Decreased Cerebral Oxygenation in Premature Infants with Progressive Posthemorrhagic Ventricular Dilatation May Help with Timing of Intervention.

OBJECTIVE: The objective of this study was to determine the degree of progressive posthemorrhagic ventricular dilatation (PHVD) that is associated with a significant decrease in regional cerebral oxygen saturation (rScO2) in premature infants at risk for periventricular-intraventricular hemorrhage (PIVH). STUDY DESIGN: Cranial ultrasound (US) and near-infrared spectroscopy (NIRS) measurements of rScO2 were performed on inborn infants with birth weights less than 1,250 g on admission and at 1, 4, and 8 weeks of age. Infants with severe PIVH were studied weekly. A 1-hour average of rScO2 was compared with the frontal-occipital horn ratio (FOHR) measured the same day. Generalized linear models were used to analyze the relationship between FOHR and rScO2, by severity of PIVH, and adjusted for gestational age. Cut-off points of 0.55 for FOHR and 45% for rScO2 were used to calculate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The study cohort included 63 infants with normal US, 15 with grade-1 or -2 PIVH (mild group), and 21 with grade-3 or -4 PIVH (severe group). Increases in FOHR in the severe group were associated with decreases in rScO2 at 1 week (p = 0.036), 4 weeks (p = 0.013), and 8 weeks of life (p = 0.001) compared with the normal and mild groups. Infants with FOHR greater than 0.55 were 92% more likely to have rScO2 less than 45% when compared with infants with FOHR less than 0.55 (OR = 0.08, 95% CI: [0.04, 0.13], p < 0.001). CONCLUSION: Progressive PHVD (FOHR > 0.55) is a strong predictor of compromised cerebral oxygenation. A combination of rScO2 and FOHR measurements may aid in identifying infants with PHVD that would benefit from early intervention. KEY POINTS: · Earlier intervention in PHVD may improve outcomes.. · PHVD is diagnosed with US measurements of ventricular size.. · FOHR > 0.55 is associated with decreased cerebral perfusion..

Therapeutic Hypothermia Inhibits the Classical Complement Pathway in a Rat Model of Neonatal Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: Complement activation is instrumental in the pathogenesis of Hypoxic-ischemic encephalopathy (HIE), a significant cause of neonatal mortality and disability worldwide. Therapeutic hypothermia (HT), the only available treatment for HIE, only modestly improves outcomes. Complement modulation as a therapeutic adjunct to HT has been considered, but is challenging due to the wide-ranging role of the complement system in neuroinflammation, homeostasis and neurogenesis in the developing brain. We sought to identify potential therapeutic targets by measuring the impact of treatment with HT on complement effector expression in neurons and glia in neonatal HIE, with particular emphasis on the interactions between microglia and C1q. METHODS: The Vannucci model was used to induce HIE in term-equivalent rat pups. At P10-12, pups were randomly assigned to three different treatment groups: Sham (control), normothermia (NT), and hypothermia (HT) treatment. Local and systemic complement expression and neuronal apoptosis were measured by ELISA, TUNEL and immunofluorescence labeling, and differences compared between groups. RESULTS: Treatment with HT is associated with decreased systemic and microglial expression of C1q, decreased systemic C5a levels, and decreased microglial and neuronal deposition of C3 and C9. The effect of HT on cytokines was variable with decreased expression of pro and anti-inflammatory effectors. HT treatment was associated with decreased C1q binding on cells undergoing apoptosis. CONCLUSION: Our data demonstrate the extreme complexity of the immune response in neonatal HIE. We propose modulation of downstream effectors C3a and C5a as a therapeutic adjunct to HT to enhance neuroprotection in the developing brain.

Perspectives from the Society for Pediatric Research. Neonatal encephalopathy clinical trials: developing the future.

