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Background: Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an autosomal recessive disease that prevents the body from utilizing long-chain fatty acids for energy, most needed during stress and fasting. Symptoms can appear from infancy through childhood and adolescence or early adulthood, and include hypoglycemia, recurrent rhabdomyolysis, myopathy, hepatopathy, and cardiomyopathy. REN001 is a peroxisome-proliferator-activated receptor delta (PPARδ) agonist that modulates the expression of the genes coding for fatty acid β-oxidation enzymes and proteins involved in oxidative phosphorylation. Here, we assessed the effect of REN001 on VLCAD-deficient patient fibroblasts. Methods: VLCAD-deficient patient and control fibroblasts were treated with REN001. Cells were harvested for gene expression analysis, protein content, VLCAD enzyme activity, cellular bioenergetics, and ATP production. Results: VLCAD-deficient cell lines responded differently to REN001 based on genotype. All cells had statistically significant increases in ACADVL gene expression. Small increases in VLCAD protein and enzyme activity were observed and were cell-line- and dose-dependent. Even with these small increases, cellular bioenergetics improved in all cell lines in the presence of REN001, as demonstrated by the oxygen consumption rate and ATP production. VLCAD-deficient cell lines containing missense mutations responded better to REN001 treatment than one containing a duplication mutation in ACADVL. Discussion: Treating VLCAD-deficient fibroblasts with the REN001 PPARδ agonist results in an increase in VLCAD protein and enzyme activity, and a decrease in cellular stress. These results establish REN001 as a potential therapy for VLCADD as enhanced expression may provide a therapeutic increase in total VLCAD activity, but suggest the need for mutation-specific treatment augmented by other treatment measures. [ABSTRACT FROM AUTHOR]

Inherited errors of mitochondrial fatty acid β‐oxidation (FAO) are life threatening, even with optimum care. FAO is the major source of energy for heart and is critical for skeletal muscles especially during physiologic stress. Clinical trials revealed that triheptanoin (commercially known as Dojolvi; C7G), improved heart function and decreased hypoglycemia in long chain FAO disorders, but other symptoms including rhabdomyolysis persisted, suggesting suboptimal tissue distribution/utilization of heptanoic acid (C7) conjugates and/or rapid liver breakdown. In this study, medium branched chain fatty acids were tested as potential anaplerotic treatments in fibroblasts from patients deficient in very long chain acyl‐CoA dehydrogenase (VLCAD), long chain 3‐hydroxyacyl‐CoA dehydrogenase (LCHAD), trifunctional protein (TFP), and carnitine palmitoyltransferase II (CPT II). Cells were cultured to near confluency and treated with C7, 2,6‐dimethylheptanoic acid (dMC7), 6‐amino‐2,4‐dimethylheptanoic acid (AdMC7), or 4,8‐dimethylnonanoic acid (dMC9) for 72 h and targeted metabolomics performed. The profile of TCA cycle intermediates was improved in cells treated with these branched chain fatty acids compared with C7. Intracellular propionate was higher in AdMC7 treated cells compared with C7 in VLCAD, LCHAD, and TFP deficient cell lines. With AdMC7 treatment, succinate was higher in CPT II and VLCAD deficient cells, compared with C7. Malate and glutamate were consistently higher in AdMC7 treated VLCAD, LCHAD, TFP, and CPT II deficient cells compared with the C7 treatment. The results provide the impetus to further evaluate and consider branched chain fatty acids as viable anaplerotic therapy for fatty acid oxidation disorders and other diseases. [ABSTRACT FROM AUTHOR]

Transport and Golgi Organization protein 2 Homolog (TANGO2)-related disease is an autosomal recessive disorder caused by mutations in the TANGO2 gene. Symptoms typically manifest in early childhood and include developmental delay, stress-induced episodic rhabdomyolysis, and cardiac arrhythmias, along with severe metabolic crises including hypoglycemia, lactic acidosis, and hyperammonemia. Severity varies among and within families. Previous studies have reported contradictory evidence of mitochondrial dysfunction. Since the clinical symptoms and metabolic abnormalities are suggestive of a broad dysfunction of mitochondrial energy metabolism, we undertook a broad examination of mitochondrial bioenergetics in TANGO2 deficient patients utilizing skin fibroblasts derived from three patients exhibiting TANGO2-related disease. Functional studies revealed that TANGO2 protein was present in mitochondrial extracts of control cells but not patient cells. Superoxide production was increased in patient cells, while oxygen consumption rate, particularly under stress, along with relative ATP levels and β-oxidation of oleate were reduced. Our findings suggest that mitochondrial function should be assessed and monitored in all patients with TANGO2 mutation as targeted treatment of the energy dysfunction could improve outcome in this condition. [ABSTRACT FROM AUTHOR]

