John J. Byrnes

We performed a focused review to better understand the pathogenesis of Agent Orange (AO)-associated myelodysplastic syndrome (MDS). We first examined the mechanisms underlying conventional (de novo) MDS, a clonal hematopoietic neoplasm that typically develops in later life, and integrated these findings with our recent analysis of obesity-associated carcinogenesis. Accordingly, we propose that genomic instability in de novo MDS results from selective inhibition of the DNA polymerase proofreading exonuclease. In obesity-associated carcinogenesis, impaired AMP-activated protein kinase (AMPK) activity disrupts mitochondrial ATP production, increasing intracellular AMP concentrations. Elevated AMP selectively inhibits the proofreading exonuclease while preserving polymerase activity, allowing replication errors to escape correction and become fixed as somatic mutations. Molecular studies demonstrate that AO-associated MDS exhibits essentially the same mutational profile as de novo disease despite arising after 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in young, otherwise healthy military personnel. Because TCDD is highly lipophilic, it accumulates in adipose tissue and is released slowly over decades, producing sustained mitochondrial dysfunction, reduced ATP synthesis, and chronic elevation of intracellular AMP. We propose that this metabolic disturbance converges on the same endpoint—selective inhibition of the proofreading exonuclease—thereby promoting mutagenesis and clonal evolution. Recent studies further strengthen the central role of proofreading by demonstrating that many mutations, including many found in MDS, previously attributed to spontaneous cytosine deamination, instead arise from DNA polymerase misincorporation of thymidine opposite cytosine, particularly at CpG dinucleotides, emphasizing the critical importance of fully active proofreading in preventing such misincorporations from accumulating as mutations in the genome of the cell.

We performed a focused review to better understand the pathogenesis of Agent Orange (AO)-associated myelodysplastic syndrome (MDS). We first examined the mechanisms underlying conventional (de novo) MDS, a clonal hematopoietic neoplasm that typically develops in later life and integrated these findings with our recent analysis of obesity-associated carcinogenesis. Accordingly, we propose that genomic instability in de novo MDS results from selective inhibition of the DNA polymerase proofreading exonuclease. In obesity associated carcinogenesis, impaired AMP-activated protein kinase (AMPK) activity disrupts mitochondrial ATP production, increasing intracellular AMP concentrations. Elevated AMP selectively inhibits the proofreading exonuclease while preserving polymerase activity, allowing replication errors to escape correction, and become fixed as somatic mutations. Molecular studies demonstrate that AO-associated MDS exhibits essentially the same mutational profile as de novo disease despite arising after dioxin exposure in young, otherwise healthy military personnel. Because TCDD is highly lipophilic, it accumulates in adipose tissue and is released slowly over decades, producing sustained mitochondrial dysfunction, reduced ATP synthesis, and chronic elevation of intracellular AMP. We propose that this metabolic disturbance converges on the same end-point—selective inhibition of the proofreading exonuclease—thereby promoting mutagenesis and clonal evolution. Recent studies further strengthen the central role of proofreading by demonstrating that many mutations, including many found in MDS, previously attributed to spontaneous cytosine deamination, instead arise from DNA polymerase misincorporation of thymidine opposite cytosine, particularly at CpG dinucleotides, emphasizing the critical importance of fully active proofreading in preventing such misincorporations from accumulating as mutations in the genome of the cell.

Obesity-associated carcinogenesis offers a model to explore the transition from metabolic dysregulation to genomic instability and carcinogenesis. Adenosine 5′-monophosphate-activated protein kinase (AMPK), the principal cellular energy sensor, coordinates adenosine triphosphate (ATP) production with metabolic demand; however, in obesity, AMPK activity is impaired, resulting in reduced ATP, elevated Adenosine Monophosphate (AMP), and cellular energy stress. Deoxyribonucleic Acid (DNA) polymerases ε (Pol ε) and δ (Pol δ) maintain replication fidelity via a 3′→5′ exonuclease proofreading activity that removes misincorporated nucleotides. Elevated AMP directly binds and selectively inhibits the exonucleases, conserving energy at the expense of genomic accuracy. As a result, replication errors escape correction and accumulate, some conferring a selective advantage and driving carcinogenic evolution. Therapeutic and lifestyle interventions that activate AMPK—including weight loss, exercise, metformin, and aspirin—restore ATP production, lower AMP, and relieve inhibition of exonuclease proofreading, thereby preserving genomic integrity and slowing mutation-driven carcinogenesis. This framework reveals two core biological principles: 1. Energy metabolism and DNAreplication fidelity are mechanistically coupled at the DNA polymerase active site. 2. The mutation rate is an adaptive metabolic phenotype, modulated by AMP levels. These concepts redefine the metabolic–genetic interface in carcinogenesis and highlight AMPK activation as a rational target for obesity-associated cancer prevention.

