A pilot study of the teratogenicity of vagus nerve stimulation in a rabbit model

Pregnancy Outcomes in Refractory Epilepsy Patients with Vagus Nerve Stimulation: Long-Term Single-Center Experience

BACKGROUND AND STUDY AIMS

 Vagus nerve stimulation (VNS) has been employed worldwide as an adjunctive therapy in drug-resistant epilepsy patients. However, the mechanisms of VNS action potentially increase the risk of obstetric complications. The study presents the long-term single-center experience with pregnancies and childbirth in women with VNS for refractory epilepsy based on prospectively collected epileptologic data and a retrospective analysis of pregnancy, childbirth, and data about long-term child development.

MATERIAL AND METHODS

 From a group of patients with VNS implanted for refractory epilepsy between October 1999 and January 2018, all the women of childbearing age (younger than 40 years) were identified. After checking their hospital records for data about any pregnancies, the women with confirmed childbirth during active VNS stimulation and their general practitioners were interviewed based on a prepared questionnaire regarding their gynecologic history, the course of pregnancy and childbirth, gestational week, birth weight and length, any congenital anomalies of the child, and the child's psychomotor development, school performance, and somatic health problems.

RESULTS

 From the group of 257 patients implanted with VNS for refractory epilepsy, 4 women (1.5%) became pregnant and gave birth (all on polypharmacotherapy). The mean interval from VNS implantation to birth was 44.3 months. Slight seizure worsening during the last trimester was reported in one woman. In one patient, acute caesarean section was required due to placental separation. Planned birth induction and caesarean section were used in the other two women because of their seizure disorder. No malfunction of the stimulation system was detected during pregnancy or after birth. No congenital malformations were observed. The two children who were of school age at the time of this study require special schooling.

CONCLUSIONS

 The study results confirmed a high rate of obstetric interventions in patients with VNS. Although no teratogenic effect of VNS has been proven, the higher incidence of children exposed to VNS needing special education requires attention.

Is vagal-nerve stimulation safe during pregnancy? A mini review

BACKGROUND

Vagus-nerve stimulation (VNS) is the most common neuromodulation technique and has been approved by the FDA for treating refractory epilepsy and refractory depression. Although VNS has been used for nearly 32 years, the impact of VNS on the safety of pregnant women and neonate remains to be evaluated.

METHODS

We first analyze the relationship between the vagus nerve and the reproductive system (ovary and uterus) and then determine whether harm is inflicted to the reproductive system, thereby affecting the pregnancy. A comprehensive literature search is performed on PubMed/MEDLINE database, Web of Science, and Scopus. Ten articles are included in the study, and 44 pregnancies of 38 patients are analyzed.

RESULTS

The vagus nerve is connected with the reproductive system, but VNS may have little effect on pregnancy. We analyze 10 articles (38 patients with 44 pregnancies) about VNS complications during pregnancy. Two of the 44 pregnancies (2/44, 4.5 %) are miscarriages, and two pregnancies have fetuses with congenital malformations (2/42, 4.8 %), which could also be attributed to polytherapy with antiepileptic drugs. The rest of the pregnant women have no postpartum complications, and their fetuses are healthy.

CONCLUSIONS

VNS may be relatively safe and effective for the fetus and mother during pregnancy, and turning off VNS during pregnancy is unnecessary. However, owing to the small sample size and short follow-up time in the present study, further research is needed.

