High dose and long-term statin therapy accelerate coronary artery calcification

Is atherosclerosis imaging the most sensitive way to assess patients' risk and the best way to conduct future drug trials? A pros-and-cons debate

Atherosclerosis imaging has been the focus of intense debate and research for several decades. Among its primary applications are risk stratification of asymptomatic individuals and follow-up of atherosclerosis progression under a variety of treatments designed to retard or regress the development of arterial disease. Although endorsed and supported by many, this approach has been fiercely opposed by several key opinion leaders over the years. Similarly, regulatory agencies have raised a number of objections to resist the approval of new drugs and devices based on surrogate imaging markers. However, there is a large body of evidence in the medical literature that shows that risk stratification is improved with implementation of atherosclerosis imaging. Additionally, numerous lipid-modifying agents have been tested as far as their ability to affect progression of atherosclerosis, and in many cases the information obtained with imaging was in line with the outcome of subsequent clinical trials. This pros-and-cons debate was staged to bring up in a fun and provoking way the main arguments in favour or against the application of atherosclerosis imaging in the main settings described above.

Suppression of Wnt Signaling and Osteogenic Changes in Vascular Smooth Muscle Cells by Eicosapentaenoic Acid

Vascular medial calcification is often observed in patients with arteriosclerosis. It is also associated with systolic hypertension, wide pulse pressure, and fluctuation of blood pressure, which results in cardiovascular events. Eicosapentaenoic acid (EPA) has been shown to suppress vascular calcification in previous animal experiments. We investigated the inhibitory effects of EPA on Wnt signaling, which is one of the important signaling pathways involved in vascular calcification. Intake of food containing 5% EPA resulted in upregulation of the mRNA expression of Klotho, an intrinsic inhibitor of Wnt signaling, in the kidneys of wild-type mice. Expression levels of β-catenin, an intracellular signal transducer in the Wnt signaling pathway, were increased in the aortas of Klotho mutant (kl/kl) mice compared to the levels in the aortas of wild-type mice. Wnt3a or BIO, a GSK-3 inhibitor that activates β-catenin signaling, upregulated mRNA levels of AXIN2 and LEF1, Wnt signaling marker genes, and RUNX2 and BMP4, early osteogenic genes, in human aorta smooth muscle cells. EPA suppressed the upregulation of AXIN2 and BMP4. The effect of EPA was cancelled by T0070907, a PPARγ inhibitor. The results suggested that EPA could suppress vascular calcification via the inhibition of Wnt signaling in osteogenic vascular smooth muscle cells via PPARγ activation.

Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes

BACKGROUND

Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and cardiovascular disease outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis.

METHODS

Middle-aged men engaged in competitive or recreational leisure sports underwent a noncontrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by metabolic equivalent of task (MET) scores to calculate MET-minutes per week. Participants' activity was categorized as <1000, 1000 to 2000, or >2000 MET-min/wk.

RESULTS

A total of 284 men (age, 55±7 years) were included. CAC was present in 150 of 284 participants (53%) with a median CAC score of 35.8 (interquartile range, 9.3-145.8). Athletes with a lifelong exercise volume >2000 MET-min/wk (n=75) had a significantly higher CAC score (9.4 [interquartile range, 0-60.9] versus 0 [interquartile range, 0-43.5]; P=0.02) and prevalence of CAC (68%; adjusted odds ratio [OR_adjusted]=3.2; 95% confidence interval [CI], 1.6-6.6) and plaque (77%; OR_adjusted=3.3; 95% CI, 1.6-7.1) compared with <1000 MET-min/wk (n=88; 43% and 56%, respectively). Very vigorous intensity exercise (≥9 MET) was associated with CAC (OR_adjusted=1.47; 95% CI, 1.14-1.91) and plaque (OR_adjusted=1.56; 95% CI, 1.17-2.08). Among participants with CAC>0, there was no difference in CAC score (P=0.20), area (P=0.21), density (P=0.25), and regions of interest (P=0.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/wk) had a lower prevalence of mixed plaques (48% versus 69%; OR_adjusted=0.35; 95% CI, 0.15-0.85) and more often had only calcified plaques (38% versus 16%; OR_adjusted=3.57; 95% CI, 1.28-9.97) compared with the least active group (<1000 MET-min/wk).

