Allogeneic hematopoietic stem cell transplantation with myeloablative conditioning for adult cerebral X-linked adrenoleukodystrophy

Targeting VEGF-mediated blood-brain barrier disruption in advanced cerebral leukodystrophy

The earliest clinical manifestation of cerebral adrenoleukodystrophy (CALD) is adrenal insufficiency (AI) characterized by elevations in ACTH and loss of cortisol. We showed high (though physiologically achievable) levels of ACTH increases endothelial permeability, increases anisotropy, and increases VEGF secretion. An ACBD1 knockout endothelial cell line had increased sensitivity to ACTH and VEGF. Inhibition of VEGF via application of anti-VEGF (bevacizumab) improved permeability. Six boys with advanced CALD were treated with bevacizumab combined with dexamethasone and ruxolitinib as immune suppressants. Most boys had decreases in gadolinium enhancement on MRI indicating improvement in endothelial function, though all boys continued to progress symptomatically.

Case report: Treatment of advanced CSF1-receptor associated leukoencephalopathy with hematopoietic stem cell transplant

CSF1 receptor-related leukoencephalopathy is a rare genetic disorder presenting with severe, adult-onset white matter dementia as one of the leading symptoms. Within the central nervous system, the affected CSF1-receptor is expressed exclusively in microglia cells. Growing evidence implicates that replacing the defective microglia with healthy donor cells through hematopoietic stem cell transplant might halt disease progression. Early initiation of that treatment is crucial to limit persistent disability. However, which patients are suitable for this treatment is not clear, and imaging biomarkers that specifically depict lasting structural damage are lacking. In this study, we report on two patients with CSF1R-related leukoencephalopathy in whom allogenic hematopoietic stem cell transplant at advanced disease stages led to clinical stabilization. We compare their disease course with that of two patients admitted in the same timeframe to our hospital, considered too late for treatment, and place our cases in context with the respective literature. We propose that the rate of clinical progression might be a suitable stratification measure for treatment amenability in patients. Furthermore, for the first time we evaluate [18F] florbetaben, a PET tracer known to bind to intact myelin, as a novel MRI-adjunct tool to image white matter damage in CSF1R-related leukoencephalopathy. In conclusion, our data add evidence for allogenic hematopoietic stem cell transplant as a promising treatment in CSF1R-related leukoencephalopathy patients with slow to moderate disease progression.

Neurocognitive and mental health impact of adrenoleukodystrophy across the lifespan: Insights for the era of newborn screening

X-linked adrenoleukodystrophy (ALD) is a rare inherited neurological disorder that poses considerable challenges for clinical management throughout the lifespan. Although males are generally more severely affected than females, the time course and presentation of clinical symptoms are otherwise difficult to predict. Opportunities to improve outcomes for individuals with ALD are rapidly expanding due to the introduction of newborn screening programs for this condition and an evolving treatment landscape. The aim of this comprehensive review is to synthesize current knowledge regarding the neurocognitive and mental health effects of ALD. This review provides investigators and clinicians with context to improve case conceptualization, inform prognostic counseling, and optimize neuropsychological and mental health care for patients and their families. Results highlight key predictive factors and brain-behavior relationships associated with the diverse manifestations of ALD. The review also discusses considerations for endpoints within clinical trials and identifies gaps to address in future research.

Safety and efficacy of leriglitazone for preventing disease progression in men with adrenomyeloneuropathy (ADVANCE): a randomised, double-blind, multi-centre, placebo-controlled phase 2-3 trial

BACKGROUND

Adult patients with adrenoleukodystrophy have a poor prognosis owing to development of adrenomyeloneuropathy. Additionally, a large proportion of patients with adrenomyeloneuropathy develop life-threatening progressive cerebral adrenoleukodystrophy. Leriglitazone is a novel selective peroxisome proliferator-activated receptor gamma agonist that regulates expression of key genes that contribute to neuroinflammatory and neurodegenerative processes implicated in adrenoleukodystrophy disease progression. We aimed to assess the effect of leriglitazone on clinical, imaging, and biochemical markers of disease progression in adults with adrenomyeloneuropathy.

