Asfotase alfa therapy for children with hypophosphatasia.

Background. Hypophosphatasia (HPP) is caused by loss-of-function mutation(s) of the gene that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). Consequently, cell-surface deficiency of TNSALP phosphohydrolase activity leads to extracellular accumulation of inorganic pyrophosphate, a natural substrate of TNSALP and inhibitor of mineralization. Children with HPP can manifest rickets, skeletal pain, deformity, fracture, muscle weakness, and premature deciduous tooth loss. Asfotase alfa is a recombinant, bone-targeted, human TNSALP injected s.c. to treat HPP. In 2012, we detailed the 1-year efficacy of asfotase alfa therapy for the life-threatening perinatal and infantile forms of HPP. Methods. Here, we evaluated the efficacy and safety of asfotase alfa treatment administered to children 6-12 years of age at baseline who were substantially impaired by HPP. Two radiographic scales quantitated HPP skeletal disease, including comparisons to serial radiographs from similarly affected historical control patients. Results. Twelve children receiving treatment were studied for 5 years. The 6-month primary endpoint was met, showing significant radiographic improvement. Additional significant improvements included patient growth, strength, motor function, agility, and quality of life, which for most patients meant achieving normal values for age- and sex-matched peers that were sustained at 5 years of treatment. For most, pain and disability resolved. Mild to moderate injection-site reactions were common and were sometimes associated with lipohypertrophy. Low anti-asfotase alfa antibody titers were noted in all patients. No evidence emerged for clinically important ectopic calcification or treatment resistance. Conclusions. Asfotase alfa enzyme replacement therapy has substantial and sustained efficacy with a good safety profile for children suffering from HPP. Trial Registration. ClinicalTrials.gov NCT00952484 (https://clinicaltrials.gov/ct2/show/NCT00952484) and NCT01203826 (https://clinicaltrials.gov/ct2/show/NCT01203826). Funding. Alexion Pharmaceuticals Inc. and Shriners Hospitals for Children.

Burden of disease in adult patients with hypophosphatasia: Results from two patient-reported surveys.

BACKGROUND: Hypophosphatasia (HPP) is a rare metabolic bone disease caused by loss-of-function mutation(s) in the tissue-nonspecific alkaline (TNSALP) phosphatase gene, which manifests as rickets and/or osteomalacia with systemic complications and affects patients of all ages. The burden of disease is poorly characterized in adult patients. AIMS: We assessed patient-reported burden of disease using two surveys reasonably specific for HPP symptomatology, the Hypophosphatasia Impact Patient Survey (HIPS) and the Hypophosphatasia Outcomes Study Telephone interview (HOST). METHODS: Patients with HPP were invited to participate via patient advocacy groups or their medical provider. Survey questions captured demography, HPP-related medical history, mobility, and health-related quality of life (using Short Form 12 [version 2] Health Survey [SF-12v2]) via internet report (HIPS) or telephone interview (HOST). RESULTS: One hundred twenty-five adults responded (mean [standard deviation, SD] age: 45 [14.3] years). Eighty-four patients (67%) reported pediatric-onset of their symptoms. Common clinical features in the study population included pain (95% of patients), fractures (86% of patients) muscle weakness (62%) and unusual gait (52%). Use of assistive devices for mobility (60%) was also prevalent. Twenty-six percent of patients reported more than 10 fractures. Seventy-four percent of patients had undergone orthopedic/dental surgical procedures. The health profile of patients responding on the SF-12 showed a broad and substantial impact of HPP on health-related quality of life, with domains related to physical ability showing the greatest decrement compared to normative data. CONCLUSIONS: In aggregate, these data indicate that HPP can confer a high burden of illness in adulthood.

Immunogenicity and safety of a novel quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) in healthy Korean adolescents and adults.

