A randomized feasibility trial of medium chain triglyceride-supplemented ketogenic diet in people with Parkinson's disease

BACKGROUND

A ketogenic diet (KD) may benefit people with neurodegenerative disorders marked by mitochondrial depolarization/insufficiency, including Parkinson's disease (PD).

OBJECTIVE

Evaluate whether a KD supplemented by medium chain triglyceride (MCT-KD) oil is feasible and acceptable for PD patients. Furthermore, we explored the effects of MCT-KD on blood ketone levels, metabolic parameters, levodopa absorption, mobility, nonmotor symptoms, simple motor and cognitive tests, autonomic function, and resting-state electroencephalography (rsEEG).

METHODS

A one-week in-hospital, double-blind, randomized, placebo-controlled diet (MCT-KD vs. standard diet (SD)), followed by an at-home two-week open-label extension. The primary outcome was KD feasibility and acceptability. The secondary outcome was the change in Timed Up & Go (TUG) on day 7 of the diet intervention. Additional exploratory outcomes included the N-Back task, Unified Parkinson's Disease Rating Scale, Non-Motor Symptom Scale, and rsEEG connectivity.

RESULTS

A total of 15/16 subjects completed the study. The mean acceptability was 2.3/3, indicating willingness to continue the KD. Day 7 TUG time was not significantly different between the SD and KD groups. The nonmotor symptom severity score was reduced at the week 3 visit and to a greater extent in the KD group. UPDRS, 3-back, and rsEEG measures were not significantly different between groups. Blood ketosis was attained by day 4 in the KD group and to a greater extent at week 3 than in the SD group. The plasma levodopa metabolites DOPAC and dopamine both showed nonsignificant increasing trends over 3 days in the KD vs. SD groups.

CONCLUSIONS

An MCT-supplemented KD is feasible and acceptable to PD patients but requires further study to understand its effects on symptoms and disease.

TRIAL REGISTRATION

Trial Registration Number NCT04584346, registration dates were Oct 14, 2020 - Sept 13, 2022.

Large-scale rare variant burden testing in Parkinson's disease

Parkinson's disease has a large heritable component and genome-wide association studies have identified over 90 variants with disease-associated common variants, providing deeper insights into the disease biology. However, there have not been large-scale rare variant analyses for Parkinson's disease. To address this gap, we investigated the rare genetic component of Parkinson's disease at minor allele frequencies <1%, using whole genome and whole exome sequencing data from 7184 Parkinson's disease cases, 6701 proxy cases and 51 650 healthy controls from the Accelerating Medicines Partnership Parkinson's disease (AMP-PD) initiative, the National Institutes of Health, the UK Biobank and Genentech. We performed burden tests meta-analyses on small indels and single nucleotide protein-altering variants, prioritized based on their predicted functional impact. Our work identified several genes reaching exome-wide significance. Two of these genes, GBA1 and LRRK2, have variants that have been previously implicated as risk factors for Parkinson's disease, with some variants in LRRK2 resulting in monogenic forms of the disease. We identify potential novel risk associations for variants in B3GNT3, AUNIP, ADH5, TUBA1B, OR1G1, CAPN10 and TREML1 but were unable to replicate the observed associations across independent datasets. Of these, B3GNT3 and TREML1 could provide new evidence for the role of neuroinflammation in Parkinson's disease. To date, this is the largest analysis of rare genetic variants in Parkinson's disease.

Genome-Wide Analysis of Structural Variants in Parkinson Disease

OBJECTIVE

Identification of genetic risk factors for Parkinson disease (PD) has to date been primarily limited to the study of single nucleotide variants, which only represent a small fraction of the genetic variation in the human genome. Consequently, causal variants for most PD risk are not known. Here we focused on structural variants (SVs), which represent a major source of genetic variation in the human genome. We aimed to discover SVs associated with PD risk by performing the first large-scale characterization of SVs in PD.

METHODS

We leveraged a recently developed computational pipeline to detect and genotype SVs from 7,772 Illumina short-read whole genome sequencing samples. Using this set of SV variants, we performed a genome-wide association study using 2,585 cases and 2,779 controls and identified SVs associated with PD risk. Furthermore, to validate the presence of these variants, we generated a subset of matched whole-genome long-read sequencing data.

RESULTS

We genotyped and tested 3,154 common SVs, representing over 412 million nucleotides of previously uncatalogued genetic variation. Using long-read sequencing data, we validated the presence of three novel deletion SVs that are associated with risk of PD from our initial association analysis, including a 2 kb intronic deletion within the gene LRRN4.

INTERPRETATION

We identified three SVs associated with genetic risk of PD. This study represents the most comprehensive assessment of the contribution of SVs to the genetic risk of PD to date. ANN NEUROL 2023;93:1012-1022.

