Urine proteomics by mass spectrometry identifies proteins involved in key pathogenic pathways in patients with juvenile dermatomyositis.

OBJECTIVES: To identify and validate biomarkers in JDM patients using a multiplexing tandem mass tag urine proteome profiling approach. METHODS: First morning void urine samples were collected from JDM patients (n = 20) and healthy control subjects (n = 21) and processed for analysis using a standardized liquid chromatography-tandem mass spectrometry approach. Biomarkers with significantly altered levels were correlated with clinical measures of myositis disease activity and damage. A subset of candidate biomarkers was validated using commercially available ELISA kits. RESULTS: In total, 2348 proteins were detected in the samples, with 275 proteins quantified across all samples. Among the differentially altered proteins, cathepsin D and galectin-3 binding protein were significantly increased in the urine of JDM patients (adjusted P < 0.05), supporting previous findings in myositis patients. These two candidate biomarkers were confirmed with ELISAs. Cathepsin D positively correlated with Myositis Damage Index (r = 0.57, P < 0.05) and negatively correlated with the Childhood Myositis Assessment Scale (r = -0.54, P < 0.05). We also identified novel JDM candidate biomarkers involved with key features of myositis, including extracellular matrix remodelling proteins. CONCLUSION: This study confirmed the presence of several proteins in the urine of JDM patients that were previously found to be elevated in the blood of myositis patients and identified novel candidate biomarkers that require validation. These results support the use of urine as a source for biomarker development in JDM.

Infant Anaphylaxis: A Diagnostic Challenge.

PURPOSE OF REVIEW: Infant anaphylaxis has been increasing in incidence; however, significant gaps in the literature remain. The aim of this article is to review the most recent literature pertaining to infant anaphylaxis and discuss recent findings related to epidemiology, diagnosis, management, and prevention. RECENT FINDINGS: There is no accurate report of the incidence and prevalence of anaphylaxis in infancy. Food is the most common trigger for infant anaphylaxis reported. The diagnosis of anaphylaxis in infants is often missed, and, even when the diagnosis is made, epinephrine continues to be under-utilized. An epinephrine autoinjector with a shorter needle and lower dose is now available for infants. Concise criteria specifically focusing on infant anaphylaxis is needed to streamline its diagnosis and management. Diagnosis is underrecognized in infants leading to improper treatment. When the diagnosis is made, epinephrine continues to be under-utilized and under-prescribed in infants.

Morpholino-induced exon skipping stimulates cell-mediated and humoral responses to dystrophin in mdx mice.

Exon skipping is a promising genetic therapeutic strategy for restoring dystrophin expression in the treatment of Duchenne muscular dystrophy (DMD). The potential for newly synthesized dystrophin to trigger an immune response in DMD patients, however, is not well established. We have evaluated the effect of chronic phosphorodiamidate morpholino oligomer (PMO) treatment on skeletal muscle pathology and asked whether sustained dystrophin expression elicits a dystrophin-specific autoimmune response. Here, two independent cohorts of dystrophic mdx mice were treated chronically with either 800 mg/kg/month PMO for 6 months (n = 8) or 100 mg/kg/week PMO for 12 weeks (n = 11). We found that significant muscle inflammation persisted after exon skipping in skeletal muscle. Evaluation of humoral responses showed serum-circulating antibodies directed against de novo dystrophin in a subset of mice, as assessed both by Western blotting and immunofluorescent staining; however, no dystrophin-specific antibodies were observed in the control saline-treated mdx cohorts (n = 8) or in aged (12-month-old) mdx mice with expanded 'revertant' dystrophin-expressing fibers. Reactive antibodies recognized both full-length and truncated exon-skipped dystrophin isoforms in mouse skeletal muscle. We found more antigen-specific T-cell cytokine responses (e.g. IFN-g, IL-2) in dystrophin antibody-positive mice than in dystrophin antibody-negative mice. We also found expression of major histocompatibility complex class I on some of the dystrophin-expressing fibers along with CD8+ and perforin-positive T cells in the vicinity, suggesting an activation of cell-mediated damage had occurred in the muscle. Evaluation of complement membrane attack complex (MAC) deposition on the muscle fibers further revealed lower MAC deposition on muscle fibers of dystrophin antibody-negative mice than on those of dystrophin antibody-positive mice. Our results indicate that de novo dystrophin expression after exon skipping can trigger both cell-mediated and humoral immune responses in mdx mice. Our data highlights the need to further investigate the autoimmune response and its long-term consequences after exon-skipping therapy. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Vamorolone, a dissociative steroidal compound, reduces collagen antibody-induced joint damage and inflammation when administered after disease onset.

