Stability of anti-drug antibodies in human serum samples.

Stability of anti-drug antibodies (ADAs) is important as ADA-analysis should be reliable over time at different storage conditions. Stability of anti-insulin antibodies in serum samples was assessed after short-term storage at different temperatures and after long-term storage at -20 °C. Correlation between measurements was tested and acceptance criteria for incurred sample reanalysis were applied. ADAs were stable after 72 h at 22 °C, after 2 weeks at 4 °C, and after 6.3 years at -20 °C. The study confirms that ADAs in serum are stable for several years at -20 °C and suggests that investigation of short- and long-term stability of ADAs is not needed if samples are handled at standard laboratory-conditions.

In vitro and in vivo immunogenicity assessment of protein aggregate characteristics.

The immunogenicity risk of therapeutic protein aggregates has been extensively investigated over the past decades. While it is established that not all aggregates are equally immunogenic, the specific aggregate characteristics, which are most likely to induce an immune response, remain ambiguous. The aim of this study was to perform comprehensive in vitro and in vivo immunogenicity assessment of human insulin aggregates varying in size, structure and chemical modifications, while keeping other morphological characteristics constant. We found that flexible aggregates with highly altered secondary structure were most immunogenic in all setups, while compact aggregates with native-like structure were found to be immunogenic primarily in vivo. Moreover, sub-visible (1-100 µm) aggregates were found to be more immunogenic than sub-micron (0.1-1 µm) aggregates, while chemical modifications (deamidation, ethylation and covalent dimers) were not found to have any measurable impact on immunogenicity. The findings highlight the importance of utilizing aggregates varying in few characteristics for assessment of immunogenicity risk of specific morphological features and may provide a workflow for reliable particle analysis in biotherapeutics.

PREvalence Study on Surgical COnditions (PRESSCO) 2020: A Population-Based Cross-Sectional Countrywide Survey on Surgical Conditions in Post-Ebola Outbreak Sierra Leone.

BACKGROUND: Understanding the burden of diseases requiring surgical care at national levels is essential to advance universal health coverage. The PREvalence Study on Surgical COnditions (PRESSCO) 2020 is a cross-sectional household survey to estimate the prevalence of physical conditions needing surgical consultation, to investigate healthcare-seeking behavior, and to assess changes from before the West African Ebola epidemic. METHODS: This study (ISRCTN: 12353489) was built upon the Surgeons Overseas Surgical Needs Assessment (SOSAS) tool, including expansions. Seventy-five enumeration areas from 9671 nationwide clusters were sampled proportional to population size. In each cluster, 25 households were randomly assigned and visited. Need for surgical consultations was based on verbal responses and physical examination of selected household members. RESULTS: A total of 3,618 individuals from 1,854 households were surveyed. Compared to 2012, the prevalence of individuals reporting one or more relevant physical conditions was reduced from 25 to 6.2% (95% CI 5.4-7.0%) of the population. One-in-five conditions rendered respondents unemployed, disabled, or stigmatized. Adult males were predominantly prone to untreated surgical conditions (9.7 vs. 5.9% women; p < 0.001). Financial constraints were the predominant reason for not seeking care. Among those seeking professional health care, 86.7% underwent surgery. CONCLUSION: PRESSCO 2020 is the first surgical needs household survey which compares against earlier study data. Despite the 2013-2016 Ebola outbreak, which profoundly disrupted the national healthcare system, a substantial reduction in reported surgical conditions was observed. Compared to one-time measurements, repeated household surveys yield finer granular data on the characteristics and situations of populations in need of surgical treatment.

Calibration-free concentration analysis for quantification of anti-drug specific antibodies in polyclonal positive control antibodies and in clinical samples.