The next phase of clinical trials in neonatal encephalopathy (NE) focuses on hypothermia adjuvant therapies targeting alternative recovery mechanisms during the process of hypoxic brain injury. Identifying infants eligible for neuroprotective therapies begins with the clinical detection of brain injury and classification of severity. Combining a variety of biomarkers (serum, clinical exam, EEG, movement patterns) with innovative clinical trial design and analyses will help target infants with the most appropriate and timely treatments. The timing of magnetic resonance imaging (MRI) and MR spectroscopy after NE both assists in identifying the acute perinatal nature of the injury (days 3-7) and evaluates the full extent and evolution of the injury (days 10-21). Early, intermediate outcome of neuroprotective interventions may be best defined by the 21-day neuroimaging, with recognition that the full neurodevelopmental trajectory is not yet defined. An initial evaluation of each new therapy at this time point may allow higher-throughput selection of promising therapies for more extensive investigation. Functional recovery can be assessed using a trajectory of neurodevelopmental evaluations targeted to a prespecified and mechanistically derived hypothesis of drug action. As precision medicine revolutionizes healthcare, it should also include the redesign of NE clinical trials to allow safe, efficient, and targeted therapeutics. IMPACT: As precision medicine revolutionizes healthcare, it should also include the redesign of NE clinical trials to allow faster development of safe, effective, and targeted therapeutics. This article provides a multidisciplinary perspective on the future of clinical trials in NE; novel trial design; study management and oversight; biostatistical methods; and a combination of serum, imaging, and neurodevelopmental biomarkers can advance the field and improve outcomes for infants affected by NE. Innovative clinical trial designs, new intermediate trial end points, and a trajectory of neurodevelopmental evaluations targeted to a prespecified and mechanistically derived hypothesis of drug action can help address common challenges in NE clinical trials and allow for faster selection and validation of promising therapies for more extensive investigation.

Elevated midline head positioning of extremely low birth weight infants: effects on cardiopulmonary function and the incidence of periventricular-intraventricular hemorrhage.

OBJECTIVE: Changes in cerebrovascular hemodynamics associated with head position may be important in the pathogenesis of periventricular-intraventricular hemorrhage (PIVH) in premature infants. This study evaluated the effect of elevated midline head positioning on cardiopulmonary function and the incidence of PIVH. STUDY DESIGN: ELBW infants were randomized to FLAT (flat, supine) or ELEV (supine, bed elevated 30 degrees) for 96 h. Cardiopulmonary function, complications of prematurity, and the occurrence of PIVH were documented. RESULTS: Infants were randomized into FLAT (n = 90) and ELEV groups (n = 90). No significant differences were seen in the incidence of BPD or other respiratory complications. The ELEV group developed significantly fewer grade 4 hemorrhages (p = 0.036) and survival to discharge was significantly higher in the ELEV group (p = 0.037). CONCLUSIONS: Managing ELBW infants in an elevated midline head position for the first 4 days of life appears safe and may decrease the likelihood of severe PIVH and improve survival.

Complement effectors, C5a and C3a, in cystic fibrosis lung fluid correlate with disease severity.

In cystic fibrosis (CF), lung damage is mediated by a cycle of obstruction, infection, inflammation and tissue destruction. The complement system is a major mediator of inflammation for many diseases with the effectors C5a and C3a often playing important roles. We have previously shown in a small pilot study that CF sputum soluble fraction concentrations of C5a and C3a were associated with clinical measures of CF disease. Here we report a much larger study of 34 CF subjects providing 169 testable sputum samples allowing longitudinal evaluation comparing C5a and C3a with clinical markers. Levels of the strongly pro-inflammatory C5a correlated negatively with FEV1% predicted (P < 0.001), whereas the often anti-inflammatory C3a correlated positively with FEV1% predicted (P = 0.01). C5a concentrations correlated negatively with BMI percentile (P = 0.017), positively with worsening of an acute pulmonary exacerbation score (P = 0.007) and positively with P. aeruginosa growth in sputum (P = 0.002). C5a levels also correlated positively with concentrations of other sputum markers associated with worse CF lung disease including neutrophil elastase (P < 0.001), myeloperoxidase activity (P = 0.006) and DNA concentration (P < 0.001). In contrast to C5a, C3a levels correlated negatively with worse acute pulmonary exacerbation score and correlated negatively with sputum concentrations of neutrophil elastase, myeloperoxidase activity and DNA concentration. In summary, these data suggest that in CF sputum, increased C5a is associated with increased inflammation and poorer clinical measures, whereas increased C3a appears to be associated with less inflammation and improved clinical measures.

Therapeutic hypothermia modulates complement factor C3a and C5a levels in a rat model of hypoxic ischemic encephalopathy.

