Slc2a10 knock-out mice deficient in ascorbic acid synthesis recapitulate aspects of arterial tortuosity syndrome and display mitochondrial respiration defects.

Arterial tortuosity syndrome (ATS) is a recessively inherited connective tissue disorder, mainly characterized by tortuosity and aneurysm formation of the major arteries. ATS is caused by loss-of-function mutations in SLC2A10, encoding the facilitative glucose transporter GLUT10. Former studies implicated GLUT10 in the transport of dehydroascorbic acid, the oxidized form of ascorbic acid (AA). Mouse models carrying homozygous Slc2a10 missense mutations did not recapitulate the human phenotype. Since mice, in contrast to humans, are able to intracellularly synthesize AA, we generated a novel ATS mouse model, deficient for Slc2a10 as well as Gulo, which encodes for L-gulonolactone oxidase, an enzyme catalyzing the final step in AA biosynthesis in mouse. Gulo;Slc2a10 double knock-out mice showed mild phenotypic anomalies, which were absent in single knock-out controls. While Gulo;Slc2a10 double knock-out mice did not fully phenocopy human ATS, histological and immunocytochemical analysis revealed compromised extracellular matrix formation. Transforming growth factor beta signaling remained unaltered, while mitochondrial function was compromised in smooth muscle cells derived from Gulo;Slc2a10 double knock-out mice. Altogether, our data add evidence that ATS is an ascorbate compartmentalization disorder, but additional factors underlying the observed phenotype in humans remain to be determined.

The Epigenetic Role of Vitamin C in Neurodevelopment.

The maternal diet during pregnancy is a key determinant of offspring health. Early studies have linked poor maternal nutrition during gestation with a propensity for the development of chronic conditions in offspring. These conditions include cardiovascular disease, type 2 diabetes and even compromised mental health. While multiple factors may contribute to these outcomes, disturbed epigenetic programming during early development is one potential biological mechanism. The epigenome is programmed primarily in utero, and during this time, the developing fetus is highly susceptible to environmental factors such as nutritional insults. During neurodevelopment, epigenetic programming coordinates the formation of primitive central nervous system structures, neurogenesis, and neuroplasticity. Dysregulated epigenetic programming has been implicated in the aetiology of several neurodevelopmental disorders such as Tatton-Brown-Rahman syndrome. Accordingly, there is great interest in determining how maternal nutrient availability in pregnancy might affect the epigenetic status of offspring, and how such influences may present phenotypically. In recent years, a number of epigenetic enzymes that are active during embryonic development have been found to require vitamin C as a cofactor. These enzymes include the ten-eleven translocation methylcytosine dioxygenases (TETs) and the Jumonji C domain-containing histone lysine demethylases that catalyse the oxidative removal of methyl groups on cytosines and histone lysine residues, respectively. These enzymes are integral to epigenetic regulation and have fundamental roles in cellular differentiation, the maintenance of pluripotency and development. The dependence of these enzymes on vitamin C for optimal catalytic activity illustrates a potentially critical contribution of the nutrient during mammalian development. These insights also highlight a potential risk associated with vitamin C insufficiency during pregnancy. The link between vitamin C insufficiency and development is particularly apparent in the context of neurodevelopment and high vitamin C concentrations in the brain are indicative of important functional requirements in this organ. Accordingly, this review considers the evidence for the potential impact of maternal vitamin C status on neurodevelopmental epigenetics.

VITAMIN C DEFICIENCY-ASSOCIATED LESIONS IN A COLONY OF COMMON VAMPIRE BATS (DESMODUS ROTUNDUS) IN A ZOO FACILITY.

