Human Breast Extracellular Matrix Microstructures and Protein Hydrogel 3D Cultures of Mammary Epithelial Cells.

Tissue extracellular matrix (ECM) is a structurally and compositionally unique microenvironment within which native cells can perform their natural biological activities. Cells grown on artificial substrata differ biologically and phenotypically from those grown within their native tissue microenvironment. Studies examining human tissue ECM structures and the biology of human tissue cells in their corresponding tissue ECM are lacking. Such investigations will improve our understanding about human pathophysiological conditions for better clinical care. We report here human normal breast tissue and invasive ductal carcinoma tissue ECM structural features. For the first time, a hydrogel was successfully fabricated using whole protein extracts of human normal breast ECM. Using immunofluorescence staining of type I collagen (Col I) and machine learning of its fibrous patterns in the polymerized human breast ECM hydrogel, we have defined the microstructural characteristics of the hydrogel and compared the microstructures with those of other native ECM hydrogels. Importantly, the ECM hydrogel supported 3D growth and cell-ECM interaction of both normal and cancerous mammary epithelial cells. This work represents further advancement toward full reconstitution of the human breast tissue microenvironment, an accomplishment that will accelerate the use of human pathophysiological tissue-derived matrices for individualized biomedical research and therapeutic development.

Distinct phenotypes of cancer cells on tissue matrix gel.

BACKGROUND: Breast cancer cells invading the connective tissues outside the mammary lobule or duct immerse in a reservoir of extracellular matrix (ECM) that is structurally and biochemically distinct from that of their site of origin. The ECM is a spatial network of matrix proteins, which not only provide physical support but also serve as bioactive ligands to the cells. It becomes evident that the dimensional, mechanical, structural, and biochemical properties of ECM are all essential mediators of many cellular functions. To better understand breast cancer development and cancer cell biology in native tissue environment, various tissue-mimicking culture models such as hydrogel have been developed. Collagen I (Col I) and Matrigel are the most common hydrogels used in cancer research and have opened opportunities for addressing biological questions beyond the two-dimensional (2D) cell cultures. Yet, it remains unclear whether these broadly used hydrogels can recapitulate the environmental properties of tissue ECM, and whether breast cancer cells grown on CoI I or Matrigel display similar phenotypes as they would on their native ECM. METHODS: We investigated mammary epithelial cell phenotypes and metabolic profiles on animal breast ECM-derived tissue matrix gel (TMG), Col I, and Matrigel. Atomic force microscopy (AFM), fluorescence microscopy, acini formation assay, differentiation experiments, spatial migration/invasion assays, proliferation assay, and nuclear magnetic resonance (NMR) spectroscopy were used to examine biological phenotypes and metabolic changes. Student's t test was applied for statistical analyses. RESULTS: Our data showed that under a similar physiological stiffness, the three types of hydrogels exhibited distinct microstructures. Breast cancer cells grown on TMG displayed quite different morphologies, surface receptor expression, differentiation status, migration and invasion, and metabolic profiles compared to those cultured on Col I and Matrigel. Depleting lactate produced by glycolytic metabolism of cancer cells abolished the cell proliferation promoted by the non-tissue-specific hydrogel. CONCLUSION: The full ECM protein-based hydrogel system may serve as a biologically relevant model system to study tissue- and disease-specific pathological questions. This work provides insights into tissue matrix regulation of cancer cell biomarker expression and identification of novel therapeutic targets for the treatment of human cancers based on tissue-specific disease modeling.

Porcine Breast Extracellular Matrix Hydrogel for Spatial Tissue Culture.

Porcine mammary fatty tissues represent an abundant source of natural biomaterial for generation of breast-specific extracellular matrix (ECM). Here we report the extraction of total ECM proteins from pig breast fatty tissues, the fabrication of hydrogel and porous scaffolds from the extracted ECM proteins, the structural properties of the scaffolds (tissue matrix scaffold, TMS), and the applications of the hydrogel in human mammary epithelial cell spatial cultures for cell surface receptor expression, metabolomics characterization, acini formation, proliferation, migration between different scaffolding compartments, and in vivo tumor formation. This model system provides an additional option for studying human breast diseases such as breast cancer.