Highly sensitive assays for anti-drug antibodies (ADAs) are both a regulatory requirement and requisite for proper evaluation of the effects of immunogenicity on clinical efficacy and safety. Determination of ADA assay sensitivity depends on positive control antibodies to represent naturally occurring or treatment-induced ADA responses. An accurate determination of the proportion of drug-specific antibodies in these polyclonal positive control batches is critical for correct evaluation of assay sensitivity. Target purification of positive control antibodies is commonly applied but infers the risk to lose a proportion of the antibodies. This may lead to an incorrect estimate of the ADA assay sensitivity, especially if high-affinity antibodies are lost that may be representative of natural ADAs with clinical implication. The Surface Plasmon Resonance platform on the Biacore™ systems offers methods for real-time analysis of biomolecular interactions without introducing any modifications to the analysed material. Calibration-free concentration analysis (CFCA) is such an application for determination of the proportion of drug-specific antibodies, which allows direct determination of active antibody concentrations, as defined by the ligand, in a flow-based system. Here, we present a novel CFCA method for ADA quantification developed and validated using polyclonal positive control antibodies against endogenous human insulin, insulin degludec (Tresiba®) and turoctocog alfa (NovoEight®). We find that CFCA precisely and accurately measures concentrations of drug-specific IgG antibodies with a precision of ±10% and 90%-112% recovery of expected values of monoclonal positive control antibodies. Additionally, we have achieved a more accurate measure of the sensitivity of a cell-based bioassay for in vitro neutralising ADAs using the specific concentration determined with CFCA. Moreover, we effectively quantified serum anti-insulin antibodies in high-titre clinical samples from individuals with diabetes mellitus. This application extends the relevance of the CFCA technology to analysis of immunogenicity for accurate quantification of ADAs in both the polyclonal positive control and in clinical samples.

Glucagon-like Peptide-1 receptor agonists activate rodent thyroid C-cells causing calcitonin release and C-cell proliferation.

Liraglutide is a glucagon-like peptide-1 (GLP-1) analog developed for type 2 diabetes. Long-term liraglutide exposure in rodents was associated with thyroid C-cell hyperplasia and tumors. Here, we report data supporting a GLP-1 receptor-mediated mechanism for these changes in rodents. The GLP-1 receptor was localized to rodent C-cells. GLP-1 receptor agonists stimulated calcitonin release, up-regulation of calcitonin gene expression, and subsequently C-cell hyperplasia in rats and, to a lesser extent, in mice. In contrast, humans and/or cynomolgus monkeys had low GLP-1 receptor expression in thyroid C-cells, and GLP-1 receptor agonists did not activate adenylate cyclase or generate calcitonin release in primates. Moreover, 20 months of liraglutide treatment (at >60 times human exposure levels) did not lead to C-cell hyperplasia in monkeys. Mean calcitonin levels in patients exposed to liraglutide for 2 yr remained at the lower end of the normal range, and there was no difference in the proportion of patients with calcitonin levels increasing above the clinically relevant cutoff level of 20 pg/ml. Our findings delineate important species-specific differences in GLP-1 receptor expression and action in the thyroid. Nevertheless, the long-term consequences of sustained GLP-1 receptor activation in the human thyroid remain unknown and merit further investigation.

Extracellular post-translational modifications of collagen are major determinants of biomechanical properties of fetal bovine cortical bone.