CONCLUSIONS

Participants in the >2000 MET-min/wk group had a higher prevalence of CAC and atherosclerotic plaques. The most active group, however, had a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants.

Association between serum alkaline phosphatase and coronary artery calcification in a sample of primary cardiovascular prevention patients

BACKGROUND AND AIMS

A high level of serum alkaline phosphatase (ALP) is associated with an increased risk of mortality and myocardial infarction. ALP hydrolyses inorganic pyrophosphate, which is a strong inhibitor of calcium phosphate deposition. The aim of this study was to determine whether ALP is associated with the coronary artery calcium score (CACS).

METHODS

We examined the association of CACS, assessed by computed tomography scanning, and ALP, in 500 patients consecutively recruited, free of cardiovascular disease. The CACS were categorized into two groups: no calcification (CACS = 0) (n = 187) and with calcification (CACS>0) (n = 313). ALP activity was divided into three tertile groups: low ALP level (<55 IU/L), intermediate (55-66 IU/L) and high ALP level (>66 IU/L).

RESULTS

The mean age was 60.9 ± 10.8 years, 49.6% of the patients were women. ALP ranged from 22 to 164 IU/L (mean 62.6 IU/L, SD 19.3). In univariate analysis, traditional cardiovascular risk factors, statin use (p = 0.001), and ALP (p = 0.001) were significantly associated with CACS. After adjusting for cardiovascular risk factors, only age (p = 0.001) and sex (p = 0.001) were independently associated with CACS. Compared to the tertile group with low levels of ALP, the intermediate tertile group [OR 2.11, 95% CI (1.12; 3.96), p = 0.02], as well as the high tertile group [OR 3.89, 95% CI (2.01; 7.54), p = 0.001)], was independently associated with CACS.

CONCLUSIONS

In patients free of cardiovascular disease, high ALP levels are positively and independently associated with coronary artery calcification. The metabolic pathway of ALP and inorganic pyrophosphate could be a target for new therapies against vascular calcification.

Does statins promote vascular calcification in chronic kidney disease?

BACKGROUND

In end-stage renal disease (ESRD), coronary artery calcification (CAC) and inflammation contribute to cardiovascular disease (CVD). Statins do not improve survival in patients with ESRD, and their effect on vascular calcification is unclear. We explored associations between CAC, inflammatory biomarkers, statins and mortality in ESRD.

MATERIALS AND METHODS

In 240 patients with ESRD (63% males; median age 56 years) from cohorts including 86 recipients of living donor kidney transplant (LD-Rtx), 96 incident dialysis patients and 58 prevalent peritoneal dialysis patients, associations of CAC score (Agatston Units, AUs), interleukin-6 (IL-6) with high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor (TNF), use of statins and all-cause mortality were analysed. Cardiac CT was repeated in 35 patients after 1·5 years of renal replacement therapy. In vitro, human vascular smooth muscle cells (hVSMCs) were used to measure vitamin K metabolism.

RESULTS

Among 240 patients, 129 (53%) had a CAC score > 100 AUs. Multivariate analysis revealed that independent predictors of 1-SD higher CAC score were age, male gender, diabetes and use of statins. The association between CAC score and mortality remained significant after adjustment for age, gender, diabetes, CVD, use of statins, protein-energy wasting and inflammation. Repeated CAC imaging in 35 patients showed that statin therapy was associated with greater progression of CAC. In vitro synthesis of menaquinone-4 by hVSMCs was significantly impaired by statins.

CONCLUSION

Elevated CAC score is a mortality risk factor in ESRD independent of inflammation. Future studies should resolve if statins promote vascular calcification and inhibition of vitamin K synthesis in the uremic milieu.

The Impact of Rosuvastatin on the Density Score of Coronary Artery Calcification in Coronary Artery Disease Patients with Type 2 Diabetes Mellitus: Rationale and Design of RosCal Study

INTRODUCTION

More and more evidence suggests that the density of calcification plays an important role in the plaque stability. However, few studies have investigated the statin treatment on the density of plaque calcification in patients with both coronary artery disease (CAD) and type 2 diabetes mellitus.

