Relationship between Composition and Environmental Degradation of Poly(isosorbide-co-diol oxalate) (PISOX) Copolyesters.

To reduce the global CO2 footprint of plastics, bio- and CO2-based feedstock are considered the most important design features for plastics. Oxalic acid from CO2 and isosorbide from biomass are interesting rigid building blocks for high Tg polyesters. The biodegradability of a family of novel fully renewable (bio- and CO2-based) poly(isosorbide-co-diol) oxalate (PISOX-diol) copolyesters was studied. We systematically investigated the effects of the composition on biodegradation at ambient temperature in soil for PISOX (co)polyesters. Results show that the lag phase of PISOX (co)polyester biodegradation varies from 0 to 7 weeks. All (co)polyesters undergo over 80% mineralization within 180 days (faster than the cellulose reference) except one composition with the cyclic codiol 1,4-cyclohexanedimethanol (CHDM). Their relatively fast degradability is independent of the type of noncyclic codiol and results from facile nonenzymatic hydrolysis of oxalate ester bonds (especially oxalate isosorbide bonds), which mostly hydrolyzed completely within 180 days. On the other hand, partially replacing oxalate with terephthalate units enhances the polymer's resistance to hydrolysis and its biodegradability in soil. Our study demonstrates the potential for tuning PISOX copolyester structures to design biodegradable plastics with improved thermal, mechanical, and barrier properties.

Overcoming the low reactivity of biobased, secondary diols in polyester synthesis.

Shifting away from fossil- to biobased feedstocks is an important step towards a more sustainable materials sector. Isosorbide is a rigid, glucose-derived secondary diol, which has been shown to impart favourable material properties, but its low reactivity has hampered its use in polyester synthesis. Here we report a simple, yet innovative, synthesis strategy to overcome the inherently low reactivity of secondary diols in polyester synthesis. It enables the synthesis of fully biobased polyesters from secondary diols, such as poly(isosorbide succinate), with very high molecular weights (Mn up to 42.8 kg/mol). The addition of an aryl alcohol to diol and diacid monomers was found to lead to the in-situ formation of reactive aryl esters during esterification, which facilitated chain growth during polycondensation to obtain high molecular weight polyesters. This synthesis method is broadly applicable for aliphatic polyesters based on isosorbide and isomannide and could be an important step towards the more general commercial adaption of fully biobased, rigid polyesters.

Biodegradability of novel high Tg poly(isosorbide-co-1,6-hexanediol) oxalate polyester in soil and marine environments.

In order to reduce the plastic accumulation in the environment, biodegradable plastics are attracting interest in the plastics market. However, the low thermal stability of most amorphous biodegradable polymers limits their application. With the aim of combining high glass transition temperature (Tg), with good (marine) biodegradation a family of novel fully renewable poly(isosorbide-co-diol) oxalate (PISOX-diol) copolyesters was recently developed. In this study, the biodegradability of a representative copolyester, poly(isosorbide-co-1,6-hexanediol) oxalate (PISOX-HDO), with 75/25 mol ratio IS/HDO was evaluated at ambient temperature (25 °C) in soil and marine environment by using a Respicond system with 95 parallel reactors, based on the principle of frequently monitoring CO2 evolution. During 50 days incubation in soil and seawater, PISOX-HDO mineralised faster than cellulose. The ready biodegradability of PISOX-HDO is related to the relatively fast non-enzymatic hydrolysis of polyoxalates. To study the underlying mechanism of PISOX-HDO biodegradation, the non-enzymatic hydrolysis of PISOX-HDO and the biodegradation of the monomers in soil were also investigated. Complete hydrolysis was obtained in approximately 120 days (tracking the formation of hydrolysis products via 1H NMR). It was also shown that (enzymatic) hydrolysis to the constituting monomers is the rate-determining step in this biodegradation mechanism. These monomers can subsequently be consumed and mineralised by (micro)organisms in the environment much faster than the polyesters. The combination of high Tg (>100 °C) and fast biodegradability is quite unique and makes this PISOX-HDO copolyester ideal for short term applications that demand strong mechanical and physical properties.

Androgen responses to adrenocorticotropic hormone infusion among individual women with polycystic ovary syndrome.

