Hematopoietic Stem- and Progenitor-Cell Gene Therapy for Hurler Syndrome

BACKGROUND

Allogeneic hematopoietic stem-cell transplantation is the standard of care for Hurler syndrome (mucopolysaccharidosis type I, Hurler variant [MPSIH]). However, this treatment is only partially curative and is associated with complications.

METHODS

We are conducting an ongoing study involving eight children with MPSIH. At enrollment, the children lacked a suitable allogeneic donor and had a Developmental Quotient or Intelligence Quotient score above 70 (i.e., none had moderate or severe cognitive impairment). The children received autologous hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with an α-L-iduronidase (IDUA)-encoding lentiviral vector after myeloablative conditioning. Safety and correction of blood IDUA activity up to supraphysiologic levels were the primary end points. Clearance of lysosomal storage material as well as skeletal and neurophysiological development were assessed as secondary and exploratory end points. The planned duration of the study is 5 years.

RESULTS

We now report interim results. The children's mean (±SD) age at the time of HSPC gene therapy was 1.9±0.5 years. At a median follow-up of 2.10 years, the procedure had a safety profile similar to that known for autologous hematopoietic stem-cell transplantation. All the patients showed prompt and sustained engraftment of gene-corrected cells and had supraphysiologic blood IDUA activity within a month, which was maintained up to the latest follow-up. Urinary glycosaminoglycan (GAG) excretion decreased steeply, reaching normal levels at 12 months in four of five patients who could be evaluated. Previously undetectable levels of IDUA activity in the cerebrospinal fluid became detectable after gene therapy and were associated with local clearance of GAGs. Patients showed stable cognitive performance, stable motor skills corresponding to continued motor development, improved or stable findings on magnetic resonance imaging of the brain and spine, reduced joint stiffness, and normal growth in line with World Health Organization growth charts.

CONCLUSIONS

The delivery of HSPC gene therapy in patients with MPSIH resulted in extensive metabolic correction in peripheral tissues and the central nervous system. (Funded by Fondazione Telethon and others; ClinicalTrials.gov number, NCT03488394; EudraCT number, 2017-002430-23.).

Mild SARS-CoV-2 Infection After Gene Therapy in a Child With Wiskott-Aldrich Syndrome: A Case Report

In this work we present the case of SARS-CoV-2 infection in a 1.5-year-old boy affected by severe Wiskott-Aldrich Syndrome with previous history of autoinflammatory disease, occurring 5 months after treatment with gene therapy. Before SARS-CoV-2 infection, the patient had obtained engraftment of gene corrected cells, resulting in WASP expression restoration and early immune reconstitution. The patient produced specific immunoglobulins to SARS-CoV-2 at high titer with neutralizing capacity and experienced a mild course of infection, with limited inflammatory complications, despite pre-gene therapy clinical phenotype.

COVID-19 cardiac involvement in a 38-day old infant

The spectrum of clinical manifestations of coronavirus disease 2019 in children is yet to be fully elucidated. We report the case of an infant who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and developed mild cardiovascular inflammation, a novelty for patients of very young age, that contributes to defining the puzzling nature of this disease in pediatric patients. The potential cardiovascular involvement of SARS-CoV-2 in children should always be taken into account.

Transcriptional deregulation and a missense mutation define ANKRD1 as a candidate gene for total anomalous pulmonary venous return

Total anomalous pulmonary venous return (TAPVR) is a congenital heart defect in which the pulmonary veins fail to enter the left atrium and drain instead into the right atrium or one of its venous tributaries. Although a genetic basis for TAPVR has long been recognized, no single gene involved in the pathogenesis of this disease has been identified to date. We previously reported a TAPVR patient bearing a de novo 10;21 balanced translocation. In this work, we cloned both translocation breakpoints from this patient and mapped the ANKRD1 gene, encoding a cardiac transcriptional regulator, 130 kb proximally to the breakpoint on chromosome 10. In situ hybridization analysis performed on murine embryos showed ANKRD1 expression in the developing pulmonary veins, suggesting a possible role for this gene in TAPVR pathogenesis. Moreover, ANKRD1 expression levels were found to be highly increased in lymphoblastoid cell lines derived from both the translocation-bearing proband and a second independent sporadic TAPVR patient, suggesting that disruption of the normal ANKRD1 expression pattern is associated with TAPVR. Finally, a nonconservative missense mutation in the ANKRD1 gene was found in a third sporadic TAPVR patient. In vitro calpain-mediated degradation assays, coupled to reporter gene analysis in transfected HeLa cells, strongly suggested that this mutation enhances both the stability of the ANKRD1/CARP protein and its transcriptional repression activity upon the cardiac-specific atrial natriuretic factor (ANF) promoter. Taken together, these results define ANKRD1 as a possible candidate gene for TAPVR pathogenesis.