The Milwaukee County Zoo has housed common vampire bats (Desmodus rotundus) since 1973. The bats are fed defibrinated cow's blood supplemented with a liquid pediatric multivitamin. From July 2013 to May 2014, multiple deaths occurred in colony bats, including five juveniles with multiple bone fractures and failure of endochondral ossification, three adults with cerebellar necrosis, and one adult with subcutaneous hemorrhage. In November 2013, an adult bat developed a nonhealing left wing hematoma and eventually succumbed 9 mo later. A postmortem examination revealed multifocal extensive necrohemorrhagic and suppurative ulcerative dermatitis with no underlying cause determined. From July to December 2014, five of nine adult bats in the colony developed similar hematomas along with gingival bleeding. One euthanized bat had a serum ascorbic acid level of 0.08 mg/dl and marked generalized subcutaneous hemorrhage. A therapeutic trial was initiated in which two bats received defibrinated cow's blood supplemented only with oral vitamin C, 100 mg/kg PO q24h for 3 d, and then 50 mg/kg PO q24h. Two other bats received nonsupplemented defibrinated cow's blood and were given vitamin K 3.3 mg/kg SC q12h for 3 d, and then 3.3 mg/kg SC q24h for 7 d. The bats supplemented with vitamin C improved, supporting a diagnosis of vitamin C deficiency. All bats were subsequently supplemented with vitamin C leading to resolution of all lesions within 10 d to 2 mo. Vitamin C is necessary for collagen synthesis, which is required for proper wound healing, capillary and cartilage strength, osteoid production, and pial membrane formation of the cerebellum. Several bat species cannot synthesize vitamin C and require a dietary source. This is the first report of vitamin C deficiency in a colony of vampire bats leading to severe chronic subcutaneous hemorrhage, bone fragility, microfractures, cerebellar necrosis, and death.

Vitamin C increases viral mimicry induced by 5-aza-2'-deoxycytidine.

Vitamin C deficiency is found in patients with cancer and might complicate various therapy paradigms. Here we show how this deficiency may influence the use of DNA methyltransferase inhibitors (DNMTis) for treatment of hematological neoplasias. In vitro, when vitamin C is added at physiological levels to low doses of the DNMTi 5-aza-2'-deoxycytidine (5-aza-CdR), there is a synergistic inhibition of cancer-cell proliferation and increased apoptosis. These effects are associated with enhanced immune signals including increased expression of bidirectionally transcribed endogenous retrovirus (ERV) transcripts, increased cytosolic dsRNA, and activation of an IFN-inducing cellular response. This synergistic effect is likely the result of both passive DNA demethylation by DNMTi and active conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) by ten-eleven translocation (TET) enzymes at LTR regions of ERVs, because vitamin C acts as a cofactor for TET proteins. In addition, TET2 knockout reduces the synergy between the two compounds. Furthermore, we show that many patients with hematological neoplasia are markedly vitamin C deficient. Thus, our data suggest that correction of vitamin C deficiency in patients with hematological and other cancers may improve responses to epigenetic therapy with DNMTis.

Vitamin D and/or calcium deficient diets may differentially affect muscle fiber neuromuscular junction innervation.

INTRODUCTION: There is evidence that supports a role for Vitamin D (Vit. D) in muscle. The exact mechanism by which Vit. D deficiency impairs muscle strength and function is not clear. METHODS: Three-week-old mice were fed diets with varied combinations of Vit. D and Ca2+ deficiency. Behavioral testing, genomic and protein analysis, and muscle histology were performed with a focus on neuromuscular junction (NMJ) -related genes. RESULTS: Vit. D and Ca2+ deficient mice performed more poorly on given behavioral tasks than animals with Vit. D deficiency alone. Genomic and protein analysis of the soleus and tibialis anterior muscles revealed changes in several Vit. D metabolic, NMJ-related, and protein chaperoning and refolding genes. CONCLUSIONS: These data suggest that detrimental effects of a Vit. D deficient or a Vit. D and Ca2+ deficient diet may be a result of differential alterations in the structure and function of the NMJ and a lack of a sustained stress response in muscles. Muscle Nerve 54: 1120-1132, 2016.

Vitamin C Depletion in Prenatal Guinea Pigs as a Model of Lissencephaly Type II.

