chemotherapy-refractory colorectal cancer. Epidermal growth factor receptor ligand epiregulin (EREG) gene expression may further predict cetuximab benefit. METHODS: Tumour samples from a phase III clinical trial of cetuximab plus best supportive care (BSC) vs BSC alone (CO.17) were analysed for EREG mRNA gene expression. Predictive effects of high vs low EREG on OS and progression-free survival (PFS) were examined for treatment-biomarker interaction. RESULTS: Both EREG and K-ras status were ascertained in 385 (193 cetuximab, 192 BSC) tumour samples. Within the high EREG and K-ras wild-type status ('co-biomarker')-positive group (n=139, 36%), median PFS was 5.4 vs 1.9 months (hazard ratio (HR) 0.31; P<0.0001), and median OS was 9.8 vs 5.1 months (HR 0.43; P<0.001) for cetuximab vs BSC, respectively. In the rest (n=246, 64%), PFS (HR 0.82; P=0.12) and OS (HR 0.90; P=0.45) were not significantly different. Test for treatment interaction showed a larger cetuximab effect on OS (HR 0.52; P=0.007) and PFS (HR 0.49; P=0.001) in the co-biomarker-positive group. CONCLUSION: In pre-treated K-ras wild-type status colorectal cancer, patients with high EREG gene expression appear to benefit more from cetuximab therapy compared with low expression. Epiregulin as a selective biomarker requires further evaluation.

Innovative estimation of survival using log-normal survival modelling on ACCENT database.

BACKGROUND: The ACCENT database, with individual patient data for 20 898 patients from 18 colon cancer clinical trials, was used to support Food and Drug Administration (FDA) approval of 3-year disease-free survival as a surrogate for 5-year overall survival. We hypothesised substantive differences in survival estimation with log-normal modelling rather than standard Kaplan-Meier or Cox approaches. METHODS: Time to relapse, disease-free survival, and overall survival were estimated using Kaplan-Meier, Cox, and log-normal approaches for male subjects aged 60-65 years, with stage III colon cancer, treated with 5-fluorouracil-based chemotherapy regimens (with 5FU), or with surgery alone (without 5FU). RESULTS: Absolute differences between Cox and log-normal estimates with (without) 5FU varied by end point. The log-normal model had 5.8 (6.3)% higher estimated 3-year time to relapse than the Cox model; 4.8 (5.1)% higher 3-year disease-free survival; and 3.2 (2.2)% higher 5-year overall survival. Model checking indicated greater data support for the log-normal than the Cox model, with Cox and Kaplan-Meier estimates being more similar. All three model types indicate consistent evidence of treatment benefit on both 3-year disease-free survival and 5-year overall survival; patients allocated to 5FU had 5.0-6.7% higher 3-year disease-free survival and 5.3-6.8% higher 5-year overall survival. CONCLUSION: Substantive absolute differences between estimates of 3-year disease-free survival and 5-year overall survival with log-normal and Cox models were large enough to be clinically relevant, and warrant further consideration.

Association of hypomagnesemia with inferior survival in a phase III, randomized study of cetuximab plus best supportive care versus best supportive care alone: NCIC CTG/AGITG CO.17.

BACKGROUND: Cetuximab-induced hypomagnesemia has been associated with improved clinical outcomes in advanced colorectal cancer (CRC). We explored this relationship from a randomized clinical trial of cetuximab plus best supportive care (BSC) versus BSC alone in patients with pretreated advanced CRC. PATIENTS AND METHODS: Day 28 hypomagnesemia grade (0 versus ≥1) and percent reduction (<20% versus ≥20%) of Mg from baseline was correlated with outcome. RESULTS: The median percentage Mg reduction at day 28 was 10% (-42.4% to 63.0%) for cetuximab (N = 260) versus 0% (-21.1% to 25%) for BSC (N = 251) [P < 0.0001]. Grade ≥1 hypomagnesemia and ≥20% reduction from baseline at day 28 were associated with worse overall survival (OS) [hazard ratio, HR 1.61 (95% CI 1.12-2.33), P = 0.01 and 2.08 (95% CI 1.32-3.29), P = 0.002, respectively] in multivariate analysis including grade of rash (0-1 versus 2+). Dyspnea (grade ≥3) was more common in patients with ≥20% versus < 20% Mg reduction (68% versus 45%; P = 0.02) and grade 3/4 anorexia were higher in patients with grade ≥1 hypomagnesemia (81% versus 63%; P = 0.02). CONCLUSIONS: In contrast to prior reports, cetuximab-induced hypomagnesemia was associated with poor OS, even after adjustment for grade of rash.

