Elastin Turnover Research Articles

Collagen and tissue turnover as a function of age: Implications for fibrosis

The extracellular matrix (ECM) is the backbone of all tissues. It is a complex grid consisting of multiple structural proteins which each play a vital role for the function and maintenance of normal tissue function. In development and growth, tissue is being formed and elaborated (tissue modeling), while in adult life, tissues are being maintained and remodeled. These processes involve likely different mechanisms. During tissue modeling and remodeling, small fragments of proteins are released into the circulation, where they may be used as biomarkers for tissue turnover. The aim of the study was to investigate ECM turnover in rodents as a function of age. Serum of rats of 1, 2, 3, 4, 5, 6, 10 and 12months of age was profiled for 15 markers of ECM turnover, including: fragments of type I, II, III, IV, V and VI collagen formation (P1NP, P4NP-7S, Pro-C5, Pro-C6) and degradation (C1M, C2M, C2M-beta, C3M, C4M, C5M, C6M); biglycan (BGM) and elastin (ELM7) degradation; and the type I and II collagen telopeptides CTX-I and CTX-II. Type I and II collagen turnover was up to 93% and 97% downregulated in old (one year) compared to young (one month) old animals (p<0.0001), while type IV and V collagen and biglycan turnover was upregulated 2.5-, 2- and 2-fold, respectively (p<0.0001). Type III and VI collagen and elastin turnover was not influenced significantly by age. ECM turnover rates were consistently different in young vs. old animals, up to 30 fold. This appears to be due to body growth, a different ECM composition and a higher regenerative capability of connective tissues in young vs. old animals. These changes have to be accounted for in translational science. Both in measuring serum levels of ECM biomarkers and in the development of therapies to speed up wound healing or inhibit fibrogenesis.

Atherogenic indices, elastin turnover and the development of microvascular complications- study in diabetic patients with arterial hypertension

Atherogenic indices, elastin turnover and the development of microvascular complications- study in diabetic patients with arterial hypertension

Cellular and Extracellular Matrix Basis for Heterogeneity in Mitral Annular Contraction.

Regional heterogeneity in mitral annular contraction, which is generally ascribed to the fibrous vs. muscular annular composition, ensures proper leaflet motion and timing of coaptation. It is unknown whether the fibroblast-like cells in the annulus modulate this heterogeneity, even though valvular interstitial cells (VICs) can be mechanically "activated." Fourteen sheep underwent implantation of radiopaque markers around the mitral annulus defining four segments: septal (SEPT), lateral (LAT), and anterior (ANT-C) and posterior (POST-C) commissures. Segmental annular contraction was calculated using biplane videofluoroscopy. Immunohistochemistry of annular cross sections assessed regional matrix content, matrix turnover, and cell phenotype. Micropipette aspiration measured the Young's modulus of the leaflets adjacent to the myocardial border. Whereas SEPT contained more collagen I and III, LAT demonstrated more collagen and elastin turnover as shown by greater decorin, lysyl oxidase, and matrix metalloprotease (MMP)-13 and smooth muscle alpha-actin (SMaA). This greater matrix turnover paralleled greater annular contraction in LAT vs. SEPT (22.5% vs. 4.1%). Similarly, POST-C had more SMaA and MMP13 than ANT-C, consistent with greater annular contraction in POST-C (18.8% vs. 11.1%). Interestingly, POST-C had the greatest effective modulus, significantly higher than LAT. These data suggest that matrix turnover by activated VICs relates to annular motion heterogeneity, maintains steady-state mechanical properties in the annulus, and could be a therapeutic target when annular motion is impaired. Conversely, alterations in this heterogeneous annular contraction, whether through disease or secondary to ring annuloplasty, could disrupt this normal pattern of cell-mediated matrix remodeling and further adversely impact mitral valve function.

Combined antiretroviral therapy attenuates hepatic extracellular matrix remodeling in HIV patients assessed by novel protein fingerprint markers.

