Metformin for treatment of cytopenias in children and young adults with Fanconi anemia

Fanconi anemia (FA), a genetic DNA repair disorder characterized by marrow failure and cancer susceptibility. In FA mice, metformin improves blood counts and delays tumor development. We conducted a single institution study of metformin in nondiabetic patients with FA to determine feasibility and tolerability of metformin treatment and to assess for improvement in blood counts. Fourteen of 15 patients with at least 1 cytopenia (hemoglobin < 10 g/dL; platelet count < 100 000 cells/µL; or an absolute neutrophil count < 1000 cells/µL) were eligible to receive metformin for 6 months. Median patient age was 9.4 years (range 6.0-26.5 ). Thirteen of 14 subjects (93%) tolerated maximal dosing for age; 1 subject had dose reduction for grade 2 gastrointestinal symptoms. No subjects developed hypoglycemia or metabolic acidosis. No subjects had dose interruptions caused by toxicity, and no grade 3 or higher adverse events attributed to metformin were observed. Hematologic response based on modified Myelodysplastic Syndrome International Working Group criteria was observed in 4 of 13 evaluable patients (30.8%; 90% confidence interval, 11.3-57.3). Median time to response was 84.5 days (range 71-128 days). Responses were noted in neutrophils (n = 3), platelets (n = 1), and red blood cells (n = 1). No subjects met criteria for disease progression or relapse during treatment. Correlative studies explored potential mechanisms of metformin activity in FA. Plasma proteomics showed reduction in inflammatory pathways with metformin. Metformin is safe and tolerable in nondiabetic patients with FA and may provide therapeutic benefit. This trial was registered at as #NCT03398824.

SPRINTing to Innovation: Children's Hospital of Philadelphia's Strategic Approach to Discovering Its Untapped Innovation Potential

PROBLEM

There is a clear and urgent need for health care innovation in the United States. Hospital employees routinely recognize pain points that affect care delivery and are in a unique position to propose innovative and practical solutions, yet leaders rarely solicit ideas for investment and development from frontline providers and staff, revealing an untapped resource with innovation potential.

APPROACH

To address these deficiencies, the Children's Hospital of Philadelphia expanded its innovation infrastructure with the competition-based SPRINT program in 2015. All hospital employees are encouraged to apply with early-stage innovative ideas, and if selected, are provided with business, legal, technical, and scientific project management support to help accelerate their projects toward commercial viability. SPRINT was modeled around 4 core tenets: (1) small, dynamic, and attentive project manager-led teams; (2) low barriers to entry; (3) emphasis on outreach; and (4) fostering innovators.

OUTCOMES

Over its first 4 cycles from 2015 to 2018, 271 innovative teams applied to the SPRINT program, which led to support for 30 projects (11% acceptance rate). About a quarter of the projects each year were submitted by physician-led teams (mean 23%), a third by nonphysician clinical providers (mean 33%), and almost half were submitted by employees without direct patient contact (mean 44%). Nurses have emerged as the largest applicant group. Eleven of the SPRINT-supported projects (37%) resulted in commercial endpoints.

NEXT STEPS

SPRINT has proven to be an effective model for supporting institution-wide, employee-driven health care innovation, especially among frontline clinical and nonclinical personnel. Critical next steps for the program include a formal cost-benefit analysis and the earlier participation of technology transfer and intellectual property experts to improve the commercialization roadmap for many SPRINT projects.

L-leucine improves anemia and growth in patients with transfusion-dependent Diamond-Blackfan anemia: Results from a multicenter pilot phase I/II study from the Diamond-Blackfan Anemia Registry

BACKGROUND

Diamond-Blackfan anemia (DBA) is an inherited bone marrow failure syndrome characterized by anemia, short stature, congenital anomalies, and cancer predisposition. Most cases are due to mutations in genes encoding ribosomal proteins (RP) leading to RP haploinsufficiency. Effective treatments for the anemia of DBA include chronic red cell transfusions, long-term corticosteroid therapy, or hematopoietic stem cell transplantation. In a small patient series and in animal models, there have been hematologic responses to L-leucine with amelioration of anemia. The study objectives of this clinical trial were to determine feasibility, safety, and efficacy of L-leucine in transfusion-dependent patients with DBA.

PROCEDURE

Patients ≥2 years of age received L-leucine 700 mg/m² orally three times daily for nine months to determine a hematologic response and any improvement in growth (NCT01362595).