OBJECTIVE: To compare androgen responses during ACTH infusion among women with polycystic ovary syndrome (PCOS) and healthy women. DESIGN: Cross-sectional study. SETTING: Academic medical center. PATIENT(S): Women with PCOS (n = 13) and healthy controls (n = 15). INTERVENTION(S): Blood samples were obtained frequently during a 6-hour dose-response ACTH infusion. MAIN OUTCOME MEASURE(S): Comparison of basal and stimulated levels of 17α-hydroxyprogesterone (17-OHP), androgens, and cortisol (F) during ACTH infusion with those after hCG injection within individual subjects. RESULT(S): In women with PCOS increased 17-OHP, androstenedione (A), and DHEA responses during ACTH infusion were comparable to those observed in healthy controls. The magnitude of responses was highly variable among women with PCOS. Within individual women with PCOS adrenal responses to ACTH and ovarian responses to hCG were significantly correlated. Cortisol responses to ACTH were similar in women with PCOS and healthy controls. CONCLUSION(S): Within individual women with PCOS, enhanced androgen responses to ACTH are accompanied by comparable androgen responsiveness to hCG. These findings suggest that dysregulated steroidogenesis leading to hyperandrogenemia in this disorder is likely present in both adrenal and ovarian tissues. CLINICAL TRIAL REGISTRATION NUMBER: NCT00747617.

17-Hydroxyprogesterone responses to human chorionic gonadotropin are not associated with serum anti-Mullerian hormone levels among adolescent girls with polycystic ovary syndrome.

BACKGROUND: In adult women with polycystic ovary syndrome (PCOS) 17-OHP responses to human chorionic gonadotropin (hCG) stimulation are highly variable and inversely correlated with serum anti-Mullerian hormone (AMH) levels. The objective of this study was to determine whether adolescents with PCOS exhibit similar variable 17-OHP responsiveness to hCG and whether these responses are correlated to AMH levels. METHODS: In a prospective study, adolescent PCOS (n=14) and normal controls (n=10) received 25 µg of hCG, intravenously. Blood samples were obtained before and 24 h afterwards for measurement of 17-OHP and basal AMH. RESULTS: Variable 17-OHP responses to hCG were observed among PCOS girls similar to that observed in adults. There was no correlation between AMH and 17-OHP responses to hCG. CONCLUSIONS: Among adult and adolescent individuals with PCOS variable 17-OHP production appears to be characteristic of the disorder. In adolescent PCOS, 17-OHP responsiveness to hCG is not correlated to AMH.

Lack of Serum anti-Mullerian hormone responses after recombinant human chorionic gonadotropin stimulation in women with polycystic ovary syndrome.

CONTEXT: Polycystic ovary syndrome (PCOS) is an anovulatory disorder characterized by excess androgen production and increased LH secretion. Serum anti-Mullerian hormone (AMH) is also elevated in this disorder. Women with PCOS exhibit a positive correlation between AMH and LH levels and recent in vitro data demonstrate that LH can directly stimulate AMH production by granulosa cells from women with PCOS. OBJECTIVE: The objective of the study was to directly test whether LH increases AMH production in women with PCOS in vivo by assessing responses after recombinant human chorionic gonadotropin (r-hCG) stimulation. DESIGN: This was a prospective study. SETTING: The study was conducted at a research center at an academic medical center. PARTICIPANTS: Women with PCOS (n = 28) and normal controls (n = 29) participated in the study. INTERVENTIONS: Blood samples were obtained before and 24 hours after iv administration of 25 µg r-hCG. MAIN OUTCOME MEASURES: Basal and stimulated serum AMH, androstenedione, T, and 17-hydroxyprogesterone levels were measured. RESULTS: Baseline AMH levels in women with PCOS were greater than in normal controls and correlated with levels of LH as well as androstenedione, T, and 17-hydroxyprogesterone. A rise of serum AMH levels was not observed after r-hCG administration in women with PCOS or normal ovaries. CONCLUSION: These findings are in contrast to in vitro evidence demonstrating that AMH secretion by granulosa cells of PCOS women in response to LH stimulation and suggest AMH regulation in vivo is complex and that the elevated serum AMH in women with PCOS is not a direct effect of the excess LH production characteristic of PCOS.

Relationship between 17-hydroxyprogesterone responses to human chorionic gonadotropin and markers of ovarian follicle morphology in women with polycystic ovary syndrome.