Electrophysiological Characterization of a MYH7 Variant with Tremor Phenotype

Background

The concept of a myopathy with associated tremor ("myogenic tremor") in humans has been previously described for specific MYBPC1 (Myosin-Binding Protein C) variants. Here we report for the first time an individual with tremor who was found to have a de-novo likely pathogenic variant in Myosin Heavy Chain 7 (MYH7).

We provide a detailed electrophysiological characterization of the tremor syndrome in a human individual with a myopathy and this pathogenic MYH7 variant to provide further insight in the phenotypic spectrum and pathomechanism of myogenic tremors in skeletal sarcomeric myopathies.

Methods

Electromyographic recordings were obtained from facial muscles, as well as bilateral upper and lower extremities.

Results

10 to 11 Hz activity was observed in the face and extremities during recordings with muscle activation. There were intermittent episodes of significant left-right coherence that would modulate across muscle groups throughout the recording, but no coherence between muscles at different levels of the neuraxis.

Conclusions

A possible explanation for this phenomenon is that the tremor originates at the sarcomere level within muscles, which is then picked up by muscle spindles and leads to activating input to the neuraxis segment. At the same time, the stability of the tremor frequency does suggest the presence of central oscillators at the segmental level. Thus, further studies will be needed to determine the origin of myogenic tremor and to better understand the pathomechanism.

Long-term safety of MRI-guided administration of AAV2-GDNF and gadoteridol in the putamen of individuals with Parkinson's disease

Direct putaminal infusion of adeno-associated virus vector (serotype 2) (AAV2) containing the human glial cell line-derived neurotrophic factor (GDNF) transgene was studied in a phase I clinical trial of participants with advanced Parkinson's disease (PD). Convection-enhanced delivery of AAV2-GDNF with a surrogate imaging tracer (gadoteridol) was used to track infusate distribution during real-time intraoperative magnetic resonance imaging (iMRI). Pre-, intra-, and serial postoperative (up to 5 years after infusion) MRI were analyzed in 13 participants with PD treated with bilateral putaminal co-infusions (52 infusions in total) of AAV2-GDNF and gadoteridol (infusion volume, 450 mL per putamen). Real-time iMRI confirmed infusion cannula placement, anatomic quantification of volumetric perfusion within the putamen, and direct visualization of off-target leakage or cannula reflux (which permitted corresponding infusion rate/cannula adjustments). Serial post-treatment MRI assessment (n = 13) demonstrated no evidence of cerebral parenchyma toxicity in the corresponding regions of AAV2-GDNF and gadoteridol co-infusion or surrounding regions over long-term follow-up. Direct confirmation of key intraoperative safety and efficacy parameters underscores the safety and tissue targeting value of real-time imaging with co-infused gadoteridol and putative therapeutic agents (i.e., AAV2-GDNF). This delivery-imaging platform enhances safety, permits delivery personalization, improves therapeutic distribution, and facilitates assessment of efficacy and dosing effect.

Trial of magnetic resonance-guided putaminal gene therapy for advanced Parkinson's disease

OBJECTIVE

To investigate the safety and tolerability of convection-enhanced delivery of an adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor into the bilateral putamina of PD patients.

METHODS

Thirteen adult patients with advanced PD underwent adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor and gadoteridol (surrogate MRI tracer) coinfusion (450 μL/hemisphere) at escalating doses: 9 × 10¹⁰ vg (n = 6); 3 × 10¹¹ vg (n = 6); and 9 × 10¹¹ vg (n = 1). Intraoperative MRI monitored infusion distribution. Patients underwent UPDRS assessment and [¹⁸ F]FDOPA-PET scanning preoperatively and 6 and 18 months postoperatively.

RESULTS

Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor was tolerated without clinical or radiographic toxicity. Average putaminal coverage was 26%. UPDRS scores remained stable. Ten of thirteen and 12 of 13 patients had increased [¹⁸ F]FDOPA Kis at 6 and 18 months postinfusion (increase range: 5-274% and 8-130%; median, 36% and 54%), respectively. Ki differences between baseline and 6- and 18-month follow-up were statistically significant (P < 0.0002).

CONCLUSION

Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor infusion was safe and well tolerated. Increased [¹⁸ F]FDOPA uptake suggests a neurotrophic effect on dopaminergic neurons. © 2019 International Parkinson and Movement Disorder Society.