METHODS

ADVANCE was a 96-week, randomised, double-blind, placebo-controlled, phase 2-3 trial done at ten hospitals in France, Germany, Hungary, Italy, the Netherlands, Spain, the UK, and the USA. Ambulatory men aged 18-65 years with adrenomyeloneuropathy without gadolinium enhancing lesions suggestive of progressive cerebral adrenoleukodystrophy were randomly assigned (2:1 without stratification) to receive daily oral suspensions of leriglitazone (150 mg starting dose; between baseline and week 12, doses were increased or decreased to achieve plasma concentrations of 200 μg·h/mL [SD 20%]) or placebo by means of an interactive response system and a computer-generated sequence. Investigators and patients were masked to group assignment. The primary efficacy endpoint was change from baseline in the Six-Minute Walk Test distance at week 96, analysed in the full-analysis set by means of a mixed model for repeated measures with restricted maximum likelihood and baseline value as a covariate. Adverse events were also assessed in the full-analysis set. This study was registered with ClinicalTrials.gov, NCT03231878; the primary study is complete; patients had the option to continue treatment in an open-label extension, which is ongoing.

FINDINGS

Between Dec 8, 2017, and Oct 16, 2018, of 136 patients screened, 116 were randomly assigned; 62 [81%] of 77 patients receiving leriglitazone and 34 [87%] of 39 receiving placebo completed treatment. There was no between-group difference in the primary endpoint (mean [SD] change from baseline leriglitazone: -27·7 [41·4] m; placebo: -30·3 [60·5] m; least-squares mean difference -1·2 m; 95% CI -22·6 to 20·2; p=0·91). The most common treatment emergent adverse events in both the leriglitazone and placebo groups were weight gain (54 [70%] of 77 vs nine [23%] of 39 patients, respectively) and peripheral oedema (49 [64%] of 77 vs seven [18%] of 39). There were no deaths. Serious treatment-emergent adverse events occurred in 14 (18%) of 77 patients receiving leriglitazone and ten (26%) of 39 patients receiving placebo. The most common serious treatment emergent adverse event, clinically progressive cerebral adrenoleukodystrophy, occurred in six [5%] of 116 patients, all of whom were in the placebo group.

INTERPRETATION

The primary endpoint was not met, but leriglitazone was generally well tolerated and rates of adverse events were in line with the expected safety profile for this drug class. The finding that cerebral adrenoleukodystrophy, a life-threatening event for patients with adrenomyeloneuropathy, occurred only in patients in the placebo group supports further investigation of whether leriglitazone might slow the progression of cerebral adrenoleukodystrophy.

FUNDING

Minoryx Therapeutics.

Activating cannabinoid receptor 2 preserves axonal health through GSK-3β/NRF2 axis in adrenoleukodystrophy

Aberrant endocannabinoid signaling accompanies several neurodegenerative disorders, including multiple sclerosis. Here, we report altered endocannabinoid signaling in X-linked adrenoleukodystrophy (X-ALD), a rare neurometabolic demyelinating syndrome caused by malfunction of the peroxisomal ABCD1 transporter, resulting in the accumulation of very long-chain fatty acids (VLCFAs). We found abnormal levels of cannabinoid receptor 2 (CB2r) and related endocannabinoid enzymes in the brain and peripheral blood mononuclear cells (PBMCs) of X-ALD patients and in the spinal cord of a murine model of X-ALD. Preclinical treatment with a selective agonist of CB2r (JWH133) halted axonal degeneration and associated locomotor deficits, along with normalization of microgliosis. Moreover, the drug improved the main metabolic disturbances underlying this model, particularly in redox and lipid homeostatic pathways, including increased lipid droplets in motor neurons, through the modulation of the GSK-3β/NRF2 axis. JWH133 inhibited Reactive Oxygen Species elicited by excess VLCFAs in primary microglial cultures of Abcd1-null mice. Furthermore, we uncovered intertwined redox and CB2r signaling in the murine spinal cords and in patient PBMC samples obtained from a phase II clinical trial with antioxidants (NCT01495260). These findings highlight CB2r signaling as a potential therapeutic target for X-ALD and perhaps other neurodegenerative disorders that present with dysregulated redox and lipid homeostasis.

Modulation of mitochondrial and inflammatory homeostasis through RIP140 is neuroprotective in an adrenoleukodystrophy mouse model

AIMS

Mitochondrial dysfunction and inflammation are at the core of axonal degeneration in several multifactorial neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease, and Parkinson's disease. The transcriptional coregulator RIP140/NRIP1 (receptor-interacting protein 140) modulates these functions in liver and adipose tissue, but its role in the nervous system remains unexplored. Here, we investigated the impact of RIP140 in the Abcd1^- mouse model of X-linked adrenoleukodystrophy (X-ALD), a genetic model of chronic axonopathy involving the convergence of redox imbalance, bioenergetic failure, and chronic inflammation.