Jugular approach for percutaneous closure of atrial septal defect

One hundred and forty-two consecutive procedures of percutaneous closure or atrial septal defect were approached by cannulation of the right femoral vein. In 3 of them, the internal jugular vein approach was also necessary because of azygos continuation or unsuccessful device implantation due to inadequate septal alignment. In all of them, device implantation was successfully performed through this alternative percutaneous vascular approach.

Prevalence and prognosis of atrial septal aneurysm in high risk fetuses without structural heart defects

BACKGROUND

The aim of this study was to evaluate the prevalence and prognostic implications of the association between atrial septal aneurysm (ASA) and fetal arrhythmias in a population of high risk fetuses.

METHODS

One thousand three hundred and two fetal echocardiograms performed during high risk pregnancies from the 17th to the 41st week of gestation were retrospectively evaluated for the presence of ASA and/or arrhythmias. An ASA was defined as redundant tissue extending at least halfway across the left atrium. Patients with an ASA were distinguished in two subgroups according to whether there was (subgroup 1) or was not (subgroup 2) cyclical contact of the atrial septum with the left atrial wall or with the mitral valve. Arrhythmias were documented during mono/two-dimensional echocardiography and Doppler evaluation.

RESULTS

Out of 1223 patients considered for the study, 93 (7.6%) fetuses had an ASA; among these 93 fetuses, 33 (36%) had premature atrial beats (p < 0.001). Ten of these patients were included in subgroup 1, and 7 of them (70%) exhibited premature atrial beats (p = 0.016 vs subgroup 2). No arrhythmias other than premature atrial beats were observed in these patients. None of them received any therapy during observation. All of them developed a regular sinus rhythm within 3 months of life.

CONCLUSIONS

On the basis of these data, we can speculate that, if accurately searched for, ASA is often present (7.6%) and is likely to represent a mechanical stimulus for the generation of premature atrial beats. Indeed, our data show an important correlation between the degree of bulging and the presence of arrhythmias, supporting the hypothesis of a mechanical stimulus. However, the observed arrhythmias did not appear to be prone to degeneration. In conclusion, ASA observed during fetal life is often associated with premature atrial beats, which are apparently in direct relation with the degree of bulging of the atrial septum. On the other hand, an ASA almost invariably disappears at birth and is not associated with major arrhythmias.

Fetal echocardiography in detecting anomalous pulmonary venous connection: four false positive cases

Prenatal detection of congenital heart disease is possible from the 16th week of pregnancy, the ideal time being the mid-trimester, when most cardiac abnormalities can be detected. However, identification of anomalous pulmonary venous connection is difficult before birth and the sensitivity of fetal echocardiography in detecting this anomaly is low. Four cases are reported in which fetal echocardiographic findings obtained during the third trimester of pregnancy were highly suggestive of anomalous pulmonary venous connection. Right ventricular and atrial dominance associated with an enlarged coronary sinus or dilated superior vena cava were identified and considered to be indirect markers of the anomaly. No other cardiac anomaly was detectable. In all cases right ventricular and atrial dominance with dilated coronary sinus or superior vena cava were confirmed after birth despite the presence of normal pulmonary venous connections. These results confirm that the prenatal detection of this condition is difficult and should be based on the direct visualisation of anomalous pulmonary venous connections. The sole detection of indirect signs, such as right atrial and ventricular dominance with or without a dilated coronary sinus, superior vena cava, or inferior vena cava, does not warrant the diagnosis of anomalous pulmonary venous connection. Since the pulmonary venous flow in the human fetus is not as small as is commonly assumed, an anomalous drainage should be detectable when present and therefore should be specifically sought if the anomaly is suspected. The reasons for the presence of such transient cardiac anomalies remain obscure, but they might be related to functional or morphological rearrangement of the heart during fetal and perinatal life.

