DNA methylation analysis of Homeobox genes implicates HOXB7 hypomethylation as risk factor for neural tube defects

Neural tube defects (NTDs) are common birth defects of complex etiology. Though family- and population-based studies have confirmed a genetic component, the responsible genes for NTDs are still largely unknown. Based on the hypothesis that folic acid prevents NTDs by stimulating methylation reactions, epigenetic factors, such as DNA methylation, are predicted to be involved in NTDs. Homeobox (HOX) genes play a role in spinal cord development and are tightly regulated in a spatiotemporal and collinear manner, partly by epigenetic modifications. We have quantified DNA methylation for the different HOX genes by subtracting values from a genome-wide methylation analysis using leukocyte DNA from 10 myelomeningocele (MMC) patients and 6 healthy controls. From the 1575 CpGs profiled for the 4 HOX clusters, 26 CpGs were differentially methylated (P-value < 0.05; β-difference > 0.05) between MMC patients and controls. Seventy-seven percent of these CpGs were located in the HOXA and HOXB clusters, with the most profound difference for 3 CpGs within the HOXB7 gene body. A validation case-control study including 83 MMC patients and 30 unrelated healthy controls confirmed a significant association between MMC and HOXB7 hypomethylation (-14.4%; 95% CI: 11.9-16.9%; P-value < 0.0001) independent of the MTHFR 667C>T genotype. Significant HOXB7 hypomethylation was also present in 12 unaffected siblings, each related to a MMC patient, suggestive of an epigenetic change induced by the mother. The inclusion of a neural tube formation model using zebrafish showed that Hoxb7a overexpression but not depletion resulted in deformed body axes with dysmorphic neural tube formation. Our results implicate HOXB7 hypomethylation as risk factor for NTDs and highlight the importance for future genome-wide DNA methylation analyses without preselecting candidate pathways.

Metformin therapy to reduce weight gain and visceral adiposity in children and adolescents with neurogenic or myogenic motor deficit

The aim of this randomized, placebo-controlled study was to explore the effect of metformin in children with a neurogenic or myogenic motor deficit, who are therefore prone to develop overweight, adiposity, and insulin resistance. Study participants (n = 42) had a mean age of 15.5 yr, a short stature (height -2.4 SD), a relatively high BMI (+1.7 SD), and a high body fat fraction (41.9% or +2.8 SD). Abdominal CT confirmed the high fat mass and disclosed a high fraction of visceral fat. As expected, insulin resistance was increased. As compared to placebo, metformin intake for 6 months exerted an insulin sensitizing effect and lowered weight (mean difference of 2 kg within 6 months, p = 0.007) and BMI (p = 0.016). Weight loss appeared to be primarily due to loss of visceral fat ( approximately 20% vs. placebo; p < 0.0001). Results were similar across diagnostic subgroups. In conclusion, metformin treatment for 6 months was associated with a rise in insulin sensitivity and with a reduction of visceral adiposity in children and adolescents with a primary muscle disorder or with a neural tube defect. These findings suggest that insulin resistance underpins, at least partly, the overweight and visceral adiposity of these patients, who are not necessarily obese.

The neurogenic bladder: medical treatment

Neurogenic bladder sphincter dysfunction (NBSD) can cause severe and irreversible renal damage and bladder-wall destruction years before incontinence becomes an issue. Therefore, the first step in adequate management is to recognize early the bladder at risk for upper- and lower-tract deterioration and to start adequate medical treatment proactively. Clean intermittent catheterization combined with anticholinergics (oral or intravesical) is the standard therapy for NBSD. Early institution of such treatment can prevent both renal damage and secondary bladder-wall changes, thereby potentially improving long-term outcomes. In children with severe side effects or with insufficient suppression of detrusor overactivity despite maximal dosage of oral oxybutynin, intravesical instillation is an effective alternative. Intravesical instillation eliminates systemic side effects by reducing the first-pass metabolism and, compared with oral oxybutynin, intravesical oxybutynin is a more potent and long-acting detrusor suppressor. There is growing evidence that with early adequate treatment, kidneys are saved and normal bladder growth can be achieved in children so they will no longer need surgical bladder augmentation to achieve safe urinary continence in adolescence and adulthood.

