Molecular imaging for neuroendocrine tumours

Molecular imaging has found numerous applications in oncology as many tumours express or activate tumour specific target molecules or pathways. This relatively new imaging technique results in a better localisation of tumours and improved tumour staging, especially in the setting of hybrid imaging that is in combination with morphological imaging such as computed tomography. In well differentiated neuroendocrine tumours, somatostatin receptor imaging, as one of the first examples of receptor targeted imaging in humans, plays an important role in the diagnostic work-up of these patients. In poorly differentiated neuroendocrine tumours or medullary thyroid carcinoma, 18F-fluorodeoxyglucose PET/CT and dihydroxyphenylalanine PET/CT play an important role due to the limitations of the somatostatin receptor imaging in these tumour entities. These limitations prompted the development of innovations such as radiolabelled somatostatin receptor antagonists for imaging all types of NET and glucagon-like peptide-1 receptor agonists for the imaging of insulinomas. The current review summarises the actual state of knowledge in the field.

Rituximab treatment in seronegative autoimmune autonomic neuropathy and autoimmune autonomic ganglionopathy: Case-report and literature review

BACKGROUND AND PURPOSE

Autoimmune autonomic ganglionopathy (AAG) is a rare disease with no well-established treatment. Until recently, AAG could be seropositive (50 to 60% of patients) or seronegative for ganglionic (α3-type) nicotinic acetylcholine receptor (Gα3NAChR) antibodies. In early 2018, the two forms of the disease were distinguished, separating seropositive from seronegative ones, designating this latter form "seronegative autoimmune autonomic neuropathy" (SAAN). Most described treatments are plasma exchange (PE) and intravenous immunoglobulin (IVIG). However in some cases with no or small benefit, other immunomodulatory therapies, such as rituximab have been reported. We report the case of a 24-year-old female patient successfully treated for SAAN with rituximab and steroids after IVIG and PE failure. We also provide a review of case-reports reporting rituximab treatment for both SAAN and AAG.

METHODS

To identify articles reporting SAAN and AAG treatment with rituximab, we searched the PubMed database using the terms "autoimmune autonomic ganglionopathy", "autoimmune autonomic neuropathy" or "seronegative autoimmune autonomic neuropathy" and "rituximab".

RESULTS

Including our patient, nine cases have been described in the literature (4 SAAN and 5 AAG). Rituximab had a significant positive effect in 2 out of 4 SAAN and all 5 AAG cases, used alone or in association with other etiologic treatments.

CONCLUSION

Our study suggests rituximab (alone or in association with other treatments) could provide efficacy in both SAAN and AAG when PE and/or IVIG are not effective enough.

Severe Protein C Deficiency in Congenital Thrombotic Disease – Description of an Immunoenzymological Assay for Protein C Determination

An immunoenzymatic assay (ELISA) is described for the quantitative assay of protein C in plasma. This technique allows a safe, reliable, and sensitive assay of protein C, and is easily used for routine investigation. Using this technique, a protein C deficiency (0.16 U/ml) was discovered in a 16 year old patient with a history of very severe thrombotic disease. Protein C deficiency was also discovered in his mother (0.62 U/ml) and father (0.50 U/ml). We therefore suggest that this case could represent a homozygous deficiency of protein C.

MED13L-related intellectual disability: involvement of missense variants and delineation of the phenotype

Molecular anomalies in MED13L, leading to haploinsufficiency, have been reported in patients with moderate to severe intellectual disability (ID) and distinct facial features, with or without congenital heart defects. Phenotype of the patients was referred to "MED13L haploinsufficiency syndrome." Missense variants in MED13L were already previously described to cause the MED13L-related syndrome, but only in a limited number of patients. Here we report 36 patients with MED13L molecular anomaly, recruited through an international collaboration between centers of expertise for developmental anomalies. All patients presented with intellectual disability and severe language impairment. Hypotonia, ataxia, and recognizable facial gestalt were frequent findings, but not congenital heart defects. We identified seven de novo missense variations, in addition to protein-truncating variants and intragenic deletions. Missense variants clustered in two mutation hot-spots, i.e., exons 15-17 and 25-31. We found that patients carrying missense mutations had more frequently epilepsy and showed a more severe phenotype. This study ascertains missense variations in MED13L as a cause for MED13L-related intellectual disability and improves the clinical delineation of the condition.