Combined antiretroviral therapy (cART) attenuates hepatic fibrosis in hepatitis C virus and HIV coinfected patients. However, the role of HIV or cART on hepatic fibrosis in HIV monoinfection is discussed controversially. During liver fibrosis, matrix metalloproteinases (MMPs) degrade extracellular matrix (ECM) proteins into small soluble fragments, which reflect hepatic remodeling processes. This study used these novel biomarkers to investigate the effect of HIV and cART on hepatic fibrosis remodeling. In 249 patients with HIV monoinfection and 55 healthy controls, the serum levels of MMP-degraded collagen type III (C3M), biglycan (BGM), elastin (ELM), as well as the formation marker 7S (P4NP 7S), and MMP-degraded collagen type IV (C4M) were determined using specific ELISAs. Sixty-eight patients underwent a follow-up visit 3 years later including assessment of ECM markers and fibrosis using transient elastography (Fibroscan). C3M, BGM, C4M and P4NP 7S were significantly elevated in HIV patients compared to controls and correlated to HIV viral loads and inversely to cART duration. C4M, P4NP 7S and ELM were lower in patients under cART therapy and in patients without HIV viremia, indicating that lowering of the HIV load by cART attenuates remodeling of ECM. The levels of C3M, C4M, P4NP 7S and ELM correlated significantly with the progression of fibrosis in these patients. Specific therapy of patients with HIV monoinfection also beneficially influences liver fibrosis. These novel markers of liver fibrosis remodeling may help to monitor the hepatic effects by HIV therapy.

Hydrogen sulfide and sodium nitroprusside compete to activate/deactivate MMPs in bone tissue homogenates

BackgroundBone microvascular remodeling is the primary predictor of bone structure and function. Remodeling by its very nature implies synthesis and degradation of the extracellular matrix. Normally, 50% of total protein in the vessel wall is elastin. During remodeling, elastin is degraded by specialized matrix metalloproteinases (MMPs). Because the turnover of elastin is 1000-fold slower than that of collagen, most of the elastin is replaced by stiffer collagen. Stiffer vessels impose pressure on the aortic valve, causing regurgitation and increased pulse pressure. On the other hand, high MMP activity will cause vascular dilatation, leading to aneurysm. Therefore, balanced constitutive remodeling is necessary for adequate bone structure and function. Interestingly, collagen-degrading MMPs are involved in various pathological conditions, including osteoporosis, osteoarthritis, and cardiovascular disease. Sodium nitroprusside is a nitric oxide donor that could potentially alter MMP activity via vasodilation in vivo, but can also produce peroxynitrite, which activates MMPs by combining with superoxide. Moreover, hydrogen sulfide is a known antioxidant as well as a vasodilator, and is also speculated to contribute directly to MMP activity. We hypothesized that hydrogen sulfide reduced activity of MMP in ex vivo bone tissue homogenates and that sodium nitroprusside would increase MMP activity in vitro.MethodsWe surgically removed the tibia and femur from anesthetized mice, and prepared bone tissue homogenates using a mortar and pestle, measured the protein concentration with a spectrophotometer, and detected MMP activity using gelatin gel zymography.ResultsOur data showed increased MMP activity at a sodium nitroprusside concentration of 1 μM, and MMP activity increased exponentially. There was a decrease in MMP activity with increasing hydrogen sulfide, beginning at 16 μM (P < 0.01) and continuing to 40 μM. Moreover, sodium nitroprusside 3 μM was able to overcome the decrease in MMP activity that occurred with hydrogen sulfide 40 μM; this resulted in a more pronounced exponential increase in MMP activity.ConclusionThere are several substances that can potentially be used to decrease MMP activity and to alleviate pathological remodeling by MMPs.

Increased elastin turnover in diabetic patients with arterial hypertension

ENWEndNote BIBJabRef, Mendeley RISPapers, Reference Manager, RefWorks, Zotero AMA Nikolov A, Tsinlikov I, Nicoloff G, et al. Increased elastin turnover in diabetic patients with arterial hypertension. Central European Journal of Immunology. 2013;38(4):537-542. doi:10.5114/ceji.2013.39772. APA Nikolov, A., Tsinlikov, I., Nicoloff, G., Blazhev, A., Tsinlikova, I., & Stanilova, S. et al. (2013). Increased elastin turnover in diabetic patients with arterial hypertension. Central European Journal of Immunology, 38(4), 537-542. https://doi.org/10.5114/ceji.2013.39772 Chicago Nikolov, Asparuh, Ivan Tsinlikov, George Nicoloff, Alexander Blazhev, Ivanka Tsinlikova, Spaska Stanilova, and Antoan Garev. 2013. "Increased elastin turnover in diabetic patients with arterial hypertension". Central European Journal of Immunology 38 (4): 537-542. doi:10.5114/ceji.2013.39772. Harvard Nikolov, A., Tsinlikov, I., Nicoloff, G., Blazhev, A., Tsinlikova, I., Stanilova, S., and Garev, A. (2013). Increased elastin turnover in diabetic patients with arterial hypertension. Central European Journal of Immunology, 38(4), pp.537-542. https://doi.org/10.5114/ceji.2013.39772 MLA Nikolov, Asparuh et al. "Increased elastin turnover in diabetic patients with arterial hypertension." Central European Journal of Immunology, vol. 38, no. 4, 2013, pp. 537-542. doi:10.5114/ceji.2013.39772. Vancouver Nikolov A, Tsinlikov I, Nicoloff G, Blazhev A, Tsinlikova I, Stanilova S et al. Increased elastin turnover in diabetic patients with arterial hypertension. Central European Journal of Immunology. 2013;38(4):537-542. doi:10.5114/ceji.2013.39772.