Humans and guinea pigs are unable to produce vitamin C, with deficiency resulting in a well-known disorder of collagen synthesis. Pial basement membrane structure preservation is essential in the proper migration of neurons. In our study, intrauterine deprivation of vitamin C in guinea pig fetuses led to a collagen synthesis disorder, weakness, and finally a breach of pial basement membrane. We found excessive migration of the external germinal layer cells into the subarachnoid space of the cerebellum through defects in the pial basement membrane. The changes ranged from focal rupture of pial basement membranes to their complete disintegration. The loss of proper folia formation resulted in macroscopically visible flattening of the cerebellar surface. Different grades of dysplastic changes in the folia of the cerebellar cortex were observed in 2 experimental groups assigned different limits to mark the time of commencement and duration of vitamin C deprivation. The most severe form of dysplastic changes was characterized by marked irregularity of the cerebellar cortex similar to that in lissencephaly type II. Thus, prenatal vitamin C deficiency represents a novel animal model to study the effects of collagen synthesis on development of breaches in the pial basement membrane, disordered migration of neurons, dysplasia of cerebellar cortex, and the pathogenesis of lissencephaly.

Methemoglobinemia and ascorbate deficiency in hemoglobin E ß thalassemia: metabolic and clinical implications.

During investigations of the phenotypic diversity of hemoglobin (Hb) E ß thalassemia, a patient was encountered with persistently high levels of methemoglobin associated with a left-shift in the oxygen dissociation curve, profound ascorbate deficiency, and clinical features of scurvy; these abnormalities were corrected by treatment with vitamin C. Studies of erythropoietin production before and after treatment suggested that, as in an ascorbate-deficient murine model, the human hypoxia induction factor pathway is not totally dependent on ascorbate levels. A follow-up study of 45 patients with HbE ß thalassemia showed that methemoglobin levels were significantly increased and that there was also a significant reduction in plasma ascorbate levels. Haptoglobin levels were significantly reduced, and the high frequency of the 2.2 haptoglobin genotype may place an additional pressure on ascorbate as a free-radical scavenger in this population. There was, in addition, a highly significant correlation between methemoglobin levels, splenectomy, and factors that modify the degree of globin-chain imbalance. Because methemoglobin levels are modified by several mechanisms and may play a role in both adaptation to anemia and vascular damage, there is a strong case for its further study in other forms of thalassemia and sickle-cell anemia, particularly when splenic function is defective.

ENA-A actimineral resource A extends lifespan associated with antioxidant mechanism in SMP30 knockout mice.

ENA-actimineral resource A (ENA-A) is an alkaline mineral water and has a few biological activities such as antioxidant activity. The aim of this study was to examine the effects of ENA-A on lifespan in mice using senescence marker protein-30 knockout mice. The present study had groups of 18-week-old mice (n = 24), 26-week-old mice (n = 12), and 46-week-old mice (n = 20). Each differently aged mice group was divided into three subgroups: a control group, a 5 % ENA-A-treated group, and a 10 % ENA-A-treated group. Mice in the 18-week-old group were treated with vitamin C drinking water 1.5 g/L. However, the mice in the 26-week-old and 46-week-old groups were not treated with vitamin C. The experiments were done for 18 weeks. All vitamin C-treated mice were alive at week 18 (100% survival rate). In the non-vitamin C group, the 10% ENA-A-treated mice were alive at week 18. The control and 5% ENA-A-treated mice died by week 15. As expected, vitamin C was not detected in the non-vitamin C-treated group. However, vitamin C levels were increased in an ENA-A dose-dependent manner in the vitamin C-treated group. In the TUNEL assay, a number of positive hepatocytes significantly decreased in an ENA-A dose-dependent manner. Periodic acid Schiff positive hepatocytes were significantly increased in an ENA-A dose-dependent manner. In addition, the expression level of CuZnSOD was increased by the ENA-A treatment. These data suggest that the intake of ENA-A has a critical role in the anti-aging mechanism and could be applied toward the lifespans of humans.

Effect of ascorbic acid deficiency on catecholamine synthesis in adrenal glands of SMP30/GNL knockout mice.