CONTEXT: Women with polycystic ovary syndrome (PCOS) have increased 17-hydroxyprogesterone (17-OHP) responses to gonadotropin stimulation although individual variability is substantial, as reflected by exaggerated as well as normal responses. The relationship between 17-OHP responses to gonadotropin stimulation and markers of ovarian function has not been assessed. OBJECTIVE: To determine whether 17-OHP responses are associated with antral follicle count (AFC), anti-Mullerian hormone (AMH), or inhibin B (Inh B) levels in PCOS and normal women. DESIGN: Prospective study. SETTING: Research center at an academic medical center. PARTICIPANTS: Women with PCOS (n = 18) and normal controls (n = 18). INTERVENTIONS: Blood samples were obtained before and 24 hours after administration of 25 µg recombinant-human chorionic gonadotropin. Ovarian imaging was conducted with three-dimensional pelvic ultrasound. MAIN OUTCOME MEASURES: Basal and stimulated levels of 17-OHP, androgens, estrogen, AMH, Inh B, and AFC. RESULTS: In women with PCOS, 17-OHP responses were heterogeneous and inversely correlated with AMH and Inh B levels, but not AFC. In a subgroup of PCOS women with exaggerated 17-OHP responses, AMH levels were equivalent to that of normal women. In PCOS women with normal 17-OHP responses, AMH levels were markedly elevated. CONCLUSION: Based on heterogeneous 17-OHP responses to human chorionic gonadotropin in women with PCOS, AMH levels are inversely linked to ovarian androgen production while positively correlated with AFC. These findings suggest that in PCOS, AMH production may reflect redistribution of the follicle population or regulation by intraovarian mechanisms.

The impact of depot GnRH agonist on AMH levels in healthy reproductive-aged women.

CONTEXT: GnRH agonists (GnRHa) are being used experimentally in an attempt to preserve fertility in young female cancer patients undergoing chemotherapy. Anti-Müllerian hormone (AMH) produced by ovarian granulosa cells may serve as a marker of ovarian reserve, but it is not clear whether this marker is useful during GnRHa treatment. OBJECTIVE: The purpose of this study was to determine the effect of a depot GnRHa on AMH levels. DESIGN: Depot leuprolide (3.75 mg) was administered in the midluteal phase (MLP) in healthy women. Assessments of AMH, FSH, LH, estradiol, and progesterone were performed in the early follicular phase (EFP) and MLP before GnRHa treatment and approximately 7, 14, and 30 days after GnRHa administration. SETTING: The study was conducted in a university research center. PATIENTS: Participants were 33 healthy, premenopausal women aged 18 to 45 years old with regular menses. RESULTS: EFP and MLP AMH levels were similar before GnRHa administration. Relative to MLP AMH levels, AMH decreased 7 days after GnRHa administration by a median of 24% (P < .001) and then increased above pretreatment levels 14 and 30 days after GnRHa by 13% and 32%, respectively (P < .001). Changes in AMH levels did not correlate with changes in gonadotropins, estradiol, or progesterone. CONCLUSIONS: Significant changes in AMH levels occur in the first 4 weeks after depot leuprolide administration, suggesting that AMH may not be a reliable marker of ovarian reserve during this interval. Changes in AMH occurred independent of gonadotropin levels, supporting a direct effect of GnRHa on granulosa cell expression of AMH or an indirect effect of GnRHa on the development and/or dynamics of the follicle pool.

Prediction of disease severity in patients with early rheumatoid arthritis by gene expression profiling.

In order to test the ability of peripheral blood gene expression profiles to predict future disease severity in patients with early rheumatoid arthritis (RA), a group of 17 patients (1 ± 0.2 years disease duration) was evaluated at baseline for gene expression profiles. Disease status was evaluated after a mean of 5 years using an index combining pain, global and recoded MHAQ scores. Unsupervised and supervised algorithms identified "predictor genes" whose combined expression levels correlated with follow-up disease severity scores. Unsupervised clustering algorithms separated patients into two branches. The only significant difference between these two groups was the disease severity score; demographic variables and medication usage were not different. Supervised T-Test analysis identified 19 "predictor genes" of future disease severity. Results were validated in an independent cohort of subjects of established RA with using Support Vector Machines and K-Nearest-Neighbor Classification. Our study demonstrates that peripheral blood gene expression profiles may be a useful tool to predict future disease severity in patients with early and established RA.

Identification of gene expression signatures in autoimmune disease without the influence of familial resemblance.

Even though autoimmune diseases are heterogeneous, believed to result from the interaction between genetic and environmental components, patients with these disorders exhibit reproducible patterns of gene expression in their peripheral blood mononuclear cells. A portion of this gene expression profile is a property of familial resemblance rather than autoimmune disease. Here, we wanted to identify the portion of this gene expression profile that is independent of familial resemblance and determine whether it is a product of disease duration, disease onset or other factors. By employing supervised clustering algorithms, we identified 100 genes whose expression profiles are shared in individuals with various autoimmune diseases but are not shared by unaffected family members of individuals with autoimmune disease or by controls. Individuals with early disease (1 year after onset) and established disease (10 years after onset) exhibit a near-identical expression pattern, suggesting that this unique profile is a product of disease onset rather than disease duration.