OBJECTIVE AND DESIGN: The objective of this study was to assess the effect of vamorolone, a first-in-class dissociative steroidal compound, to inhibit inflammation when administered after disease onset in the murine collagen antibody-induced arthritis model of arthritis. ANIMALS: 84 DBA1/J mice were used in this study (n = 12 per treatment group). TREATMENT: Vamorolone or prednisolone was administered orally after disease onset for a duration of 7 days. METHODS: Disease score and bone erosion were assessed using previously described scoring systems. Cytokines were measured in joints via immunoassay, and joint cathepsin B activity (marker of inflammation) was assessed using optical imaging of joints on live mice. RESULTS: We found that vamorolone treatment led to a reduction of several disease parameters including disease score, joint inflammation, and the presence of pro-inflammatory mediators to a degree similar of that observed with prednisolone treatment. More importantly, histopathological analysis of affected joints showed that vamorolone treatment significantly reduced the degree of bone erosion while this bone-sparing property was not observed with prednisolone treatment at any of the tested doses. CONCLUSIONS: While many intervention regimens in other studies are administered prior to disease onset in animal models, the current study involves delivery of the potential therapeutic after disease onset. Based on the findings, vamorolone may offer an efficacious, yet safer alternative to conventional steroidal compounds in the treatment of rheumatoid arthritis and other inflammatory diseases.

Enthalpic Effects of Chain Length and Unsaturation on Water Permeability across Droplet Bilayers of Homologous Monoglycerides.

A deeper understanding of unassisted passive transport processes can better delineate basic lipid dynamics in biological membranes. A droplet interface bilayer (DIB) is made by contacting two aqueous droplets covered with a lipid monolayer, and has increasingly been employed as a model artificial biological membrane. In this study, we have investigated the effect of acyl chain structure of amphiphilic monoglycerides on the osmotic permeability of water across DIB membranes composed of these monoglycerides, where the acyl chain length (C14-C24), number of double bonds (1-4), and the position of double bond are varied systematically along the acyl chains. Both permeability values and activation energies have been extracted for water transport across a lipid bilayer formed of a homologous series of lipids, allowing us to make ready comparisons between the different lipids and potentially better elucidate the contributions that molecular motifs make to the permeation process.

[Burden of salmonellosis and shigellosis in four departments of Guatemala, 2010]. / Carga de salmonelosis y shigelosis en cuatro departamentos de Guatemala, 2010.

OBJECTIVE: Estimate the burden of disease from Salmonella spp. and Shigella spp. in four departments of Guatemala in 2010. METHODS: Burden of disease study based on document analysis of published population surveys, laboratory files, and surveillance data from the Health Management Information System (SIGSA) in four departments of Guatemala: Huehuetenango, Jutiapa, Quetzaltenango, and Santa Rosa, in 2010. Information was supplemented by a laboratory survey. Burden of disease was estimated using methodology adapted by the World Health Organization from the United States Centers for Disease Control and Prevention. RESULTS: Surveillance data yielded 72 salmonellosis and 172 shigellosis cases. According to population surveys, the percentage of the population that consults health services for diarrhea is 64.7% (95% CI: 60.6%-68.7%) in Quetzaltenango and 61.0% (95% CI: 56.0%-66.0%) in Santa Rosa. In the 115 laboratories that answered the survey (72.8% response rate), 6 051 suspected samples were collected for stool culture and 3 290 for hemoculture; 39.4% and 100.0% of them were processed, respectively. In all, 85 Salmonella spp. and 113 Shigella spp. strains were isolated. For each reported case of salmonellosis and shigellosis, it was estimated that 40 cases are not reported in Quetzaltenango, 55 in Huehuetenango, 345 in Santa Rosa, and 466 in Jutiapa. Estimated burden of disease ranged from 5 to 2 230 cases per 100 000 population for salmonellosis and from 60 to 1 195 cases per 100 000 population for shigellosis. CONCLUSIONS: Salmonellosis and shigellosis are a major public health problem in the departments studied and in Guatemala. Burden of disease from these pathogens is higher than that reported by SIGSA.

Pre-pubertal gonadectomy and the social consequences of acute ethanol in adolescent male and female rats.

