Interictal psychosis following temporal lobe surgery: dentate gyrus pathology

Radiological findings in brain MRI scans in youth with early-onset psychosis: A controlled study

There is a lack of consensus on whether routine brain magnetic resonance imaging (MRI) should be recommended as part of the initial assessment in patients with psychosis. No study so far has qualitatively assessed brain MRI in patients with early-onset psychosis (EOP), in whom neurodevelopmental factors may play a stronger role. We aimed to determine the prevalence of brain MRI findings in patients with EOP compared to healthy controls, and assess whether these findings were clinically relevant. Retrospective clinical chart review of all patients with EOP in whom a brain MRI scan was acquired during admission to an inpatient child and adolescent psychiatry unit during January 2013-December 2017, compared to age and biologically assigned gender matched healthy controls. Between group analyses tested differences in rates of qualitatively abnormal MRI scans and changes in clinical management as a result of radiological findings. A total of 256 individuals were included (128 patients with EOP and 128 healthy controls). Patients with EOP presented with a significantly higher rate of abnormal MRI scans relative to healthy controls (21.9% vs 11.7%, p = .030; OR = 2.11, [95% CI:1.06-4.17]). Radiological findings in the EOP group triggered clinical referral for further evaluation or management more often than in the healthy control group (7.0% vs 1.6%, p = .030; OR = 4.76, [95% CI:1.01-22.50]). MRI scans in youth with EOP may be characterized by an increased number of radiological abnormalities than in controls. The rates of MRI findings requiring clinical referral suggests that routine MRI acquisition may need to be considered in patients with EOP.

Expression of reelin with age in the human hippocampal formation

Reelin plays a key role in neuronal migration and lamination in the cortex and hippocampus. Animal studies have shown that reelin expression decreases with age. The aim of this study was to evaluate the expression of reelin in all layers of the human hippocampal formation across three age groups. We used immunohistochemistry in formalin fixed and paraffin embedded hippocampal tissue from infants (1-10 months; n = 9), children (4-10 years; n = 4), and adults (45-60 years; n = 6) to stain for reelin. Expression was quantified (measured as the number of positive reelin cells/mm² ) in the granule cell layer of the dentate gyrus (DG), the molecular layer of the dentate gyrus (ML), the hippocampal fissure (HF), stratum lacunosum moleculare (SLM), CA4/Hilus and the stratum pyramidale layer of CA3, CA2, and CA1. Expression of reelin was highest in the HF irrespective of age, followed by the SLM and ML. Minimal to no expression was seen in the stratum pyramidale layer of CA1-3. With age, reelin expression decreased and was statistically significant from infancy to childhood in the HF (p = .02). This study confirms that reelin expression decreases with age in the human hippocampus, and shows for the first time that the major decrease occurs between infancy and early childhood.

Pathology-Based Approach to Seizure Outcome After Surgery for Pharmacoresistant Medial Temporal Lobe Epilepsy

BACKGROUND

Hippocampal sclerosis (HS) is the most common cause of drug-resistant medial temporal lobe epilepsy (MTLE). Structural abnormalities such as HS, granule cell pathology (GCP), and focal cortical dysplasia (FCD) have been classified histopathologically, possibly allowing a more accurate assessment of prognostic seizure and neuropsychologic outcomes. We correlated seizure outcome with comprehensive temporal lobe pathologic findings, identified according to the most recent classification systems of HS, GCP, and FCD.

METHODS

All the 83 patients who underwent anterior temporal lobectomy (ATL) for drug-resistant MTLE and with a proven diagnosis of HS between April 2001 and May 2014 were collected. Patients were divided in 2 main groups: 1) isolated HS with/without GCP (HS +/- GCP); and 2) HS associated with FCD with/without GCP (HS+FCD +/- GCP). Patients were followed up at least 1 year, and seizure outcome was reported in accordance with Engel classification.

RESULTS

Group I: HS +/- GCP: Statistical analysis confirmed a better outcome in HS + GCP patients than in HS-no GCP (P < 0.05). Moreover, a better outcome for the patients affected by GCP type I was observed (P < 0.05). Group II: HS+FCD +/- GCP: Patients with HS variant type I presented a better seizure outcome than the patients with HS type II (Engel class IA HS type I vs. type II: 69% vs. 40%).