OBJECTIVES: This phase III placebo-controlled study evaluated the immunogenicity and safety of MenACWY-CRM vaccination in healthy Korean adolescents and adults. METHODS: Serum bactericidal activity with human complement (hSBA) was measured before and 1 month after vaccination against all four meningococcal serogroups. The IgG concentration specific for serogroup W capsular polysaccharide was measured in a subset of subjects in a post-hoc analysis. Adverse reactions were monitored throughout the study. RESULTS: Four hundred and fifty subjects were randomized 2:1 to receive MenACWY-CRM (N=297) or a saline placebo (N=153). MenACWY-CRM induced a good immune response against all four serogroups, with seroprotection rates (hSBA titers ≥8) of 79%, 99%, 98%, and 94% for serogroups A, C, W, and Y, respectively. Seroresponse rates were high for serogroups A, C, and Y, i.e. 76%, 86%, and 69%, respectively; the rate for serogroup W was 28%. MenACWY-CRM vaccine induced serum bactericidal antibodies against all four serogroups in a majority of subjects regardless of their baseline hSBA titers. MenACWY-CRM was generally well tolerated with most reactions being transient and mild to moderate in severity. CONCLUSIONS: Findings of this first study of a quadrivalent meningococcal polysaccharide conjugate vaccine in Korean adults and adolescents demonstrated that a single dose of MenACWY-CRM was well tolerated and immunogenic, as indicated by the percentages of subjects with hSBA titers ≥8 (79%, 99%, 98%, and 94% of subjects) and geometric mean titers (48, 231, 147, and 107) against serogroups A, C, W, and Y, respectively, at 1 month post-vaccination.

Immunogenicity and safety of a quadrivalent meningococcal polysaccharide CRM conjugate vaccine in infants and toddlers.

OBJECTIVES: This phase III study assessed the safety and immunogenicity of MenACWY-CRM, a quadrivalent meningococcal conjugate vaccine, administered with routine vaccines starting at 2 months of age. METHODS: Healthy infants received MenACWY-CRM in a two- or three-dose primary infant series plus a single toddler dose. In addition, a two-dose toddler catch-up series was evaluated. Immune responses to MenACWY-CRM were assessed for serum bactericidal activity with human complement (hSBA). Reactogenicity and safety results were collected systematically. RESULTS: After a full infant/toddler series or two-dose toddler catch-up series, MenACWY-CRM elicited immune responses against the four serogroups in 94-100% of subjects. Noninferiority of the two- versus three-dose MenACWY-CRM infant dosing regimen was established for geometric mean titers for all serogroups. Following the three-dose infant primary series, 89-98% of subjects achieved an hSBA ≥ 8 across all serogroups. Immune responses to concomitant routine vaccines given with MenACWY-CRM were noninferior to responses to routine vaccines alone, except for pertactin after the two-dose infant series. Noninferiority criteria were met for all concomitant antigens after the three-dose infant series. CONCLUSIONS: MenACWY-CRM vaccination regimens in infants and toddlers were immunogenic and well tolerated. No clinically meaningful effects of concomitant administration with routine infant and toddler vaccines were observed.

Antibody persistence after primary and booster doses of a quadrivalent meningococcal conjugate vaccine in adolescents.

BACKGROUND: The aim of this study was to evaluate antibody persistence 5 years after primary vaccination with the quadrivalent meningococcal conjugate vaccines MenACWY-CRM or MenACWY-D and 2 years after a booster dose of MenACWY-CRM, in the context of a phase 3 study. METHODS: Subjects (aged 19.2 ± 2.3 years) were assigned to 5 groups according to whether they had previously received primary vaccination (at 14.2 ± 2.2 years) with MenACWY-CRM (N = 131) or MenACWY-D (N = 76), a booster dose of MenACWY-CRM 3 years after primary vaccination with MenACWY-CRM (N = 44) or MenACWY-D (N = 31) or no vaccination (N = 107). The immunogenicity measures were percentages of subjects with serum bactericidal activity (hSBA) ≥ 1:8 for serogroups A, C, W and Y and hSBA geometric mean titers. Comparisons with age-matched, vaccine-naive subjects were performed. RESULTS: A majority of subjects vaccinated 5 years previously maintained hSBA ≥ 1:8 against serogroups C, W and Y in the MenACWY-CRM (59%-82%) and MenACWY-D groups (54%-73%); this was lower for serogroup A in both groups. There was a decline in antibody titers after primary vaccination, especially in the first 2 years postprimary vaccination, with steady concentrations during the next 3 years. Two years after MenACWY-CRM booster vaccination the percentages of subjects with hSBA ≥ 1:8 ranged from 77% to 100% across serogroups and geometric mean titers were 2.5- to 8-fold higher than prebooster values across serogroups. CONCLUSIONS: Booster vaccination with MenACWY-CRM elicited a robust immune response during the 2-year follow-up period, irrespective of previous vaccination.