Polymorphisms in the Human Tropoelastin Gene Modify In Vitro Self-Assembly and Mechanical Properties of Elastin-Like Polypeptides

Elastin is a major structural component of elastic fibres that provide properties of stretch and recoil to tissues such as arteries, lung and skin. Remarkably, after initial deposition of elastin there is normally no subsequent turnover of this protein over the course of a lifetime. Consequently, elastic fibres must be extremely durable, able to withstand, for example in the human thoracic aorta, billions of cycles of stretch and recoil without mechanical failure. Major defects in the elastin gene (ELN) are associated with a number of disorders including Supravalvular aortic stenosis (SVAS), Williams-Beuren syndrome (WBS) and autosomal dominant cutis laxa (ADCL). Given the low turnover of elastin and the requirement for the long term durability of elastic fibres, we examined the possibility for more subtle polymorphisms in the human elastin gene to impact the assembly and long-term durability of the elastic matrix. Surveys of genetic variation resources identified 118 mutations in human ELN, 17 being non-synonymous. Introduction of two of these variants, G422S and K463R, in elastin-like polypeptides as well as full-length tropoelastin, resulted in changes in both their assembly and mechanical properties. Most notably G422S, which occurs in up to 40% of European populations, was found to enhance some elastomeric properties. These studies reveal that even apparently minor polymorphisms in human ELN can impact the assembly and mechanical properties of the elastic matrix, effects that over the course of a lifetime could result in altered susceptibility to cardiovascular disease.

Reversibility of liver fibrosis

Liver fibrosis, and its end stage cirrhosis are a major cause of morbidity and mortality and therapeutic options are limited. However, the traditional view of liver disease as an irreversible process is obsolete and it is now evident that the development of liver fibrosis is a dynamic and potentially bidirectional process. Spontaneous resolution of scarring is seen in animal models of liver fibrosis and in human trials in which the stimuli responsible for chronic or repeated hepatic inflammation is successfully removed. Key players in the process are hepatic stellate cells, macrophages, MMPs and their inhibitors Timps. It is also evident that in advanced fibrotic liver disease, specific histological features define what is currently described as "irreversible" fibrosis. This includes the development of paucicellular scars enriched in extensively cross-linked matrix components, such as fibrillar collagen and elastin. Our recent work has focused on the role of macrophage metalloelastase (MMP-12) in the turnover of elastin in reversible and irreversible models of fibrosis. We have shown that elastin turnover in liver injury and fibrosis is regulated by macrophages via Mmp-12 expression, activity and ratio to its inhibitor Timp-1. Failure of elastin degradation, together with increased deposition leads to accumulation of elastin in the fibrotic scars.

Abstract 206: PPARγ Deficiency Causes Aortic Stiffness and Dysregulated Elastin Turnover