BACKGROUND: Therapeutic hypothermia (HT) is the only intervention that improves outcomes in neonatal hypoxic-ischemic encephalopathy (HIE). However, the multifactorial mechanisms by which HT impacts HIE are incompletely understood. The complement system plays a major role in the pathogenesis of ischemia-reperfusion injuries such as HIE. We have previously demonstrated that HT modulates complement activity in vitro. METHODS: Term equivalent rat pups were subjected to unilateral carotid ligation followed by hypoxia (8% O2) for 45 min to simulate HIE. A subset of animals was subjected to HT (31-32°C for 6 h). Plasma and brain levels of C3a and C5a were measured. Receptors for C3a (C3aR) and C5a (C5aR) along with C1q, C3, and C9 were characterized in neurons, astrocytes, and microglia. RESULTS: We found that HT increased systemic expression of C3a and decreased expression of C5a after HIE. In the brain, C3aR and C5aR are predominantly expressed on microglia after HIE. HT increased local expression of C3aR and decreased expression on C5aR after HIE. Furthermore, HT decreased local expression of C1q, C3-products, and C9 in the brain. CONCLUSION: HT is associated with significant alteration of complement effectors and their cognate receptors. Complement modulation may improve outcomes in neonatal HIE.

Peptide inhibitor of complement C1 modulates acute intravascular hemolysis of mismatched red blood cells in rats.

BACKGROUND: Acute hemolytic transfusion reactions have a broad clinical presentation from mild and transitory signs and symptoms to shock, disseminated intravascular coagulation, renal failure, and death. We have recently developed a rat model of acute intravascular hemolysis showing that the classical complement pathway mediates antibody-dependent hemolysis. The objective of this study was to evaluate the role of the classical pathway inhibitor peptide inhibitor of complement C1 (PIC1) in this animal model. STUDY DESIGN AND METHODS: Male Wistar rats received a 15% transfusion of human red blood cells (RBCs) and blood was isolated from the animals up to 120 minutes. Animals received PIC1 either 2 minutes before or 0.5 minutes after transfusion. Sham-, vehicle-, and cobra venom factor (CVF)-treated animals were used as control groups with a subset of rats also receiving an equivalent dose of intravenous immunoglobulin (IVIG) before transfusion. Blood was analyzed for transfused RBC survival by flow cytometry and free hemoglobin (Hb) in isolated plasma by spectrophotometry. RESULTS: Vehicle-treated rats showed decreased human RBC survival and increased free Hb as expected. Rats receiving PIC1 before transfusion showed increased human RBC survival and decreased Hb similar to CVF-treated rats. Notably, rats receiving PIC1 after initiation of transfusion showed similar decreases in hemolysis as animals receiving PIC1 before transfusion. Compared to IVIG and saline controls, PIC1-treated animals demonstrated decreased hemolysis and protection from acute kidney injury. CONCLUSIONS: These results demonstrate that PIC1 has efficacy in an animal model of acute intravascular hemolysis in both prevention and rescue scenarios.

Eosinophil Quantitated Urine Kinetic: A novel assay for assessment of eosinophilic esophagitis.

BACKGROUND: Eosinophilic esophagitis (EoE) is a chronic disease that requires long-term medical management and monitoring. The eosinophil count determined during esophageal biopsy remains the gold standard for diagnosis and monitoring of EoE. Although markers of eosinophil degranulation correlate with symptoms, eosinophil counts do not correlate. Development of a noninvasive, cost-effective biomarker of eosinophil activation for the evaluation of EoE is an unmet medical need. OBJECTIVE: To conduct a proof-of-concept study to evaluate the potential for measuring urinary 3-bromotyrosine (3-BT) levels in creatinine normalized urine for quantifying eosinophil degranulation in EoE disease. METHODS: A mass spectrometry-based method of measuring normalized 3-BT levels, the Eosinophil Quantitated Urine Kinetic (EoQUIK), was developed, and proof-of-concept evaluation was performed for patients with EoE (n = 27), atopic controls (n = 24), and nonatopic controls (n = 24). RESULTS: EoQUIK revealed that median normalized 3-BT levels were increased 93-fold in patients with EoE compared with nonatopic controls (P = .01) and increased 13-fold in patients with EoE compared with atopic controls (P = .01). Cutoff thresholds were selected for EoQUIK that yielded a specificity of 100% and a negative predictive value of 100% for nonatopic controls and a specificity of 79% and a negative predictive value of 90% for atopic controls. In a logistic regression model, a urine 3-BT level greater than 20 pg per 400 mg of creatinine increased the odds of a patient having EoE by 4.8 (95% confidence interval, 1.14-20.5; P = .03) when compared with atopic controls after controlling for race and sex. CONCLUSION: These data provide proof of concept that EoQUIK can potentially be a useful noninvasive clinical tool in the evaluation of possible EoE.