METHODS

One hundred and twenty-two CAD patients with type 2 diabetes with confirmed coronary artery calcification (CAC) will be recruited consecutively in a 12-month period. These patients will receive rosuvastatin (20 mg/day) therapy in the next 24 months. Blood tests and adverse events will be collected at routine follow-up of 1, 3, 6, 12, 18 and 24 months. The primary endpoint will be the change of CAC density score measured by coronary CT angiography after 24 months' treatment of rosuvastatin (20 mg/day) compared with baseline. The secondary endpoints will be the change of serum sclerostin and the effect on the volume score of CAC in those patients.

RESULTS

We expect that rosuvastatin could both increase the density of CAC to improve plaque stability and up-regulate serum sclerostin, which would suggest the underlying mechanism of the plaque stabilization by a statin.

CONCLUSION

This study would be the first to demonstrate the impact of rosuvastatin on the density score of coronary artery calcification in CAD patients with type 2 diabetes. This study has been registered in ClinicalTrials.gov (NCT02418884).

Rosuvastatin slows progression of subclinical atherosclerosis in patients with treated HIV infection

OBJECTIVE

To determine the effect of statins on the progression of subclinical atherosclerosis in a population of HIV-infected adults on antiretroviral therapy.

DESIGN

Double-blind, randomized clinical trial.

METHODS

Stopping Atherosclerosis and Treating Unhealthy Bone with RosuvastatiN in HIV infection was a 96-week double-blind, randomized clinical trial of 10 mg daily rosuvastatin (n = 72) vs. placebo (n = 75) in a population of HIV-infected subjects on stable antiretroviral therapy with LDL-cholesterol 130 mg/dl or less (≤3.36 mmol/l) and evidence of heightened T-cell activation (CD8CD38HLA-DR ≥19%) or increased inflammation [high sensitivity C-reactive protein ≥2 mg/l (≥19 mmol/l)]. Change in common carotid artery intima-media thickness (IMT) (CCA-IMT) was the primary outcome. Secondary outcomes were changes in LDL and coronary artery calcium.

RESULTS

Median (Q1, Q3) age was 46 (40, 53) years; 78% were man and 68% African-American; 49% were on a protease inhibitor. Mean (95% confidence interval) change in LDL was -21 (-27 to -15) mg/dl [-0.54 (-0.70 to -0.39) mmol/l] in the rosuvastatin arm. In a multivariable linear mixed-effects model, assignment to statin was associated with 0.019 mm (95% confidence interval: 0.002-0.037 mm) less progression of CCA-IMT over 96 weeks. We did not find substantial effect modification by level of inflammation or immune activation biomarkers, except for a borderline statistically significant interaction for soluble vascular cell adhesion molecule (P = 0.065). There was no difference in coronary artery calcium change (P = 0.61).

CONCLUSION

Rosuvastatin effectively lowers LDL and appears to substantially slow progression of CCA-IMT in patients with treated HIV infection. Future study is needed to determine whether subjects with higher levels of inflammation or immune activation derive greater cardiovascular benefit from statin therapy.

Therapeutic modulation of the natural history of coronary atherosclerosis: lessons learned from serial imaging studies

Despite advances in risk prediction, preventive and therapeutic strategies, atherosclerotic cardiovascular disease remains a major public health challenge worldwide, carrying considerable morbidity, mortality and health economic burden. There continues to be a need to better understand the natural history of this disease to guide the development of more effective treatment, integral to which is the rapidly evolving field of coronary artery imaging. Various imaging modalities have been refined to enable detailed visualization of the pathological substrate of atherosclerosis, providing accurate and reproducible measures of coronary plaque burden and composition, including the presence of high-risk characteristics. The serial application of such techniques, including coronary computed tomography angiography (CTA), intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have uncovered important insights into the progression of coronary plaque over time in patients with stable and unstable coronary artery disease (CAD), and its responsiveness to therapeutic interventions. Here we review the use of different imaging modalities for the surveillance of coronary atherosclerosis and the lessons they have provided about the modulation of CAD by both traditional and experimental therapies.