Spatiotemporal analysis of 3D kinematic asymmetry in professional cycling during an incremental test to exhaustion

This study investigated the influence of an incremental exercise on bilateral asymmetry through the spatio-temporal evolution of 3D joint angular displacement, using the Normalized Symmetry Index ([Formula: see text]) and cross-correlation methods. Twelve professional cyclists performed an incremental test to exhaustion, during which motion capture was used. Results revealed a decrease in range of motion between the first and last stages for twelve of the eighteen joint rotations, with the highest impact observed for right hip flexion/extension (61.8 ± 4.7° to 58.8 ± 4.1°, p < 0.05, ES = 0.68). For both stages, significant bilateral differences greater than 10° were observed for hip and knee flexion/extension (p < 0.05, ES>0.90) and ankle and hip internal/external rotation (p < 0.05, ES>0.25). Cross-correlation displayed the lowest pattern similarities for hip abduction/adduction and the highest similarities for knee flexion/extension, ankle plantarflexion/dorsiflexion and hip internal/external rotation. The cross-correlation method showed that the right leg was mostly ahead of time with respect to the left leg, a trend that was accentuated with power output increase. Instantaneous [Formula: see text] fluctuated up to 18% throughout the pedalling cycle, with different behaviour between the power and recovery phases. This study demonstrated the workload effects on side-to-side joint angular pattern similarity.

Guillain-BarrÉ syndrome subtype diagnosis: A prospective multicentric European study

INTRODUCTION

There is uncertainty as to whether the Guillain-Barré syndrome (GBS) subtypes, acute inflammatory demyelinating polyradiculoneuropathy (AIDP) and acute motor axonal neuropathy (AMAN), can be diagnosed electrophysiologically.

METHODS

We prospectively included 58 GBS patients. Electrodiagnostic testing (EDX) was performed at means of 5 and 33 days after disease onset. Two traditional and one recent criteria sets were used to classify studies as demyelinating or axonal. Results were correlated with anti-ganglioside antibodies and reversible conduction failure (RCF).

RESULTS

No classification shifts were observed, but more patients were classified as axonal with recent criteria. RCF and anti-ganglioside antibodies were present in both subtypes, more frequently in the axonal subtype.

DISCUSSION

Serial EDX has no effect on GBS subtype proportions. The absence of exclusive correlation with RCF and anti-ganglioside antibodies may challenge the concept of demyelinating and axonal GBS subtypes based upon electrophysiological criteria. Frequent RCF indicates that nodal/paranodal alterations may represent the main pathophysiology. Muscle Nerve, 2018.

Left bundle branch block in Duchenne muscular dystrophy: Prevalence, genetic relationship and prognosis

Background

Duchenne muscular dystrophy (DMD) is an inherited myogenic disorder due to mutations in the dystrophin gene on chromosome Xp21.1. We designed this study to determine the prevalence of left bundle branch block (LBBB), whether there is a relationship between LBBB and genetic pattern, and to assess predictive factors for acute cardiac events and mortality in adult DMD patients.

Methods

We reviewed the charts of DMD followed at the Home Mechanical Ventilation Unit of the Raymond Poincare University Hospital.

Results

A total of 121 patients, aged from 18 to 41 years have been included in our study. Median vital capacity (VC) was 12% [7; 19.5] of predicted. Almost all patients were on home mechanical ventilation (95%). LBBB was present in 15 patients (13%); among them, 10 disclosed exonic deletions. After a median follow up of 6 years, 21 patients (17%) experienced acute heart failure (AHF), 7 patients (6%) supraventricular arrhythmia, 3 patients (2.4%) ventricular tachycardia, 4 patients (3%) significant electrical disturbances. LBBB was significantly associated with cardiac events (OR = 12.7; 95%CI [3.78–42.7]; p <0.0001) and mortality (OR = 4.4; 95%CI [1.44–13.7]; p 0.009). Presence of residual dystrophin protein was not associated with significant less cardiac events. Age and LVEF were also predictive factors for cardiac events and mortality.

Conclusion

LBBB is relatively frequent in DMD and is a major predictive factor for cardiac events and mortality. Presence of residual dystrophin protein was not associated with a lower incidence of cardiac events.