Segmental spinal cord hypoplasia and meningocele with preservation of medullary function: case report

BACKGROUND

In very rare dysraphic cases, it is not clear whether the primary abnormalities are in the neural elements, or in the bony elements.

CASE DESCRIPTION

We describe a case of segmental hypoplasia of the spinal cord, with absent nerve roots in the afflicted segments, and associated meningocele and vertebral abnormalities. We illustrate the arguments for and against the classification of this lesion either as an atypical case of myelomeningocele (MMC) or as a mild case of segmental spinal dysgenesis (SSD).

CONCLUSIONS

Possibly, in this exceptional case, the primary defect is in the neural tissue like in more usual cases of MMC and not in the spine, like in segmental spinal dysgenesis.

Results after surgery for lumbosacral lipoma: the significance of early and late worsening

We retrospectively reviewed 32 patients operated on for lipoma of the conus and lipomyeloschisis, the two main anatomical subtypes of congenital lumbosacral lipomas associated with tethered cord syndrome. Surgery was proposed to patients when they were symptomatic, and in most cases for progressive symptoms. The evolution of the different symptoms was studied separately. In most patients, symptoms improved or stabilized after surgery; in some, however, postoperative worsening, at least of some of the symptoms, was seen. This postoperative worsening became apparent either early or late after the operation, and was not associated with surgical trauma or postoperative complications. We suggest it was caused mainly by the natural course of the disease (especially in the case of the orthopedic deformities), and in some cases by retethering. Our series is not large enough to detect statistical significance for the different symptoms or for the anatomical subgroups. Importantly, according to our analysis by the different symptoms, the operation did not seem to protect the patients from later development of new deficits. This can be interpreted as an argument against prophylactic surgery in asymptomatic patients.

Intravesical application of a stable oxybutynin solution improves therapeutic compliance and acceptance in children with neurogenic bladder dysfunction

PURPOSE

To improve patient compliance with and acceptance of intravesical oxybutynin therapy for neurogenic bladder dysfunction we developed a stable oxybutynin solution that eliminates the complicated crushing procedure.

MATERIALS AND METHODS

From January 1995 to January 1997 we prospectively evaluated 15 children with a mean age of 6.1 years with persistent detrusor hyperactivity or significant side effects on oral oxybutynin therapy who received intravesically 0.2 mg./kg. (maximum 5 mg.) of a stable oxybutynin solution (5 mg./5 ml., pH 5.85) twice daily.

RESULTS

The oxybutynin solution remained stable up to 24 months. In 13 of the 15 children therapeutic compliance was excellent. Detrusor hyperactivity decreased and systemic side effects were absent or minimal. After 4 and 24 months mean cystometric bladder capacity plus or minus standard error of mean increased from 114+/-15.2 to 161+/-26.6 and 214+/-21.7 ml. (p <0.01), mean ratio of cystometric-to-expected bladder capacity increased from 0.88+/-0.12 to 1.18+/-0.14 and 1.24+/-0.16 (p <0.01), and end filling bladder pressure decreased from 57.0+/-7.1 to 25.6+/-4.4 and 30.8+/-4.4 cm. water (p <0.01), respectively.

CONCLUSIONS

Intravesical instillation of a specially prepared oxybutynin solution is safe and reliable in children with persistent detrusor hyperactivity or side effects on oral oxybutynin therapy. Eliminating the complex crushing preparation of the solution by the child or parent has made this therapy easy to use and acceptable in the long term.

Intravesical oxybutynin for neurogenic bladder dysfunction: less systemic side effects due to reduced first pass metabolism

PURPOSE

To unravel why intravesical oxybutynin is more effective and causes significantly fewer systemic side effects than oral oxybutynin in the treatment of neurogenic bladder dysfunction, we tested the hypothesis that the absorption and metabolism of oxybutynin are changed after intravesical instillation.

MATERIALS AND METHODS

A high-performance liquid chromatography assay was developed for both oxybutynin and its active metabolite, N-desethyl-oxybutynin. Plasma concentrations were quantified after intravesical (n = 11) and oral (n = 5) administration of oxybutynin in children under steady-state conditions. Pharmacokinetic parameters were calculated.