It has previously been shown that pre-pubertal or adult gonadectomy (GX) increases ethanol intake in male rats. This study examined whether this sex-selective increase reflects a GX-induced maintenance in males of more adolescent-typical responsiveness to ethanol characterized by enhanced sensitivity to positive (e.g., socially facilitating) and a decreased sensitivity to adverse (e.g., socially inhibitory) effects of ethanol. Male and female Sprague-Dawley rats were pre-pubertally GX, sham (SH)-operated, or non-manipulated (NM) at postnatal day (P) 25. During the late adolescent transition into adulthood (P48 - baseline day), rats were given a saline injection, placed alone into a familiar test apparatus for 30min and then exposed for 10min to an unfamiliar partner of the same age and sex. On the following day (P49), similar testing occurred after administration of 0.5, 0.75, 1.0 or 1.25g/kg ethanol. At baseline, GX males and females displayed higher levels of social activity (especially adolescent-typical play and contact behavior) than SH and NM animals, with GX females displaying greater social activity than GX males. Neither males nor females demonstrated social facilitation at lower ethanol doses, regardless of hormonal status. Whereas the social inhibitory effects of higher doses of ethanol were similar across groups among females, SH males were less sensitive than both GX and NM males to ethanol-induced social inhibition. These results suggest that enhanced ethanol intake in GX males is not related to alterations in sensitivity to ethanol's social inhibitory effects. GX, however, results in retention of adolescent-typical social behaviors, with older GX adolescent rats resembling early adolescents in exhibiting elevated social activity-particularly play and contact behavior.

Effects of the kappa opioid receptor antagonist, nor-binaltorphimine, on ethanol intake: impact of age and sex.

The kappa opioid receptor (KOR) antagonist, nor-binaltorphimine (nor-BNI), was used to investigate the role of the KOR system in mediating ethanol intake. On P25 (adolescent) or P67 (adult) male and female rats were individually housed and given ad libitum access to food and water. The experimental procedure was initiated on P28 or P70: animals were given 30 min/day access to a 10% ethanol/supersaccharin solution every other day (3 baseline exposures). On the day after the final baseline test, rats were injected with nor-BNI (0, 2.5, 5, 10 mg/kg), with testing initiated 24 hr later (30-min access every other day, 3 test exposures). Nor-BNI (10 mg/kg) increased ethanol intake in adult males, whereas the same dose decreased intake in adult females, suggesting pronounced sex differences in KOR-associated mediation of ethanol intake in adulthood. There was no impact of nor-BNI in adolescent animals of either sex, suggesting that the KOR may play less of a role in modulating ethanol intake during adolescence.

Clinical manifestations of Rickettsia rickettsii in a familial outbreak in Panama.

We report an isolated outbreak of Rickettsia rickettsii in the Ngäbe-Buglé indigenous region, located 750 m (tropical wet) above sea level, in a jungle and mountainous area of Western Panama. Seven members of a family were infected simultaneously, resulting in four deaths. Family outbreaks have been previously described and are responsible for 4-8% of the cases described [1-4]. The simultaneous onset of symptoms in the affected population group is extremely unusual [1,5], but it should not dissuade the clinician from considering the possibility of Rickettsia rickettsii infection.

Agammaglobulinemia: from X-linked to Autosomal Forms of Disease.

Interruptions or alterations in the B cell development pathway can lead to primary B cell immunodeficiency with resultant absence or diminished immunoglobulin production. While the most common cause of congenital agammaglobulinemia is X-linked agammaglobulinemia (XLA), accounting for approximately 85% of cases, other genetic forms of agammaglobulinemia have been identified. Early recognition and diagnosis of these conditions are pivotal for improved outcomes and prevention of sequelae and complications. The diagnosis of XLA is often delayed, and can be missed if patient has a mild phenotype. The lack of correlation between phenotype and genotype in this condition makes management and predicting outcomes quite difficult. In contrast, while less common, autosomal recessive forms of agammaglobulinemia present at younger ages and with typically more severe clinical features resulting in an earlier diagnosis. Some diagnostic innovations, such as KREC level measurements and serum BCMA measurements, may aid in facilitating an earlier identification of agammaglobulinemia leading to prompt treatment. Earlier diagnosis may improve the overall health of patients with XLA.

Deep ecomorphological and genetic divergence in Steller's Jays (Cyanocitta stelleri, Aves: Corvidae).