Acyl-CoA dehydrogenase 10 (Acad10)-deficient mice develop impaired glucose tolerance, peripheral insulin resistance, and abnormal weight gain. In addition, they exhibit biochemical features of deficiencies of fatty acid oxidation, such as accumulation of metabolites consistent with abnormal mitochondrial energy metabolism and fasting induced rhabdomyolysis. ACAD10 has significant expression in mouse brain, unlike other acyl-CoA dehydrogenases (ACADs) involved in fatty acid oxidation. The presence of ACAD10 in human tissues was determined using immunohistochemical staining. To characterize the effect of ACAD10 deficiency on the brain, micro-MRI and neurobehavioral evaluations were performed. Acad10-deficient mouse behavior was examined using open field testing and DigiGait analysis for changes in general activity as well as indices of gait, respectively. ACAD10 protein was shown to colocalize to mitochondria and peroxisomes in lung, muscle, kidney, and pancreas human tissue. Acad10-deficient mice demonstrated subtle behavioral abnormalities, which included reduced activity and increased time in the arena perimeter in the open field test. Mutant animals exhibited brake and propulsion metrics similar to those of control animals, which indicates normal balance, stability of gait, and the absence of significant motor impairment. The lack of evidence for motor impairment combined with avoidance of the center of an open field arena and reduced vertical and horizontal exploration are consistent with a phenotype characterized by elevated anxiety. These results implicate ACAD10 function in normal mouse behavior, which suggests a novel role for ACAD10 in brain metabolism. [ABSTRACT FROM AUTHOR]

The Native American Pima population has the highest incidence of insulin resistance (IR) and type 2 diabetes mellitus (T2DM) of any reported population, but the pathophysiologic mechanism is unknown. Genetic studies in Pima Indians have linked acyl-CoA dehydrogenase 10 ( ACAD10) gene polymorphisms, among others, to this predisposition. The gene codes for a protein with a C-terminus region that is structurally similar to members of a family of flavoenzymes-the acyl-CoA dehydrogenases (ACADs)-that catalyze α,β-dehydrogenation reactions, including the first step in mitochondrial FAO (FAO), and intermediary reactions in amino acids catabolism. Dysregulation of FAO and an increase in plasma acylcarnitines are recognized as important in the pathophysiology of IR and T2DM. To investigate the deficiency of ACAD10 as a monogenic risk factor for T2DM in human, an Acad-deficient mouse was generated and characterized. The deficient mice exhibit an abnormal glucose tolerance test and elevated insulin levels. Blood acylcarnitine analysis shows an increase in long-chain species in the older mice. Nonspecific variable pattern of elevated short-terminal branch-chain acylcarnitines in a variety of tissues was also observed. Acad10 mice accumulate excess abdominal adipose tissue, develop an early inflammatory liver process, exhibit fasting rhabdomyolysis, and have abnormal skeletal muscle mitochondria. Our results identify Acad10 as a genetic determinant of T2DM in mice and provide a model to further investigate genetic determinants for insulin resistance in humans. [ABSTRACT FROM AUTHOR]

Allograft tissues are used in over one million musculoskeletal procedures per year. Consequently, it is crucial tissue banks use procedures to militate against allograft associated bacterial and viral infections. Recent studies have identified an important pathogen inactivation technology for musculoskeletal allografts that utilizes high-dose gamma irradiation (50 kGy) under controlled conditions. A total dose of 50 kGy assures that the current standard for medical devices for a microbial sterility assurance level of 10-6 is met. Furthermore, the pathogen inactivation technology results in a greater than four log inactivation of enveloped and nonenveloped viruses. Efficacious clinical outcome from musculoskeletal allografts exposed to this innovative sterilization procedure will require that there is no performance decrement in the allograft's biological properties. Therefore, to validate this objective, we executed a study focusing on remodeling and osteoconduction of bone allografts treated with a high dose of gamma irradiation (50 kGy), radioprotectants and well-defined operating parameters of temperature and water content. A rabbit calvarial model was used to test the hypothesis that remodeling and osteoconduction of allogeneic bone treated with the new pathogen inactivation technology would be equivalent to nontreated allogeneic bone. Results indicated treated bone allografts were comparable to nontreated allografts. We conclude, therefore, that based on this outcome and other reports, that high doses of gamma irradiation under optimized conditions designed to reduce free radical damage to tissue will provide safer allografts. [ABSTRACT FROM AUTHOR]