Complement Effectors of Inflammation in Cystic Fibrosis Lung Fluid Correlate with Clinical Measures of Disease.

In cystic fibrosis (CF), lung damage is mediated by a cycle of obstruction, infection, and inflammation. Here we explored complement inflammatory effectors in CF lung fluid. In this study soluble fractions (sols) from sputum samples of 15 CF patients were assayed for complement effectors and analyzed with clinical measurements. The pro-inflammatory peptide C5a was increased 4.8-fold (P = 0.04) in CF sols compared with controls. Incubation of CF sols with P. aeruginosa or S. aureus increased C5a concentration 2.3-fold (P = 0.02). A peptide inhibitor of complement C1 (PIC1) completely blocked the increase in C5a concentration from P. aeruginosa in CF sol in vitro (P = 0.001). C5a concentration in CF sol correlated inversely with body mass index (BMI) percentile in children (r = -0.77, P = 0.04). C3a, which has anti-inflammatory effects, correlated positively with FEV1% predicted (rs = 0.63, P = 0.02). These results suggest that complement effectors may significantly impact inflammation in CF lung fluid.

Foxm1 regulates resolution of hyperoxic lung injury in newborns.

Current treatments for inflammation associated with bronchopulmonary dysplasia (BPD) fail to show clinical efficacy. Foxm1, a transcription factor of the Forkhead box family, is a critical mediator of lung development and carcinogenesis, but its role in BPD-associated pulmonary inflammation is unknown. Immunohistochemistry and RNA analysis were used to assess Foxm1 in lung tissue from hyperoxia-treated mice and patients with BPD. LysM-Cre/Foxm1(-/-) mice, in which Foxm1 was deleted from myeloid-derived inflammatory cells, including macrophages, monocytes, and neutrophils, were exposed to neonatal hyperoxia, causing lung injury and remodeling. Measurements of lung function and flow cytometry were used to evaluate the effects of Foxm1 deletion on pulmonary inflammation and repair. Increased Foxm1 expression was observed in pulmonary macrophages of hyperoxia-exposed mice and in lung tissue from patients with BPD. After hyperoxia, deletion of Foxm1 from the myeloid cell lineage decreased numbers of interstitial macrophages (CD45(+)CD11b(+)Ly6C(-)Ly6G(-)F4/80(+)CD68(-)) and impaired alveologenesis and lung function. The exaggerated BPD-like phenotype observed in hyperoxia-exposed LysM-Cre/Foxm1(-/-) mice was associated with increased expression of neutrophil-derived myeloperoxidase, proteinase 3, and cathepsin g, all of which are critical for lung remodeling and inflammation. Our data demonstrate that Foxm1 influences pulmonary inflammatory responses to hyperoxia, inhibiting neutrophil-derived enzymes and enhancing monocytic responses that limit alveolar injury and remodeling in neonatal lungs.

Clinical hypothermia temperatures increase complement activation and cell destruction via the classical pathway.

BACKGROUND: Therapeutic hypothermia is a treatment modality that is increasingly used to improve clinical neurological outcomes for ischemia-reperfusion injury-mediated diseases. Antibody-initiated classical complement pathway activation has been shown to contribute to ischemia-reperfusion injury in multiple disease processes. However, how therapeutic hypothermia affects complement activation is unknown. Our goal was to measure the independent effect of temperature on complement activation, and more specifically, examine the relationship between clinical hypothermia temperatures (31-33°C), and complement activation. METHODS: Antibody-sensitized erythrocytes were used to assay complement activation at temperatures ranging from 0-41°C. Individual complement pathway components were assayed by ELISA, Western blot, and quantitative dot blot. Peptide Inhibitor of complement C1 (PIC1) was used to specifically inhibit activation of C1. RESULTS: Antibody-initiated complement activation resulting in eukaryotic cell lysis was increased by 2-fold at 31°C compared with 37°C. Antibody-initiated complement activation in human serum increased as temperature decreased from 37°C until dramatically decreasing at 13°C. Quantitation of individual complement components showed significantly increased activation of C4, C3, and C5 at clinical hypothermia temperatures. In contrast, C1s activation by heat-aggregated IgG decreased at therapeutic hypothermia temperatures consistent with decreased enzymatic activity at lower temperatures. However, C1q binding to antibody-coated erythrocytes increased at lower temperatures, suggesting that increased classical complement pathway activation is mediated by increased C1 binding at therapeutic hypothermia temperatures. PIC1 inhibited hypothermia-enhanced complement-mediated cell lysis at 31°C by up to 60% (P = 0.001) in a dose dependent manner. CONCLUSIONS: In summary, therapeutic hypothermia temperatures increased antibody-initiated complement activation and eukaryotic cell destruction suggesting that the benefits of therapeutic hypothermia may be mediated via other mechanisms. Antibody-initiated complement activation has been shown to contribute to ischemia-reperfusion injury in several animal models, suggesting that for diseases with this mechanism hypothermia-enhanced complement activation may partially attenuate the benefits of therapeutic hypothermia.