Epidemiology of Microsatellite Instability High (MSI-H) and Deficient Mismatch Repair (dMMR) in Solid Tumors: A Structured Literature Review

Background. Given limited data on the epidemiology of MSI-H and dMMR across solid tumors (except colorectal cancer (CRC)), the current study was designed to estimate their prevalence. Materials and Methods. A structured literature review identified English language publications that used immunohistochemistry (IHC) or polymerase chain replication (PCR) techniques. Publications were selected for all tumors except CRC using MEDLINE, EMBASE, and Cochrane databases and key congresses; CRC and pan-tumor genomic publications were selected through a targeted review. Meta-analysis was performed to estimate pooled prevalence of MSI-H/dMMR across all solid tumors and for selected tumor types. Where possible, prevalence within tumor types was estimated by disease stages. Results. Of 1,176 citations retrieved, 103 and 48 publications reported prevalence of MSI-H and dMMR, respectively. Five pan-tumor genomic studies supplemented the evidence base. Tumor types with at least 5 publications included gastric (n = 39), ovarian (n = 23), colorectal (n = 20), endometrial (n = 53), esophageal (n = 6), and renal cancer (n = 8). Overall MSI-H prevalence (with 95% CI) across 25 tumors was based on 90 papers (28,213 patients) and estimated at 14% (10%–19%). MSI-H prevalence among Stage 1/2 cancers was estimated at 15% (8%–23%); Stages 3 and 4 prevalence was estimated at 9% (3%–17%) and 3% (1%–7%), respectively. Overall, dMMR prevalence across 13 tumor types (based on 54 papers and 20,383 patients) was estimated at 16% (11%–22%). Endometrial cancer had the highest pooled MSI-H and dMMR prevalence (26% and 25% all stages, respectively). Conclusions. This is the first comprehensive attempt to report pooled prevalence estimates of MSI-H/dMMR across solid tumors based on published data. Prevalence determined by IHC and PCR was generally comparable, with some variations by cancer type. Late-stage prevalence was lower than that in earlier stages.

Experience on the use of Vagus Nerve Stimulation during pregnancy

OBJECTIVE

Vagus Nerve Stimulation (VNS) is a neuromodulation device approved for the treatment of medically refractory epilepsy. Worldwide, only 35 cases of pregnancies that has been described. This study aims to continue to increase the limited knowledge of the use of VNS during pregnancy.

METHODS

We interrogated the database of the Epilepsy program at Western University (1998-2018), and identified those patients who were implanted with VNS and became pregnant.

RESULTS

From 114 patients implanted with VNS in our centre, four patients had a total of seven pregnancies. This is the first report with one woman implanted with VNS having three pregnancies. Three patients had genetic generalized epilepsy and one focal epilepsy due to periventricular nodular heterotopia. The median duration since implantation was 3.17 years (IQR: 1.33-4.33) and the output was 2.75 mA (IQR: 1.5-3.5). No modifications in stimulation settings were made in any patient during pregnancy. Three patients had obstetric complications, requiring c-sections. All babies were healthy, except one with intellectual disabilities of unclear severity.

CONCLUSION

Our small sample suggests VNS could increase the obstetrical complications, but is likely safe for the fetus. However, a larger sample size should be collected to determine safety and potential teratogenicity of VNS.

VNS and pregnancy: A multicentric experience of four cases

BACKGROUND

Vagus nerve stimulation system (VNS) has been employed worldwide as adjunctive therapy in drug-resistant epileptic patients. Only nine previous pregnancies with six-positive outcomes have been reported in women with epilepsy treated with VNS since 1998.

AIMS OF THE STUDY

To communicate the experience of pregnancies in women treated with VNS in our country.

METHODS

Clinical data of four female patients treated with VNS during pregnancy and delivery in five gestations is described.

RESULTS

Four pregnancy outcomes were positive and one ended in spontaneous abortion, probably more related to the use antiepileptic drugs than VNS itself. Two births were vaginal and the other two with cesarean section. None of the complications during delivery were attributed to VNS. No teratogenicity was documented.

CONCLUSIONS

Based on our experience VNS constitutes a safe therapy for the treatment of drug-resistant epilepsy in women of childbearing potential and during pregnancy and delivery. Larger series will be useful to confirm this finding.