RESULTS

This multicenter, phase I/II study enrolled 55 subjects; 43 were evaluable. There were 21 males; the median age at enrollment was 10.4 years (range, 2.5-46.1 years). No significant adverse events were attributable to L-leucine. Two subjects had a complete erythroid response and five had a partial response. Nine of 25, and 11 of 25, subjects experienced a positive weight and height percentile change, respectively, at the end of therapy.

CONCLUSIONS

L-leucine is safe, resulted in an erythroid response in 16% of subjects with DBA, and led to an increase in weight and linear growth velocity in 36% and 44% of evaluable subjects, respectively. Further studies will be critical to understand the role of L-leucine in the management of patients with DBA.

Red blood cell alloimmunization in transfused patients with bone marrow failure syndromes

BACKGROUND

Red blood cell (RBC) alloimmunization is a concern for patients who receive multiple or chronic transfusions. Alloimmunization prevalence in transfused patients with bone marrow failure syndrome (BMFS) is unknown. This study aimed to determine physician practice for RBC antigen matching, immunization rates, and antibody specificities in patients with BMFS.

STUDY DESIGN AND METHODS

The clinical records of all patients with BMFS seen at the Children's Hospital of Philadelphia between 2001 and 2015 were reviewed. Immunization rate was determined per 100 units transfused.

RESULTS

ABO/D, C, E, and K (CEK) RBC matching was requested for 21.8% of patients. A total of 3782 RBC units were transfused to 87 patients, of which 2551 (67.5%) were CEK matched and 1231 (32.5%) were ABO/D only matched. The majority of units transfused to patients on a chronic transfusion regimen were CEK matched (89.6% of 2728 units). No anti-C, -E, or -K antibodies formed in any patient during the 14-year study period. Two alloantibodies and two autoantibodies formed, resulting in a rate of 0.05 alloantibodies and 0.05 autoantibodies per 100 units transfused. The prevalence of alloimmunization was 2.3%.

CONCLUSION

The rate and prevalence of RBC alloimmunization were low in patients with BMFS. CEK matching avoided alloimmunization to these antigens in chronically transfused patients.

Disrupted lymphocyte homeostasis in hepatitis-associated acquired aplastic anemia is associated with short telomeres

Hepatitis‐associated aplastic anemia (HAA) is a variant of acquired aplastic anemia (AA) in which immune‐mediated bone marrow failure (BMF) develops following an acute episode of seronegative hepatitis. Dyskeratosis congenita (DC) is an inherited BMF syndrome characterized by the presence of short telomeres, mucocutaneous abnormalities, and cancer predisposition. While both conditions may cause BMF and hepatic impairment, therapeutic approaches are distinct, making it imperative to establish the correct diagnosis. In clinical practice, lymphocyte telomere lengths (TL) are used as a first‐line screen to rule out inherited telomeropathies before initiating treatment for AA. To evaluate the reliability of TL in the HAA population, we performed a retrospective analysis of TL in 10 consecutively enrolled HAA patients compared to 19 patients with idiopathic AA (IAA). HAA patients had significantly shorter telomeres than IAA patients (P = 0.009), including four patients with TL at or below the 1st percentile for age‐matched controls. HAA patients had no clinical features of DC and did not carry disease‐causing mutations in known genes associated with inherited telomere disorders. Instead, short TLs were significantly correlated with severe lymphopenia and skewed lymphocyte subsets, features characteristic of HAA. Our results indicate the importance of caution in the interpretation of TL measurements in HAA, because, in this patient population, short telomeres have limited specificity. Am. J. Hematol. 91:243–247, 2016. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.

Abstract 2977: Most patients with acquired aplastic anemia develop clonal hematopoiesis early in disease