Mechanical behavior of bone depends on its mass and architecture, and on the material properties of the matrix, which is composed of a mineral phase and an organic component mainly constituted of type I collagen. Mineral accounts largely for the stiffness of bone, whereas type I collagen provides bone its ductility and toughness, i.e., its ability to undergo deformation and absorb energy after it begins to yield. The molecular mechanisms underlying the effect of alterations in type I collagen on bone mechanical properties are unclear. We used an in vitro model of fetal bovine cortical bone specimens (n = 44), where the extent of type I collagen cross-linking was modified by incubation at 37 degrees C for 0, 60, 90 and 120 days, keeping constant the architecture and the mineral content. At each incubation time, the following parameters were determined: (1) the bone concentration of enzymatic (pyridinoline; PYD and deoxypyridinoline, DPD) and non-enzymatic (pentosidine) crosslinks by HPLC, (2) the extent of aspartic acid isomerization of the type I collagen C-telopeptide (CTX) by ELISA of native (alpha CTX) and isomerized (beta CTX) forms, (3) the mineral density by DXA, (4) the porosity by micro-computed tomography and (5) the bending and compressive mechanical properties. Incubation of bone specimens at 37 degrees C for 60 days increased the level (per molecule of collagen) of PYD (+98%, P = 0.005), DPD (+42%, P = 0.013), pentosidine (+55-fold, P = 0.005), and the degree of type I collagen C-telopeptide isomerization (+4.9-fold, P = 0.005). These biochemical changes of collagen were associated with a 30% decrease in bending and compressive yield stress and a 2.5-fold increase in compressive post-yield energy absorption (P < 0.02 for all), with no significant change of bone stiffness. In multivariate analyses, the level of collagen cross-linking was associated with yield stress and post-yield energy absorption independently of bone mineral density, explaining up to 25% of their variance. We conclude that the extent and nature of collagen cross-linking contribute to the mechanical properties of fetal bovine cortical bone independently of bone mineral density.

Non-isomerized C-telopeptide fragments are highly sensitive markers for monitoring disease activity and treatment efficacy in Paget's disease of bone.

UNLABELLED: A new resorption assay measuring non-isomerized collagen type I C-telopeptide fragments (alpha-alpha CTX) was evaluated in a cohort comprising 32 Pagetic patients and 48 healthy controls. alpha-alpha CTX was found to be a sensitive marker for assessing disease activity and monitoring treatment efficacy in Paget's disease of bone compared with isomerized CTX (beta-beta CTX) and a number of other established bone turnover markers. INTRODUCTION: Collagen type I fragments are generated by resorbing osteoclasts, and some of them can be measured using a C-telopeptide (CTX) immunoassay. The C-telopeptide of collagen type I comprises a DG-motif susceptible to isomerization. In newly synthesized collagen, this motif is in the native form denoted alpha, but spontaneously converts to an isomerized form (beta) during aging of bone. CTX fragments composed of at least two alpha CTX chains (alpha-alpha CTX) originating from degradation of newly formed bone can be determined in the urine using a newly developed sandwich ELISA. The aim of this study was to assess the ability of this marker to monitor disease activity and treatment efficacy in patients with Paget's disease compared with established bone turnover markers. MATERIALS AND METHODS: A total of 32 patients diagnosed with Paget's disease of bone was included in the study. All received 400 mg/day of oral tiludronate for 3 months. Urinary alpha-alpha CTX (U alpha-alpha CTX) was measured at baseline and at 1 and 6 months after discontinuation of therapy and in 48 untreated age-matched and healthy controls. Other markers of bone turnover, including urinary beta-beta CTX, N-terminal cross-linking telopeptide of type I collagen, and deoxypyridinoline, were also measured for comparison. RESULTS AND CONCLUSIONS: The U alpha-alpha CTX marker showed a marked reduction (-82% and -77% at 1 and 6 months of treatment, respectively) in response to antiresorptive therapy in patients with Paget's disease. The response to treatment in this marker exceeded that of the other markers (p < 0.01). The alpha-alpha CTX marker also provided a high correlation (r = 0.89) to disease activity as assessed by scintigraphic activity index. In conclusion, alpha-alpha CTX seems to be a sensitive marker for assessing disease activity and monitoring treatment efficacy in Paget's disease.

An immunoassay for measuring fragments of newly synthesized collagen type I produced during metastatic invasion of bone.