Epicardial damage induced by topical cooling during paediatric cardiac surgery

OBJECTIVE

To study electrocardiographic changes in infants and children in whom topical cooling was used during surgical repair of congenital heart defects.

DESIGN

A retrospective study of all patients who had surgical repair of congenital heart disease during cold blood cardioplegia and topical cooling from January to August 1990. Eleven patients (group 1) had topical cooling with ice and 15 (group 2) with cold saline.

PATIENTS

All 36 paediatric patients operated on during this period. All the available electrocardiographic records were analysed. Ten patients in whom reliable records were not available were excluded. Twenty six patients entered in this retrospective study.

INTERVENTIONS

Topical cooling with ice or with a slush of cold saline.

MAIN OUTCOME MEASURE

Recordings from all the precordial leads were examined and scored as the sum of the maximum ST elevation (mV) in each precordial lead. The score obtained for each electrocardiogram was recorded together with the timing of the electrocardiogram (preoperative, arrival in intensive care unit immediately after surgery, postoperatively in the intensive care unit, and at discharge).

RESULTS

There were no differences between the two groups in terms of demographic data, diagnosis, duration of ischaemia, and postoperative myocardial performance. There was temporary ST elevation during the first 48 postoperative hours in all the children in group 1 but in only seven of the 15 children in group 2 (Fisher's test, p less than 0.005). The mean (SD) score for maximum ST elevation was 1.34 (0.83) mV in group 1 and 0.52 (0.64) mV in group 2 (Student's t test, p less than 0.01).

CONCLUSIONS

These temporary electrocardiographic changes in the presence of adequate myocardial performance were attributed to epicardial damage induced by hypothermicosmotic injury. The use of ice for topical cooling may damage the epicardium in children.

Antihypertensive effect of a new formulation of slow release oxprenolol in essential hypertension

To test whether a new formulation of a slow release oxprenolol (SLOx) can produce a steady 24-h antihypertensive effect, we recorded 24-h intraarterial blood pressure (Oxford technique) in eight ambulant inpatients (age 44.5 +/- 3.0 years, mean +/- SE) with a mild or moderate hypertension who were untreated since three weeks. The study was started seven days after hospitalization and was conducted according to a randomized doubleblind cross-over design. Blood pressure recordings were made after (a) a 7-day administration of SLOx in a single evening dose, and (b) a 7-day administration of placebo. This design allowed to determine the effect of SLOx without interference from nonspecific blood pressure lowering factors. Blood pressure effects of handgrip, submaximal cyclette exercise, and cold pressor test 20-24 h after the administration of SLOx and placebo were also evaluated. The blood pressure tracing was analyzed beat-to-beat by a computer which provided also the analysis of the heart rate data. The 24-h mean systolic and diastolic blood pressure measured during placebo were 144.6 +/- 6.4 and 81.1 +/- 3.9 mm Hg, the corresponding heart rate being 76.9 +/- 3.5 beats/min. SLOx reduced these values by 6.2, 10.6, and 4.8%, respectively, all effects being similarly evident throughout the blood pressure recording. The pressor responses to handgrip, cyclette exercise, and cold pressor test were not affected by SLOx. By contrast, the small tachycardic response to handgrip and the large tachycardic response to submaximal cyclette exercise were significantly reduced by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

24-hour blood pressure measurements: methodological and clinical problems

Awareness that sphygmomanometry is encompassed with serious limitations has led to the development of techniques that allow blood pressure (BP) to be monitored intraarterially or noninvasively during the day or over a 24-hour period. Although intraarterial BP monitoring allows an accurate evaluation of 24-hour BP mean and variability, its invasiveness prevents routine use in the clinical practice. This use can be more easily foreseen for noninvasive ambulatory BP monitoring, provided that the questions posed by this approach are answered. In the present study we show that the intermittent cuff inflations which allow BP to be measured noninvasively do not induce an alerting reaction and a BP rise in the patients, which means that this approach does not disrupt the daily BP profile. We also show that noninvasive BP monitoring does not alter the nocturnal hypotension, thus, preserving the day and night BP rhythm. Finally, we present evidence from a cross-sectional study that 24-hour BP monitoring reflects more closely the hypertension-related target organ damage than sphygmomanometric BP measurement and that target organ damage is related not only to average BP regimens but also to the degree of BP variability. Although support from prospective studies is necessary, this suggests that the diagnosis of hypertension and the prediction of its risk may be improved by ambulatory BP monitoring.