Clonal hematopoiesis is an expansion of hematopoietic stem cells, caused by somatic mutations or epigenetic changes that confer a growth advantage to the host cell. Although recently recognized as a phenomenon of aging, clonal hematopoiesis has been traditionally associated with pre-cancerous states and malignant transformation. Acquired aplastic anemia (AA), a non-neoplastic autoimmune blood disorder occurring in children and adults, has been associated with clonal hematopoietic disorders; transformation to myelodysplastic syndrome (MDS) or acute leukemia is a late complication in 10-15% of AA patients. Based on the association of AA with clonal disorders, we hypothesized that clonal hematopoiesis is a general phenomenon in AA, and can be seen in the majority of AA patients, including children. To evaluate somatic genetic changes in AA, we used a combination of single nucleotide polymorphism array (SNP-A) genotyping and comparative whole exome sequencing of paired bone marrow aspirates and skin in twenty nine patients with AA. All somatic mutations were validated by bi-directional Sanger sequencing. The median age of diagnosis was 14 years (range 1.5-65). Patients were analyzed at a median of 1.1 years from diagnosis. None of the patients had histopathological evidence of MDS at the time of analysis. Somatic mutations were identified in the majority of patients, including patients with pediatric-onset AA. Three patients (10%) had somatic loss-of-function mutations in HLA class I alleles. Although MDS-associated mutations were identified in 2 of 29 patients, the majority of mutations were not in genes associated with MDS and hematologic malignancies. Pathway analysis of mutated genes revealed an enrichment of genes in pathways of immunity and transcriptional regulation. Comparison of somatic mutations in AA to a patient with a 30-year history of AA who progressed to MDS revealed that, unlike in AA, which was characterized by diverse and frequently oligoclonal hematopoiesis, progression to MDS was associated with an expansion of a dominant clone carrying multiple classical mutations linked to malignancy: pathogenic mutations in SUZ12 (homozygous for the mutated region due to copy number-neutral loss of heterozygosity (CN-LOH) at the chromosomal region 17q11.2qter), ASXL1, RUNX1, and PHF6. In conclusion, our data show that clonal hematopoiesis emerges in the majority of patients with AA, including children and young adults, can be detected early in disease, and has a mutational spectrum largely distinct from MDS. Our results highlight that in the absence of morphologic features of myelodysplasia, the presence of clonal hematopoiesis with somatic mutations cannot be used to distinguish MDS from AA. Future longitudinal studies of clonal hematopoiesis in AA will help to explain differences in patients’ disease course, and will enable personalized treatment approaches in AA.

Citation Format: Daria V. Babushok, Nieves Perdigones, Juan C. Perin, Timothy S. Olson, Wenda Ye, Jacquelyn J. Roth, Curt Lind, Carine Cattier, Yimei Li, Helge Hartung, Michele E. Paessler, Dale M. Frank, Hongbo M. Xie, Tracy M. Busse, Shanna Cross, Gregory M. Podsakoff, Dimitrios Monos, Jaclyn A. Biegel, Philip J. Mason, Monica Bessler. Most patients with acquired aplastic anemia develop clonal hematopoiesis early in disease. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2977. doi:10.1158/1538-7445.AM2015-2977

Emergence of clonal hematopoiesis in the majority of patients with acquired aplastic anemia

Acquired aplastic anemia (aAA) is a nonmalignant disease caused by autoimmune destruction of early hematopoietic cells. Clonal hematopoiesis is a late complication, seen in 20-25% of older patients. We hypothesized that clonal hematopoiesis in aAA is a more general phenomenon, which can arise early in disease, even in younger patients. To evaluate clonal hematopoiesis in aAA, we used comparative whole exome sequencing of paired bone marrow and skin samples in 22 patients. We found somatic mutations in 16 patients (72.7%) with a median disease duration of 1 year; of these, 12 (66.7%) were patients with pediatric-onset aAA. Fifty-eight mutations in 51 unique genes were found primarily in pathways of immunity and transcriptional regulation. Most frequently mutated was PIGA, with seven mutations. Only two mutations were in genes recurrently mutated in myelodysplastic syndrome. Two patients had oligoclonal loss of the HLA alleles, linking immune escape to clone emergence. Two patients had activating mutations in key signaling pathways (STAT5B (p.N642H) and CAMK2G (p.T306M)). Our results suggest that clonal hematopoiesis in aAA is common, with two mechanisms emerging-immune escape and increased proliferation. Our findings expand conceptual understanding of this nonneoplastic blood disorder. Future prospective studies of clonal hematopoiesis in aAA will be critical for understanding outcomes and for designing personalized treatment strategies.

High-frequency stimulation of the subthalamic nucleus inhibits the firing of juxtacellular labelled 5-HT-containing neurones