Gender and age effects on risk factor-based prediction of coronary artery calcium in symptomatic patients: A Euro-CCAD study

BACKGROUND AND AIMS

The influence of gender and age on risk factor prediction of coronary artery calcification (CAC) in symptomatic patients is unclear.

METHODS

From the European Calcific Coronary Artery Disease (EURO-CCAD) cohort, we retrospectively investigated 6309 symptomatic patients, 62% male, from Denmark, France, Germany, Italy, Spain and USA. All of them underwent risk factor assessment and CT scanning for CAC scoring.

RESULTS

The prevalence of CAC among females was lower than among males in all age groups. Using multivariate logistic regression, age, dyslipidaemia, hypertension, diabetes and smoking were independently predictive of CAC presence in both genders. In addition to a progressive increase in CAC with age, the most important predictors of CAC presence were dyslipidaemia and diabetes (β = 0.64 and 0.63, respectively) in males and diabetes (β = 1.08) followed by smoking (β = 0.68) in females; these same risk factors were also important in predicting increasing CAC scores. There was no difference in the predictive ability of diabetes, hypertension and dyslipidaemia in either gender for CAC presence in patients aged <50 and 50-70 years. However, in patients aged >70, only dyslipidaemia predicted CAC presence in males and only smoking and diabetes were predictive in females.

CONCLUSIONS

In symptomatic patients, there are significant differences in the ability of conventional risk factors to predict CAC presence between genders and between patients aged <70 and ≥70, indicating the important role of age in predicting CAC presence.

Relationship between indexed epicardial fat volume and coronary plaque volume assessed by cardiac multidetector CT

We explored whether baseline indexed epicardial fat volume (EFVi) and serial changes in EFVi were associated with increase in coronary plaque volume as assessed by multidetector computed tomography.We retrospectively reviewed 87 patients with coronary artery plaque, identified during either baseline or follow-up cardiac computed tomography (CT) examinations. Each plaque volume was measured in volumetric units using a semiautomatic software tool. EFVi was quantified by calculating the total volume of epicardial tissue of CT density -190 to -30 HU, indexed to the body surface area. Clinical cardiovascular risk factors were extracted by medical record review at the time of the cardiac CT examinations. The relationship between EFVi and coronary plaque volume was explored by regression analysis.Although the EFVi did not change significantly from baseline to the time of the follow-up CT (65.7 ± 21.8 vs 66.0 ± 21.8 cm/m, P = 0.620), the plaque volumes were increased significantly on the follow-up CT scans. The annual change in EFVi was not accompanied by a parallel change in coronary plaque volume (P = 0.096-0.500). On univariate analysis, smoking, hypercholesterolemia, 10-year coronary heart disease risk, obesity, and baseline EFVi predicted rapid increases in lipid-rich and fibrous plaque volumes. On multivariate analysis, baseline EFVi (odds ratio = 1.029, P = 0.016) was an independent predictor of a rapid increase in lipid-rich plaque volume.EFVi was shown to be an independent predictor of a rapid increase in lipid-rich plaque volume. However, changes in EFVi were not associated with parallel changes in coronary plaque volume.

Progression of CAC Score and Risk of Incident CVD

OBJECTIVES

The authors sought to determine the relative contributions of baseline coronary artery calcification (CAC), follow-up CAC, and CAC progression on incident cardiovascular disease (CVD).

BACKGROUND

Repeat CAC scanning has been proposed as a method to track progression of total atherosclerotic burden. However, whether CAC progression is a useful predictor of future CVD events remains unclear.

METHODS

This was a prospective observational study of 5,933 participants free of CVD who underwent 2 examinations, including CAC scores, and subsequent CVD event assessment. CAC progression was calculated using the square root method. The primary outcome was total CVD events (CVD death, nonfatal myocardial infarction, nonfatal atherosclerotic stroke, coronary artery bypass surgery, percutaneous coronary intervention). Secondary outcomes included hard CVD events, total coronary heart disease (CHD) events, and hard CHD events.