Bipolar electrosurgical vessel-sealing device with compressive force monitoring.

Bipolar electrosurgical vessel sealing is commonly used in surgery to perform hemostasis. The electrode compressive force is demonstrably an important factor affecting the vessel seal burst pressure, an index of the seal quality. Using a piezoresistive force sensor attached to the handle of a laparoscopic surgical device, applied handle force was measured and used to predict the electrosurgical vessel compressive force and the pressure at the electrode. The sensor enables the monitoring of vessel compressive force during surgery. Four levels of compressive force were applied to seal three types of porcine vessels (carotid artery, femoral artery, and jugular vein). The burst pressure of the vessel seal was tested to evaluate the seal quality. Compressive pressure was found to be a statistically significant factor affecting burst pressure for femoral arteries and jugular veins. Vessels sealed with low compressive pressure (<300 kPa) have a higher failure rate (burst pressure<100 mm Hg) than vessels sealed with high compressive pressure. An adequate compressive force is required to generate the compressive pressure needed to form a seal with high burst pressure. A laparoscopic surgical device with compressive force monitoring capability can help ensure adequate compressive pressure, vessel burst pressure, and quality of seal.

Thermoelectrical modeling of bipolar coagulation on posterior spinal artery in a porcine spinal surgery model.

The primary objective of our study was to develop a thermoelectrical model with both solid and liquid phases to calculate tissue temperature during bipolar coagulation of a posterior spinal artery on the spinal cord. Control of thermal spread caused by coagulation is a concern in spinal surgery. This model utilizes a nonisothermal flow to account for the heat transfer due to the movement of cerebrospinal fluid that is induced by electrical field and temperature gradient. The model is validated by in situ temperature measurements on a porcine spinal cord model. The maximum error for tissue temperature of this model is 12.6%, and the overall average error is 4.2%. The lesional region (>50°C) is identified to be as wide as 5 mm, and thermal dose cumulative equivalent minutes at 43°C (CEM 43) is also calculated with this model. The incorporation of nonisothermal flow has been shown to be crucial in order to accurately predict thermal dose in tissue. The developed model can be further used to establish a guideline for the use of bipolar coagulation.

Comparison of thermal coagulation profiles for bipolar forceps with different cooling mechanisms in a porcine model of spinal surgery.

BACKGROUND: Coagulation accomplished using bipolar forceps is common in neurosurgery. Control of thermal spread from the forceps tips into surrounding neural tissues is a persistent concern, as neural tissues are especially vulnerable to heat injury. The purpose of our investigation was to compare the efficacy of cooling mechanisms for four different bipolar forceps and to understand thermal spread when coagulating vessels on the spinal cord. METHODS: Immediately following euthanasia, the dura mater of an ex vivo porcine model was opened to expose vessels on the spinal cord for coagulation. Temperature profiles were measured at generator power of 25 W and at fixed 5-second activation times. The bipolar forceps used in this study included regular stainless steel, titanium, heat-pipe embedded, and SILVERGlide forceps. Temperature was measured by micro-thermistor at the midpoint between the bipolar tips, and 1 and 2 mm away from the midpoint along the centerline. Statistical analysis was performed to evaluate temperature differences. RESULTS: Temperature profiles indicated that heat-pipe embedded forceps create the least amount of temperature increase and the highest normalized temperature decreasing slope after activation. The decreasing slope of SILVERGlide forceps is slightly higher than that of regular stainless steel forceps. CONCLUSIONS: Bipolar forceps incorporating either heat-pipe embedded technology or SILVERGlide coating can effectively limit excessive thermal spread, thus decreasing potential injury to adjacent tissues when compared with standard stainless steel and titanium bipolar forceps. Of the two, heat-pipe embedded technology appeared safest, having better cooling efficiency at higher temperature.

The design and rationale of the saxagliptin assessment of vascular outcomes recorded in patients with diabetes mellitus-thrombolysis in myocardial infarction (SAVOR-TIMI) 53 study.