Defective ATM-p53-mediated apoptotic pathway in multiple sclerosis.

Defective elimination of autoreactive cells is thought to play a role in the development of autoimmune diseases including multiple sclerosis (MS). We examined the activation of the ATM-CHK2-p53 pathway in MS patients after subjecting their peripheral blood mononuclear cells to gamma-irradiation. We found that peripheral blood mononuclear cells from a subset of MS patients show resistance to cell death induced by irradiation. This defect is due to impaired constitutive expression and activation of ATM (ataxia telangiectasia mutated), resulting in impaired stabilization of p53. We predict that these fundamental defects likely alter the regulation of the immune population of cells in MS and may contribute to the development or progression of the disease.

Reduced p53 in peripheral blood mononuclear cells from patients with rheumatoid arthritis is associated with loss of radiation-induced apoptosis.

OBJECTIVE: Patients with autoimmune disorders exhibit highly reproducible gene expression profiles in their peripheral blood mononuclear cells. This profile includes, at least in part, a collection of underexpressed genes that encode proteins that inhibit cell cycle progression and stimulate apoptosis. We aimed to determine whether this gene expression profile confers functional liability on lymphocytes from patients with rheumatoid arthritis (RA). METHODS: Viability studies in response to a panel of proapoptotic stimuli revealed that T lymphocytes from patients with RA were resistant to gamma radiation-induced apoptosis, a process known to be dependent on p53. To assess p53 function in RA peripheral blood mononuclear cells, baseline levels of p53 protein and TP53 transcript were measured in patients with RA and controls. The cellular p53 response to gamma radiation was also assessed by immunoblotting. RESULTS: Lymphocytes from patients with RA had lower baseline levels of TP53 messenger RNA (mRNA) and p53 protein than did those from control subjects and were deficient in their ability to increase p53 after exposure to gamma radiation. A subgroup of patients with RA had a second biochemical defect characterized by expression of very low baseline levels of checkpoint kinase 2 mRNA and protein. CONCLUSION: We conclude that defects in the expression of TP53 mRNA and, in a subgroup, defects in expression of CHK2 mRNA, lead to severe defects in apoptosis in patients with RA. We hypothesize that this liability may contribute to autoimmunity.

Shared gene expression profiles in individuals with autoimmune disease and unaffected first-degree relatives of individuals with autoimmune disease.

Patients with autoimmune disorders exhibit highly reproducible gene expression profiles in their peripheral blood mononuclear cells. These signatures may result from chronic inflammation, other disease manifestations, or may reflect family resemblance. To test the latter hypothesis, we determined gene expression profiles in unaffected first-degree relatives of individuals with autoimmune disease. Gene expression profiles in unaffected first-degree relatives resembled the profiles found in individuals with autoimmune diseases. A high percentage of differentially expressed genes in unaffected first-degree relatives were previously identified as autoimmune signature genes. Examination of the linear regression relationship of gene transcript levels between parent-offspring pairs revealed that autoimmune signature genes display high levels of family resemblance. Taken together, these results support the hypothesis that these variations in gene transcript levels are associated with family resemblance rather than clinical manifestations of disease.

Co-localization of differentially expressed genes and shared susceptibility loci in human autoimmunity.

Autoimmune diseases arise from complex interactions between environmental and genetic factors. Genetic linkage scans show that different autoimmune diseases share overlapping susceptibility loci. Lymphocytes from individuals with different autoimmune diseases, as well as unaffected first-degree relatives, also share a common gene expression profile. We sought to determine if genes within this autoimmune expression profile were nonrandomly distributed in the genome and if their distribution overlapped with shared disease susceptibility loci. We found that differentially expressed genes were distributed in a nonrandom fashion in chromosomal domains within the genome. Furthermore, positions of these domains were not statistically different from a number of shared autoimmune disease susceptibility loci. To our knowledge, this is the first study showing concordance between gene expression and genetic linkage results in common complex multifactorial human diseases.

Comparison of differentially expressed genes in T lymphocytes between human autoimmune disease and murine models of autoimmune disease.

A general view is that critical genes involved in biological pathways are highly conserved among species. To understand human autoimmune diseases, a great deal of effort has been devoted to the study of murine models that mirror many pathologic properties observed in the human disease. We have found that lymphocytes from humans with different autoimmune disease all carry a common conserved gene expression profile. Therefore, we wanted to determine if lymphocytes from common murine models of autoimmune disease carried a gene expression profile similar to the human profile and if both mouse models carried a shared gene expression profile. We identified numerous differentially expressed genes (DEGs) in the autoimmune strains compared to non-autoimmune strains. However, we found very little overlap in the gene expression profile between human autoimmune disease and murine models of autoimmune disease and between different murine autoimmune models. Our research further confirms that murine models of autoimmunity do not perfectly match human autoimmune diseases.