PPARγ, a nuclear receptor that regulates adipocyte development and glucose homeostasis, is the molecular target of a class of insulin-sensitizing drugs. Loss-of-function mutations in PPARG gene are implicated in human hypertension and PPARγ agonists decrease blood pressure both in animal models and human patients. We have previously generated mice with varying Pparg expression created by modifying its 3′-UTR sequence, and concluded an inverse relationship between PPARγ expression level and blood pressure. Interestingly, mice with extremely low PPARγ expression exhibited an increase in systolic blood pressure without significant change in diastolic blood pressure, ultimately causing a significant increase in pulse pressure. Thus, we hypothesized that PPARγ deficiency impairs aortic elasticity, resulting in the increase in pulse pressure. Aortic pulse wave velocity (PWV) was significantly increased in PPARγ hypomorphic mice, suggesting that aortas of PPARγ hypomorphic mice were stiffer than those of wild-type mice. The measurement of mechanical property by atomic force microscope (AFM) showed higher tissue rigidity in the aorta of PPARγ hypomorphic mice. Expression of elastin in aortas was significantly decreased, and negatively correlated with aortic PWV in PPARγ hypomorphic mice. This was accompanied by increased elastin fiber breaks, elastolytic activity, and expressions of MMP-9 in aortas of PPARγ hypomorphic mice. The elevated PWV in PPARγ hypomorphic mice was ameliorated after treatment of PPARγ agonist. Together, our results suggest that PPARγ deficiency impairs elasticity in aorta and underscore the importance of PPARγ in the regulation of blood pressure and vascular reactivity.

Elastin Degradation Is Associated With Progressive Aortic Stiffening and All-Cause Mortality in Predialysis Chronic Kidney Disease

In the large conduit arteries, elastin is important in maintaining vascular compliance. Studies in animal models suggest that elastin degradation may promote arteriosclerotic vascular changes. There is already a well-established link between aortic stiffening and mortality in the general population and in patients undergoing dialysis. Elastin degradation is mediated by several proteases, including matrix metalloproteinase 2 and cathepsin S. Elastin turnover may be inferred by measuring serum levels of elastin-derived peptides. We analyzed the serum concentration of these biomarkers, their endogenous inhibitors, and aortic pulse wave velocity in 200 patients with stages 3 and 4 chronic kidney disease and then serially in a subgroup of 65 patients over 36 months. Serum matrix metalloproteinase 2, cathepsin S, and elastin-derived peptide levels were independently associated with baseline aortic pulse wave velocity and changes in stiffness over the follow-up period. Higher matrix metalloproteinase 2 and elastin-derived peptide levels were also independently associated with preexisting cardiovascular disease. In multivariable Cox regression, higher serum elastin-derived peptide levels were independently associated with increased all-cause mortality (hazard ratio per SD increase=1.78; P=0.021). In predialysis chronic kidney disease, elastin degradation is an important determinant of arterial stiffness and is associated with all-cause mortality.

Effects of selenium on the vessel walls and anti-elastin antibodies in spontaneously hypertensive rats

Selenium (Se) is an exogenous antioxidant that performs its role via expression of selenoproteins. Pathological changes of the structure of the vessel wall, elastin turnover and collagen production may lead to increased stiffness of the vessels with decreased blood flow to the peripheries. The level of anti-elastin antibodies (AEABs) may give information for elastin metabolism. The aim of the study is to investigate the influence of Se intake on the vessel wall changes and production of AEABs in spontaneously hypertensive rats (SHR). Twenty-four male, 32-week-old SHR were used, divided into three groups, G1, G2 and G3. Before blood and morphological testing, G1 received a low-Se diet for eight weeks, G2 received a diet with adequate Se content and G3 received a diet with Se supplementation. The Se nutritional status was assessed by determination of glutathione peroxidase-1 (GPx-1) activity in whole blood, using the 'Ransel' kit. The rats from group G3 showed higher GPx-1 activity and lower level of AEABs than the other groups (P = 0.021), and the aortic wall histology showed slight degenerative changes compared with other rats. A low-Se diet caused severe changes to the aortic wall's ultrastructure, whereas Se supplementation slowed the changes down. The morphometry revealed a thicker abdominal aortic wall in rats of G1 compared with the other groups, and reduced thickness of the wall of the left coronary artery in G3 compared with the other groups (P < 0.05). Our results have shown that low Se intake leads to severe changes in the vessel walls in SHR, whereas selenium supplementation slows down the elastin degradation and degenerative changes of the vessel walls.