PURPOSE: The effect of an AA deficiency on catecholamine biosynthesis in adult mice in vivo is unknown. Therefore, we quantified catecholamine and the expression of catecholamine synthetic enzymes in the adrenal glands of senescence marker protein-30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice placed in an AA-deficient state. METHODS: At 30 days of age, mice were divided into the following 4 groups: AA (-) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (-) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (-) groups received water without AA until the experiment ended. In addition, all mice were fed an AA-depleted diet. Catecholamine levels were measured by a liquid chromatographic method. Tyrosine hydroxylase, dopa decarboxylase, dopamine ß-hydroxylase, and phenylethanolamine N-methyltransferase mRNA expression levels were measured with the quantitative real-time polymerase chain reaction (qPCR). Tyrosine hydroxylase and dopamine ß-hydroxylase protein levels were quantified by Western blot analysis. RESULTS: In the adrenals of AA (-) SMP30/GNL KO mice, noradrenaline and adrenaline levels decreased significantly compared to other three groups of mice, although there were no significant differences in dopamine ß-hydroxylase or phenylethanolamine N-methyltransferase mRNA content. Moreover, there was no significant difference in their dopamine ß-hydroxylase protein levels. On the other hand, AA depletion did not affect dopamine levels in adrenal glands of mice. CONCLUSION: An AA deficiency decreases the noradrenaline and adrenaline levels in adrenal glands of mice in vivo.

Evidence of non-adult vitamin C deficiency in three early medieval sites in the Jaun/Podjuna Valley, Carinthia, Austria.

OBJECTIVE: This study aims to determine and discuss the prevalence of non-adult scurvy cases from the early medieval Jaun/Podjuna Valley in southern Austria. MATERIALS: 86 non-adult individuals were assessed from three early medieval sites. METHODS: Morphological characteristics associated with suggestive and probable scurvy were observed macroscopically and under 20-40x magnification. RESULTS: A significant relationship between the prevalence of scurvy and age group was observed. Perinates (46%, 6/13) and children (27.5%, 8/28) showed a high prevalence of skeletal features indicating a diagnosis of scurvy, while no cases of scurvy were observed in adolescents and adults. CONCLUSIONS: In this Alpine region, scurvy occurred frequently in infants and children. Seasonal fluctuations of diet are discussed as factors triggering scurvy. SIGNIFICANCE: This study sheds new light on the prevalence of scurvy in the Alpine region and how the region developed after the fall of the Roman Noricum. It also models ways in which multiple lines of evidence can contribute to the diagnostic process. LIMITATIONS: Poor preservation posed a challenge to identifying probable cases of scurvy. Likewise, non-adult remains are difficult to diagnose due to their developing nature and it is not always possible to distinguish between normal bone growth and pathological growth. SUGGESTIONS FOR FURTHER RESEARCH: Future applications of biomolecular studies will help illustrate changes in diet that may have contributed to vitamin deficiencies.

Vitamin C deficiency accelerates bone loss inducing an increase in PPAR-γ expression in SMP30 knockout mice.

Senescence marker protein (SMP) 30 knockout (KO) mice display symptoms of scurvy, including spontaneous bone fractures, and this was considered to be induced by a failure of collagen synthesis owing to vitamin C deficiency. However, low bone mineral density is also known to be associated with spontaneous bone fracture. Therefore, we investigated the effects of vitamin C deficiency on the balance between osteoblasts and osteoclasts in SMP30 KO mice as evidenced by histopathology. All mice were fed a vitamin C-free diet, and only one group (KV) mice were given water containing 1.5 g/l of vitamin C, whereas wild-type (WT) and KO mice were given normal drinking tap water without vitamin C for 16 weeks. After 16 weeks, all femur samples were removed for histopathological examination. The femurs of KO mice showed significantly reduced bone area and decreased number of osteoblasts compared with those of WT mice and KV mice. KO mice also exhibited the lowest level of alkaline phosphatase (ALP) expression in their femurs. However, KO mice showed the most elevated expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Moreover, KO mice had the strongest peroxisome proliferator-activated receptor (PPAR)-γ expression level in their osteoblasts and the highest number of TUNEL-positive bone marrow cells. Therefore, we concluded that vitamin C deficiency plays an important role in spontaneous bone fracture by inhibiting osteoblast differentiation and promoting transition of osteoblasts to adipocytes, and this could in turn be related to the increased PPAR-γ expression.

The effect of vitamin C deficiency and chronic ultraviolet-B exposure on corneal ultrastructure: a preliminary investigation.