The relationship between ecology and morphology is a cornerstone of evolutionary biology, and quantifying variation across environments can shed light on processes that give rise to biodiversity. Three morphotypes of the Steller's Jay (Cyanocitta stelleri) occupy different ecoregions in western North America, which vary in climate and landcover. These morphotypes (Coastal, Interior, Rocky Mountain) differ in size, plumage coloration, and head pattern. We sampled 1080 Steller's Jays from 68 populations (plus 11 outgroups) to address three main questions using data on morphology, plumage, genetics (mtDNA, microsatellites), and ecological niches: (1) How do phenotypic and genetic traits vary within and among populations, morphotypes, and ecoregions? (2) How do population-level differences in Steller's Jays compare with other sister species pairs of North American birds? (3) What can we infer about the population history of Steller's Jays in relation to past climates, paleoecology, and niche evolution? We found substantial morphological, genetic, and ecological differentiation among morphotypes. The greatest genetic divergence separated Coastal and Interior morphotypes from the Rocky Mountain morphotype, which was associated with warmer, drier, and more open habitats. Microsatellites revealed additional structure between Coastal and Interior groups. The deep mtDNA split between Coastal/Interior and Rocky Mountain lineages of Steller's Jay (ND2 ~ 7.8%) is older than most North American avian sister species and dates to approximately 4.3 mya. Interior and Rocky Mountain morphotypes contact across a narrow zone with steep clines in traits and reduced gene flow. The distribution of the three morphotypes coincides with divergent varieties of ponderosa pine and Douglas fir. Species distribution models support multiple glacial refugia for Steller's Jays. Our integrative dataset combined with extensive geographic sampling provides compelling evidence for recognizing at least two species of Steller's Jay.

Age differences in the expression of acute and chronic tolerance to ethanol in male and female rats.

BACKGROUND: Ontogenetic differences in response to ethanol (EtOH) challenge have been observed under a variety of circumstances, including varying reports of developmental differences in the expression of tolerance to EtOH. The purpose of the present experiment was to further explore potential differences in acute (AT) and chronic (CT) tolerance expression between adolescent and adult, male and female Sprague-Dawley rats, using the social interaction test. METHODS: AT and CT to the social suppressing effects of a moderate dose of EtOH was assessed in adolescent and adult rats following intraperitoneal injections of 2.0 g/kg EtOH or saline daily for 10 days. At test, adults and adolescents were challenged with 1.0 or 1.25 g/kg EtOH, respectively, with AT and CT assessed at 5 and 25 minutes postinjection using ratios of impairment to brain ethanol concentrations (BrECs) at each time period (CT) and within-session declines in impairment relative to BrECs (AT). RESULTS: In adolescents, 10 days of EtOH pre-exposure resulted in evidence of CT at 25 minutes postinjection, perhaps associated with an enhanced expression of AT. Among adults, signs of CT were seen at 5 minutes postinjection in adults, and may reflect neuroadaptations unassociated with AT, as with evidence of tolerance emerging only in adult control animals repeatedly exposed to saline injection prior to EtOH challenge on test day. Sex differences in tolerance expression were not observed at either age. CONCLUSIONS: Our results show ontogenetic differences between adolescents and adults in the short- and long-term neuroadaptations that they express in response to repeated perturbations with EtOH. Together these findings add age of exposure and time of testing within the intoxication period as critical variables to be considered when exploring the complex relationship between AT and CT.

The Effect of Immunomodulatory Treatments on Anti-Dystrophin Immune Response After AAV Gene Therapy in Dystrophin Deficient mdx Mice.