Human platelet-derived growth factor-BB (hPDGF-BB) is a basic polypeptide growth factor released from platelets at the injury site. It is amultifunctional molecule that regulates DNA synthesis and cell division and induces biological effects that are implicated in tissue repair, atherosclerosis, inflammatory responses, and neoplastic diseases. This paper is an overview of the toxicology data generated from a broad testing platform to determine bone, soft tissue, and systemic responses following administration of rhPDGF-BB.Moreover, the systemic and local toxicity of recombinant human PDGF-BB (rhPDGF-BB) in combination with either beta-tricalcium phosphate (β-TCP) or collagen combined with β-TCP was studied to determine dermal sensitization, irritation, intramuscular tissue responses, pyrogenicity, genotoxicity, and hemolytic properties. All data strongly suggest that rhPDGF-BB either alone or in combination with β-TCP or collagen with β-TCP is biocompatible and has neither systemic nor local toxicity, supporting its safe use in enhancing wound healing in patients. [ABSTRACT FROM AUTHOR]

Reticular dysgenesis is an autosomal recessive form of severe combined immunodeficiency (SCID) that usually manifests in newborns. It is a unique example of an immune deficiency that is linked to dysfunctional mitochondrial energy metabolism and caused by adenylate kinase 2 (AK2) deficiency. It is characterized by an early differentiation arrest in the myeloid lineage, impaired lymphoid maturation, and sensorineural hearing loss. In this study, a novel AK2 homozygous mutation, c.622 T > C [p.Ser208Pro], was identified in an Old Order Amish patient through whole exome sequencing. Functional studies showed that the patient's cells have no detectable AK2 protein, as well as low oxygen consumption rate (OCR), extracellular acidification rate (ECAR) and proton production rate (PPR). An increased production of reactive oxygen species, mitochondrial membrane permeability, and mitochondrial mass, and decreased ATP production, were also observed. The results confirm the pathogenicity of the AK2 mutation and demonstrate that reticular dysgenesis should be considered in Amish individuals presenting with immune deficiency. We also describe other pathophysiological aspects of AK2 deficiency not previously reported. [ABSTRACT FROM AUTHOR]

Ethylmalonic encephalopathy protein 1 (ETHE1) and molybdenum cofactor (MoCo) deficiencies are hereditary disorders that affect the catabolism of sulfur-containing amino acids. ETHE1 deficiency is caused by mutations in the ETHE1 gene, while MoCo deficiency is due to mutations in one of three genes involved in MoCo biosynthesis (MOCS1, MOCS2 and GPHN). Patients with both disorders exhibit abnormalities of the mitochondrial respiratory chain, among other biochemical findings. However, the pathophysiology of the defects has not been elucidated. To characterize cellular derangements, mitochondrial bioenergetics, dynamics, endoplasmic reticulum (ER)-mitochondria communication, superoxide production and apoptosis were evaluated in fibroblasts from four patients with ETHE1 deficiency and one with MOCS1 deficiency. The effect of JP4-039, a promising mitochondrial-targeted antioxidant, was also tested on cells. Our data show that mitochondrial respiration was decreased in all patient cell lines. ATP depletion and increased mitochondrial mass was identified in the same cells, while variable alterations in mitochondrial fusion and fission were seen. High superoxide levels were found in all cells and were decreased by treatment with JP4-039, while the respiratory chain activity was increased by this antioxidant in cells in which it was impaired. The content of VDAC1 and IP3R, proteins involved in ER-mitochondria communication, was decreased, while DDIT3, a marker of ER stress, and apoptosis were increased in all cell lines. These data demonstrate that previously unrecognized broad disturbances of cellular function are involved in the pathophysiology of ETHE1 and MOCS1 deficiencies, and that reduction of mitochondrial superoxide by JP4-039 is a promising strategy for adjuvant therapy of these disorders. [ABSTRACT FROM AUTHOR]