Comorbidity, age and overall survival in patients with advanced pancreatic cancer - results from NCIC CTG PA.3: a phase III trial of gemcitabine plus erlotinib or placebo.

BACKGROUND: The effect of comorbidity, age and performance status (PS) on treatment of advanced pancreatic cancer is poorly understood. We examined these factors as predictors of outcome in advanced pancreatic cancer patients treated with gemcitabine +/- erlotinib. PATIENTS AND METHODS: Comorbidity was evaluated by two physicians using the Charlson Comorbidity Index (CCI) and correlated with clinical outcome data from the NCIC Clinical Trials Group (NCIC CTG) PA.3 clinical trial. RESULTS: Five hundred and sixty-nine patients were included; 47% were aged ≥ 65 years old, 36% had comorbidity (CCI>0). In multivariate analysis, neither age (p=0.22) nor comorbidity (p=0.21) was associated with overall survival. The baseline presence of better PS and lower pain intensity scores was associated with better overall survival (p < 0.0001 and p=0.01, respectively). An improvement in survival with the addition of erlotinib therapy was seen in patients age < 65 (adjusted hazard ratio (HR) 0.73, p=0.01) or in the presence of comorbidity (adjusted HR 0.72, p=0.03). However, neither age nor CCI score was predictive of erlotinib benefit after test for interaction. Patients treated with gemcitabine plus erlotinib who were ≥ 65 years of age or those with comorbidity had a higher rate of infections ≥ grade 3. CONCLUSION: Low baseline pain intensity and better PS were associated with improved overall survival, while age and comorbidity were not independent prognostic factors for patients treated with gemcitabine-based therapy.

Comorbidity, age and overall survival in cetuximab-treated patients with advanced colorectal cancer (ACRC)--results from NCIC CTG CO.17: a phase III trial of cetuximab versus best supportive care.

BACKGROUND: the interplay between comorbidity, age and performance status (PS) as predictors of outcome in advanced colorectal cancer (ACRC) is poorly understood. We examined these factors as predictors of treatment toxicity and outcome in cetuximab-treated patients with ACRC. PATIENTS AND METHODS: comorbidity was independently evaluated using the Charlson Comorbidity Index (CCI), a validated measure of comorbidity based on the presence of medical conditions weighted according to their effect on mortality. CCI score was correlated with clinical and outcome data. RESULTS: five hundred and seventy-two patients were included; 41% were ≥ 65 years and 25% had comorbidities at randomization. In multivariate analysis (MVA) of all covariates, only older age was associated with greater comorbidity (P = 0.008). Overall survival (OS) was significantly better for patients with greater comorbidity in univariate analysis (P = 0.047). Conversely, better PS was associated with better OS in MVA (hazard ratio 1.92 for PS = 2 versus PS = 0, P < 0.0001). Age was not associated with OS (P = 0.13). Elderly patients had significantly less grade ≥ 3 vomiting (P = 0.034) but more dyspnea (P = 0.005). Patients with greater comorbidity had significantly less grade ≥ 3 vomiting (P = 0.002) but more non-neutropenic fever (P = 0.005). CONCLUSION: better PS was associated with improved OS. For patients with good PS, restricting cetuximab use in the setting of significant comorbidity does not appear justified.