Complement inhibition significantly decreases red blood cell lysis in a rat model of acute intravascular hemolysis.

BACKGROUND: Prevention of acute hemolytic transfusion reactions is a worldwide concern. The objective of this study was to develop a simple rat model of complement-mediated acute intravascular hemolysis. STUDY DESIGN AND METHODS: Human AB red blood cells (RBCs) were incubated with complement-sufficient or complement-deficient Wistar rat serum (WRS) in the presence and absence of human RBC antibody in vitro to elucidate the mechanism of hemolysis. To study the role of complement in acute intravascular hemolysis in vivo, Wistar rats were treated either with or without cobra venom factor (CVF) to deplete complement activity. Human AB RBCs were then injected into both groups of rats, followed by serial blood draws up to 2 hours. Venous blood clearance and lysis of transfused RBCs at each time point were measured by flow cytometry and spectrophotometry. RBC sequestration was determined in the liver, spleen, and kidney by immunohistochemistry. RESULTS: In vitro incubation of human RBCs with WRS demonstrated that RBC lysis was mediated via the classical complement pathway and that hemolysis was antibody dependent. Transfusion of human RBCs into rats showed significantly less hemolysis in the CVF group versus untreated group. RBC sequestration in the spleen and liver 2 hours posttransfusion were not quantitatively different between the two groups. CONCLUSIONS: Given the much higher degree of similarity for rat and human complement compared to mice, this simple rat model is ideal for testing novel inhibitors of classical pathway activation for the prevention and treatment of acute intravascular hemolysis.

FOXM1 promotes allergen-induced goblet cell metaplasia and pulmonary inflammation.

Chronic airway disorders, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, and asthma, are associated with persistent pulmonary inflammation and goblet cell metaplasia and contribute to significant morbidity and mortality worldwide. While the molecular pathogenesis of these disorders is actively studied, little is known regarding the transcriptional control of goblet cell differentiation and mucus hyperproduction. Herein, we demonstrated that pulmonary allergen sensitization induces expression of FOXM1 transcription factor in airway epithelial and inflammatory cells. Conditional deletion of the Foxm1 gene from either airway epithelium or myeloid inflammatory cells decreased goblet cell metaplasia, reduced lung inflammation, and decreased airway resistance in response to house dust mite allergen (HDM). FOXM1 induced goblet cell metaplasia and Muc5AC expression through the transcriptional activation of Spdef. FOXM1 deletion reduced expression of CCL11, CCL24, and the chemokine receptors CCR2 and CX3CR1, resulting in decreased recruitment of eosinophils and macrophages to the lung. Deletion of FOXM1 from dendritic cells impaired the uptake of HDM antigens and decreased cell surface expression of major histocompatibility complex II (MHC II) and costimulatory molecule CD86, decreasing production of Th2 cytokines by activated T cells. Finally, pharmacological inhibition of FOXM1 by ARF peptide prevented HDM-mediated pulmonary responses. FOXM1 regulates genes critical for allergen-induced lung inflammation and goblet cell metaplasia.

Forkhead box M1 transcription factor is required for macrophage recruitment during liver repair.