METHODS AND RESULTS

We provide evidence that RIP140 is modulated through a redox-dependent mechanism driven by very long-chain fatty acids (VLCFAs), the levels of which are increased in X-ALD. Genetic inactivation of RIP140 prevented mitochondrial depletion and dysfunction, bioenergetic failure, inflammatory dysregulation, axonal degeneration and associated locomotor disabilities in vivo in X-ALD mouse models.

CONCLUSIONS

Together, these findings show that aberrant overactivation of RIP140 promotes neurodegeneration in X-ALD, underscoring its potential as a therapeutic target for X-ALD and other neurodegenerative disorders that present with metabolic and inflammatory dyshomeostasis.

[X-Linked Adrenoleukodystrophy or the Management of Rare Diseases in the General Practice]

X-Linked Adrenoleukodystrophy or the Management of Rare Diseases in the General Practice Abstract. We report on a 48-year-old patient with X-linked adrenoleukodystrophy with slowly progressive leg-accentuated spastic paraparesis, vegetative dysfunction with bladder and sexual dysfunction, and primary adrenal insufficiency. The diagnosis of adrenomyeloneuropathy, the adult form of adrenoleukodystrophy, and Addison's disease was made at the age of 20 by evidence of an increased concentration of long-chain fatty acids in the plasma. The therapy is symptom-oriented.

Cognitive Functions in Adult-Onset Phenotypes of X-Linked Adrenoleukodystrophy

OBJECTIVE

X-linked adrenoleukodystrophy (X-ALD) is a rare genetic disorder characterized by progressive demyelination ranging from mild myelopathic forms (adrenomyeloneuropathy [AMN]) to severe cerebral variants (adult cerebral adrenoleukodystrophy [ACALD]). The aim of this study was to compare cognitive function in adult-onset X-ALD phenotypes.

METHODS

Cognitive function in various domains (intelligence, attention, memory, executive function, and processing speed) was assessed in 172 adults (117 with AMN, 30 with arrested ACALD, and 25 with acute ACALD) using comprehensive neuropsychological batteries. Phenotype differences were examined by analyses of variance.

RESULTS

X-ALD phenotypes significantly differed in nonverbal intelligence, sustained attention, verbal encoding, nonverbal recognition, and processing speed (ps < 0.050). No group differences emerged regarding verbal intelligence, verbal retrieval and recognition, and executive function (ps > 0.050). Specifically, patients with acute ACALD showed severe cognitive deficits compared to AMN and normal data, with largest effects on processing speed. Contrary, cognition was overall intact in patients with AMN, independent of sex and corticospinal tract involvement, and those with arrested ACALD showed mild cognitive dysfunction, particularly in verbal encoding and processing speed.

INTERPRETATION

Cerebral demyelination in patients with X-ALD causes white matter dementia, mainly characterized by an extreme slowdown in processing speed associated with deficits in attention and learning. Most patients with AMN show intact cognitive function. Future prospective, longitudinal studies with more sensitive imaging techniques are required to clarify whether early mild cognitive dysfunction found in some patients with AMN may be associated with subtle myelin abnormalities that do not yet appear as white matter lesions on cerebral MRI (cMRI) but have the potential to serve as early predictors of later cerebral progression. ANN NEUROL 2021;90:266-273.

New Insights on the Role of the Mesenchymal-Hematopoietic Stem Cell Axis in Autologous and Allogeneic Hematopoiesis

Cytoreductive protocols are integral both as conditioning regimens for bone marrow (BM) transplantation and as part of therapies for malignancies, but their associated comorbidities represent a long-standing clinical problem. In particular, they cause myeloablation that debilitates the physiological role of mesenchymal stem and precursor cells (MSPCs) in sustaining hematopoiesis. This review addresses the damaging impact of cytoreductive regimens on MSPCs. In addition, it discusses prospects for alleviating the resulting iatrogenic comorbidities. New insights into the structural and functional dynamics of hematopoietic stem cell (HSC) niches reveal the existence of "empty" niches and the ability of the donor-derived healthy HSCs to outcompete the defective HSCs in occupying these niches. These findings support the notion that conditioning regimens, conventionally used to ablate the recipient hematopoiesis to create space for engraftment of the donor-derived HSCs, may not be a necessity for allogeneic BM transplantation. In addition, the capacity of the MSPCs to cross-talk with HSCs, despite major histocompatibility complex disparity, and suppress graft versus host disease indicates the possibility for development of a conditioning-free, MSPCs-enhanced protocol for BM transplantation. The clinical advantage of supplementing cytoreductive protocols with MSPCs to improve autologous hematopoiesis reconstitution and alleviate cytopenia associated with chemo and radiation therapies for cancer is also discussed.

