Preliminary insights into RNA in CSF of pediatric SMA patients after 6 months of nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a rare autosomal-recessive neurodegenerative disorder caused by mutations in survival motor neuron 1 (SMN1) gene, and consequent loss of function of SMN protein, which results in progressive loss of lower motor neurons, and muscular wasting. Antisense oligonucleotide (ASO) nusinersen (Spinraza®) modulates the pre-mRNA splicing of the SMN2 gene, allowing rebalance of biologically active SMN. It is administered intrathecally via lumbar puncture after removing an equal amount of cerebrospinal fluid (CSF). Its effect was proven beneficial and approved since 2017 for SMA treatment. Given the direct effect of nusinersen on RNA metabolism, the aim of this project was to evaluate cell-free RNA (cfRNA) in CSF of SMA patients under ASOs treatment for biomarker discovery.

METHODS

By RNA-sequencing approach, RNA obtained from CSF of pediatric SMA type 2 and 3 patients was processed after 6 months of nusinersen treatment, at fifth intrathecal injection (T6), and compared to baseline (T0).

RESULTS

We observed the deregulation of cfRNAs in patients at T6 and we were able to classify these RNAs into disease specific, treatment specific and treatment dependent. Moreover, we subdivided patients into "homogeneous" and "heterogeneous" according to their gene expression pattern. The "heterogeneous" group showed peculiar activation of genes coding for ribosomal components, meaning that in these patients a different molecular effect of nusinersen is observable, even if this specific molecular response was not referable to a clinical pattern.

CONCLUSIONS

This study provides preliminary insights into modulation of gene expression dependent on nusinersen treatment and lays the foundation for biomarkers discovery.

[Neonatal asphyxia: neurologic outcome]

AIM

The neonatal asphyxia is recognized as an important cause of morbidity and mortality during the pediatric age. The objective of this study was to evaluate the correlation between some neonatal variables and neurological outcome at two years of life in infants with asphyxia, in order to produce a correct prognosis and to grant a rapid and targeted therapy.

METHODS

We have recruited 63 patients whose history and neuroimages suggested a neonatal asphyxia, and we have analysed their clinical- instrumental parameters every three months until two years of life. A correlation study was carried out in order to find a statistical significance indicated by p-value < 0,05. The correlation was made by means of Chi-square and ANOVA (analysis of variance) test.

RESULTS

Only one patient developed isolated epilepsy, 17 developed CP associated to epilepsy (14 of them were term infants, 3 were preterm); 25 patients, 13 term and 12 preterm, developed only CP; 20 patients, 11 preterm and 9 term infants, developed a psychomotor delay. The most severe clinical picture (CP associated with epilepsy) appeared in 12 infants of adequate weight and in 5 LBW children; the CP appeared in 14 NW patients, 5 LBW, 4 VLBW and 2 ELBW. Psychomotor delay was developed by 8 NW children, 2 LBW and 10 ELBW. Most patients with severe CP presented severe neurological symptoms at birth. Moderate CP involved those who had a mild neurological or systemic symptoms. Furthermore an association emerged between early epilepsy and CP onset and their severity.

CONCLUSION

Neonatal seizures are not related to an increased risk to develop epilepsy. Epilepsy alone is a rare event and it usually complicates CP picture. Most subject with both epilepsy and CP are term infants with adequate weight. Preterm VLBW infants have a greater risk to develop a psychomotor delay. Clinical conditions at birth are related to CP severity (several neonatal neurological signs are the greater risk factors). Severely pathological neonatal EEG (background activity) is related to CP severity and an early symptomatic epilepsy onset is related with both epilepsy and CP severity.