Functional neuroimaging and chorea: a systematic review

Chorea is a hyperkinetic movement disorder consisting of involuntary irregular, flowing movements of the trunk, neck or face. Although Huntington’s disease is the most common cause of chorea in adults, chorea can also result from many other neurodegenerative, metabolic, and autoimmune conditions. While the pathophysiology of these different conditions is quite variable, recent advances in functional imaging have enabled the development of new methods for analysis of brain activity and neuronal dysfunction. In this paper we review the growing body of functional imaging data that has been performed in chorea syndromes and identify particular trends, which can be used to better understand the underlying network changes within the basal ganglia. While it can be challenging to identify whether changes are primary, secondary, or compensatory, identification of these trends can ultimately be useful in diagnostic testing and treatment in many of the conditions that cause chorea.

The phenomenology and treatment of idiopathic adult-onset truncal dystonia: a retrospective review

Background

Focal dystonia is the most common type of adult-onset dystonia; however, it infrequently affects truncal musculature. Although commonly attributed to secondary etiologies such as a neurodegenerative illness or tardive syndromes, the entity of idiopathic adult-onset truncal dystonia has only been previously described in a few case reports and small case series. Here we characterize seven cases of adult-onset primary truncal dystonia and present them within the scope of the existing literature.

Methods

Retrospective chart review of medical records and patient videos of seven adult patients with idiopathic truncal dystonia evaluated by the senior movement disorder neurologists in an urban outpatient clinic.

Results

The mean age of onset of idiopathic truncal dystonia was 47.6 years old and the majority of patients were male. Truncal flexion was the most common direction of dystonic movement and the dystonia was most frequently induced by action and could be improved by use of a sensory trick. The majority of patients were refractory to 3 or more oral treatments and only two patients exhibited significant functional improvement with botulinum toxin injections. One patient enjoyed significant benefit with bilateral internal globus pallidus deep brain stimulation.

Conclusions

Although a relatively rare presentation, patients with idiopathic adult-onset truncal dystonia can be identified by a common phenomenology. Diagnosis of this highly disabling condition is important because these patients are frequently refractory to multiple oral treatments and may benefit from early treatment with botulinum toxin or deep brain stimulation.

Electronic supplementary material

The online version of this article (doi:10.1186/s40734-016-0044-9) contains supplementary material, which is available to authorized users.

Molecular alterations in the cerebellum of the plasma membrane calcium ATPase 2 (PMCA2)-null mouse indicate abnormalities in Purkinje neurons

PMCA2, a major calcium pump, is expressed at particularly high levels in Purkinje neurons. Accordingly, PMCA2-null mice exhibit ataxia suggesting cerebellar pathology. It is not yet known how changes in PMCA2 expression or activity affect molecular pathways in Purkinje neurons. We now report that the levels of metabotropic glutamate receptor 1 (mGluR1), which plays essential roles in motor coordination, synaptic plasticity, and associative learning, are reduced in the cerebellum of PMCA2-null mice as compared to wild type littermates. The levels of inositol 1,4,5-triphosphate receptor type 1 (IP3R1), an effector downstream to mGluR1, which mediates intracellular calcium signaling, and the expression of Homer 1b/c and Homer 3, scaffold proteins that couple mGluR1 to IP3R1, are also reduced in somata and dendrites of some Purkinje cell subpopulations. In contrast, no alterations occur in the levels of mGluR1 and its downstream effectors in the hippocampus, indicating that the changes are region specific. The reduction in cerebellar mGluR1, IP3R1 and Homer 3 levels are neither due to a generic decrease in Purkinje proteins nor extensive dendritic loss as immunoreactivity to total and non-phosphorylated neurofilament H (NFH) is increased in Purkinje dendrites and microtubule associated protein 2 (MAP2) staining reveals a dense dendritic network in the molecular layer of the PMCA2-null mouse cerebellum. PMCA2 coimmunoprecipitates with mGluR1, Homer 3 and IP3R1, suggesting that the calcium pump is a constituent of the mGluR1 signaling complex. Our results suggest that the decrease in the expression of mGluR1 and its downstream effectors and perturbations in the mGluR1 signaling complex in the absence of PMCA2 may cumulatively result in aberrant metabotropic glutamate receptor signaling in Purkinje neurons leading to cerebellar deficits in the PMCA2-null mouse.

Microfluidic devices for DNA analysis

Microfabricated electrophoresis devices allow us to perform short-tandem-repeat genotyping assays in under 2 min and sequence single-stranded DNA in under 15 min. This is 10-100 times faster than standard slab-gel and capillary systems. The microdevice format is the natural extension of 100 years of gradual improvements to electrophoresis but operates in an almost-perfect way, limited only by the sieving medium.

