Longitudinal evaluation of motor function in patients who underwent prenatal or postnatal neural tube defect repair

OBJECTIVE

To compare the evolution of motor function from mid-gestation to 12 months of age between prenatally and postnatally repaired cases of open neural tube defect (ONTD).

METHODS

This was a retrospective cohort study of all fetuses that underwent prenatal (fetoscopic or open hysterotomy) or postnatal ONTD repair at a single institution between November 2011 and December 2018. The anatomical level of the lesion was defined as the upper bony spinal defect at initial magnetic resonance imaging assessment. Prenatal motor function of the lower extremities was evaluated by ultrasound according to the metameric level of the neurological lesion, based on the methodology of Carreras et al. Fetal motor function was assessed at referral, at 6 weeks after surgery in prenatally repaired cases or 6 weeks after referral in postnatally repaired cases (6-week follow-up) and at the last scan before delivery. In addition, motor function was assessed by a detailed neurological examination at birth and 12 months of age. First sacral (S1) neurological level of the lesion was considered as intact motor function. For statistical comparisons, we attributed numerical scores to each neurological level and motor function was expressed as median (range) neurological level. Motor function (as numerical score) and the proportion of cases with intact motor function and with motor function two or more levels better than expected based on the anatomical level of the lesion were compared between the prenatal- and postnatal-repair groups. Fetal motor function was compared to the anatomical level of the lesion at referral and a better motor function was defined when it was two or more levels better than the anatomical level of the lesion. To assess the evolution of motor function, we compared motor function at referral with that at each follow-up assessment using paired t-tests.

RESULTS

We included 127 patients with ONTD, of whom 93 underwent prenatal (51 fetoscopic and 42 open hysterotomy) and 34 postnatal repair. At the time of referral, cases in the prenatal- and postnatal-repair groups presented with a similar anatomical level of lesion (L3 (T9-S1) vs L3 (T7-S1); P = 0.52), similar motor function (S1 (L1-S1) vs S1 (L1-S1); P = 0.52) and a similar proportion of cases with intact motor function (81% vs 79%; P = 0.88) and with motor function two or more levels better than expected based on the anatomical level of the lesion (62% vs 74%; P = 0.24). When compared with prenatally repaired cases, postnatally repaired cases showed worse motor function at birth (S1 (L1-S1) vs L4 (L1-S1); P < 0.01) and at 12 months of age (S1 (L1-S1) vs L4 (L1-S1); P < 0.01). In the prenatal-repair group, motor function remained stable from the time of referral to 12 months of age (P = 0.26). Furthermore, the proportion of patients with intact motor function at referral (81% (75/93)) was similar to that at the 6-week follow-up (74% (64/87)), at the last scan before birth (74% (42/57)), at birth (68% (63/93)) and at 12 months of age (67% (39/58)) in the prenatal-repair group. In the postnatal-repair group, worse motor function, starting from the third trimester to 12 months of age, was observed. The proportion of patients with intact motor function at referral (79% (27/34)) was similar to that at 6-week follow-up (80% (12/15); P = 0.92), but was lower at the last assessment before birth (25% (2/8); P < 0.01), at birth (24% (8/34); P < 0.01) and at 12 months of age (28% (7/25); P < 0.01). Similar findings were noted when assessing the evolution of the proportion of cases with motor function two or more levels better than expected based on the anatomical level of the lesion in each group.

CONCLUSIONS

Infants with ONTD that underwent postnatal repair had worse motor function at birth and at 12 months of age than at mid-gestation and when compared with infants that underwent prenatal ONTD repair. Prenatal motor function assessment by ultrasound is an adequate tool to identify those infants who should have a good clinical motor function after delivery. Information obtained by fetal motor function assessment can have an important role for patient counseling and case selection for surgery. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

DNA from both high-capacity and first-generation adenoviral vectors remains intact in skeletal muscle

Previous studies of the use of adenoviral vectors in animal models of gene therapy have focused on the immune response against transduced cells as the major limiting factor to long-term transgene expression. In this study we eliminated the variable of immunity induced by expression of the transgene in order to investigate vector DNA stability of both first-generation and high-capacity adenoviral vectors after gene transfer to skeletal muscle. Transgene expression from a high-capacity adenoviral vector remained at a high level for at least 20 weeks and was accompanied by persistence of intact vector genomes. In contrast, transgene expression from a first-generation adenoviral vector markedly diminished by 6 weeks after gene transfer and was accompanied by mild and variable inflammatory cell infiltrates. Surprisingly, despite this loss of transgene expression, the first-generation adenoviral vector genomes persisted like the high-capacity adenoviral vector genomes. Therefore, in the absence of immunity to transgene proteins, loss of expression from the first-generation vector was due to inhibition of transgene expression rather than to the elimination of vector-containing cells. DNA stability and persistent expression of the high-capacity adenoviral vector supports the potential of this vector for clinical applications of muscle gene transfer.