OBJECTIVES: Saxagliptin, a dipeptidyl peptidase 4 inhibitor, improves glycemic control in patients with type 2 diabetes mellitus (T2DM) by increasing endogenous active, intact glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide in response to food, which augments insulin secretion and decreases glucagon release. RESEARCH DESIGN AND METHODS: SAVOR-TIMI 53 is a phase 4, randomized, double-blind, placebo-controlled trial conducted in 25 countries that is designed to evaluate the safety and efficacy of saxagliptin during long-term treatment of approximately 16,500 patients with T2DM. Eligible patients who are either treatment naive or on any background antidiabetic treatment (except incretin therapy) with history of established cardiovascular (CV) disease or multiple risk factors are randomized 1:1 to saxagliptin 5 mg QD (2.5 mg in subjects with moderate/severe renal impairment) or matching placebo, stratified by qualifying disease state. The primary end point is the composite of CV death, nonfatal myocardial infarction, or nonfatal ischemic stroke. The trial will continue until approximately 1,040 primary end points accrue, providing 85% power to identify a 17% relative reduction of the primary end point with saxagliptin versus placebo and 98% power to test for noninferiority of saxagliptin versus placebo (reject the upper limit of 95% CI for a hazard ratio <1.3 at a 1-sided α of .025). CONCLUSION: SAVOR-TIMI 53 is testing the hypothesis that treatment with saxagliptin is safe and reduces CV events in high-risk patients with T2DM.

A systematic assessment of cardiovascular outcomes in the saxagliptin drug development program for type 2 diabetes.

OBJECTIVE: The objective was to assess the relative risk (RR) for cardiovascular (CV) events across all 8 randomized phase 2/3 trials evaluating saxagliptin in patients with type 2 diabetes mellitus. METHODS: Cardiovascular events (death, myocardial infarction [MI], stroke, revascularization procedures, and cardiac ischemia) were reported by investigators through standard adverse event reporting procedures and were systematically identified. Post hoc blinded adjudication of all deaths, MIs, and strokes was performed using prespecified endpoint definitions by an independent clinical events committee (CEC). RESULTS: A total of 4607 randomized and treated patients (n = 3356 treated with saxagliptin [2.5-100 mg/d]; n = 1251, comparator [n = 656, placebo; n = 328, metformin; n = 267, uptitrated glyburide]) were included. The median ages were 54 years (saxagliptin) and 55 years (comparator) (interquartile range, 47-61 each); 51% were female, 73% were white, 52% were hypertensive, 44% had hypercholesterolemia, 39% had a smoking history, 20% had a first-degree family member with premature coronary heart disease, and 12% had prior CV disease. Cardiovascular events were experienced by 61 patients (38 [1.1%], saxagliptin; 23 [1.8%], comparator), and CV death/MI/stroke events were reported by investigators in 41 patients: 23 (0.7%), saxagliptin; 18 (1.4%), comparator (relative risk, 95% confidence interval [CI], 0.44 [0.24-0.82]). The CEC reviewed 147 patients with potential CV events and identified a total of 40 patients with CV death/MI/stroke: 22 (0.7%), saxagliptin; 18 (1.4%), comparator (RR, 0.43 [0.23-0.80]). Component proportions for CV death, MI, and stroke were (saxagliptin vs comparator): 7 (0.2%) vs 10 (0.8%), 8 (0.2%) vs 8 (0.6%), and 11 (0.3%) vs 5 (0.4%), respectively. CONCLUSION: No increased risk of CV death/MI/stroke was observed in patients randomly assigned saxagliptin across a broad drug development program. Although this systematic overview has inherent and important limitations, the data support a potential reduction in CV events with saxagliptin. The hypothesis of CV protection with saxagliptin will be tested prospectively in a large randomized clinical outcome trial evaluating saxagliptin compared with standard of care in patients with type 2 diabetes at increased risk for CV events.

A health economic analysis of screening and optimal treatment of nephropathy in patients with type 2 diabetes and hypertension in the USA.