Direct detection of nucleic acid hybridization on the surface of a charge coupled device

A method is described for the detection of DNA hybrids formed on a solid support, based upon the pairing of oligonucleotide chemistry and the technologies of electronic microdevice design. Surface matrices have been created in which oligonucleotide probes are covalently linked to a thin SiO2 film. 32P labeled target nucleic acid is then hybridized to this probe matrix under conditions of high stringency. The salient feature of the method is that to achieve the highest possible collection efficiency, the hybridization matrix is placed directly on the surface of a charge coupled device (CCD), which is used to detect 32P decay from hybridized target molecules (1, Eggers, M.D., Hogan, M.E., Reich, R.K., Lamture, J.B., Beattie, K.L., Hollis, M.A., Ehrilich, D.J., Kosicki, B.B., Shumaker, J.M., Varma, R.S., Burke, B.E., Murphy, A., and Rathman, D.D., (1993), Advances in DNA Sequencing Technology, Proc. SPIE, 1891, 13-26). Two implementations of the technology have been employed. The first involves direct attachment of the matrix to the surface of a CCD. The second involves attachment of the matrix to a disposible SiO2 coated chip, which is then placed face to face upon the CCD surface. As can be predicted from this favorable collection geometry and the known characteristics of a CCD, it is found that as measured by the time required to obtain equivalent signal to noise ratios, 32P detection speed by the direct CCD approach is at least 10 fold greater than can be obtained with a commercial gas phase array detector, and at least 100 fold greater than when X-ray film is used for 32P detection. Thus, it is shown that excellent quality hybridization signals can be obtained from a standard hybridization reaction, after only 1 second of CCD data acquisition.

Reflectometric spectroscopy of adsorbed molecular layers

A normal-incidence technique is described for obtaining IR absorption spectra of molecular layers adsorbed on a dielectric thin-film surface. In the experiment described, a low-power CO(2) laser beam is scanned across a molecular layer of 2-propanol adsorbed on a ZnSe film. Spectra for 1-5 monolayer coverages are compared with the liquid spectrum of the adsorbate.

Deep-ultraviolet spatial-period division using an excimer laser

We have used the deep-UV output from an ArF laser and a grating mask with 199-nm spatial period to fabricate a 99.5-nm-period grating pattern in polymethyl methacrylate resist by spatial-period division. For sub 100 nm, lithography of periodic and quasi-periodic patterns (including Fresnel zone plates) by spatial-period division, deep-UV radiation offers a number of advantages over soft x rays.

Optically induced microstructures in laser-photodeposited metal films

Regular 0.15- to 0.5-microm-period ripple structures have been seen in laser-photodeposited Cd and Zn films. Electron-microscope observations have established the evolution of these microstructures in the growing films.

Optical reflectance technique for observations of submonolayer adsorbed films

An optical technique is described for detecting and measuring thicknesses of adsorbed films with subangstrom sensitivity. The technique relies on optical interference from an antireflecting thin-film structure that is predeposited on a transparent cell window: the reflectivity of the window depends linearly on the thickness of the molecular layer adsorbed from the gas in the cell.

Atomic-transition lasers based on two-photon dissociation of metal-triiodide vapors

Visible laser action on atomic transitions of Ga, In, Al, and Bi has been obtained by using an ArF excimer laser to photodissociate vapors of the corresponding metal triiodides. The excitation process involves sequential two-photon dissociation. Output energies of as much as 0.24 mJ at 417.2 nm and energy efficiencies of 2.9% have been obtained with Ga.

Ultraviolet solid-state Ce:YLF laser at 325 nm

We describe the first reported observation of stimulated emission from a 5d-4f transition in a triply ionized rare-earth-doped crystal. Ce(+3) ions in LiYF(4) (YLF), optically pumped at 249 nm, emitted at 325.5 nm, the shortest wavelength yet obtained from an optically pumped solid-state laser. The large fluorescence linewidth of the laser transition makes the Ce:YLF laser a potentially tunable source of coherent near-ultraviolet radiation between 305 and 335 nm.

Changes in the apparent lengths of lines as a function of degree of retinal eccentricity

Magnitude estimates were obtained for the apparent lengths of (i) seven vertical lines of different lengths at eleven positions along the horizontal meridian and (ii) the same seven lines presented horizontally at ten different angles of elevation. In experiments 1 and 2 (experienced and naive subjects, respectively) the seven vertical lines were permutated randomly in the eleven azimuth positions within a session. In experiment 3, the seven vertical lines were all presented first at a single azimuth position before being presented at another azimuth position. In experiment 4, the same seven line lengths (presented in horizontal orientation) were permutated randomly within the ten angles of elevation. The results showed that the apparent length of a line decreases as the line was moved away from the midline position into the periphery. Power functions described the growth of line lengths at each azimuth position and each angle of elevation. The exponents of the power functions in experiments 1,2, and 4 were smallest at the midline position and became larger for the line lengths presented more peripherally. For lines presented vertically the exponents tended to decrease again at the more extreme azimuth positions. Equal-length contours were derived from the power functions of experiments 1, 2, and 4.