Persistence in muscle of an adenoviral vector that lacks all viral genes

Genetic correction of inherited muscle diseases, such as Duchenne muscular dystrophy, will require long term expression of the recombinant protein following gene transfer. We have shown previously that a new adenoviral vector that lacks all viral genes expressed both full-length dystrophin and beta-galactosidase in mdx (dystrophin-deficient) mouse muscle. We observed a significant histologic improvement of vector-transduced mdx muscle before the eventual loss of vector-encoded transgene expression. In this study, we investigated whether an immunological response against vector-encoded beta-galactosidase contributed to the loss of vector expression and affected vector persistence in muscle. Intramuscular vector injection in control normal mice resulted in an early and complete loss of beta-galactosidase expression accompanied by predominantly CD4+ and CD8+ lymphocytic infiltration and a significant loss of vector DNA. In contrast, intramuscular vector injection in lacZ transgenic mice resulted in persistent expression of beta-galactosidase for at least 84 days with no evidence of inflammation or significant loss of vector DNA. Our studies demonstrate that, in the absence of an immune response induced by beta-galactosidase expression, an adenoviral vector lacking all viral genes is stably maintained in muscle.

Glutathione S-transferases of female A/J mouse liver and forestomach and their differential induction by anti-carcinogenic organosulfides from garlic

This study characterizes glutathione (GSH) S-transferase (GST) isoenzymes of the liver and forestomach of the female A/J mouse and compares their specificities in catalyzing the conjugation of GSH with 7beta,8alpha-dihydroxy-9alpha,10alpha-oxy-7,8,9, 10-tetrahydrobenzo[a] pyrene (anti-BPDE), the ultimate carcinogenic metabolite of benzo[a]pyrene (BP). The GST activity in female A/J mouse liver was expressed by a minimum of seven isoenzymes which arose from different homo- or heterodimeric combinations of at least two alpha class (designated as alpha1 and alpha4), four micro class (micro1 to micro4), and one pi class GST subunit. The GST isoenzyme composition of A/J mouse forestomach appeared to be different from that of the liver. For example, while GST isoenzymes containing micro3 and micro4 type subunits were selectively expressed in the liver, an alpha class heterodimeric GST isoenzyme (containing alpha2 and alpha3 subunits) was expressed in the forestomach but could not be detected in the liver. The (+)-anti-BPDE appeared to be a better substrate than the (-)-enantiomer for all GSTs, except for isoenzymes containing the alpha4 type GST subunit. The murine pi class GST isoenzyme displayed relativey higher specific activity toward (+)-anti-BPDE compared to other GSTs. The specific activities of mouse GSTs toward (+)-anti-BPDE were in the order of pi > micro > alpha. These results suggest that the pi class GST isoenzyme may play an important role in providing protection against BP-induced cancer. Therefore, it seems logical to postulate that the ability of a chemoprotector to increase the expression of GST pi may be an important determinant of its effectiveness against BP-induced cancer. To test the validity of this contention, we have determined the effects on hepatic and forestomach GST isoenzyme/subunit expression of three naturally occurring organosulfides (OSCs) from garlic, which significantly differ in their effectiveness against BP-induced forestomach cancer. Treatment of mice with diallyl sulfide (DAS) and diallyl trisulfide (DATS), which are potent inhibitors of BP-induced fore- stomach cancer in mice, resulted in a significant increase in hepatic and forestomach GST activity toward anti-BPDE. On the contrary, this activity was not increased in either organ by dipropyl sulfide (DPS), which is ineffective against BP-induced forestomach cancer. The chemopreventive efficacy of these OSCs correlated with their ability to increase the expression of GST pi. For example, DAS treatment resulted in approximate increases of 1.7- and 2.2-fold in hepatic and forestomach GST pi expression, respectively, over the control. Treatment of mice with DATS, which is a relatively more potent inhibitor of BP-induced forestomach cancer than DAS, resulted in about 3.8- and 3.2-fold increases, respectively, in hepatic and forestomach GST pi expression over the control. On the contrary, the expression of hepatic and forestomach GST pi was increased only marginally (10-20%) upon DPS administration. In conclusion, the results of the present study suggest that induction of GST pi can be used as a bioassay for screening potential inhibitors of BP-induced cancer.