Stephen A. Goutman

Amyotrophic lateral sclerosis: mechanisms and therapeutics in the epigenomic era

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the motor neurons, which results in weakness and atrophy of voluntary skeletal muscles. Treatments do not modify the disease trajectory effectively, and only modestly improve survival. A complex interaction between genes, environmental exposure and impaired molecular pathways contributes to pathology in patients with ALS. Epigenetic mechanisms control the hereditary and reversible regulation of gene expression without altering the basic genetic code. Aberrant epigenetic patterns—including abnormal microRNA (miRNA) biogenesis and function, DNA modifications, histone remodeling, and RNA editing—are acquired throughout life and are influenced by environmental factors. Thus, understanding the molecular processes that lead to epigenetic dysregulation in patients with ALS might facilitate the discovery of novel therapeutic targets and biomarkers that could reduce diagnostic delay. These achievements could prove crucial for successful disease modification in patients with ALS. We review the latest findings regarding the role of miRNA modifications and other epigenetic mechanisms in ALS, and discuss their potential as therapeutic targets.

Painful diabetic neuropathy

Diabetes is a worldwide epidemic, and associated neuropathy is its most costly and disabling complication. Given the rising prevalence of painful diabetic neuropathy, it is increasingly important that we understand the best ways to diagnose and treat this condition. Diagnostic tests in this field are evolving rapidly. These include the use of skin biopsies to measure small unmyelinated fibers, as well as even newer techniques that can measure both small unmyelinated fibers and large myelinated fibers in the same biopsy. The main treatments for painful diabetic neuropathy remain management of the underlying diabetes and drugs for the relief of pain. However, emerging evidence points to major differences between type 1 and type 2 diabetes, including the ability of glycemic control to prevent neuropathy. Enhanced glucose control is much more effective at preventing neuropathy in patients with type 1 diabetes than in those with type 2 disease. This dichotomy emphasizes the need to study the pathophysiologic differences between the two types of diabetes, because different treatments may be needed for each condition. The impact of the metabolic syndrome on neuropathy in patients with type 2 diabetes may account for the difference between the two types of diabetes and requires further study. Finally, neuropathic pain is under-recognized and undertreated despite an ever evolving list of effective drugs. Evidence exists to support several drugs, but the optimal sequence and combination of these drugs are still to be determined.

Transplantation of spinal cord–derived neural stem cells for ALS Analysis of phase 1 and 2 trials

Objective: To test the safety of spinal cord transplantation of human stem cells in patients with amyotrophic lateral sclerosis (ALS) with escalating doses and expansion of the trial to multiple clinical centers. Methods: This open-label trial included 15 participants at 3 academic centers divided into 5 treatment groups receiving increasing doses of stem cells by increasing numbers of cells/injection and increasing numbers of injections. All participants received bilateral injections into the cervical spinal cord (C3-C5). The final group received injections into both the lumbar (L2-L4) and cervical cord through 2 separate surgical procedures. Participants were assessed for adverse events and progression of disease, as measured by the ALS Functional Rating Scale–Revised, forced vital capacity, and quantitative measures of strength. Statistical analysis focused on the slopes of decline of these phase 2 trial participants alone or in combination with the phase 1 participants (previously reported), comparing these groups to 3 separate historical control groups. Results: Adverse events were mostly related to transient pain associated with surgery and to side effects of immunosuppressant medications. There was one incident of acute postoperative deterioration in neurologic function and another incident of a central pain syndrome. We could not discern differences in surgical outcomes between surgeons. Comparisons of the slopes of decline with the 3 separate historical control groups showed no differences in mean rates of progression. Conclusions: Intraspinal transplantation of human spinal cord–derived neural stem cells can be safely accomplished at high doses, including successive lumbar and cervical procedures. The procedure can be expanded safely to multiple surgical centers. Classification of evidence: This study provides Class IV evidence that for patients with ALS, spinal cord transplantation of human stem cells can be safely accomplished and does not accelerate the progression of the disease. This study lacks the precision to exclude important benefit or safety issues.