Degradation products of collagen type I can be measured by CrossLaps (CTX) immunoassays, providing an index of bone resorption. The CTX epitope EKAHDGGR comprises a DG-motif susceptible to post-translational modifications. In newly synthesized collagen this motif is in the native form denoted alphaCTX, but converts to an isomerized form (betaCTX) during aging of bone. Furthermore, the lysine residue (K) within the CTX epitope participates in inter-molecular cross-links in mature bone. The present paper describes an assay, ALPHA CTX ELISA for measurement of cross-linked alphaCTX molecules (alpha-alphaCTX) in urine. The ALPHA CTX ELISA demonstrated a high specificity and technical precision for measuring such fragments. The assay was evaluated in a cross-sectional study, comparing the urinary excretion of the marker in 100 breast cancer patients with bone metastases (BC+) and 15 breast cancer patients without metastases to bone (BC-) as well as 31 age-matched healthy post-menopausal women (PM). For comparison alpha, beta, and beta-betaCTX was also measured using commercially available immunoassays. In BC+ urinary alpha-alphaCTX increased significantly compared to BC- and PM with p-values of 0.005 and <0.0001, respectively. In contrast, the age-modified form beta-betaCTX, representing the degradation of old bone, was less increased. Z-score analysis was used to compare the ability of the CTX markers to discriminate between BC+ and PM. The alpha-alphaCTX marker was found to provide a far better discrimination (Z=7.5) than beta-betaCTX (Z=3.6). In conclusion, measurement of alpha-alphaCTX fragments may provide a clinically relevant assessment of bone resorption related to bone metastases.

The chloride channel inhibitor NS3736 [corrected] prevents bone resorption in ovariectomized rats without changing bone formation.

UNLABELLED: Chloride channel activity is essential for osteoclast function. Consequently, inhibition of the osteoclastic chloride channel should prevent bone resorption. Accordingly, we tested a chloride channel inhibitor on bone turnover and found that it inhibits bone resorption without affecting bone formation. This study indicates that chloride channel inhibitors are highly promising for treatment of osteoporosis. INTRODUCTION: The chloride channel inhibitor, NS3736, blocked osteoclastic acidification and resorption in vitro with an IC50 value of 30 microM. When tested in the rat ovariectomy model for osteoporosis, daily treatment with 30 mg/kg orally protected bone strength and BMD by approximately 50% 6 weeks after surgery. Most interestingly, bone formation assessed by osteocalcin, mineral apposition rate, and mineralized surface index was not inhibited. MATERIALS AND METHODS: Analysis of chloride channels in human osteoclasts revealed that ClC-7 and CLIC1 were highly expressed. Furthermore, by electrophysiology, we detected a volume-activated anion channel on human osteoclasts. Screening 50 different human tissues showed a broad expression for CLIC1 and a restricted immunoreactivity for ClC-7, appearing mainly in osteoclasts, ovaries, appendix, and Purkinje cells. This highly selective distribution predicts that inhibition of ClC-7 should specifically target osteoclasts in vivo. We suggest that NS3736 is inhibiting ClC-7, leading to a bone-specific effect in vivo. RESULTS AND CONCLUSION: In conclusion, we show for the first time that chloride channel inhibitors can be used for prevention of ovariectomy-induced bone loss without impeding bone formation. We speculate that the coupling of bone resorption to bone formation is linked to the acidification of the resorption lacunae, thereby enabling compounds that directly interfere with this process to be able to positive uncouple this process resulting in a net bone gain.

A functional overlap of plasminogen and MMPs regulates vascularization during placental development.

Both plasminogen activators and matrix metalloproteinases (MMPs) have been implicated in a variety of developmental processes in the mouse during embryo implantation and placentation. We show here that pharmacological treatment of plasminogen-deficient mice with the broad spectrum MMP inhibitor galardin leads to a high rate of embryonic lethality. Implantation sites from plasminogen-deficient galardin-treated mice at 7.5 days post coitus (dpc) showed delay in both decidualization and invasion of maternal vessels into the decidua. At 8.5 dpc, half of the embryos were runted and still at the developmental stage of a 7.5 dpc embryo. Most embryos that escaped these initial defects eventually died, probably from defective vascularization and development of the labyrinth layer of the placenta, although a direct role on embryo development cannot be ruled out. These results demonstrate that the combination of MMPs and plasminogen is essential for the proper development of the placenta. Plasminogen deficiency alone and galardin treatment alone had much less effect and there was a pronounced synergism on both placental vascularization and embryonic lethality, indicating a functional overlap between plasminogen and MMPs.