Reduction in mortality and teratogenicity following simultaneous administration of folic acid and vitamin E with antiepileptic, antihypertensive and anti-allergic drugs

Aim:

The present study was designed to evaluate the teratogenic effects on breeding pattern in mice following administration of lamotrigine (LT) and levetiracetam (LV) and its combination with anti-hypertensive and anti-allergic drugs. Moreover, possibility of decrease in teratogenic effect was also evaluated upon simultaneous administration of these combinations with folic acid or vitamin E.

Materials and Methods:

The study was carried out on mature female mice housed in polycarbonate breeding cages. Drugs were administered continuously till the birth of neonates and pups were examined for any teratogenic potential of drugs.

Results:

The results of the study reveals that teratogenic effects of lamotrigine, methyldopa and loratadine (LTMLO) combination were seems to be reduced upon simultaneous administration with folic acid, while addition of vitamin E was found to be more effective in reducing the mortality rate of levetiracetam, methyldopa and loratadine combination.

Conclusion:

Teratogenic effects of LTMLO combination were better prevented by folic acid. However, further studies on large number of animals and humans are required before reaching to definite conclusion.

Biologically based treatment approaches to the patient with resistant perinatal depression

This study aims to summarize the current state of knowledge regarding approaches to treatment-resistant depression in pregnancy and the postpartum period and to develop algorithms for ante- and postnatal management in cases of refractory major depression. PubMed, Scopus, Google Scholar, and the Cochrane Library databases were searched without temporal restriction. Search terms included pregnancy and depression, perinatal depression, postnatal depression, treatment resistance and depression, antipsychotics and pregnancy, antidepressants and pregnancy, and mood stabilizers and pregnancy. Abstracts were reviewed for relevance, and further articles were obtained from bibliographic citations. There is a significant subpopulation of patients in pregnancy and postpartum whose depressive symptoms do not respond to first-line treatments. No research studies have focused specifically on this population. Data extracted from studies on women with depressive symptoms in pregnancy suggest that in the absence of evidence on which to base clinical decisions, many are receiving combinations of psychotherapeutic medications that have not been specifically studied for use in pregnancy. Antidepressant use in pregnancy is well studied, but studies specifically addressing the case of the patient who does not respond to first-line treatments are absent. Research in this area is urgently needed. The authors review a number of possible therapeutic approaches to treatment-resistant depression in pregnancy and the postpartum period.

Neurostimulation-past, present, and beyond

Neurostimulation as a treatment for epilepsy has been around for almost 20 years in the form of vagus nerve stimulation. Newer types of neurostimulation are being developed and stand on the brink of approval for use. The two newest therapies, not yet approved in the United States, are deep brain stimulation and the Responsive Neurostimulator System . In fact, in Europe, approval has already been given for deep brain stimulation and newer forms of vagus nerve stimulation. Efficacy is similar between these therapies, and side effects are moderate, so what will be the future? The challenge will be to learn how to use these therapies correctly and offer the right treatment for the right patient.

Robust observer-based tracking control of hodgkin-huxley neuron systems under environmental disturbances

A nervous system consists of a large number of highly interconnected nerve cells. Nerve cells communicate by generation and transmission of short electrical pulses (action potential). In addition, membrane voltage is the only measurable state in nervous systems. A robust observer-based model reference tracking control is proposed for Hodgkin-Huxley (HH) neuron systems to generate a desired reference response in spite of environmental noises, uncertain initial values, and diffusion currents from other interconnected nerve cells. In order to simplify the robust tracking control design of nonlinear stochastic HH neuron systems, a fuzzy interpolation method is employed to interpolate several linear stochastic systems to approximate a nonlinear stochastic HH neuron system so that the nonlinear robust tracking control problem can be solved by the linear matrix inequality (LMI) technique with the help of Robust Control Toolbox in Matlab. The proposed robust observer-based tracking control scheme can provide new methods for desired action potential generation, suppression of oscillations, and blockage of action potential transmission under environmental noise and diffusion currents. These new methods are useful for patients with different neuron system dysfunctions. Finally, three simulation examples of tracking control of nervous systems are given to illustrate the design procedure and confirm the tracking performance of the proposed method.