Projected effects of climate change on tick phenology and fitness of pathogens transmitted by the North American tick Ixodes scapularis.

Ixodes scapularis is the principal tick vector of the Lyme borreliosis agent Borrelia burgdorferi and other tick-borne zoonoses in northeastern North America. The degree of seasonal synchrony of nymphal and larval ticks may be important in influencing the basic reproductive number of the pathogens transmitted by I. scapularis. Because the seasonal phenology of tick vectors is partly controlled by ambient temperature, climate and climate change could shape the population biology of tick-borne pathogens. We used projected monthly normal temperatures, obtained from the second version of the Canadian Coupled Global Climate Model (CGCM2) under emissions scenario A2 of the Intergovernmental Panel on Climate Change for a site in southern Ontario, Canada, to simulate the phenology of I. scapularis in a mathematical model. The simulated seasonal abundance of ticks then determined transmission of three candidate pathogens amongst a population of white-footed mice (Peromyscus leucopus) using a susceptible-infected-recovered (SIR) model. Fitness of the different pathogens, in terms of resilience to changes in tick and rodent mortality, minima for infection duration, transmission efficiency and particularly any additional mortality of rodents specifically associated with infection, varied according to the seasonal pattern of immature tick activity, which was different under the temperature conditions projected for the 2020s, 2050s and 2080s. In each case, pathogens that were long-lived, highly transmissible and had little impact on rodent mortality rates were the fittest. However, under the seasonal tick activity patterns projected for the 2020s and 2050s, the fitness of pathogens that are shorter-lived, less efficiently transmitted, and more pathogenic to their natural hosts, increased. Therefore, climate change may affect the frequency and distribution of I. scapularis-borne pathogens and alter their evolutionary trajectories.

Role of migratory birds in introduction and range expansion of Ixodes scapularis ticks and of Borrelia burgdorferi and Anaplasma phagocytophilum in Canada.

During the spring in 2005 and 2006, 39,095 northward-migrating land birds were captured at 12 bird observatories in eastern Canada to investigate the role of migratory birds in northward range expansion of Lyme borreliosis, human granulocytic anaplasmosis, and their tick vector, Ixodes scapularis. The prevalence of birds carrying I. scapularis ticks (mostly nymphs) was 0.35% (95% confidence interval [CI] = 0.30 to 0.42), but a nested study by experienced observers suggested a more realistic infestation prevalence of 2.2% (95% CI = 1.18 to 3.73). The mean infestation intensity was 1.66 per bird. Overall, 15.4% of I. scapularis nymphs (95% CI = 10.7 to 20.9) were PCR positive for Borrelia burgdorferi, but only 8% (95% CI = 3.8 to 15.1) were positive when excluding nymphs collected at Long Point, Ontario, where B. burgdorferi is endemic. A wide range of ospC and rrs-rrl intergenic spacer alleles of B. burgdorferi were identified in infected ticks, including those associated with disseminated Lyme disease and alleles that are rare in the northeastern United States. Overall, 1.4[corrected]% (95% CI = 0.3 [corrected] to 0.41) of I. scapularis nymphs were PCR positive for Anaplasma phagocytophilum. We estimate that migratory birds disperse 50 million to 175 million I. scapularis ticks across Canada each spring, implicating migratory birds as possibly significant in I. scapularis range expansion in Canada. However, infrequent larvae and the low infection prevalence in ticks carried by the birds raise questions as to how B. burgdorferi and A. phagocytophilum become endemic in any tick populations established by bird-transported ticks.

Vector seasonality, host infection dynamics and fitness of pathogens transmitted by the tick Ixodes scapularis.