Elastin Degradation and Vascular Smooth Muscle Cell Phenotype Change Precede Cell Loss and Arterial Medial Calcification in a Uremic Mouse Model of Chronic Kidney Disease

Arterial medial calcification (AMC), a hallmark of vascular disease in uremic patients, is highly correlated with serum phosphate levels and cardiovascular mortality. To determine the mechanisms of AMC, mice were made uremic by partial right-side renal ablation (week 0), followed by left-side nephrectomy at week 2. At 3 weeks, mice were switched to a high-phosphate diet, and various parameters of disease progression were examined over time. Serum phosphate, calcium, and fibroblast growth factor 23 (FGF-23) were up-regulated as early as week 4. Whereas serum phosphate and calcium levels declined to normal by 10 weeks, FGF-23 levels remained elevated through 16 weeks, consistent with an increased phosphate load. Elastin turnover and vascular smooth muscle cell (VSMC) phenotype change were early events, detected by week 4 and before AMC. Both AMC and VSMC loss were significantly elevated by week 8. Matrix metalloprotease 2 (MMP-2) and cathepsin S were present at baseline and were significantly elevated at weeks 8 and 12. In contrast, MMP-9 was not up-regulated until week 12. These findings over time suggest that VSMC phenotype change and VSMC loss (early phosphate-dependent events) may be necessary and sufficient to promote AMC in uremic mice fed a high-phosphate diet, whereas elastin degradation might be necessary but is not sufficient to induce AMC (because elastin degradation occurred also in uremic mice on a normal-phosphate diet, but they did not develop AMC).

Oxidative and Nitrosative Modifications of Tropoelastin Prevent Elastic Fiber Assembly in Vitro

Elastic fibers are extracellular structures that provide stretch and recoil properties of tissues, such as lungs, arteries, and skin. Elastin is the predominant component of elastic fibers. Tropoelastin (TE), the precursor of elastin, is synthesized mainly during late fetal and early postnatal stages. The turnover of elastin in normal adult tissues is minimal. However, in several pathological conditions often associated with inflammation and oxidative stress, elastogenesis is re-initiated, but newly synthesized elastic fibers appear abnormal. We sought to determine the effects of reactive oxygen and nitrogen species (ROS/RNS) on the assembly of TE into elastic fibers. Immunoblot analyses showed that TE is oxidatively and nitrosatively modified by peroxynitrite (ONOO(-)) and hypochlorous acid (HOCl) and by activated monocytes and macrophages via release of ONOO(-) and HOCl. In an in vitro elastic fiber assembly model, oxidatively modified TE was unable to form elastic fibers. Oxidation of TE enhanced coacervation, an early step in elastic fiber assembly, but reduced cross-linking and interactions with other proteins required for elastic fiber assembly, including fibulin-4, fibulin-5, and fibrillin-2. These findings establish that ROS/RNS can modify TE and that these modifications affect the assembly of elastic fibers. Thus, we speculate that oxidative stress may contribute to the abnormal structure and function of elastic fibers in pathological conditions.

Detection of Elastin Degradation Products in the Blood and Urine of Patients With Pulmonary Arterial Hypertension

PURPOSE: Pulmonary arterial hypertension (PAH) is a disease of pulmonary arteries characterized by vasoconstriction and remodeling. This hypertrophic process involves synthesis of collagen and elastin. The objective of this study is to determine whether changes in pulmonary vascular structure are associated with increased elastin turnover by measuring two aminoacids specific for mature elastin, i.e. desmosine (D) and isodesmosine (I).

Vascular aging: From molecular mechanism to clinical significance

The large and medium-sized arteries in elderly people show varying degrees of intimal and medial change. The medial change is known as age-related medial degeneration and sclerosis (ARMDS). The ARMDS results in systolic hypertension and left ventricular hypertrophy of the heart as a result of loss of arterial elasticity. It also causes aortic dilatation, or even aortic aneurysm. The ARMDS and atherosclerosis are distinct entities, but are often overlapped and confused with each other. The present review mainly focuses on ARMDS and briefly addresses atherosclerosis, and aging of arterioles, capillaries and veins. The smooth muscle cells in the inner half of the aortic media of elderly people degenerate and undergo apoptosis. This causes degradation of elastin fibers and the accumulation of collagen fibers in the media, but the inflammatory infiltrates are scarce. Biochemical studies showed an age-related decrease of elastin and its crosslinks, and an increase of collagen and its crosslink. Because the turnover of elastin is very long, it likely suffers from glycation (Maillard reaction) and glyco-oxidative reaction. The advanced glycation end-products accumulate in the aortic media with increasing age. Alcian-blue positive mucin accumulates in aortic media in elderly people. The major component of the increase of aortic mucin is chondroitin-6-sulfate. Microcalcification is frequent in the inner acellular portion of the aortic media in elderly people. Calcium contents increase with age. In conclusion, the ARMDS is a distinct pathological entity with clinical significance. The pathogenesis of ARMDS is unclear; the mechanical stress of elastin, endothelial dysfunction, and glycation of elastin are proposed.