17q21.31 duplication causes prominent tau-related dementia with increased MAPT expression

To assess the role of rare copy number variations in Alzheimer's disease (AD), we conducted a case-control study using whole-exome sequencing data from 522 early-onset cases and 584 controls. The most recurrent rearrangement was a 17q21.31 microduplication, overlapping the CRHR1, MAPT, STH and KANSL1 genes that was found in four cases, including one de novo rearrangement, and was absent in controls. The increased MAPT gene dosage led to a 1.6-1.9-fold expression of the MAPT messenger RNA. Clinical signs, neuroimaging and cerebrospinal fluid biomarker profiles were consistent with an AD diagnosis in MAPT duplication carriers. However, amyloid positon emission tomography (PET) imaging, performed in three patients, was negative. Analysis of an additional case with neuropathological examination confirmed that the MAPT duplication causes a complex tauopathy, including prominent neurofibrillary tangle pathology in the medial temporal lobe without amyloid-β deposits. 17q21.31 duplication is the genetic basis of a novel entity marked by prominent tauopathy, leading to early-onset dementia with an AD clinical phenotype. This entity could account for a proportion of probable AD cases with negative amyloid PET imaging recently identified in large clinical series.

68Ga-DOTATATE PET/CT Interobserver Agreement for Neuroendocrine Tumor Assessment: Results of a Prospective Study on 50 Patients

We evaluated observer agreement for ⁶⁸Ga-DOTATATE PET/CT interpretations in patients with neuroendocrine tumor (NET).

METHODS

⁶⁸Ga-DOTATATE PET/CT was performed on 50 patients with known or suspected NET of the small bowel (n = 19), pancreas (n = 14), lung (n = 4), or other location (n = 13). The images were reviewed by 7 observers, who used a standardized interpretation approach. The observers were classified as having a low level of experience (<500 scans or <5 y experience with ⁶⁸Ga-DOTATATE PET/CT; n = 4) or a high level of experience (≥500 scans or ≥5 y experience with ⁶⁸Ga-DOTATATE PET/CT; n = 3). Interpretation by the primary nuclear medicine physician, who had access to all clinical and imaging data, served as the reference standard. Interobserver agreement was determined by the Cohen κ statistic and intraclass correlation coefficient (ICC) with corresponding 95% confidence interval (95%CI).

RESULTS

Interobserver agreement was substantial, and the median number of false findings was low for the overall scan result: that is, positive versus negative scan result (κ = 0.80; 95%CI, 0.74-0.86; false findings, 3), organ involvement (κ = 0.70; 95%CI, 0.64-0.76; false findings, 5), and lymph node involvement (κ = 0.71; 95%CI, 0.65-0.78; false findings, 6). Interobserver agreement was substantial to almost perfect, and the average absolute difference (Δ) from the reference observer was low for number of organ and lymph node metastases (organ: ICC, 0.84; 95%CI, 0.77-0.89; Δ = 0.45; lymph node: ICC, 0.77; 95%CI, 0.69-0.84; Δ = 0.45), tumor SUV_max (ICC, 0.99; 95%CI, 0.97-0.99; Δ = 0.44), and reference SUV (spleen: ICC, 0.81; Δ = 1.10; liver: ICC, 0.79; Δ = 0.62). Interpretations of appropriateness for peptide-receptor radionuclide therapy varied more significantly among observers (κ = 0.64; 95%CI, 0.57-0.70), and a higher frequency of false-positive recommendations for peptide-receptor radionuclide therapy occurred in observers with low experience than in those with high experience (range, 7-12 vs. 4-8).

CONCLUSION

The interpretation of ⁶⁸Ga-DOTATATE PET/CT images for NET staging is consistent among observers with low and high levels of experience. However, image-based recommendations for or against peptide-receptor radionuclide therapy require experience and training.

SORL1 rare variants: a major risk factor for familial early-onset Alzheimer's disease

The SORL1 protein plays a protective role against the secretion of the amyloid β peptide, a key event in the pathogeny of Alzheimer's disease. We assessed the impact of SORL1 rare variants in early-onset Alzheimer's disease (EOAD) in a case-control setting. We conducted a whole exome analysis among 484 French EOAD patients and 498 ethnically matched controls. After collapsing rare variants (minor allele frequency ≤1%), we detected an enrichment of disruptive and predicted damaging missense SORL1 variants in cases (odds radio (OR)=5.03, 95% confidence interval (CI)=(2.02-14.99), P=7.49.10(-5)). This enrichment was even stronger when restricting the analysis to the 205 cases with a positive family history (OR=8.86, 95% CI=(3.35-27.31), P=3.82.10(-7)). We conclude that predicted damaging rare SORL1 variants are a strong risk factor for EOAD and that the association signal is mainly driven by cases with positive family history.

Somatostatin receptor-targeted radionuclide therapy for progressive meningioma: benefit linked to 68Ga-DOTATATE/-TOC uptake

BACKGROUND

The prognosis of patients with progressive meningioma after failure of surgery and radiotherapy is poor.