BACKGROUND: Nephropathy is an indicator of end-organ damage and is a strong predictor of an increased risk of cardiovascular disease and death in patients with diabetes. Screening can lead to early identification and treatment, both of which incur costs. However, identification and treatment may slow or prevent progression to a more expensive stage of the disease and thus may save money. We assessed the health economic impact of screening for nephropathy (microalbuminuria and overt nephropathy) followed by optimal renoprotective-based antihypertensive therapy in a US setting. METHODS: A Markov model simulated the lifetime impact of screening with semi-quantitative urine dipsticks in a primary care setting of hypertensive patients with type 2 diabetes and subsequent treatment with irbesartan 300 mg in patients identified as having nephropathy. Progression from no nephropathy to end-stage renal disease (ESRD) was simulated. Probabilities, utilities, medication and ESRD treatment costs came from published sources. Clinical outcomes and direct medical costs were projected. Second order Monte Carlo simulation was used to account for uncertainty in multiple parameters. Annual discount rates of 3% were used where appropriate. RESULTS: Screening, followed by optimized treatment, led to a 44% reduction in the cumulative incidence of ESRD and improvements in non-discounted life expectancy of 0.25 +/- 0.22 years/patient (mean +/- SD). Quality-adjusted life expectancy was improved by 0.18 +/- 0.15 quality-adjusted life years (QALYs)/patient and direct costs increased by $244 +/- 3499/patient. The incremental cost-effectiveness ratio was $20 011 per QALY gained for screening and optimized treatment versus no screening. There was a 77% probability that screening and optimized therapy would be considered cost effective with a willingness to pay a threshold of $50 000. CONCLUSION: In patients with type 2 diabetes and hypertension, screening for nephropathy and treatment with a renoprotective-based antihypertensive agent was projected to improve patient outcomes and represent excellent value in a US setting.

Cost-effectiveness of irbesartan 300 mg given early versus late in patients with hypertension and a history of type 2 diabetes and renal disease: a Canadian perspective.

BACKGROUND: The Irbesartan in Reduction of Microalbuminuria trial and the Irbesartan in Diabetic Nephropathy Trial found that irbesartan is renoprotective in patients having hypertension with type 2 diabetes. OBJECTIVE: The objective of this study was to assess whether treatment with irbesartan is cost-effective in Canada relative to conventional care in this patient population and whether it is more cost-effective to treat patients early rather than later in the development of renal disease from the perspective of the Canadian health and social care system. METHODS: The analysis compared 3 alternative strategies for the management of hypertension in patients with type 2 diabetes and early renal disease: (1) conventional hypertensive treatment excluding the use of angiotensin II receptor antagonists (AIIRAs); (2) the early addition of irbesartan (an AIIRA) to conventional treatment; and (3) the late addition of irbesartan to conventional treatment. A Markov model was used to simulate the progression of renal disease (microalbuminuria to death) in hypertensive patients with type 2 diabetes over a 25-year time horizon. Transition probabilities were derived from the 2 randomized controlled trials. A cost-effectiveness analysis was conducted with outcome measured in life-years gained (LYGs). RESULTS: The early addition of irbesartan during microalbuminuria was cost-saving and more effective than both delaying irbesartan treatment until advanced overt nephropathy (AON) (0.45 LYG, Can $54,100 saved) and conventional antihypertensive use (0.62 LYG, $68,400 saved). This was due to the increased drug costs associated with the use of irbesartan being offset by savings arising from delays in the development of overt nephropathy and the subsequent delay to end-stage renal disease (ESRD). Sensitivity analyses confirmed the robustness of the study results. CONCLUSIONS: The early use of irbesartan for patients with hypertension and type 2 diabetes who have yet to develop overt nephropathy is both more effective and less costly than delaying irbesartan treatment until AON and conventional antihypertensive use. Analysis suggests that the earlier irbesartan is added to conventional antihypertensive treatment, the greater the delays in the onset of ESRD and the overall savings in health care resource utilization from the perspective of the Canadian health and social care system.

Prevalence and control of dyslipidemia among persons with diabetes in the United States.