Antibody persistence and booster response of a quadrivalent meningococcal conjugate vaccine in adolescents.

OBJECTIVE: To evaluate the tolerability and immunogenicity of a booster dose of the quadrivalent meningococcal conjugate vaccine MenACWY-CRM (Menveo, Novartis Vaccines and Diagnostics, Siena, Italy) administered 3 years after primary vaccination of adolescents enrolled in a phase 3 study with either MenACWY-CRM or MenACWY-D (Menactra, Sanofi Pasteur, Swiftwater, Pennsylvania). STUDY DESIGN: A total of 730 healthy adolescents participated, including 622 initial study participants who received primary vaccination with MenACWY-CRM (n = 367) or MenACWY-D (n = 255) 3 years previously and 108 age-matched vaccine-naïve controls. A subset of MenACWY-CRM (n = 83) and MenACWY-D (n = 77) recipients were administered a MenACWY-CRM booster dose 3 years postprimary vaccination. Immunogenicity prior to and after the booster dose of MenACWY-CRM was measured by serum bactericidal assay with human complement (hSBA). Local and systemic reactions and adverse events were monitored in subjects receiving the booster dose. RESULTS: At 3 years postprimary vaccination, 64%, 82%, and 65% of subjects initially vaccinated with MenACWY-CRM (n = 367) showed hSBA titers ≥8 against serogroups C, W-135, and Y, respectively; this was lower for serogroup A (28%). Significantly more MenACWY-CRM recipients had hSBA titers ≥8 for serogroups W-135 and Y than MenACWY-D recipients (n = 255). A MenACWY-CRM booster dose resulted in 99%-100% of subjects demonstrating hSBA titers ≥8 against all serogroups, irrespective of primary vaccination (MenACWY-CRM, n = 83; MenACWY-D, n = 77). The booster dose was well tolerated without significant adverse events. CONCLUSIONS: MenACWY-CRM can be used to boost adolescents who have received a primary vaccination with either MenACWY-CRM or MenACWY-D.

Safety of a quadrivalent meningococcal serogroups A, C, W and Y conjugate vaccine (MenACWY-CRM) administered with routine infant vaccinations: results of an open-label, randomized, phase 3b controlled study in healthy infants.

BACKGROUND: The highest risk for invasive meningococcal disease (IMD) is in infants aged <1 year. Quadrivalent meningococcal conjugate vaccination has the potential to prevent IMD caused by serogroups A, C, W and Y. This phase 3b, multinational, open-label, randomized, parallel-group, multicenter study evaluated the safety of a 4-dose series of MenACWY-CRM, a quadrivalent meningococcal conjugate vaccine, concomitantly administered with routine vaccinations to healthy infants. METHODS: Two-month-old infants were randomized 3:1 to receive MenACWY-CRM with routine vaccines or routine vaccines alone at ages 2, 4, 6 and 12 months. Adverse events (AEs) that were medically attended and serious adverse events (SAEs) were collected from all subjects from enrollment through 18 months of age. In a subset, detailed safety data (local and systemic solicited reactions and all AEs) were collected for 7 days post vaccination. The primary objective was a non-inferiority comparison of the percentages of subjects with ≥1 severe systemic reaction during Days 1-7 after any vaccination of MenACWY-CRM plus routine vaccinations versus routine vaccinations alone (criterion: upper limit of 95% confidence interval [CI] of group difference <6%). RESULTS: A total of 7744 subjects were randomized with 1898 in the detailed safety arm. The percentage of subjects with severe systemic reactions was 16% after MenACWY-CRM plus routine vaccines and 13% after routine vaccines alone (group difference 3.0% (95% CI -0.8, 6.4%). Although the non-inferiority criterion was not met, post hoc analysis controlling for significant center and group-by-center differences revealed that MenACWY-CRM plus routine vaccinations was non-inferior to routine vaccinations alone (group difference -0.1% [95% CI -4.9%, 4.7%]). Rates of solicited AEs, medically attended AEs, and SAEs were similar across groups. CONCLUSION: In a large multinational safety study, a 4-dose series of MenACWY-CRM concomitantly administered with routine vaccines was clinically acceptable with a similar safety profile to routine vaccines given alone.