Profiles of gene expression in human autoimmune disease.

Human autoimmune diseases arise from complex interactions between genetic and environmental factors, result from immune attack upon target tissues, and affect 3-5% of the population. We compared gene expression profiles (>4000 genes) in the peripheral blood mononuclear cells of normal individuals after immunization to individuals with four different autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus, and multiple sclerosis). All autoimmune individuals, including unaffected first-degree relatives, share a common gene expression profile that is completely distinct from the immune profile. Therefore, this expression pattern is not simply a recapitulation of the immune response to nonself, is not a result of the disease process, and results, as least in part, from genetic factors. Surprisingly, these genes are clustered in chromosomal domains suggesting there is some genome-wide logic to this unique expression pattern. These data argue that that there is a constant pattern of gene expression in autoimmunity that is independent of the specific autoimmune disease and clinical parameters associated with any individual autoimmune disease.

Gene expression profiles in human autoimmune disease.

To acquire a functional view of human autoimmunity, we compared differences in gene expression (>4000 genes) in the peripheral blood mononuclear cells of normal individuals following immunization to those in individuals with four different autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, insulin dependent diabetes mellitus, and multiple sclerosis). Each individual from all disease groups displayed a similar pattern of gene expression that was highly distinct from the gene expression pattern of the immunized group. These findings indicate that the expression pattern accompanying autoimmunity is not simply a recapitulation of the immune response to non-self. Of note, expression levels of genes that encode key proteins in several distinct apoptosis pathways were markedly reduced in all autoimmune disease groups. Taken together, these data indicate that the pattern of gene expression describes a molecular portrait of autoimmunity that is constant among individuals with autoimmune disease but is independent of the specific autoimmune disease and the clinical parameters associated with any individual autoimmune disease.

Expression of genes involved in vascular development and angiogenesis in endothelial cells of adult lung.

Profiling gene expression in endothelial cells advances the understanding of normal vascular physiology and disease processes involving angiogenesis. However, endothelial cell purification has been challenging because of the difficulty of isolating cells and their low abundance. Here we examine gene expression in endothelial cells freshly isolated from lung capillaries after in vivo labeling with fluorescent cationic liposomes and purification by fluorescence-activated cell sorting (FACS). Of the 39,000 genes and expressed sequence tags evaluated on custom oligonucleotide arrays, 555 were enriched in endothelial cell fraction. These included familiar endothelial cell-associated genes such as VEGF, VEGF receptor (VEGFR)-1, VEGFR-2, angiopoietin-2, Tie1, Tie2, Edg1 receptor, VE-cadherin, claudin 5, connexin37, CD31, and CD34. Also enriched were genes in semaphorin/neuropilin (Sema3c and Nrp1), ephrin/Eph (ephrin A1, B1, B2, and EphB4), delta/notch (Hey1, Jagged 2, Notch 1, Notch 4, Numb, and Siah1b), and Wingless (Frizzled-4 and Tle1) signaling pathways involved in vascular development and angiogenesis. Expression of representative genes in alveolar capillary endothelial cells was verified by immunohistochemistry. Such expression reflects features that endothelial cells of normal lung capillaries have in common with embryonic and growing blood vessels. About half of the enriched genes, including exostosin 2, lipocalin 7, phospholipid scramblase 2, pleckstrin 2, protocadherin 1, Ryk, scube 1, serpinh1, SNF-related kinase, and several tetraspanins, had little or no previous association with endothelial cells. This approach can readily be used to profile genes expressed in blood vessels in tumors, chronic inflammation, and other sites in which endothelial cells avidly take up cationic liposomes.

Cutting edge: molecular portrait of human autoimmune disease.

Autoimmune diseases affect 3-5% of the population, are mediated by the immune response to self-Ags, and are characterized by the site of tissue destruction. We compared expression levels of >4,000 genes in PBMC of control individuals before and after immunization to those of individuals with four distinct autoimmune diseases. The gene expression profile of the normal immune response exhibits coordinate changes in expression of genes with related functions over time. In contrast, each individual from all autoimmune diseases displays a similar gene expression profile unrelated to the pattern of the immunized group. To our surprise, genes with a distinct expression pattern in autoimmunity are not necessarily "immune response" genes, but are genes that encode proteins involved in apoptosis, cell cycle progression, cell differentiation, and cell migration.