High-frequency stimulation (HFS) of the subthalamic nucleus (STN) is an established neurosurgical therapy for movement disability in advanced Parkinson's disease (PD), but some patients experience psychiatric side-effects like depression. In a previous electrophysiological study, we observed that HFS of the STN inhibited a population of neurones in the rat dorsal raphe nucleus (DRN), with firing properties characteristic of 5-HT neurones. The present study extended these findings to a second population of neurones, and combined extracellular recording with juxtacellular-labelling to investigate the chemical identity of the neurones affected by HFS. Bilateral HFS (130 Hz, 100-200 μA, 5 min) of the STN inhibited (26.0±2.9%) the firing of 37/74 DRN neurones displaying a slow, regular firing pattern. Slower firing neurones were more strongly inhibited than those firing faster. Importantly, 10 inhibited DRN neurones were juxtacellular-labelled with neurobiotin, and all neurones contained 5-HT as shown by post-mortem 5-HT immunocytochemistry. A minority of slow firing DRN neurones (18/74) were activated by STN HFS (37.9±8.3%) which was not observed previously. Of these neurones, three were juxtacellular-labelled and one was 5-HT immunopositive. Also a small number of DRN neurones (19/74) did not respond to HFS, four of which were juxtacellular-labelled and all contained 5-HT. These data show that individual chemically-identified 5-HT-containing neurones in the DRN were modulated by STN HFS, and that the majority were inhibited but some were activated and some failed to respond. These data extend previous findings of modulation of the 5-HT system by STN HFS but suggest a destabilisation of the 5-HT system rather than simple inhibition as indicated previously. Although the mechanism is not yet known, such changes may contribute to the psychiatric side-effects of STN stimulation in some PD patients.

Genome architecture marked by retrotransposons modulates predisposition to DNA methylation in cancer

Epigenetic silencing plays an important role in cancer development. An attractive hypothesis is that local DNA features may participate in differential predisposition to gene hypermethylation. We found that, compared with methylation-resistant genes, methylation-prone genes have a lower frequency of SINE and LINE retrotransposons near their transcription start site. In several large testing sets, this distribution was highly predictive of promoter methylation. Genome-wide analysis showed that 22% of human genes were predicted to be methylation-prone in cancer; these tended to be genes that are down-regulated in cancer and that function in developmental processes. Moreover, retrotransposon distribution marks a larger fraction of methylation-prone genes compared to Polycomb group protein (PcG) marking in embryonic stem cells; indeed, PcG marking and our predictive model based on retrotransposon frequency appear to be correlated but also complementary. In summary, our data indicate that retrotransposon elements, which are widespread in our genome, are strongly associated with gene promoter DNA methylation in cancer and may in fact play a role in influencing epigenetic regulation in normal and abnormal physiological states.

NUP98-HOX translocations lead to myelodysplastic syndrome in mice and men

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, dysplasia, and a propensity for transformation to acute myeloid leukemia (AML). A wide spectrum of genetic aberrations has been associated with MDS, including chromosomal translocations involving the NUP98 gene, most commonly leading to fusions of NUP98 with abd-b group HOX genes, including HOXD13. We used vav regulatory elements to direct expression of a NUP98-HOXD13 (NHD13) fusion gene in hematopoietic tissues. NHD13 transgenic mice faithfully recapitulate all the key features of MDS, including peripheral blood cytopenias, bone marrow dysplasia and apoptosis, and transformation to acute leukemia. The MDS that develops in NHD13 transgenic mice is highly lethal; within 14 months, 90% of the mice died of either leukemic transformation or severe anemia and leukopenia due to progressive MDS. These mice provide a preclinical model that can be used for the evaluation of MDS therapy and biology.

Retroviral insertional mutagenesis identifies genes that collaborate with NUP98-HOXD13 during leukemic transformation

The t(2;11)(q31;p15) chromosomal translocation results in a fusion between the NUP98 and HOXD13 genes and has been observed in patients with myelodysplastic syndrome (MDS) or acute myelogenous leukemia. We previously showed that expression of the NUP98-HOXD13 (NHD13) fusion gene in transgenic mice results in an invariably fatal MDS; approximately one third of mice die due to complications of severe pancytopenia, and about two thirds progress to a fatal acute leukemia. In the present study, we used retroviral insertional mutagenesis to identify genes that might collaborate with NHD13 as the MDS transformed to an acute leukemia. Newborn NHD13 transgenic mice and littermate controls were infected with the MOL4070LTR retrovirus. The onset of leukemia was accelerated, suggesting a synergistic effect between the NHD13 transgene and the genes neighboring retroviral insertion events. We identified numerous common insertion sites located near protein-coding genes and confirmed dysregulation of a subset of these by expression analyses. Among these genes were Meis1, a known collaborator of HOX and NUP98-HOX fusion genes, and Mn1, a transcriptional coactivator involved in human leukemia through fusion with the TEL gene. Other putative collaborators included Gata2, Erg, and Epor. Of note, we identified a common insertion site that was >100 kb from the nearest coding gene, but within 20 kb of the miR29a/miR29b1 microRNA locus. Both of these miRNA were up-regulated, demonstrating that retroviral insertional mutagenesis can target miRNA loci as well as protein-coding loci. Our data provide new insights into NHD13-mediated leukemogenesis as well as retroviral insertional mutagenesis mechanisms.