Immunogenicity and safety of a CRM-conjugated meningococcal ACWY vaccine administered concomitantly with routine vaccines starting at 2 months of age.

BACKGROUND: Infants are at the highest risk for meningococcal disease and a broadly protective and safe vaccine is an unmet need in this youngest population. We evaluated the immunogenicity and safety of a 4-dose infant/toddler regimen of MenACWY-CRM given at 2, 4, 6, and 12 months of age concomitantly with pentavalent diphtheria-tetanus-acellular pertussis-Hemophilus influenzae type b-inactivated poliovirus-combination vaccine (DTaP-IPV/Hib), hepatitis B vaccine (HBV), 7- or 13-valent conjugate pneumococcal vaccine (PCV), and measles, mumps, and rubella vaccine (MMR). RESULTS: Four doses of MenACWY-CRM induced hSBA titers ≥8 in 89%, 95%, 97%, and 96% of participants against serogroups A, C, W-135, and Y, respectively. hSBA titers ≥8 were present in 76-98% of participants after the first 3 doses. A categorical linear analysis incorporating vaccine group and study center showed responses to routine vaccines administered with MenACWY-CRM were non-inferior to routine vaccines alone, except for seroresponse to the pertussis antigen fimbriae. The reactogenicity profile was not affected when MenACWY-CRM was administered concomitantly with routine vaccines. CONCLUSION: MenACWY-CRM administered with routine concomitant vaccinations in young infants was well tolerated and induced highly immunogenic responses against each of the serogroups without significant interference with the immune responses to routine infant vaccinations. METHODS: Healthy 2 month old infants were randomized to receive MenACWY-CRM with routine vaccines (n = 258) or routine vaccines alone (n = 271). Immunogenicity was assessed by serum bactericidal assay using human complement (hSBA). Medically attended adverse events (AEs), serious AEs (SAEs) and AEs leading to study withdrawal were collected throughout the study period.

The B-cell response to a primary and booster course of MenACWY-CRM197 vaccine administered at 2, 4 and 12 months of age.

A quadrivalent meningococcal vaccine conjugated to CRM197 (MenACWY-CRM197) is immunogenic in young infants. We assessed the memory B-cell and antibody responses after a primary and booster course of MenACWY-CRM197 in children. At 5 months of age, following primary immunisation, serogroup-specific memory B-cells were detectable in fewer than 25% of children, although protective antibody titres (hSBA ≥ 4) were detectable in 69% of children against serogroup A and more than 95% against the other serogroups. At 12 months, before booster immunisation the percentages with hSBA ≥ 4 were 5% for serogroup A, and between 44 and 70% for the other serogroups. One month after booster immunisation with MenACWY-CRM197 over 50% of children had detectable memory B-cells, and 91% had hSBA ≥ 4 against serogroup A and more than 99% against the other serogroups. These data show that few antigen-specific anticapsular memory B-cells can be detected after two-doses priming with MenACWY-CRM197. For MenC and CRM197, the antigens with the highest number of B-cells at 5 months, there was a definite (p ≤0 .02) but weak correlation with antibody persistence at 12 months. Although previous studies suggest that measuring memory B-cell responses after priming immunisations in infancy can be used to predict antibody persistence and memory responses, this may not be suitable for all antigens in young children.

Antibody persistence and response to a booster dose of a quadrivalent conjugate vaccine for meningococcal disease in adolescents.

BACKGROUND: In a previous randomized phase 2 study in adolescents, a CRM197 meningococcal conjugate vaccine against serogroups A, C, W-135 and Y (MenACWY-CRM) was well tolerated and immunogenic, compared with a plain polysaccharide vaccine (MenACWY-PS). METHODS: This extension study assessed antibody persistence 5 years after primary vaccination with MenACWY-CRM (n = 50) or MenACWY-PS (n = 51), and the immunogenicity and reactogenicity of a dose of MenACWY-CRM given 5 years after primary vaccination; antibody response was also compared with vaccine-naive controls (n = 54). The primary endpoints were the percentage of subjects with titers ≥8 by serum bactericidal activity assay using human complement (hSBA) 5 years after primary vaccination and hSBA geometric mean titers 1 month after the MenACWY-CRM dose given in the current study. RESULTS: Five years after primary vaccination, over 70% of subjects who had received MenACWY-CRM were seropositive (hSBA titers ≥8) for serogroups C, W-135 and Y; for serogroups C and Y, the percentages of seropositive subjects were significantly higher in subjects previously vaccinated with MenACWY-CRM than in subjects previously vaccinated with MenACWY-PS. The MenACWY-CRM dose given 5 years postprimary vaccination elicited an anamnestic response across serogroups in those previously vaccinated with MenACWY-CRM. Responses in those previously vaccinated with MenACWY-PS were less robust but adequate and similar to that seen in the vaccine-naive group, both in magnitude and kinetics. MenACWY-CRM was well tolerated in all 3 groups. CONCLUSION: MenACWY-CRM provided a broad and persistent immune response in adolescents. A subsequent dose of MenACWY-CRM elicited an adequate antibody response, regardless of vaccine history.