BACKGROUND: AAV-based gene therapy is an attractive approach to treat Duchenne muscular dystrophy (DMD) patients. Although the long-term consequences of a gene therapy approach for DMD are unknown, there is evidence in both DMD patients and animal models that dystrophin replacement by gene therapy leads to an anti-dystrophin immune response that is likely to limit the long-term use of these therapeutic strategies. OBJECTIVE: Our objective is to test whether the anti-dystrophin immune response is affected by immunomodulatory drugs in mdx mice after rAAV gene therapy. METHODS: mdx mice were treated with rAAV microdystrophin alone or in combination with immunomodulatory drugs. Dystrophin expression in skeletal muscle was assessed by mass spectrometry. Immune responses were assessed by immunophenotyping, western blot for anti-dystrophin antibodies and flow cytometry assays for antigen-specific T-cell cytokine expression. The impact on muscle was measured by grip strength assessment, in vivo torque, optical imaging for inflammation and H&E staining of sections to assess muscle damage. RESULTS: We found that AAV-9-microdystrophin gene therapy induced expression of microdystrophin, anti-dystrophin antibodies, and T-cell cytokine responses. Immunomodulatory treatments, rituximab and VBP6 completely abrogated the anti-dystrophin antibody response. Prednisolone, CTLA4-Ig, and eplerenone showed variable efficacy in blocking the anti-dystrophin immune response. In contrast, none of the drugs completely abrogated the antigen specific IFN-γ response. AAV-microdystrophin treatment significantly reduced inflammation in both forelimbs and hindlimbs, and the addition of prednisolone and VBP6 further reduced muscle inflammation. Treatment with immunomodulatory drugs, except eplerenone, enhanced the beneficial effects of AAV-microdystrophin therapy in terms of force generation. CONCLUSIONS: Our data suggest that AAV-microdystrophin treatment results in anti-dystrophin antibody and T-cell responses, and immunomodulatory treatments have variable efficacy on these responses.

Dominance Hierarchies in Marine Invertebrates.

AbstractDominance hierarchies have been well studied in myriad terrestrial animals, but surprisingly little is known about hierarchies in marine invertebrates; examples are limited to a few species of decapod crustaceans and cephalopods. Is the marine environment less conducive to the establishment of dominance hierarchy structures, or does this just underline the lack of detailed behavioral information about most marine invertebrates? In this review, we highlight the published information about marine invertebrate dominance hierarchies, which involve ranks established through fights or displays. We focus on the method of hierarchy formation, examine the ecological implications of this population structure, and compare the habitat and behavioral characteristics of species that exhibit this behavior. Because dominance hierarchies can influence habitat use, population distributions, energetics, mating, resource exploitation, and population genetic structure, it is crucial to understand how this trait evolves and which species are likely to exhibit it. A better understanding of marine invertebrate hierarchies could change the way we think about population dynamics of some species and could have important implications for fisheries, conservation, or even modeling of social and economic inequality.

Effects of Chronic, Maximal Phosphorodiamidate Morpholino Oligomer (PMO) Dosing on Muscle Function and Dystrophin Restoration in a Mouse Model of Duchenne Muscular Dystrophy.

BACKGROUND: Phosphorodiamidate morpholino oligomer (PMO)-mediated exon skipping is currently used in clinical development to treat Duchenne muscular dystrophy (DMD), with four exon-skipping drugs achieving regulatory approval. Exon skipping elicits a truncated, but semi-functional dystrophin protein, similar to the truncated dystrophin expressed in patients with Becker Muscular dystrophy (BMD) where the disease phenotype is less severe than DMD. Despite promising results in both dystrophic animal models and DMD boys, restoration of dystrophin by exon skipping is highly variable, leading to contradictory functional outcomes in clinical trials. OBJECTIVE: To develop optimal PMO dosing protocols that result in increased dystrophin and improved outcome measures in preclinical models of DMD. METHODS: Tested effectiveness of multiple chronic, high dose PMO regimens using biochemical, histological, molecular, and imaging techniques in mdx mice. RESULTS: A chronic, monthly regimen of high dose PMO increased dystrophin rescue in mdx mice and improved specific force in the extensor digitorum longus (EDL) muscle. However, monthly high dose PMO administration still results in variable dystrophin expression localized throughout various muscles. CONCLUSIONS: High dose monthly PMO administration restores dystrophin expression and increases muscle force; however, the variability of dystrophin expression at both the inter-and intramuscular level remains. Additional strategies to optimize PMO uptake including increased dosing frequencies or combination treatments with other yet-to-be-defined therapies may be necessary to achieve uniform dystrophin restoration and increases in muscle function.

Effect of impact factor and discipline on journal data sharing policies.

Data sharing is crucial to the advancement of science because it facilitates collaboration, transparency, reproducibility, criticism, and re-analysis. Publishers are well-positioned to promote sharing of research data by implementing data sharing policies. While there is an increasing trend toward requiring data sharing, not all journals mandate that data be shared at the time of publication. In this study, we extended previous work to analyze the data sharing policies of 447 journals across several scientific disciplines, including biology, clinical sciences, mathematics, physics, and social sciences. Our results showed that only a small percentage of journals require data sharing as a condition of publication, and that this varies across disciplines and Impact Factors. Both Impact Factors and discipline are associated with the presence of a data sharing policy. Our results suggest that journals with higher Impact Factors are more likely to have data sharing policies; use shared data in peer review; require deposit of specific data types into publicly available data banks; and refer to reproducibility as a rationale for sharing data. Biological science journals are more likely than social science and mathematics journals to require data sharing.