Environmental risk factors and Amyotrophic Lateral Sclerosis (ALS): A case-control study of ALS in Michigan

An interim report of a case-control study was conducted to explore the role of environmental factors in the development of amyotrophic lateral sclerosis (ALS). Sixty-six cases and 66 age- and gender-matched controls were recruited. Detailed information regarding residence history, occupational history, smoking, physical activity, and other factors was obtained using questionnaires. The association of ALS with potential risk factors, including smoking, physical activity and chemical exposure, was investigated using conditional logistic regression models. As compared to controls, a greater number of our randomly selected ALS patients reported exposure to fertilizers to treat private yards and gardens and occupational exposure to pesticides in the last 30 years than our randomly selected control cases. Smoking, occupational exposures to metals, dust/fibers/fumes/gas and radiation, and physical activity were not associated with ALS when comparing the randomly selected ALS patients to the control subjects. To further explore and confirm results, exposures over several time frames, including 0–10 and 10–30 years earlier, were considered, and analyses were stratified by age and gender. Pesticide and fertilizer exposure were both significantly associated with ALS in the randomly selected ALS patients. While study results need to be interpreted cautiously given the small sample size and the lack of direct exposure measures, these results suggest that environmental and particularly residential exposure factors warrant close attention in studies examining risk factors of ALS.

Increased ratio of circulating neutrophils to monocytes in amyotrophic lateral sclerosis

Objective: To elucidate amyotrophic lateral sclerosis (ALS) biomarkers and potential mechanisms of disease, we measured immune cell populations in whole blood from a large cohort of patients with ALS. Methods: Leukocytes were isolated from the blood of 44 control patients and 90 patients with ALS. The percentages and total numbers of each cell population were analyzed using flow cytometry and matched with patient ALS Functional Rating Scale–Revised (ALSFRS-R) score to correlate leukocyte metrics with disease progression. Results: We show a significant increase in the percentage of neutrophils and a significant decrease in the percentage of CD4 T cells and CD16− monocytes in the blood of patients with ALS compared to controls; however, only CD16− monocyte levels correlated with disease progression. We also examined the monocyte surface expression of CCRL2 and CCR3; CD16− monocytes displayed decreased percentages and total numbers expressing CCR3, but these numbers did not correlate with ALSFRS-R score. We found that combining multiple disease metrics yielded the most accurate predictor of disease progression: the ratio of neutrophils to CD16− monocytes (N:M ratio) is significantly increased in patients with ALS and better correlates with disease progression than any other single metric. Conclusions: These observations implicate neutrophils and monocytes as important factors in late disease progression.

Recent Advances and the Future of Stem Cell Therapies in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease of the motor neurons without a known cure. Based on the possibility of cellular neuroprotection and early preclinical results, stem cells have gained widespread enthusiasm as a potential treatment strategy. Preclinical models demonstrate a protective role of engrafted stem cells and provided the basis for human trials carried out using various types of stem cells, as well as a range of cell delivery methods. To date, no trial has demonstrated a clear therapeutic benefit; however, results remain encouraging and are the basis for ongoing studies. In addition, stem cell technology continues to improve, and induced pluripotent stem cells may offer additional therapeutic options in the future. Improved disease models and clinical trials will be essential in order to validate stem cells as a beneficial therapy.

Minorities, men, and unmarried amyotrophic lateral sclerosis patients are more likely to die in an acute care facility

Abstract Studies suggest that dying at home is a more favorable experience. This study investigated where amyotrophic lateral sclerosis (ALS) patients die and the patient demographics associated with dying in an acute care facility or nursing home compared to home or hospice. Centers for Disease Control and Prevention Multiple Cause Mortality Files from 2005 to 2010 were used to identify ALS patients and to classify place of death. Multinomial logistic regression was used to determine the association between patient demographics and place of death. Between 2005 and 2010, 40,911 patients died of ALS in the United States. Place of death was as follows: home or hospice facility 20,231 (50%), acute care facility (25%), and nursing home (20%). African Americans (adjusted multinomial odds ratio (aMOR) 2.56, CI 2.32–2.83), Hispanics (aMOR 1.44, CI 1.30–1.62), and Asians (aMOR 1.87, CI 1.57–2.22) were more likely to die in an acute care facility, whereas females (aMOR 0.76, CI 0.72–0.80) and married individuals were less likely. Hispanics (aMOR 0.68, CI 0.58–0.79) and married individuals were less likely to die in a nursing home. In conclusion, minorities, men, and unmarried individuals are more likely to die in an acute care facility. Further studies are needed to better understand place of death preferences.