Immunogenicity and safety of a quadrivalent meningococcal conjugate vaccine administered concomitantly with measles, mumps, rubella, varicella vaccine in healthy toddlers.

BACKGROUND: Invasive meningococcal disease can have devastating outcomes, especially in high-risk groups such as infants. As infants are recommended to receive multiple vaccines during a single office visit, this phase 3 study assessed the safety and immune response to MenACWY-CRM at alternative visits in older infants and concomitant use with measles, mumps, rubella, varicella vaccine (MMRV) at 12 months of age. METHODS: Two age groups were concurrently enrolled: 7- to 9-month-old infants who received 2 doses of MenACWY-CRM at 7-9 and 12 months and were randomized 1:1 to receive MenACWY-CRM with or without MMRV at 12 months, and 12-month-old infants who received MMRV only at 12 months. Using predefined non-inferiority criteria, immune responses to the antigens in MMRV were compared between those who did and did not receive MenACWY-CRM; immune responses to MenACWY-CRM as measured by the percentage of subjects with human serum bactericidal activity (hSBA) titers ≥ 8, were compared between those who did and did not receive concomitant MMRV. Adequacy of the immune response to 2 doses of MenACWY-CRM administered at 7-9 and 12 months was also assessed. Local and systemic reactions, adverse events resulting in withdrawal or requiring medical attention and serious adverse events were monitored. RESULTS: Concomitant administration of MMRV with MenACWY-CRM did not affect the immune response to either vaccine. The 2-dose series of MenACWY-CRM induced adequate immune response to all 4 serogroups. No increased reactogenicity was observed with MenACWY-CRM+MMRV compared with MMRV alone, and there were no study-related serious adverse events. CONCLUSIONS: Concomitant administration of MenACWY-CRM with MMRV vaccinations at 12 months was well-tolerated, without safety concerns. Robust immune responses to all components of both vaccines were produced and all criteria for non-inferiority were met, supporting the use of a 2-dose regimen of MenACWY-CRM in this age group.

Safety and immunogenicity of a novel quadrivalent meningococcal CRM-conjugate vaccine given concomitantly with routine vaccinations in infants.

BACKGROUND: In phase II studies, MenACWY-CRM elicited robust immunologic responses in young infants. We now present results from our pivotal phase III infant immunogenicity/safety study. METHODS: In this open-label phase III study, we randomized full-term 2-month-old infants to 4 doses of MenACWY-CRM coadministered with routine vaccines at 2, 4, 6, and 12 months of age or with routine vaccines alone. We monitored for local and systemic reactions and serious adverse events among all study participants and evaluated for sufficiency of the immune responses to MenACWY-CRM through serum bactericidal activity assay with human complement. RESULTS: Bactericidal antibodies were present in 94% to 100% of subjects against each of the serogroups in MenACWY-CRM after the 4-dose series and were 67% to 97% after the first 3 doses. Geometric mean titers were higher after the fourth dose of MenACWY-CRM compared with a single dose of MenACWY-CRM at 12 months of age for all serogroups (range of ratios, 4.5-38). Responses to 3 doses of routine vaccines coadministered with MenACWY-CRM were noninferior to routine vaccinations alone, except for small differences in pneumococcal serotype 6B responses after dose 3 but not dose 4 and pertactin after dose 3. Inclusion of MenACWY-CRM did not affect the safety or reactogenicity profiles of the routine infant vaccine series. CONCLUSIONS: A 4-dose series of MenACWY-CRM was highly immunogenic and well tolerated in young infants, and it can be coadministered with routine infant vaccines. Substantial immunity was conferred after the first 3 doses administered at 2, 4, and 6 months of age.