OBJECTIVE: We assessed the prevalence, treatment, and control of dyslipidemia among United States (U.S.) adults with diabetes. METHODS: Among 498 adults (projected to 13.4 million) aged >or=18 years with diabetes representative of the U.S. population and surveyed within the cross-sectional National Health and Nutrition Examination Survey 1999-2000, control of lipids was classified according to American Diabetes Association criteria. The extent of low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), and triglyceride (TG) control was examined by gender and ethnicity, in comparison to those without diabetes, and according to lipid-lowering treatment. Analyses were weighted to the U.S. population. RESULTS: Less than one-third of men and only one-fifth of women with diabetes are in control for LDL-C, defined as <2.6 mmol/l (<100mg/dl); over 70% are not at goal. Over half of men and over two-thirds of women have low levels of HDL-C (or=1.7 mmol/l [150 mg/dl]). Low HDL-C was more common in Caucasians (70.1%) than in Hispanics (58.8%) or African-Americans (41.5%) (p<0.001). 28.2% of subjects with diabetes were on lipid-lowering treatment. Control of LDL-C did not differ by treatment status and only 3% of subjects were controlled to target levels for all lipids. CONCLUSION: Many persons with diabetes remain uncontrolled for dyslipidemia. Intensified efforts at screening and treatment according to current guidelines are warranted.

Cardiovascular disease in U.S. patients with metabolic syndrome, diabetes, and elevated C-reactive protein.

OBJECTIVE: C-reactive protein (CRP) independently predicts cardiovascular disease (CVD); whether it can stratify risk in those with metabolic syndrome and diabetes is not well documented. We evaluated whether elevated CRP levels modify the relationship of metabolic syndrome and diabetes with CVD in U.S. adults. RESEARCH DESIGN AND METHODS: In a cross-sectional study of 3,873 subjects (weighted to 156 million) aged >/=18 years participating in the National Health and Nutrition Examination Survey 1999-2000, subjects were classified as having diabetes, metabolic syndrome according to modified National Cholesterol Education Program criteria, or neither condition by low (<1 mg/l), intermediate (1-3 mg/l), or high (>3 mg/l) CRP levels. Logistic regression examined the odds of CVD by disease condition and CRP group. RESULTS: After adjusting for age, sex, smoking, and total cholesterol, compared with those with neither metabolic syndrome nor diabetes and low CRP levels, the odds of CVD were 1.99 (95% CI 1.10-3.59) for those with no disease and high CRP levels and 2.67 (1.30-5.48) for those with metabolic syndrome and intermediate CRP. Persons with metabolic syndrome but high CRP had an odds ratio (OR) of 3.33 (1.80-6.16), similar to those with diabetes and low CRP (3.21 [1.27-8.09]). The likelihood of CVD was highest in those with diabetes who had intermediate CRP levels (6.01 [2.54-14.20]) and in those with diabetes and high CRP (7.73 [3.99-14.95]). CONCLUSIONS: In this cross-sectional analysis, CVD is more common in those with metabolic syndrome or diabetes who have elevated CRP. Stratification by CRP may add prognostic information in patients with metabolic syndrome or diabetes.

Quality of care for hypertension in the United States.

BACKGROUND: Despite heavy recent emphasis on blood pressure (BP) control, many patients fail to meet widely accepted goals. While access and adherence to therapy certainly play a role, another potential explanation is poor quality of essential care processes (QC). Yet little is known about the relationship between QC and BP control. METHODS: We assessed QC in 12 U.S. communities by reviewing the medical records of a randomly selected group of patients for the two years preceding our study. We included patients with either a diagnosis of hypertension or two visits with BPs of >or=140/90 in their medical records. We used 28 process indicators based on explicit evidence to assess QC. The indicators covered a broad spectrum of care and were developed through a modified Delphi method. We considered patients who received all indicated care to have optimal QC. We defined control of hypertension as BP < 140/90 in the most recent reading. RESULTS: Of 1,953 hypertensive patients, only 57% received optimal care and 42% had controlled hypertension. Patients who had received optimal care were more likely to have their BP under control at the end of the study (45% vs. 35%, p = .0006). Patients were more likely to receive optimal care if they were over age 50 (76% vs. 63%, p < .0001), had diabetes (77% vs. 71%, p = .0038), coronary artery disease (87% vs. 69%, p < .0001), or hyperlipidemia (80% vs. 68%, p < .0001), and did not smoke (73% vs. 66%, p = .0005). CONCLUSIONS: Higher QC for hypertensive patients is associated with better BP control. Younger patients without cardiac risk factors are at greatest risk for poor care. Quality measurement systems like the one presented in this study can guide future quality improvement efforts.