Correlation of Peripheral Immunity With Rapid Amyotrophic Lateral Sclerosis Progression

Importance Amyotrophic lateral sclerosis (ALS) has an immune component, but previous human studies have not examined immune changes over time. Objectives To assess peripheral inflammatory markers in participants with ALS and healthy control individuals and to track immune changes in ALS and determine whether these changes correlate with disease progression. Design, Setting, and Participants In this longitudinal cohort study, leukocytes were isolated from peripheral blood samples from 35 controls and 119 participants with ALS at the ALS Clinic of the University of Michigan, Ann Arbor, from June 18, 2014, through May 26, 2016. Follow-up visits occurred every 6 to 12 months. Fifty-one participants with ALS provided samples at multiple points. Immune cell populations were measured and compared between control and ALS groups. Surface marker expression of CD11b+ myeloid cells was also assessed. Changes over time were correlated with disease progression using multivariate regression. Main Outcomes and Measures The number of immune cells per milliliter of blood and the fold expression of cell surface markers. Multivariate regression models were used to correlate changes in immune metrics with changes on the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R). Results Thirty-five controls (17 women [48.6%] and 18 men [51.4%]; mean [SD] age, 63.5 [9.9] years) and 119 participants with ALS (50 women [42.0%] and 69 men [68.0%]; mean [SD] age, 61.4 [11.5] years) were enrolled. Compared with controls, participants with ALS had increased mean (SEM) counts ( × 106/mL) of total leukocytes (4.57 [0.29; 95% CI, 3.94-5.11] vs 5.53 [0.16; 95% CI, 5.21-5.84]), neutrophils (2.87 [0.23; 95% CI, 2.40-3.35] vs 3.80 [0.12; 95% CI, 3.56-4.04]), CD16+ monocytes (0.03 [0.003; 95% CI, 0.02-0.04] vs 0.04 [0.002; 95% CI, 0.03-0.04]), CD16− monocytes (0.25 [0.02; 95% CI, 0.21-0.30] vs 0.29 [0.01; 95% CI, 0.27-0.31]), and natural killer cells (0.13 [0.02; 95% CI, 0.10-0.17] vs 0.18 [0.01; 95% CI, 0.16-0.21]). We also observed an acute, transient increase in a population of CD11b+ myeloid cells expressing HLA-DR, CD11c, and CX3CR1. Finally, early changes in immune cell numbers had a significant correlation with disease progression measured by change in ALSFRS-R score, particularly neutrophils (−4.37 [95% CI, −6.60 to −2.14] per 11.47 × 104/mL [SD, 58.04 × 104/mL] per year) and CD4 T cells (−30.47 [95% CI, −46.02 to −14.94] per −3.72 × 104/mL [SD, 26.21 × 104/mL] per year). Conclusions and Relevance Changes in the immune system occur during ALS and may contribute to the pathologic features of ALS.

Screening for novel hexanucleotide repeat expansions at ALS- and FTD-associated loci

Objective: To determine whether GGGGCC (G4C2) repeat expansions at loci other than C9orf72 serve as common causes of amyotrophic lateral sclerosis (ALS). Methods: We assessed G4C2 repeat number in 28 genes near known ALS and frontotemporal dementia (FTD) loci by repeat-primed PCR coupled with fluorescent fragment analysis in 199 patients with ALS (17 familial, 182 sporadic) and 136 healthy controls. We also obtained blood from patients with ALS4 for evaluation of repeats surrounding the SETX gene locus. C9orf72 expansions were evaluated in parallel. Results: Expansions of G4C2 repeats in C9orf72 explained 8.8% of sporadic and 47% of familial ALS cases analyzed. Repeat variance was observed at one other locus, RGS14, but no large expansions were observed, and repeat sizes were not different between cases and controls. No G4C2 repeat expansions were identified at other ALS or FTD risk loci or in ALS4 cases. Conclusions: G4C2 expansions near known ALS and FTD loci other than C9orf72 are not a common cause of ALS.

Long-term Phase 1/2 intraspinal stem cell transplantation outcomes in ALS

Intraspinal human spinal cord‐derived neural stem cell (HSSC) transplantation is a potential therapy for amyotrophic lateral sclerosis (ALS); however, previous trials lack controls. This post hoc analysis compared ambulatory limb‐onset ALS participants in Phase 1 and 2 (Ph1/2) open‐label intraspinal HSSC transplantation studies up to 3 years after transplant to matched participants in Pooled Resource Open‐Access ALS Clinical Trials (PRO‐ACT) and ceftriaxone datasets to provide required analyses to inform future clinical trial designs.