PURPOSE: In the visually debilitating condition of climatic droplet keratopathy, corneal transparency is progressively lost. Although the precise cause of the disease and the mechanism by which it progresses are not known, a lifetime exposure to high solar radiation and a vitamin C-deficient diet may be involved in its development. This study examines the effect of dietary ascorbate levels and ultraviolet (UV)-B exposure on corneal stromal structure. METHODS: Eight guinea pigs were divided into four treatment groups (A, B, C, and D). For 15 weeks, Groups A and C were fed an ascorbate-rich diet (2 mg/100 g bodyweight/day), while Groups B and D received an ascorbate-deficient diet (0.07 mg/100 g bodyweight/day). For the last 12 weeks of the study, Groups C and D also experienced chronic UVB exposure (0.12 J/cm² for 40 min/day). Following euthanasia, the corneas were enucleated and their stromal ultrastructure examined using X-ray scattering and electron microscopy. RESULTS: UVB exposure resulted in an increased corneal thickness (p<0.001), but this was not accompanied by a widespread expansion of the collagen fibrillar array, and in the case of ascorbate-deficient animals, stromal thickening was associated with the compaction of collagen fibrils (p<0.01). Neither UVB exposure nor ascorbic acid deficiency caused any change in the average diameter or D-periodicity of the stromal collagen fibrils. CONCLUSIONS: UVB-induced changes in the corneal ultrastructure were most pronounced in animals fed an ascorbic acid-deficient diet. This suggests that ascorbic acid may play a vital role in protecting the corneal stroma from the harmful effects of UVB.

Osteological evidence of metabolic diseases from a post medieval North Italy archaeological site.

Skeletal lesions related to metabolic diseases in children have been systematically investigated in paleopathological literature only in recent years. This work presents an infant pathological specimen from the post-medieval cemetery of the St. Mary's Nativity church (15th-18th centuries, Segno, Trento, Trentino, Northeast Italy). The bones belonged to an individual of 9 ± 3 months of age, estimated upon an assessment of the stage of dental eruption. Metabolic diseases were diagnosed with paleopathological criteria according to previous literature. Differential diagnosis of the osteological evidence indicates a disease that might be caused by the lack of vitamin D or C. Comorbidity of vitamin C and D deficiency has been widely studied in clinical literature, particularly in children between 3 months and 5 years of age. The study of ancient osteoarchaeological materials allows us to improve our knowledge on diseases' effects on bone development in children and, in this case, it represents additional evidence of the presence of metabolic diseases in a rural contest of the Italian post-medieval period.

Effects of vitamin C deficiency on the skin of the senescence marker protein-30 (SMP30) knockout mouse.

Senescence marker protein-30 (SMP30) is a gluconolactonase required for vitamin C (VC) synthesis. We examined effects of VC deficiency on the mouse skin using SMP30 knockout (KO) mice. SMP30 KO or wild type male mice were weaned around day 30 of age, and fed VC-deficient diet. They were given either VC water or control water. VC deficiency for 36 days did not affect skin hydroxyproline contents, while VC deficiency for 60 days decreased the hydroxyproline levels. Levels of some collagen mRNAs were different among the groups, but did not correlate with skin VC levels. The epidermis was morphologically abnormal in VC-deficient SMP30 KO mouse at 60 days after the weaning. Interestingly, the hair cycle was not synchronized among the groups. These data suggest low susceptibility of the mouse skin to VC deficiency and involvement of VC in the regulation of keratinocyte function and hair cycle in vivo.

Vitamin C deficiency: rare cause of severe anemia with hemolysis.

Historically known to be a disease of sailors and soldiers in the seventeenth and eighteenth century, scurvy is a rare nutritional deficiency in the developed world, but it can still be seen among the alcoholics and the malnourished. We present a case of a 39-year-old alcoholic male who presented with progressive fatigue and diffuse purpuric rash with scattered ecchymosis for 2 months. Blood work was remarkable for hemoglobin of 9.1 g/dl, which further dropped to 7 g/dl over the next few days. He was then found to have hemolysis on lab work. After an extensive workup, the common causes of hemolytic anemia were ruled out, vitamin C level was checked, which interestingly resulted as 0 mg/dl. Supplementation with oral vitamin C resulted in the gradual resolution of hemolytic anemia and rash. Hemoglobin improved to 15 g/dl in 4 weeks, with normalization of vitamin C level. The clinical features of scurvy can easily be confused with conditions such as vasculitis, deep venous thrombosis, and systemic bleeding disorders. Therefore, comprehensive workup up is required prior to the diagnosis. Although rare, being a reversible condition, early diagnosis and treatment of scurvy in high-risk populations cannot be stressed enough.