Mid-dermal elastolysis revisited

The clinical as well as histological data of 79 mid-dermal elastolysis (MDE) patients reported in the literature were evaluated. MDE is an acquired skin condition of the elastic tissue predominantly manifesting on the trunk and proximal extremities of young women. Most commonly observed skin changes include patches of well-circumscribed fine wrinkles (type I) and perifollicular papular protrusions (type II). Rarely, MDE may also occur with persistent reticular erythema and wrinkling (type III). The critical diagnostic histopathological feature of MDE is the selective loss of elastic fibres in the mid-dermis. Mild lymphohistiocytic infiltrates, elastophagocytosis of elastic fibres by macrophages, and even multinucleate giant cells are occasionally observed in MDE lesions. Immunohistological studies and cell culture experiments indicate that dysbalances in elastin turnover are associated with pathological degradative processes including increased elastolytic activity that finally lead to loss of elastic fibres in the mid-dermis. First-line differential diagnoses may include closely related conditions such as anetoderma, annular elastolytic giant cell granuloma, cutis laxa acquisita and pseudoxanthoma elasticum-like papillary dermal elastolysis. Future therapeutic approaches in MDE patients should focus on agents that are able to block increased elastase activity and induce elastin synthesis.

Collagen and Elastin Degradation Products as Potential Biomarkers for Chronic Graft-Versus-Host Disease (cGVHD).

Abstract 1156Poster Board I-178 IntroductioncGVHD is the main cause of impaired quality of life, morbidity and mortality in patients surviving after allogeneic transplantation. To date, no validated biomarkers for diagnosis and follow-up of cGVHD have been established. Among proposed pathophysiological mechanisms, one involves increased turnover of extracellular matrix components as a result of immune-mediated tissue destruction. We hypothesized that analysis of urinary excretion of degradation peptides from collagen (hydroxylysylpyridinoline [HP] and lysylpyridinoline [LP]) and elastin (desmosine [DES]) using high-sensitivity nano-flow liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) might lead to identification of potential biomarkers in patients with cGVHD. Patients and MethodsWe elected to compare 3 groups: 16 allogeneic transplant recipients with newly diagnosed or relapsing cGVHD before initiation of systemic immunosuppressive therapy (group A), 13 pts with lymphoma who underwent autologous transplantation, in order to measure the impact of high-dose chemotherapy (group B) and 10 healthy volunteers (group C). Clinical characterization of cGVHD was performed according to NIH criteria. Pts already on glucocorticoids and those with bloodstream infection or proteinuria were excluded. Morning urine samples were collected in fasting subjects, then processed and frozen at -80°C until analysis by nanoLC-MS/MS. Samples were purified using mixed-mode strong cation exchange cartridges, derivatized using propionic anhydride and analyzed with nanoLC-MS/MS. ResultsPts with cGVHD (group A) were collected at a median of 229 (107-2966) days post transplant; 8 pts had de novo cGVHD, 8 presented with obvious clinical flare-up and 3 had previously suffered from acute GVHD. cGVHD was mild in 1 (6%), moderate in 8 (50%) and severe in 7 (44%) pts. Affected organs included mouth in 12 pts, skin in 11, liver in 11, eyes in 5, GI tract in 5, joints/fascia in 2, genital tract in 1 and lungs in 1. Thrombocytopenia was present in 4 (25%) pts and eosinophilia in 7 (44%). All transplants had been performed for hematological malignancies, using myeloablative (7 pts) or reduced-intensity conditioning (9 pts). Donors were HLA-identical siblings (13 pts), 10/10 (2 pts) or 9/10 (1 pt) unrelated volunteers. Stem cell source was peripheral blood in all but one pts. Pts from group B were collected at a median of 123 (90-377) days post transplant. As shown in enclosed figure, urinary concentrations of DES and HP in group A and B were similar, but both groups showed a marked increase in levels of these compounds compared to group C (p<0.0001, except HP in group B vs C: p=0.0003). We observed no difference in concentrations of LP, a bone collagen cross-linker, between studied groups. Total and free forms of studied peptides showed excellent correlation. ConclusionsWe found an increase in the urinary excretion of extracellular matrix components in patients with cGVHD. Our results also suggest that the conditioning regimen has significant early effects on the turnover of elastin and collagen. Prospective sampling in a cohort of allogeneic transplant recipients is currently underway to further elucidate the kinetics and the value of HP and DES as potential biomarkers for cGVHD. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