Clinical and radiographic course of arrested cerebral adrenoleukodystrophy

OBJECTIVE

To gain insight into the natural history of arrested cerebral adrenoleukodystrophy (CALD) by quantifying the change in Neurologic Function Score (NFS) and Loes Score (LS) over time in patients whose cerebral lesions spontaneously stopped progressing.

METHODS

We retrospectively reviewed a series of 22 patients with arrested CALD followed longitudinally over a median time of 2.4 years (0.7-17.0 years). Primary outcomes were change in radiographic disease burden (measured by LS) and clinical symptoms (measured by NFS) between patients who never developed a contrast-enhancing lesion (gadolinium enhancement (GdE)- subgroup) and those who did (GdE+ subgroup). Secondary analyses comparing patterns of neuroanatomic involvement and lesion number, and prevalence estimates, were performed.

RESULTS

Cerebral lesions were first detected at a median age of 23.3 years (8.0-67.6 years) with an initial LS of 4 (0.5-9). NFS was 0.5 (0-6). Overall change in NFS or LS per year did not differ between subgroups. No patients who remained GdE- converted to a progressive CALD phenotype. The presence of contrast enhancement was associated with disease progression (r _s = 0.559, p < 0.001). Four patients (18.2%) underwent step-wise progression, followed by spontaneous resolution of contrast enhancement and rearrest of disease. Three patients (13.6%) converted to progressive CALD. Nineteen patients (86.4%) had arrested CALD at the most recent follow-up. The prevalence of arrested CALD is 12.4%.

CONCLUSION

Arrested CALD lesions can begin in childhood, and patients are often asymptomatic early in disease. The majority of patients remain stable. However, clinical and MRI surveillance is recommended because a minority of patients undergo step-wise progression or conversion to progressive CALD.

Genetic profile considerations for induction of allogeneic chimerism as a therapeutic approach for type 1 diabetes mellitus

The major therapeutic modality for type 1 diabetes mellitus (T1DM) remains sustaining euglycemia by exogenous administration of insulin. Based on a new understanding of bone marrow structural and functional dynamics, a conditioning-free bone marrow transplantation (BMT), with reduced adverse effects, opens the possibility for evaluating β cell regeneration and restoration of euglycemia by induction of allogeneic chimerism in patients T1DM, as shown in a mouse model. With this therapeutic modality, donor bone marrow (BM) selection based on T1DM-predisposing and preventive phenotypes will improve treatment outcomes by limiting the risk of exacerbating the autoimmune processes in the BM recipient.

Lipids in the Physiopathology of Hereditary Spastic Paraplegias

Hereditary spastic paraplegias (HSP) are a group of neurodegenerative diseases sharing spasticity in lower limbs as common symptom. There is a large clinical variability in the presentation of patients, partly underlined by the large genetic heterogeneity, with more than 60 genes responsible for HSP. Despite this large heterogeneity, the proteins with known function are supposed to be involved in a limited number of cellular compartments such as shaping of the endoplasmic reticulum or endolysosomal function. Yet, it is difficult to understand why alteration of such different cellular compartments can lead to degeneration of the axons of cortical motor neurons. A common feature that has emerged over the last decade is the alteration of lipid metabolism in this group of pathologies. This was first revealed by the identification of mutations in genes encoding proteins that have or are supposed to have enzymatic activities on lipid substrates. However, it also appears that mutations in genes affecting endoplasmic reticulum, mitochondria, or endolysosome function can lead to changes in lipid distribution or metabolism. The aim of this review is to discuss the role of lipid metabolism alterations in the physiopathology of HSP, to evaluate how such alterations contribute to neurodegenerative phenotypes, and to understand how this knowledge can help develop therapeutic strategy for HSP.