Obesity-associated carcinogenesis offers a model to explore the transition from metabolic dysregulation to genomic instability and carcinogenesis. AMPK, the principal cellular energy sensor, coordinates ATP production with metabolic demand; however, in obesity, AMPK activity is impaired, resulting in reduced ATP, elevated AMP, and cellular energy stress. DNA polymerases ε (Pol ε) and δ (Pol δ) maintain replication fidelity via a 3′→5′ exonuclease proofreading activity that removes misincorporated nucleotides. Elevated AMP directly binds and selectively inhibits the exonuclease, conserving energy at the expense of genomic accuracy. As a result, replication errors escape correction and accumulate, some conferring selective advantage and driving carcinogenic evolution. Therapeutic and lifestyle interventions that activate AMPK — including weight loss, exercise, metformin, and aspirin — restore ATP production, lower AMP, and relieve inhibition of exonuclease proofreading, thereby preserving genomic integrity and slowing mutation-driven carcinogenesis. This framework reveals two core biological principles: 1. Energy metabolism and DNA replication fidelity are mechanistically coupled at the DNA polymerase active site. 2. The mutation rate is an adaptive metabolic phenotype, modulated by AMP levels. These concepts redefine the metabolic-genetic interface in carcinogenesis and highlight AMPK activation as a rational target for obesity associated cancer prevention.

The etiology of anemia in liver cirrhosis is multifactorial; one less recognized cause is hemolytic anemia due to spur cells, known as spur cell anemia. We present the case of a 57-year-old woman with alcoholic cirrhosis who presented with symptomatic macrocytic anemia with a hemoglobin level of 7.4g/dL and signs of decompensated liver disease. Notably, she had no signs of overt bleeding. Further workup was consistent with hemolysis, with peripheral smear demonstrating spur cells. The patient was treated with both steroids and IVIG, although she eventually expired. The characteristic morphology of spur cells is due to alteration of the lipid composition of the erythrocyte membrane, changing its shape and leading to splenic sequestration and destruction. Characteristic of this disorder is an increased ratio of cholesterol to phospholipid on the membrane, as well as low levels of apolipoproteins and low- and high-density lipoproteins. The presence of spur cells is an indicator of poor prognosis and high risk of mortality. Currently, the only definitive cure is liver transplantation. There is a paucity of literature on the prevalence of this phenomenon and even less about treatment. This case highlights the importance of recognition of spur cell anemia as a cause of anemia in cirrhosis as well as the importance of the peripheral smear in the diagnostic workup. Early recognition can lead to avoidance of unnecessary procedures. Further research is needed to elucidate the true prevalence of spur cell anemia and examine further treatment options.

When assessing the importance of materials (or other components) to a given set of applications, machine analysis of a very large corpus of scientific abstracts can provide an analyst a base of insights to develop further. The use of text analytics reduces the time required to conduct an evaluation, while allowing analysts to experiment with a multitude of different hypotheses. Because the scope and quantity of metadata analyzed can, and should, be large, any divergence from what a human analyst determines and what the text analysis shows provides a prompt for the human analyst to reassess any preliminary findings. In this work, we have successfully extracted material-application pairs and ranked them on their importance. This method provides a novel way to map scientific advances in a particular material to the application for which it is used. Approximately 438,000 titles and abstracts of scientific papers published from 1992 to 2011 were used to examine sixteen materials. This analysis used co-clustering text analysis to associate individual materials with specific clean energy applications, evaluate the importance of materials to specific applications, and assess their importance to clean energy overall. Our analysis reproduced the judgements of experts in assigning material importance to applications. The validated methods were then used to map the replacement of one material with another material in a specific application (batteries).