Fitness of tick-borne pathogens may be determined by the degree to which their infection dynamics in vertebrate hosts permits transmission cycles if infective and uninfected tick stages are active at different times of the year. To investigate this hypothesis we developed a simulation model that integrates the transmission pattern imposed by seasonally asynchronous nymphal and larval Ixodes scapularis ticks in northeastern North America, with a model of infection in white-footed mice (Peromyscus leucopus) reservoir hosts, using the bacteria Borrelia burgdorferi and Anaplasma phagocytophilum as examples. In simulations, survival of microparasites, their sensitivity to reduced rodent and tick abundance, and to 'dilution' by a reservoir-incompetent host depended on traits that allowed (i) highly efficient transmission from acutely-infected hosts, (ii) long-lived acute or 'carrier' host infections, and/or (iii) transmission amongst co-feeding ticks. Minimum values for transmission efficiency to ticks, and duration of host infectivity, necessary for microparasite persistence, were always higher when nymphal and larval ticks were seasonally asynchronous than when these instars were synchronous. Thus, traits influencing duration of host infectivity, transmission efficiency to ticks and co-feeding transmission are likely to be dominant determinants of fitness in I. scapularis-borne microparasites in northeastern North America due to abiotic forcings influencing I. scapularis seasonality.

Reductions of circulating matrix metalloproteinase 2 and vascular endothelial growth factor levels after treatment with pegvisomant in subjects with acromegaly.

BACKGROUND: Vascular endothelial growth factor (VEGF) is involved in activation of the matrix metalloproteinase (MMP) system; the latter is implicated in atherosclerosis and cardiovascular disease. Patients with acromegaly have reduced life expectancy primarily due to cardiac disease. AIM: This study assessed plasma MMPs and VEGF levels in patients with active acromegaly (IGF-I > 130% upper limit of normal), and on treatment with pegvisomant. SUBJECTS AND METHODS: Twenty patients [nine female, mean age 56.1 +/- 13.8 yr (mean +/- sd)] were studied at baseline and on pegvisomant therapy and compared with data from 25 healthy volunteers (12 female; 56.6 +/- 14.2 yr). Plasma MMP-2, MMP-9, and VEGF levels were measured. RESULTS: Serum IGF-I fell from a baseline (mean +/- sd) level of 620.1 +/- 209.3 ng/ml to 237.5 +/- 118.5 ng/ml on pegvisomant (doses 10-60 mg; P < 0.001). MMP-2 levels at baseline were significantly higher in patients compared with healthy controls (380.7 +/- 204.8 vs. 207.4 +/- 62.6 ng/ml; P < 0.001), but with treatment a significant reduction in MMP-2 [380.7 +/- 204.8 vs. 203.0 +/- 77.4 ng/ml; P < 0.001] and VEGF (283.4 +/- 233.6 vs. 229.1 +/- 157.4 pg/ml; P = 0.008) was noted. There was no significant difference in MMP-9 levels between patients and controls at baseline (797.5 +/- 142.1 vs. 788.3 +/- 218.0 ng/ml; P = 0.87) or between baseline and posttreatment levels (797.5 +/- 142.1 vs. 780.0 +/- 214 ng/ml; P = 0.76). CONCLUSIONS: Our novel data demonstrate that treatment of acromegaly with pegvisomant leads to reductions in MMP-2 and VEGF concentrations. Further studies are required to determine the significance of these findings with relation to cardiac disease.

Effects of hormone replacement therapy type and route of administration on plasma matrix metalloproteinases and their tissue inhibitors in postmenopausal women.