Association of the metabolic syndrome with history of myocardial infarction and stroke in the Third National Health and Nutrition Examination Survey.

BACKGROUND: The combination of cardiovascular risk factors known as the metabolic syndrome is receiving increased attention from physicians, but data on the syndrome's association with morbidity are limited. METHODS AND RESULTS: Applying National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria, we evaluated 10 357 NHANES III subjects for the 5 component conditions of the metabolic syndrome: insulin resistance, abdominal obesity based on waist circumference, hypertriglyceridemia, low HDL cholesterol (HDL-C), and hypertension, as well as the full syndrome, defined as at least 3 of the 5 conditions. Logistic regression was used to estimate the cross-sectional association of the syndrome and each of its 5 component conditions separately with history of myocardial infarction (MI), stroke, and either MI or stroke (MI/stroke). Models were adjusted for age, sex, race, and cigarette smoking. The metabolic syndrome was significantly related in multivariate analysis to MI (OR, 2.01; 95% CI, 1.53 to 2.64), stroke (OR, 2.16; 95% CI, 1.48 to 3.16), and MI/stroke (OR, 2.05; 95% CI, 1.64 to 2.57). The syndrome was significantly associated with MI/stroke in both women and men. Among the component conditions, insulin resistance (OR, 1.30; 95% CI, 1.03 to 1.66), low HDL-C (OR, 1.35; 95% CI, 1.05 to 1.74), hypertension (OR, 1.44; 95% CI, 1.00 to 2.08), and hypertriglyceridemia (OR, 1.66; 95% CI=1.20 to 2.30) were independently and significantly related to MI/stroke. CONCLUSIONS: These results indicate a strong, consistent relationship of the metabolic syndrome with prevalent MI and stroke.

Blood pressure lowering and life expectancy based on a Markov model of cardiovascular events.

The life expectancy benefits of antihypertensive treatment, based on both systolic and diastolic blood pressure reduction, was estimated with a cardiovascular disease event Markov model with prospective data from 57 573 men and women. Seven patient states were defined, including (1) no cardiovascular disease, (2) stroke, (3) myocardial infarction, (4) revascularization, (5) history of cardiovascular disease, (6) noncardiovascular disease death, and (7) cardiovascular death. Risk functions were developed from gender-specific multivariate Cox proportional hazards models for primary events and age-, smoking-, and diabetes-adjusted models for secondary events. At baseline we assumed (1) hypothetical pretreatment blood pressures of 160/95 or 150/90 mm Hg; (2) strategies A and B lower blood pressure by 20/13 and 13/8 mm Hg, respectively; and (3) baseline age of 35 years. For subjects initially at 160/95 mm Hg, those with antihypertensive treatment, antihypertensive treatment and diabetes, or antihypertensive treatment, diabetes, and currently smoking had corresponding gains in life expectancy of 2.43, 2.80, and 2.43 years for Strategy A. An initial blood pressure of 150/90 mm Hg resulted in similar gains. Compared with Strategy B, with blood pressure reductions of 13/8 mm Hg, Strategy A provided additional gains in life expectancy of 0.84, 0.99, and 0.87 years for those with antihypertensive treatment, antihypertensive treatment and diabetes, or antihypertensive treatment, diabetes, and currently smoking. The initial blood pressure level did not affect the magnitude of life expectancy gains for equivalent blood pressure reductions. Greater gains in life expectancy among hypertensive and diabetic women suggest that blood pressure lowering may yield greater benefits in selected subgroups.