CONCLUSIONS

A pathology-based approach to epilepsy surgery might improve the interpretation of the results, could predict which cases will enjoy a better seizure outcome, and could help to the comprehension of the causes of failures.

Mesial temporal lobe epilepsy with psychiatric comorbidities: a place for differential neuroinflammatory interplay

BACKGROUND

Despite the strong association between epilepsy and psychiatric comorbidities, few biological substrates are currently described. We have previously reported neuropathological alterations in mesial temporal lobe epilepsy (MTLE) patients with major depression and psychosis that suggest a morphological and neurochemical basis for psychopathological symptoms. Neuroinflammatory-related structures and molecules might be part of the altered neurochemical milieu underlying the association between epilepsy and psychiatric comorbidities, and such features have not been previously investigated in humans.

METHODS

MTLE hippocampi of subjects without psychiatric history (MTLEW), MTLE + major depression (MTLE + D), and MTLE + interictal psychosis (MTLE + P) derived from epilepsy surgery and control necropsies were investigated for reactive astrocytes (glial fibrillary acidic protein (GFAP)), activated microglia (human leukocyte antigen, MHC class II (HLA-DR)), glial metallothionein-I/II (MT-I/II), and aquaporin 4 (AQP4) immunohistochemistry.

RESULTS

We found an increased GFAP immunoreactive area in the molecular layers, granule cell layer, and cornus ammonis region 2 (CA2) and cornus ammonis region 1 (CA1) of MTLEW and MTLE + P, respectively, compared to MTLE + D. HLA-DR immunoreactive area was higher in cornus ammonis region 3 (CA3) of MTLE + P, compared to MTLE + D and MTLEW, and in the hilus, when compared to MTLEW. MTLEW cases showed increased MT-I/II area in the granule cell layer and CA1, compared to MTLE + P, and in the parasubiculum, when compared to MTLE + D and MTLE + P. Differences between MTLE and control, such as astrogliosis, microgliosis, increased MT-I/II, and decreased perivascular AQP4 in the epileptogenic hippocampus, were in agreement to what is currently described in the literature.

CONCLUSIONS

Neuroinflammatory-related molecules in MTLE hippocampus show a distinct pattern of expression when patients present with a comorbid psychiatric diagnosis, similar to what is found in the pure forms of schizophrenia and major depression. Future studies focusing on inflammatory characteristics of MTLE with psychiatric comorbidities might help in the design of better therapeutic strategies.

Neurotrophin receptors expression in mesial temporal lobe epilepsy with and without psychiatric comorbidities and their relation with seizure type and surgical outcome

Epilepsy and psychiatric comorbidities are frequently associated, but their common biological substrate is unknown. We have previously reported altered structural elements and neurotrophins (NTs) expression in mesial temporal lobe epilepsy (MTLE) patients with psychiatric comorbidities. NTs receptors can regulate neurotransmission and promote neuroplasticity, being important candidates in the regulation and manifestation of psychopatological states and seizure-related events. MTLE hippocampi of subjects without psychiatric history, MTLE + major depression, MTLE + interictal psychosis derived from epilepsy surgery, and control necropsies were investigated for p75^NTR, TrkB, TrkA, and TrkC immunohistochemistry. Increased expression of p75^NTR, decreased TrkA, unaltered TrkC, and complex alterations involving TrkB expression were seen in MTLE groups. Increased TrkB expression in patients without complete seizure remission and in those with secondarily generalized seizures was seen. Decreased p75^NTR expression associated with interictal psychosis, and increased TrkB in those with psychosis or major depression was also reported, although their p75^NTR/TrkB ratios were lower than in MTLE without psychiatric comorbidities. Our results provide evidence of alterations in expression of NTs receptors in the epileptogenic hippocampus that are differentially modulated in presence of psychiatric comorbidities. As already explored in animal models, even in chronic human MTLE increased TrkB expression, among other NT receptors alterations, may play a major role in seizure type, frequency and surgery outcome.