RESULTS

CAC was detected at baseline in 2,870 individuals (48%). The average time between scans was 3.5 ± 2.0 years. After their second scan, 161 individuals experienced a total CVD event during a mean follow-up of 7.3 years. CAC progression was significantly associated with total CVD events (hazard ratio: 1.14, 95% confidence interval: 1.01 to 1.30 per interquartile range; p = 0.042) in the model including baseline CAC, but the contribution of CAC progression was small relative to baseline CAC (chi-square 4.16 vs. 65.92). Furthermore, CAC progression was not associated with total CVD events in the model including follow-up CAC instead of baseline CAC (hazard ratio: 1.05, 95% confidence interval: 0.92 to 1.21; p = 0.475). A model that included follow-up CAC alone performed as well as the model that included baseline CAC and CAC progression.

CONCLUSIONS

Although CAC progression was independently, but modestly, associated with CVD outcomes, this relationship was no longer significant when including follow-up CAC in the model. These findings imply that if serial CAC scanning is performed, the latest scan should be used for risk assessment, and in this context, CAC progression provides no additional prognostic information.

Coronary Calcification and Plaque Vulnerability: An Optical Coherence Tomographic Study

BACKGROUND

Spotty superficial calcium deposits have been implicated in plaque vulnerability based on previous intravascular imaging studies. Biomechanical models suggest that microcalcifications between 5 and 65 µm in diameter can intensify fibrous cap stress, promoting plaque rupture. However, the 100- to 200-µm resolution of intravascular ultrasound limits its ability to discriminate single calcium deposits from clusters of smaller deposits, and a previous optical coherence tomographic investigation evaluated calcifications within a long segment of artery, which may not truly reflect the mechanics involved in potentiating focal plaque rupture.

METHODS AND RESULTS

Detailed optical coherence tomographic assessment of coronary calcification at the culprit plaque (10-mm length) was performed in 53 patients with acute ST-segment-elevation myocardial infarction mediated by plaque rupture and 55 patients with stable angina pectoris. The number and longitudinal length of individual calcium deposits were recorded. Cross-sectional images were analyzed every 1 mm for calcium arc and depth, and these quantitative parameters were used to define individual deposits as spotty, large, and superficial. There was no significant difference between ST-segment-elevation myocardial infarction mediated by plaque rupture and stable angina pectoris groups in the number of total (P=0.58), spotty (P=0.87), or large calcium deposits (P=0.27). Minimum calcium depth was similar between groups (P=0.27), as was the number of superficial deposits (P=0.35 using a 65-µm depth threshold and P=0.84 using a 100-µm depth threshold).

CONCLUSIONS

The number and pattern of culprit plaque calcifications did not differ between patients presenting with ST-segment-elevation myocardial infarction mediated by plaque rupture versus stable angina pectoris. The optical coherence tomographic assessment of coronary calcification may not be a useful marker of local plaque vulnerability as previously suspected.

REGISTRATION INFORMATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01110538.

Fruit Intake and Abdominal Aortic Calcification in Elderly Women: A Prospective Cohort Study

Cardiovascular disease (CVD) is the leading cause of death worldwide. There is a consistent inverse relationship between fruit intake with CVD events and mortality in cross-sectional and prospective observational studies, but the relationship of fruit intake with measurements of atherosclerosis in humans is less clear. Nutritional effects on abdominal aortic calcification (AAC), a marker for subclinical intimal and medial atherosclerotic vascular disease, have not been studied previously. The aim of this study was to examine the cross-sectional relationship of total and individual fruit (apple, pear, orange and other citrus, and banana) intake with AAC, scored between 0 and 24. The current study assessed baseline data for a cohort of 1052 women over 70 years of age who completed both a food frequency questionnaire assessing fruit intake, and underwent AAC measurement using dual energy X-ray absorptiometry. AAC scores were significantly negatively correlated with total fruit and apple intakes (p < 0.05), but not with pear, orange or banana intakes (p > 0.25). In multivariable-adjusted logistic regression, each standard deviation (SD; 50 g/day) increase in apple intake was associated with a 24% lower odds of having severe AAC (AAC score >5) (odd ratio OR): 0.76 (0.62, 0.93), p = 0.009). Total and other individual fruit intake were not associated with increased odds of having severe AAC. Apple but not total or other fruit intake is independently negatively associated with AAC in older women.