Acute liver injury results from exposure to toxins, pharmacological agents, or viral infections, contributing to significant morbidity and mortality worldwide. While hepatic inflammation is critical for liver repair, the transcriptional mechanisms required for the recruitment of inflammatory cells to the liver are not understood. Forkhead box M1 (Foxm1) transcription factor is a master regulator of hepatocyte proliferation, but its role in inflammatory cells remains unknown. In this study, we generated transgenic mice in which Foxm1 was deleted from myeloid-derived cells, including macrophages, monocytes, and neutrophils. Carbon tetrachloride liver injury was used to demonstrate that myeloid-specific Foxm1 deletion caused a delay in liver repair. Although Foxm1 deficiency did not influence neutrophil infiltration into injured livers, the total numbers of mature macrophages were dramatically reduced. Surprisingly, Foxm1 deficiency did not influence the proliferation of macrophages or their monocytic precursors but impaired monocyte recruitment during liver repair. Expression of L-selectin and the CCR2 chemokine receptor, both critical for monocyte recruitment to injured tissues, was decreased. Foxm1 induced transcriptional activity of the mouse CCR2 promoter in cotransfection experiments. Adoptive transfer of monocytes to Foxm1-deficient mice restored liver repair and rescued liver function. Foxm1 is critical for liver repair and is required for the recruitment of monocytes to the injured liver.

Pulmonary and systemic expression of monocyte chemotactic proteins in preterm sheep fetuses exposed to lipopolysaccharide-induced chorioamnionitis.

Monocyte chemoattractant proteins (MCP-1 and MCP-2) mediate monocyte and T-lymphocyte chemotaxis, and IL-1 contributes to the pathogenesis of chorioamnionitis-induced lung inflammation and fetal inflammatory responses. We tested the hypothesis that IL-1 mediates the systemic and pulmonary induction of MCP-1 and MCP-2 in response to lipopolysaccharide (LPS)-induced chorioamnionitis. MCP-1 mRNA, MCP-2 mRNA, and MCP-1 protein expression were measured in two models: 1) intra-amniotic LPS and 2) intra-amniotic recombinant sheep IL-1alpha given at varying intervals before preterm delivery at 124 d GA. Intra-amniotic LPS or IL-1alpha induced MCP-1 mRNA and protein and MCP-2 mRNA in fetal lung many fold at 1-2 d. LPS induced intense MCP-1 expression in subepithelial mesenchymal cells and interstitial inflammatory cells in the lung. Inhibition of IL-1 signaling with recombinant human IL-1 receptor antagonist (rhIL-1ra) did not attenuate LPS induced increase in MCP-1 or MCP-2 expression. MCP-1 and MCP-2 were not induced in liver or chorioamnion, but MCP-1 increased in cord plasma. LPS or IL-1 can induce robust expression of MCP-1 or MCP-2 in the fetal lung. LPS induction of MCP-1 is not IL-1 dependent in fetal sheep. MCP-1 and MCP-2 may be significant contributors to fetal inflammation.

Cardiac and pulmonary function variability in Duchenne/Becker muscular dystrophy: an initial report.

The Duchenne and Becker forms of muscular dystrophy are associated with dilated cardiomyopathy and are diseases in which pulmonary function peaks and then progressively declines. In this report, the authors quantify cardiopulmonary function variability among brothers. Brothers in 3 of 7 eligible sibships had discordant pulmonary function, with significant differences between the brothers' peak forced vital capacities and their vital capacities at last comparable age. There was no relationship between pulmonary and cardiac function among the siblings. The authors concluded that despite identical genetic mutations, cardiac and pulmonary function variability was common among brothers in their clinic with Duchenne or Becker muscular dystrophy. If confirmed by larger studies, these results have negative implications for the use of genetic testing to predict cardiopulmonary course and response to therapies in Duchenne or Becker muscular dystrophy.

Symptomatic nephrolithiasis in prolonged survivors of Duchenne muscular dystrophy.

In this study, we describe the association between Duchenne muscular dystrophy (DMD) and symptomatic nephrolithiasis. The DMD patients were matched to non-ambulatory control patients with non-DMD neurological diagnoses via retrospective chart review. All patients with DMD and symptomatic nephrolithiasis were over 20 years old. We found that six of the 29 at-risk DMD patients had nephrolithiasis (20.7%) while only one of the 68 control patients had nephrolithiasis (1.5%) (p<0.0001). Controlling for duration of immobilization with stratified analysis, the risk ratio for nephrolithiasis among DMD patients compared with controls was 9.94. Using rate-based estimates of renal stone development per 10,000 patient-years, the ratio of stone development among DMD patients compared with controls was 18.5. On logistic regression analysis, the corrected odds ratio for nephrolithiasis comparing DMD patients to controls was 14.26. We conclude that, in our study group, DMD was an independent risk factor for symptomatic nephrolithiasis.