Clinical efficacy of haematopoietic stem cell transplantation for adult adrenoleukodystrophy

Accumulated experience supports the efficacy of allogenic haematopoietic stem cell transplantation in arresting the progression of childhood-onset cerebral form of adrenoleukodystrophy in early stages. For adulthood-onset cerebral form of adrenoleukodystrophy, however, there have been only a few reports on haematopoietic stem cell transplantation and the clinical efficacy and safety of that for adulthood-onset cerebral form of adrenoleukodystrophy remain to be established. To evaluate the clinical efficacy and safety of haematopoietic stem cell transplantation, we conducted haematopoietic stem cell transplantation on 12 patients with adolescent-/adult-onset cerebral form/cerebello-brainstem form of adrenoleukodystrophy in a single-institution-based prospective study. Through careful prospective follow-up of 45 male adrenoleukodystrophy patients, we aimed to enrol patients with adolescent-/adult-onset cerebral form/cerebello-brainstem form of adrenoleukodystrophy at early stages. Indications for haematopoietic stem cell transplantation included cerebral form of adrenoleukodystrophy or cerebello-brainstem form of adrenoleukodystrophy with Loes scores up to 13, the presence of progressively enlarging white matter lesions and/or lesions with gadolinium enhancement on brain MRI. Clinical outcomes of haematopoietic stem cell transplantation were evaluated by the survival rate as well as by serial evaluation of clinical rating scale scores and neurological and MRI findings. Clinical courses of eight patients who did not undergo haematopoietic stem cell transplantation were also evaluated for comparison of the survival rate. All the patients who underwent haematopoietic stem cell transplantation survived to date with a median follow-up period of 28.6 months (4.2–125.3 months) without fatality. Neurological findings attributable to cerebral/cerebellar/brainstem lesions became stable or partially improved in all the patients. Gadolinium-enhanced brain lesions disappeared or became obscure within 3.5 months and the white matter lesions of MRI became stable or small. The median Loes scores before haematopoietic stem cell transplantation and at the last follow-up visit were 6.0 and 5.25, respectively. Of the eight patients who did not undergo haematopoietic stem cell transplantation, six patients died 69.1 months (median period; range 16.0–104.1 months) after the onset of the cerebral/cerebellar/brainstem lesions, confirming that the survival probability was significantly higher in patients with haematopoietic stem cell transplantation compared with that in patients without haematopoietic stem cell transplantation (P = 0.0089). The present study showed that haematopoietic stem cell transplantation was conducted safely and arrested the inflammatory demyelination in all the patients with adolescent-/adult-onset cerebral form/cerebello-brainstem form of adrenoleukodystrophy when haematopoietic stem cell transplantation was conducted in the early stages. Further studies are warranted to optimize the procedures of haematopoietic stem cell transplantation for adolescent-/adult-onset cerebral form/cerebello-brainstem form of adrenoleukodystrophy.

The Landscape of Hematopoietic Stem Cell Transplant and Gene Therapy for X-Linked Adrenoleukodystrophy

PURPOSE OF REVIEW

To present an updated appraisal of hematopoietic stem cell transplant (HSCT) and gene therapy for X-linked adrenoleukodystrophy (ALD) in the setting of a novel, presymptomatic approach to disease.

RECENT FINDINGS

Outcomes in HSCT for ALD have been optimized over time due to early patient detection, improved myeloablative conditioning regimens, and adjunctive treatment for patients with advanced cerebral disease. Gene therapy has arrested disease progression in a cohort of boys with childhood cerebral ALD. New therapeutic strategies have provided the clinical basis for the implementation of Newborn Screening (NBS). With the help of advocacy groups, NBS has been implemented, allowing for MRI screening for the onset of cerebral ALD from birth. Gene therapy and optimized hematopoietic stem cell transplant for childhood CALD have changed the natural history of this previously devastating neurological disease.

Hematopoietic Stem Cell Transplantation to Treat Leukodystrophies: Clinical Practice Guidelines from the Hunter's Hope Leukodystrophy Care Network

The leukodystrophies are a heterogeneous group of inherited diseases characterized by progressive demyelination of the central nervous system leading to devastating neurologic symptoms and premature death. Hematopoietic stem cell transplantation (HSCT) has been successfully used to treat certain leukodystrophies, including adrenoleukodystrophy, globoid leukodystrophy (Krabbe disease), and metachromatic leukodystrophy, over the past 30 years. To date, these complex patients have primarily been transplanted at a limited number of pediatric centers. As the number of cases identified through pregnancy and newborn screening is increasing, additional centers will be required to treat these children. Hunter's Hope created the Leukodystrophy Care Network in part to create and standardize high-quality clinical practice guidelines to guide the care of affected patients. In this report the clinical guidelines for the care of pediatric patients with leukodystrophies undergoing treatment with HSCT are presented. The initial transplant evaluation, determination of patient eligibility, donor selection, conditioning, supportive care, and post-transplant follow-up are discussed. Throughout these guidelines the need for early detection and treatment and the role of the partnership between families and multidisciplinary providers are emphasized.