METHODS

We retrospectively evaluated the safety and efficacy of somatostatin-receptor (SSTR)-targeted radionuclide therapy (¹⁷⁷Lu-DOTATATE [n = 16], ⁹⁰Y-DOTATOC [n = 3], or both [n = 1]) in patients with progressive, treatment-refractory meningiomas (5 World Health Organization [WHO] grade I, 7 WHO grade II, 8 WHO grade III) and in part multifocal disease (17 of 20 patients).

RESULTS

SSTR radionuclide treatment (median of 3 treatment cycles, median administered dose/cycle 7400 MBq) led to a disease stabilization in 10 of 20 patients for a median time of 17 months. Stratification according to WHO grade showed a median progression-free survival (PFS) of 32.2 months for grade I tumors, 7.2 for grade II, and 2.1 for grade III. PFS at 6 months was 100% for grade I, 57% for grade II, and 0% for grade III. Median overall survival was 17.2 months in WHO grade III patients and not reached for WHO I and II at a median follow-up of 20 months. In the analysis of single meningioma lesions, maximal and mean standardized uptake values in pretherapeutic ⁶⁸Ga-DOTATOC/-TATE PET/CT were significantly higher in those lesions with radiographic stability after 6 months. In line with this, high expression of SSTR via immunohistochemistry was associated with PFS >6 months.

CONCLUSIONS

SSTR-targeted radionuclide treatment has activity in a subset of patients with meningioma. Expression of SSTR via immunohistochemistry or radionuclide uptake might serve as a predictive biomarker for outcome to facilitate individualized treatment optimization in patients with uni- and multifocal meningiomas.

Gastroenteropancreatic neuroendocrine tumours (GEP-NET) - Imaging and staging

Detection of gastroenteropancreatic neuroendocrine tumours (GEP-NETs) and monitoring of treatment response relies mainly on morphological imaging such as computed tomography (CT) and magnetic resonance imaging (MRI). Molecular imaging techniques also in combination with CT (hybrid imaging) greatly benefit patient management, including better localization of occult tumours and better staging. Somatostatin receptor scintigraphy (SRS) and somatostatin receptor (SSTR) positron emission tomography (PET) play a central role in the diagnostic work-up of patients with well-differentiated GEP-NETs. SSTR PET/CT is superior to SRS and should be used whenever available. (18)F-DOPA and (18)F-FDG PET/CT is inferior to SSTR PET/CT at least in patients with well-differentiated GEP-NETs. Both SSTR PET/CT and SRS have limitations, such as relatively low detection rate of benign insulinomas, poorly differentiated GEP-NETs and liver metastases. New innovations such as SSTR PET/MRI, radiolabelled SSTR antagonists and glucagon-like peptide-1 receptor (GLP-1R) agonists might further improve imaging of GEP-NETs.

Genotype-phenotype correlation and course of transthyretin familial amyloid polyneuropathies in France

OBJECTIVE

To compare the natural history of familial transthyretin amyloid polyneuropathies (FAP) due to the Val30Met, Ser77Tyr, and Ile107Val mutations in France with the classical Portuguese Val30Met FAP.

METHODS

We compared 84 French patients with a control group of 110 Portuguese patients carrying the Val30Met mutation also living in France, all referred to and followed at the French National FAP Reference Center from 1988 to 2010. Clinical examination, functional and walking disability scores, nerve conduction studies, and muscle biopsies are reported. We also conducted a comprehensive literature review to further determine the range of phenotypic expression.

RESULTS

By comparison with Portuguese Val30Met FAP, French Ile107Val, Ser77Tyr, and LateVal30Met FAP showed more rapid and severe disease progression; onset of gait disorders was 3 times more rapid (p < 0.0001) and the rate of modified Norris test decline was up to 40 times faster in Ile107Val patients (p < 0.0001). Median survival was much shorter in Ile107Val and in Val30Met mutation with late onset (>50 years; LateMet30) FAP (p = 0.0005). Other distinctive features relative to the Portuguese patients included atypical clinical presentations, demyelination on nerve conduction studies (p = 0.0005), and difficult identification of amyloid deposits in nerve and muscle biopsies.

INTERPRETATION

Ile107Val and LateMet30 mutations are associated with the most debilitating and severe FAP ever described, with rapid onset of tetraparesis and shorter median survival. It could be explained by frequent large-fiber involvement and associated demyelination and more severe axonal loss. These findings have major implications for genetic counseling and patient management as new therapeutic options are being assessed in clinical trials (TTR gene silencing).