A high dose of an idiotype generates high levels of Ab2s.

BACKGROUND: Network perturbations have been reported in autoimmune processes which could cause polyclonal cell activation. MATERIALS AND METHODS: Hyper-immunization was achieved by the injection of 3 mg of human monoclonal IgM DJ into BALB/c mice. Indirect ELISA was performed to detect induced antibody specificities. Competitive ELISAs were carried out on sera to detect the idiotypes expressed in first (Ab1) and second (Ab2) antibodies in sequence. RESULTS: In the sera of hyper-immunized mice, the concentrations of Ab1 and Ab2 were respectively five and ten times higher than in the sera of normoimmunized mice. Polyclonal lymphocyte activation was demonstrated by an increase in antibodies specific for antigens (cytochrome C) not related to the immunizing antigen, elevated levels of IgM antibodies specific for the immunogen and elevated levels of Ab2s of the IgM isotype. CONCLUSION: These findings are indicative of antigen-dependent network perturbation being a causative factor in polyclonal lymphocyte activation.

Calpain mediates calcium-induced activation of the erk1,2 MAPK pathway and cytoskeletal phosphorylation in neurons: relevance to Alzheimer's disease.

Aberrant phosphorylation of the neuronal cytoskeleton is an early pathological event in Alzheimer's disease (AD), but the underlying mechanisms are unclear. Here, we demonstrate in the brains of AD patients that neurofilament hyperphosphorylation in neocortical pyramidal neurons is accompanied by activation of both Erk1,2 and calpain. Using immunochemistry, Western blot analysis, and kinase activity measurements, we show in primary hippocampal and cerebellar granule (CG) neurons that calcium influx activates calpain and Erk1,2 and increases neurofilament phosphorylation on carboxy terminal polypeptide sites known to be modulated by Erk1,2 and to be altered in AD. Blocking Erk1,2 activity either with antisense oligonucleotides to Erk1,2 mRNA sequences or by specifically inhibiting its upstream activating kinase MEK1,2 markedly reduced neurofilament phosphorylation. Calpeptin, a cell-permeable calpain inhibitor, blocked both Erk1,2 activation and neurofilament hyperphosphorylation at concentrations that inhibit calpain-mediated cleavage of brain spectrin. By contrast, inhibiting Erk1,2 with U-0126, a specific inhibitor of Mek1,2, had no appreciable effect on ionomycin-induced calpain activation. These findings demonstrate that, under conditions of calcium injury in neurons, calpains are upstream activators of Erk1,2 signaling and are likely to mediate in part the hyperphosphorylation of neurofilaments and tau seen at early stages of AD as well as the neuron survival-related functions of the MAP kinase pathway.

The incorporation of fibrinogen into extracellular matrix is dependent on active assembly of a fibronectin matrix.

Fibrinogen is a soluble protein produced by hepatocytes and secreted into plasma, where it functions in hemostasis. During inflammation, the hepatic synthesis of fibrinogen is induced 2-10 fold. Recent studies demonstrate that after an inflammatory stimulus, fibrinogen gene expression and protein production is upregulated in lung epithelial cells, where it is secreted basolaterally and consequently deposited into the extracellular matrix in fibrils that extensively colocalize with fibronectin fibrils. In this study, we show that the deposition of fibrinogen into the matrix of fibroblasts occurred rapidly and in a Rho-dependent manner in response to serum or lysophosphatidic acid; RhoA GTPase signaling is also required for fibronectin matrix assembly. Using mouse embryonic fibronectin-null cells, we show that incorporation of exogenous fibrinogen into matrix fibrils occurred only in the presence of exogenous fibronectin, which is also assembled into matrix fibrils. Furthermore, treatment of fibroblasts and fibronectin-null cells with an antibody that inhibits fibronectin matrix assembly impaired incorporation of fibrinogen into matrix fibrils. Collectively, these data suggest that incorporation of fibrinogen into the extracellular matrix requires active fibronectin polymer elongation into matrix fibrils. From these data, we hypothesize that fibrinogen deposition rapidly changes the topology of the extracellular matrix to provide a surface for cell migration and matrix remodeling during tissue repair.