BACKGROUND: Matrix metalloproteinases (MMPs) are implicated in numerous disease states including cardiovascular disease and cancer. Because recent studies have shown a detrimental effect of hormone replacement therapy on cardiovascular disease and breast cancer, we investigated whether there are any differences in the concentrations of MMPs and their tissue inhibitors (TIMPs) in women receiving various forms of postmenopausal therapy. MATERIAL AND METHODS: A total of 195 healthy postmenopausal women were assessed: 46 were taking tibolone, 47 were taking transdermal estradiol, 46 were taking conjugated equine estrogens (CEE), and 56 were not taking any menopausal therapy (CTR). Plasma levels of MMP-2 and -9 and TIMP-1 and TIMP-2 were measured by ELISA methods. RESULTS: MMP-9 levels were significantly higher in the CEE group in comparison with healthy women not receiving menopausal therapy (P < 0.05). In contrast, MMP-9 levels in the tibolone group were significantly lower than in any other group (P < 0.01, compared with transdermal estradiol and CTR, and P < 0.001, compared with CEE). MMP-9 to TIMP-1 ratio was also significantly higher in the CEE, compared with CTR (P < 0.05), and lower in the tibolone group (P < 0.01, compared with all groups). MMP-2 levels were higher in the CEE group, compared with healthy women not receiving any menopausal therapy, and women taking tibolone (P < 0.05). CONCLUSIONS: Our study demonstrates differential effects of various forms of postmenopausal therapy on serum levels of MMP-9 and MMP-2. It remains to be established whether these differences might be associated with differences in risks of cardiovascular disease and cancer in these women.

Investigation of ground level and remote-sensed data for habitat classification and prediction of survival of Ixodes scapularis in habitats of southeastern Canada.

In southeastern Canada, most populations of Ixodes scapularis Say, the Lyme disease vector, occur in Carolinian forests. Climate change projections suggest a northward range expansion of I. scapularis this century, but it is unclear whether more northerly habitats are suitable for I. scapularis survival. In this study, we assessed the suitability of woodlands of the Lower Great Lakes/St. Lawrence Plain region for I. scapularis by comparing tick egg survival in four different woodlands. Woodlands where I. scapularis are established, and sand dune where I. scapularis do not survive, served as positive and negative control sites, respectively. At two woodland sites, egg survival was the same as at the positive control site, but at two of the sites survival was significantly less than either the positive control site, or one of the other test sites. Egg survival in all woodland sites was significantly higher than in the sand dune site. Ground level habitat classification discriminated among woodlands in which tick survival differed. The likelihood that I. scapularis populations could persist in the different habitats, as deduced using a population model of I. scapularis, was significantly associated with variations in Landsat 7 ETM+ data (normalized difference vegetation index [NDVI] and Tasselled Cap indices). The NDVI index predicted habitat suitability at Long Point, Ontario, with high sensitivity but moderate specificity. Our study suggests that I. scapularis populations could establish in more northerly woodland types than those in which they currently exist. Suitable habitats may be detected by ground-level habitat classification, and remote-sensed data may assist this process.

Climate change and the potential for range expansion of the Lyme disease vector Ixodes scapularis in Canada.

We used an Ixodes scapularis population model to investigate potential northward spread of the tick associated with climate change. Annual degree-days >0 degrees C limits for I. scapularis establishment, obtained from tick population model simulations, were mapped using temperatures projected for the 2020s, 2050s and 2080s by two Global Climate Models (the Canadian CGCM2 and the UK HadCM3) for two greenhouse gas emission scenario enforcings 'A2'and 'B2' of the Intergovernmental Panel on Climate Change. Under scenario 'A2' using either climate model, the theoretical range for I. scapularis establishment moved northwards by approximately 200 km by the 2020s and 1000 km by the 2080s. Reductions in emissions (scenario 'B2') had little effect on projected range expansion up to the 2050s, but the range expansion projected to occur between the 2050s and 2080s was less than that under scenario 'A2'. When the tick population model was driven by projected annual temperature cycles (obtained using CGCM2 under scenario 'A2'), tick abundance almost doubled by the 2020s at the current northern limit of I. scapularis, suggesting that the threshold numbers of immigrating ticks needed to establish new populations will fall during the coming decades. The projected degrees of theoretical range expansion and increased tick survival by the 2020s, suggest that actual range expansion of I. scapularis may be detectable within the next two decades. Seasonal tick activity under climate change scenarios was consistent with maintenance of endemic cycles of the Lyme disease agent in newly established tick populations. The geographic range of I. scapularis-borne zoonoses may, therefore, expand significantly northwards as a consequence of climate change this century.