Atherosclerotic Calcification Detection: A Comparative Study of Carotid Ultrasound and Cone Beam CT

BACKGROUND AND AIM

Arterial calcification is often detected on ultrasound examination but its diagnostic accuracy is not well validated. The aim of this study was to determine the accuracy of carotid ultrasound B mode findings in detecting atherosclerotic calcification quantified by cone beam computed tomography (CBCT).

METHODS

We analyzed 94 carotid arteries, from 88 patients (mean age 70 ± 7 years, 33% females), who underwent pre-endarterectomy ultrasound examination. Plaques with high echogenic nodules and posterior shadowing were considered calcified. After surgery, the excised plaques were examined using CBCT, from which the calcification volume (mm3) was calculated. In cases with multiple calcifications the largest calcification nodule volume was used to represent the plaque. Carotid artery calcification by the two imaging techniques was compared using conventional correlations.

RESULTS

Carotid ultrasound was highly accurate in detecting the presence of calcification; with a sensitivity of 88.2%. Based on the quartile ranges of calcification volumes measured by CBCT we have divided plaque calcification into four groups: <8; 8-35; 36-70 and >70 mm3. Calcification volumes ≥8 were accurately detectable by ultrasound with a sensitivity of 96%. Of the 21 plaques with <8 mm3 calcification volume; only 13 were detected by ultrasound; resulting in a sensitivity of 62%. There was no difference in the volume of calcification between symptomatic and asymptomatic patients.

CONCLUSION

Carotid ultrasound is highly accurate in detecting the presence of calcified atherosclerotic lesions of volume ≥8 mm3; but less accurate in detecting smaller volume calcified plaques. Further development of ultrasound techniques should allow better detection of early arterial calcification.

Ultrasound assessment of carotid plaque echogenicity response to statin therapy: a systematic review and meta-analysis

OBJECTIVE

To evaluate in a systematic review and meta-analysis model the effect of statin therapy on carotid plaque echogenicity assessed by ultrasound.

METHODS

We have systematically searched electronic databases (PubMed, MEDLINE, EMBASE and Cochrane Center Register) up to April, 2015, for studies evaluating the effect of statins on plaque echogenicity. Two researchers independently determined the eligibility of studies evaluating the effect of statin therapy on carotid plaque echogenicity that used ultrasound and grey scale median (GSM) or integrated back scatter (IBS).

RESULTS

Nine out of 580 identified studies including 566 patients' carotid artery data were meta-analyzed for a mean follow up of 7.2 months. A consistent increase in the echogenicity of carotid artery plaques, after statin therapy, was reported. Pooled weighted mean difference % (WMD) on plaque echogenicity after statin therapy was 29% (95% CI 22%-36%), p<0.001, I2=92.1%. In a meta-regression analysis using % mean changes of LDL, HDL and hsCRP as moderators, it was shown that the effects of statins on plaque echogenicity were related to changes in hsCRP, but not to LDL and HDL changes from the baseline. The effect of statins on the plaque was progressive; it showed significance after the first month of treatment, and the echogenicity continued to increase in the following six and 12 months.

CONCLUSIONS

Statin therapy is associated with a favorable increase of carotid plaque echogenicity. This effect seems to be dependent on the period of treatment and hsCRP change from the baseline, independent of changes in LDL and HDL.

Catalysis in abiotic structured media: an approach to selective synthesis of biopolymers

Micro- and nanoenvironments formed by amphiphile self-assembled structures, water-ice lattices and minerals have well-defined, repeating, chemical and physical properties that can be used for selective synthesis of biopolymers, such as RNAs and proteins. The advances made in the development of polymerization supported by these micro- and nanosystems are reviewed here. In particular, it is shown that these systems promote non-enzymatic biopolymerization, yielding long polymers whose sequence composition is determined by the interactions between monomers and the supporting environment. When used to compartmentalize enzymatic biopolymerization, micro- and nanostructures allow the implementation of molecular selection and evolution schemes, which are difficult in homogeneous medium, yielding very active molecules. Thus, micro- and nanoenvironment approaches to the synthesis and selection of biopolymers could be developed into a new biotechnological tool for the production of biopolymers with novel functions.