Chronic Intermittent Ethanol Exposure Modulation of Glutamatergic Neurotransmission in Rat Lateral/Basolateral Amygdala is Duration-, Input-, and Sex-Dependent.

The basolateral amygdala (BLA) controls numerous behaviors, like anxiety and reward seeking, via the activity of glutamatergic principal neurons. These BLA neurons receive excitatory inputs primarily via two major anatomical pathways - the external capsule (EC), which contains afferents from lateral cortical structures, and the stria terminalis (ST), containing synapses from more midline brain structures. Chronic intermittent ethanol (CIE) exposure/withdrawal produces distinct alterations in these pathways. Specifically, 10 days of CIE (via vapor inhalation) increases presynaptic function at ST synapses and postsynaptic function at EC synapses. Given that 10-day CIE/withdrawal also increases anxiety-like behavior, we sought to examine the development of these alterations at these inputs using an exposure time-course in both male and female rats. Specifically, using 3, 7, and 10 days CIE exposure, we found that all three durations increase anxiety-like behavior in the elevated plus maze. At BLA synapses, increased presynaptic function at ST inputs required shorter exposure durations relative to post-synaptic alterations at EC inputs in both sexes. But, synaptic alterations in females required longer ethanol exposures compared to males. These data suggest that presynaptic alteration at ST-BLA afferents is an early neuroadaptation during repeated ethanol exposures. And, the similar patterns of presynaptic-then-postsynaptic facilitation across the sexes suggest the former may be required for the latter. These cooperative interactions may contribute to the increased anxiety-like behavior that is observed following CIE-induced withdrawal and may provide novel therapeutic targets to reverse withdrawal-induced anxiety.

Skeletal, cardiac, and respiratory muscle function and histopathology in the P448Lneo- mouse model of FKRP-deficient muscular dystrophy.

BACKGROUND: Fukutin-related protein (FKRP) mutations are the most common cause of dystroglycanopathies known to cause both limb girdle and congenital muscular dystrophy. The P448Lneo- mouse model has a knock-in mutation in the FKRP gene and develops skeletal, respiratory, and cardiac muscle disease. METHODS: We studied the natural history of the P448Lneo- mouse model over 9 months and the effects of twice weekly treadmill running. Forelimb and hindlimb grip strength (Columbus Instruments) and overall activity (Omnitech Electronics) assessed skeletal muscle function. Echocardiography was performed using VisualSonics Vevo 770 (FujiFilm VisualSonics). Plethysmography was performed using whole body system (ADInstruments). Histological evaluations included quantification of inflammation, fibrosis, central nucleation, and fiber size variation. RESULTS: P448Lneo- mice had significantly increased normalized tissue weights compared to controls at 9 months of age for the heart, gastrocnemius, soleus, tibialis anterior, quadriceps, and triceps. There were no significant differences seen in forelimb or hindlimb grip strength or activity monitoring in P448Lneo- mice with or without exercise compared to controls. Skeletal muscles demonstrated increased inflammation, fibrosis, central nucleation, and variation in fiber size compared to controls (p < 0.05) and worsened with exercise. Plethysmography showed significant differences in respiratory rates and decreased tidal and minute volumes in P448Lneo- mice (p < 0.01). There was increased fibrosis in the diaphragm compared to controls (p < 0.01). Echocardiography demonstrated decreased systolic function in 9-month-old mutant mice (p < 0.01). There was increased myocardial wall thickness and mass (p < 0.001) with increased fibrosis in 9-month-old P448Lneo- mice compared to controls (p < 0.05). mRNA expression for natriuretic peptide type A (Nppa) was significantly increased in P448Lneo- mice compared to controls at 6 months (p < 0.05) and for natriuretic peptide type B (Nppb) at 6 and 9 months of age (p < 0.05). CONCLUSIONS: FKRP-deficient P448Lneo- mice demonstrate significant deficits in cardiac and respiratory functions compared to control mice, and this is associated with increased inflammation and fibrosis. This study provides new functional outcome measures for preclinical trials of FKRP-related muscular dystrophies.