Rationale:: Cell dose and concentration play crucial roles in phenotypic responses to cell-based therapy for heart failure. Objective:: To compare the safety and efficacy of 2 doses of allogeneic bone marrow–derived human mesenchymal stem cells identically delivered in patients with ischemic cardiomyopathy. Methods and Results:: Thirty patients with ischemic cardiomyopathy received in a blinded manner either 20 million (n=15) or 100 million (n=15) allogeneic human mesenchymal stem cells via transendocardial injection (0.5 cc per injection × 10 injections per patient). Patients were followed for 12 months for safety and efficacy end points. There were no treatment-emergent serious adverse events at 30 days or treatment-related serious adverse events at 12 months. The Major Adverse Cardiac Event rate was 20.0% (95% confidence interval [CI], 6.9% to 50.0%) in 20 million and 13.3% (95% CI, 3.5% to 43.6%) in 100 million ( P =0.58). Worsening heart failure rehospitalization was 20.0% (95% CI, 6.9% to 50.0%) in 20 million and 7.1% (95% CI, 1.0% to 40.9%) in 100 million ( P =0.27). Whereas scar size reduced to a similar degree in both groups: 20 million by −6.4 g (interquartile range, −13.5 to −3.4 g; P =0.001) and 100 million by −6.1 g (interquartile range, −8.1 to −4.6 g; P =0.0002), the ejection fraction improved only with 100 million by 3.7 U (interquartile range, 1.1 to 6.1; P =0.04). New York Heart Association class improved at 12 months in 35.7% (95% CI, 12.7% to 64.9%) in 20 million and 42.9% (95% CI, 17.7% to 71.1%) in 100 million. Importantly, proBNP (pro-brain natriuretic peptide) increased at 12 months in 20 million by 0.32 log pg/mL (95% CI, 0.02 to 0.62; P =0.039), but not in 100 million (−0.07 log pg/mL; 95% CI, −0.36 to 0.23; P =0.65; between group P =0.07). Conclusions:: Although both cell doses reduced scar size, only the 100 million dose increased ejection fraction. This study highlights the crucial role of cell dose in the responses to cell therapy. Determining optimal dose and delivery is essential to advance the field, decipher mechanism(s) of action and enhance planning of pivotal Phase III trials. Clinical Trial Registration:: URL: http://www.clinicaltrials.gov . Unique identifier: NCT02013674.

Aging frailty, characterized by decreased physical and immunological functioning, is associated with stem cell depletion. Human allogeneic mesenchymal stem cells (allo-hMSCs) exert immunomodulatory effects and promote tissue repair. This is a randomized, double-blinded, dose-finding study of intravenous allo-hMSCs (100 or 200-million [M]) vs placebo delivered to patients (n = 30, mean age 75.5 ± 7.3) with frailty. The primary endpoint was incidence of treatment-emergent serious adverse events (TE-SAEs) at 1-month postinfusion. Secondary endpoints included physical performance, patient-reported outcomes, and immune markers of frailty measured at 6 months postinfusion. No therapy-related TE-SAEs occurred at 1 month. Physical performance improved preferentially in the 100M-group; immunologic improvement occurred in both the 100M- and 200M-groups. The 6-minute walk test, short physical performance exam, and forced expiratory volume in 1 second improved in the 100M-group (p = .01), not in the 200M- or placebo groups. The female sexual quality of life questionnaire improved in the 100M-group (p = .03). Serum TNF-α levels decreased in the 100M-group (p = .03). B cell intracellular TNF-α improved in both the 100M- (p < .0001) and 200M-groups (p = .002) as well as between groups compared to placebo (p = .003 and p = .039, respectively). Early and late activated T-cells were also reduced by MSC therapy. Intravenous allo-hMSCs were safe in individuals with aging frailty. Treated groups had remarkable improvements in physical performance measures and inflammatory biomarkers, both of which characterize the frailty syndrome. Given the excellent safety and efficacy profiles demonstrated in this study, larger clinical trials are warranted to establish the efficacy of hMSCs in this multisystem disorder. www.clinicaltrials.gov: CRATUS (#NCT02065245).

Impaired endogenous stem cell repair capacity is hypothesized to be a biologic basis of frailty. Therapies that restore regenerative capacity may therefore be beneficial. This Phase 1 study evaluated the safety and potential efficacy of intravenous, allogeneic, human mesenchymal stem cell (allo-hMSC)-based therapy in patients with aging frailty. In this nonrandomized, dose-escalation study, patients received a single intravenous infusion of allo-hMSCs: 20-million (n = 5), 100-million (n = 5), or 200-million cells (n = 5). The primary endpoint was incidence of any treatment-emergent serious adverse events measured at 1 month postinfusion. The secondary endpoints were functional efficacy domains and inflammatory biomarkers, measured at 3 and 6 months, respectively. There were no treatment-emergent serious adverse events at 1-month postinfusion or significant donor-specific immune reactions during the first 6 months. There was one death at 258 days postinfusion in the 200-million group. In all treatment groups, 6-minute walk distance increased at 3 months (p = .02) and 6 months (p = .001) and TNF-α levels decreased at 6 months (p < .0001). Overall, the 100-million dose showed the best improvement in all parameters, with the exception of TNF-α, which showed an improvement in both the 100- and 200-million groups (p = .0001 and p = .0001, respectively). The 100-million cell-dose group also showed significant improvements in the physical component of the SF-36 quality of life assessment at all time points relative to baseline. Allo-hMSCs are safe and immunologically tolerated in aging frailty patients. Improvements in functional and immunologic status suggest that ongoing clinical development of cell-based therapy is warranted for frailty.