RESULTS

Oral administration of oxybutynin (0.2 mg./kg./dose) resulted in peak plasma concentrations for N-desethyl-oxybutynin which were 7.4 +/- 1.3 times higher than corresponding values for oxybutynin (n = 5). Also the AUC (area under the plasma concentration time curve) values were higher for N-desethyl-oxybutynin compared with those of oxybutynin, the ratio being 10.8 +/- 1.0 (n = 5). Intravesical instillation (0.2 mg./kg./dose), on the other hand, resulted in reduced metabolite generation and peak plasma concentrations for N-desethyl-oxybutynin which were in the same range as those for oxybutynin, the ratio being 1.2 +/- 0.1 (n = 11). The ratio for the AUC values for N-desethyl-oxybutynin and oxybutynin was 2.1 +/- 0.2 (n = 11).

CONCLUSIONS

The significantly lower AUC ratio of the N-desethyl metabolite over the mother compound, due to a reduced first pass metabolism, may explain the clinically relevant reduction of side effects that characterizes intravesical compared with oral oxybutynin therapy.

Intravesical oxybutynin for neurogenic bladder dysfunction: less systemic side effects due to reduced first pass metabolism

PURPOSE

To unravel why intravesical oxybutynin is more effective and causes significantly fewer systemic side effects than oral oxybutynin in the treatment of neurogenic bladder dysfunction, we tested the hypothesis that the absorption and metabolism of oxybutynin are changed after intravesical instillation.

MATERIALS AND METHODS

A high-performance liquid chromatography assay was developed for both oxybutynin and its active metabolite, N-desethyl-oxybutynin. Plasma concentrations were quantified after intravesical (n = 11) and oral (n = 5) administration of oxybutynin in children under steady-state conditions. Pharmacokinetic parameters were calculated.

RESULTS

Oral administration of oxybutynin (0.2 mg./kg./dose) resulted in peak plasma concentrations for N-desethyl-oxybutynin which were 7.4 +/- 1.3 times higher than corresponding values for oxybutynin (n = 5). Also the AUC (area under the plasma concentration time curve) values were higher for N-desethyl-oxybutynin compared with those of oxybutynin, the ratio being 10.8 +/- 1.0 (n = 5). Intravesical instillation (0.2 mg./kg./dose), on the other hand, resulted in reduced metabolite generation and peak plasma concentrations for N-desethyl-oxybutynin which were in the same range as those for oxybutynin, the ratio being 1.2 +/- 0.1 (n = 11). The ratio for the AUC values for N-desethyl-oxybutynin and oxybutynin was 2.1 +/- 0.2 (n = 11).

CONCLUSIONS

The significantly lower AUC ratio of the N-desethyl metabolite over the mother compound, due to a reduced first pass metabolism, may explain the clinically relevant reduction of side effects that characterizes intravesical compared with oral oxybutynin therapy.

Tethered cord syndrome in occult spinal dysraphism: timing and outcome of surgical release

OBJECTIVE

To investigate the influence of neurosurgical intervention on the appearance of upper motor neuron (UMN) signs in newborns diagnosed with occult spinal dysraphism and tethered cord (TC) during the first month of life.

METHODS

A prospective study (1990 to 1996) of 22 consecutive newborns with occult spinal dysraphism monitored for the appearance of UMN signs. Untethering was performed when neurologic or urodynamic investigation indicated the presence of UMN dysfunction.

RESULTS

Of 22 patients, 10 remained free of UMN symptoms during follow-up (mean, 67+/-22 months). Untethering was performed in 12 of 22 patients because of the presence of UMN symptoms. In 7 of these 12 patients, there was a documented asymptomatic period of 13+/-11 months before the onset of UMN symptoms. Untethering at a mean age of 18+/-17 months restored normal neurologic and urinary function in all patients (mean postoperative follow-up, 25+/-16 months). Of the 12 children, 5 presented with UMN signs at birth. In these children, untethering was performed at a mean age of 9+/-5 months. In two of these five patients, UMN symptoms did not resolve after surgery, and ongoing conservative bladder treatment was required (mean follow-up, 37+/-14 months). In none of the 12 operated children did signs of retethering occur.

CONCLUSIONS

A significant number (10/22) of children born with occult spinal dysraphism and TC did not develop UMN symptoms during follow-up; neurosurgical correction after the appearance of an UMN sign restored normal neurologic and urinary function in all children; and untethering in children presenting at birth with UMN symptoms resulted in poorer outcome.