A neurologic presentation of familial hemophagocytic lymphohistiocytosis which mimicked septic emboli to the brain

Familial hemophagocytic lymphohistiocytosis is an inherited deficiency of natural killer cell function and excessive cytokine activity, which predominantly presents in early childhood. The initial symptoms of familial hemophagocytic lymphohistiocytosis are often nonspecific but may be predominantly neurologic. The case presented here describes an 18-month-old boy who initially presented with fever, encephalopathy, and hemiparesis. He had innumerable brain lesions visualized on magnetic resonance imaging scans. An infectious etiology was excluded, and brain, liver, and bone marrow biopsies were nonspecific but consistent with hemophagocytic lymphohistiocytosis. Cells were sent for flow cytometry perforin analysis, which demonstrated defective natural killer cell function. A diagnosis of familial hemophagocytic lymphohistiocytosis was confirmed by mutation analysis and decreased expression of the perforin gene, in the patient and immediate family members. These results showed the patient to be a compound heterozygote for perforin mutations. His case illustrates the potential for a fulminant neurological presentation of familial hemophagocytic lymphohistiocytosis with widespread lesions in the brain.

Effects of essential oils from fennel (Foeniculi aetheroleum) and caraway (Carvi aetheroleum) in pigs

The ban of antibiotics as a feed additive requires alternatives to stabilize the health and performance particularly of the young animals. Essential oils obtained from fennel seed (Foeniculi aetheroleum) and caraway seed (Carvi aetheroleum) were tested in diets for weaned piglets in comparison with either a diet without feed additive or with a combination of formic acid and copper (positive control). Four groups of sixteen piglets (live weight 7 kg, age 26 days) received diets without (1) or with supplements of 7.5 g formic acid + 160 mg Cu/kg (2), 100 mg fennel oil/kg (3) or 100 mg caraway oil/kg (4) during 3 weeks after weaning. In the subsequent 4 weeks, all piglets were fed a diet without these additions. Fennel oil contained almost 2/3 anethol, approximately 1/5 fenchon and the remaining part consisting of alpha + beta-pinen, limonen (p-mentha-1,8-dien) and estragol. In the caraway oil, half of the contents was represented by limonen and the other half by carvon. There were no piglet losses and only few cases of diarrhoea. The combination of formic acid and copper increased feed consumption by 27% and daily weight gain by 25%. There were no differences in the performance between the group fed fennel oil and the control without additives. Piglets fed caraway oil tended to consume less feed and to gain approximately 10% less. In feed choice experiments, pigs consumed the same two diets from two troughs with 50% of total feed amount, as expected. The diets containing fennel or caraway oils were consumed at less than 50%. If the diet contained 100 mg fennel oil/kg, the decrease of percentual feed intake was significant. The results of the feeding experiment and of the feed choice experiment question the classification of fennel and caraway oils as flavour additives or as 'appetite promoters' in diets for weaned piglets.

Characterizing the mechanisms of progression in multiple sclerosis: evidence and new hypotheses for future directions

Major advancements have been achieved in our ability to diagnose multiple sclerosis (MS) and to commence treatment intervention with agents that can favorably affect the disease course. Although MS exacerbations and the emergence of disability constitute the more conspicuous aspects of the disease process, evidence has confirmed that most of the disease occurs on a constitutive and occult basis. Disease-modifying therapies appear to be modest in the magnitude of their treatment effects, particularly in the progressive stage of the disease. Therapeutic strategies currently used for MS primarily target the inflammatory cascade. Several potential mechanisms appear to be involved in the progression of MS. Characterizing these mechanisms will result in a better understanding of the various forms of the disorder and how to effectively treat its clinical manifestations. It is our objective within this 2-part series on progression in MS to offer both evidence-based observations and hypothesis-driven expert perspectives on what constitutes the cause of progression in MS. We have chosen areas of inquiry that appear to have been most productive in helping us to better conceptualize the landscape of what MS looks like pathologically, immunologically, neuroscientifically, radiographically, and genetically. We have attempted to advance hypotheses focused on a deeper understanding of what contributes to the progression of this illness and to illustrate new technical capabilities that are catalyzing novel research initiatives targeted at achieving a more complete understanding of progression in MS.