NanoLC-MS/MS Analyses of Urinary Desmosine, Hydroxylysylpyridinoline and Lysylpyridinoline as Biomarkers for Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is a common and potentially lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT). cGVHD as well as the transplant procedure itself (chemotherapy with or without radiotherapy) can lead to the degradation of connective tissue components such as elastin and collagen. The catabolism of these structural proteins releases desmosine (DES), lysylpyridinoline (LP), hydroxylysylpyridonoline (HP), and related pyridinium-based cross-linkers analogues that could represent potential biomarkers for cGVHD. This study reports the development of a sensitive liquid chromatography/tandem mass spectrometry method for the simultaneous analysis of N-propyl derivatives of DES, HP, and LP. The concentrations of free and total forms of urinary DES, HP, and LP were determined using synthetic deuterated internal standards. This method enabled accurate quantitation of these pyridinium-based cross-linkers from as little as 100 microL of urine with detection limits of 0.03-0.10 ng/mL. These compounds were analyzed in urine samples from three groups of patients: (1) Healthy volunteers, (2) Autologous HSCT recipients (who cannot develop cGVHD), and (3) Allogeneic HSCT recipients at onset of cGHVD. These analyses revealed that the urinary concentrations of DES, HP, and LP in the autologous recipients were greater or equal to the cGVHD group although both groups showed marked increase in the levels of these compounds compared to healthy individuals. These results suggest that the chemotherapy treatment has significant effects on the turnover of elastin and collagen, and that these biomarkers could be effective during prospective analyses to determine the onset of cGVHD.

ORIGINAL ARTICLE: Anti‐Elastin Antibodies and Elastin Turnover in Normal Pregnancy and Recurrent Pregnancy Loss

Problem The aim of this study was to investigate elastin turnover and autoimmunity in patients with a history of recurrent pregnancy loss (RPL) and during normal pregnancy.Method of study Anti‐α‐elastin and anti‐tropoelastin IgG and IgM antibodies were measured by a home‐made ELISA in serum samples of 60 medically and obstetrically normal pregnant women, classified to three trimester groups, 18 female patients with RPL and 18 healthy non‐pregnant women with a history of successful pregnancies. One way analyses of variance and Least Significant Difference method were used for a statistical analysis.Results Anti‐α‐elastin IgG autoantibodies were significantly decreased in the third trimester pregnant women. IgM anti‐α‐elastin autoantibodies were significantly decreased in all pregnancy groups compared with the controls. Synthesis/degradation ratio of elastin was significantly increased in the third trimester pregnancy group, suggesting decreased elastin degradation during this period of pregnancy. Comparing the RPL patients with the healthy non‐pregnant controls showed a significantly increased anti‐α‐elastin IgG antibody and significantly decreased synthesis/degradation ratio in the patient’s group, suggesting increased elastin degradation in RPL.Conclusion Elastin degradation is decreased during normal pregnancy. Increased anti‐elastin IgG antibodies may contribute to the pathogenesis of pregnancy losses.

Elastin in lung development and disease.

Elastic fibres are present in lung structures including alveoli, alveolar ducts, airways, vasculature and pleura. The rate of lung elastin synthesis is greatest during fetal and neonatal development, and is minimal in the healthy adult. We have determined that glucocorticoids up-regulate fetal lung tropoelastin expression while concomitantly accelerating terminal airspace maturation. Because there is minimal turnover of elastin in healthy adult lung, the elastin incorporated into the lung early in development supports lung function for the normal lifespan. However, in the adult lung, in pathological circumstances such as emphysema or pulmonary fibrosis there may be reactivation of elastin expression. We have found in silica-induced pulmonary fibrosis that expression of tropoelastin is primarily increased in the walls and the septal tips of the alveolus, with modest increases in other compartments which normally express tropoelastin during development. This finding suggests that the mesenchymal cell of the alveolar wall increases tropoelastin expression during fibrotic disorders. In emphysema and fibrosis, elastin is present in abnormal-appearing, probably non-functional, elastic fibres, suggesting that the adult lung cannot recapitulate the elastic fibre assembly mechanisms operative during normal lung growth.