Alcoholism and emotional reactivity: more heterogeneous film-induced emotional response in newly detoxified alcoholics compared to controls--a preliminary study

Alcoholics are thought to be characterized by irregular emotional responses, having trouble reaching an optimal level of emotional arousal. They therefore may use alcohol to restore emotional homeostasis. This study investigated whether recently detoxified alcoholics show different emotional responses as compared to controls. Film excerpts were used to induce emotions in 14 newly detoxified alcoholics (9 men, 5 women) and matched controls in a standardized laboratory setting. Subjective emotional (questionnaires) and physiological measures were employed. Depression and cognitive deterioration were controlled. Based on subjective ratings, alcoholics displayed greater variability of emotion; they displayed also fewer or no physiological arousal changes. Subjective emotional responses were exceedingly high or low. These differences were not accounted for by depression or cognitive deterioration. We hypothesize that alcohol could be used to restore an optimal level of emotional arousal. This homeostatic function of alcohol is yet to be clearly assessed.

Closed spinal dysraphism: a review on diagnosis and treatment in infancy

This article reviews the clinical presentation, pathophysiology, diagnostic strategies, and therapeutic management of closed spinal dysraphism in infancy. Four groups of symptoms are distinguished: (1) cutaneous abnormalities, (2) lower motor neuron dysfunction due to congenital spinal and nerve root abnormalities, (3) upper motor neuron dysfunction due to tethering of the spinal cord, and (4) symptoms caused by associated malformations. Guidelines are proposed concerning timing and type of diagnostic investigations in infancy. This essentially encompasses a neurological assessment, including spinal ultrasonography and nuclear magnetic resonance imaging of the spine and the brain, and a urological assessment, including ultrasonography of kidneys and bladder, cystourethrography and a urodynamic study. As to the tethered cord syndrome it is concluded that first, already in infancy, a progressive neurological dysfunction can be detected; second, surgical untethering should be performed only upon appearance of upper motor neuron signs or upon progression of lower motor neuron signs. Despite its frequently asymptomatic course, the diagnosis of a congenital lumbosacral lipoma, and in the more general sense, of a closed spinal dysraphism, implies a periodic, multidisciplinary follow-up for life.

Treatment of neurogenic bladder dysfunction in infants and children with neurospinal dysraphism with clean intermittent (self)catheterisation and optimized intravesical oxybutynin hydrochloride therapy

Clean intermittent (self)catheterisation (CIC) in combination with oral anticholinergic drugs (oxybutynin hydrochloride [OH] is the present standard therapy for neurogenic bladder dysfunction (NBD) with detrusor hyperactivity. However, complete suppression of detrusor contractions and complete urinary continence is not always obtained despite maximal dosage, and the high incidence of severe systemic anticholinergic side-effects often impairs therapeutic compliance, resulting in dose reduction or even discontinuation of therapy. The intravesical administration of OH has been shown recently to be an effective alternative for treating persistent detrusor hyperactivity, and occurrence and severity of systemic side-effects appeared to be significantly decreased. However, available data are limited from a paediatric view. Furthermore, it is our belief that the use of crushed OH tablets with consequent problems of impracticability accounts for the variable long-term patient compliance reported to be the only disadvantage to intravesical OH. Using an optimized drug preparation we demonstrate the superiority of intravesical OH for treatment of NBD in 15 children (range 0.6-13.75 years, mean 6.1) with incomplete detrusor activity suppression and/or intolerable systemic side-effects on oral OH therapy. Since the previous reported problems of impracticability and variable long-term patient compliance can be resolved by optimized drug preparation, we therefore conclude that the era of crushing OH tablets should be over in order to allow the intravesical OH therapy on a long-lasting and large-scale basis.

Conservative versus neurosurgical treatment of tethered cord patients

We compared the outcome of neurosurgical release of a tethered spinal cord in 20 children with the neurological evolution of 21 other children known iwth a tethered spinal cord on nuclear magnetic resonance scan (NMR). Neurosurgery yielded stabilisation of the symptoms without any lasting improvement. Pre-operative conservative medical treatment had to be continued in all operated children. Three of the 20 operated children are showing signs of retethering despite appropriate neurosurgery, indicating that retethering should be considered as a major and frequent complication. In the majority of our children, symptomatic (re)tethering was recognised by the appearance of increased tendon reflexes and a progressive pes cavus, suggestive of an upper motor neuron disease involvement.