Adult vitamin D deficiency disrupts hippocampal-dependent learning and structural brain connectivity in BALB/c mice.

Converging evidence from human and animal studies support an association between vitamin D deficiency and cognitive impairment. Previous studies have shown that hippocampal volume is reduced in adults with vitamin D deficiency as well as in a range of disorders, such as schizophrenia. The aim of the current study was to examine the effect of adult vitamin D (AVD) deficiency on hippocampal-dependent spatial learning, and hippocampal volume and connectivity in healthy adult mice. Ten-week-old male BALB/c mice were fed a control (vitamin D 1500 IU/kg) or vitamin D-depleted (vitamin D 0 IU/kg) diet for a minimum of 10 weeks. The mice were then tested for hippocampal-dependent spatial learning using active place avoidance (APA) and on tests of muscle and motor coordination (rotarod and grip strength). The mice were perfused and brains collected to acquire ex vivo structural and diffusion-weighted images using a 16.4 T MRI scanner. We also performed immunohistochemistry to quantify perineuronal nets (PNNs) and parvalbumin (PV) interneurons in various brain regions. AVD-deficient mice had a lower latency to enter the shock zone on APA, compared to control mice, suggesting impaired hippocampal-dependent spatial learning. There were no differences in rotarod or grip strength, indicating that AVD deficiency did not have an impact on muscle or motor coordination. AVD deficiency did not have an impact on hippocampal volume. However, AVD-deficient mice displayed a disrupted network centred on the right hippocampus with abnormal connectomes among 29 nodes. We found a reduction in PNN positive cells, but no change in PV, centred on the hippocampus. Our results provide compelling evidence to show that AVD deficiency in otherwise healthy adult mice may play a key role in hippocampal-dependent learning and memory formation. We suggest that the spatial learning deficits could be due to the disruption of right hippocampal structural connectivity.

Vitamin C deficiency aggravates tumor necrosis factor α-induced insulin resistance.

Chronic low-grade inflammation plays a major role in the development of insulin resistance. The potential role and underlying mechanism of vitamin C, an antioxidant and anti-inflammatory agent, was investigated in tumor necrosis factor-α (TNF-α)-induced insulin resistance. Gulonolactone oxidase knockout (Gulo-/-) mice genetically unable to synthesize vitamin C were used to induce insulin resistance by continuously pumping small doses of TNF-α for seven days, and human liver hepatocellular carcinoma cells (HepG2 cells) were used to induce insulin resistance by treatment with TNF-α. Vitamin C deficiency aggravated TNF-α-induced insulin resistance in Gulo-/- mice, resulting in worse glucose tolerance test (GTT) results, higher fasting plasma insulin level, and the inactivation of the protein kinase B (AKT)/glycogen synthase kinase-3ß (GSK3ß) pathway in the liver. Vitamin C deficiency also worsened liver lipid accumulation and inflammation in TNF-α-treated Gulo-/- mice. In HepG2 cells, vitamin C reversed the TNF-α-induced reduction of glucose uptake and glycogen synthesis, which were mediated by increasing GLUT2 levels and the activation of the insulin receptor substrate (IRS-1)/AKT/GSK3ß pathway. Furthermore, vitamin C inhibited the TNF-α-induced activation of not only the mitogen-activated protein kinase (MAPKs), but also nuclear factor-kappa B (NF-κB) signaling. Taken together, vitamin C is essential for preventing and improving insulin resistance, and the supplementing with vitamin C may be an effective therapeutic intervention for metabolic disorders.

Basilar portion porosity: A pathological lesion possibly associated with infantile scurvy.

Recent analysis of the juvenile (≤12 years) human remains from a 19th century site in Wolverhampton, England revealed a relatively high level of nutritional deficiency diseases within the population. Indeed, 41.7% of the 48 juvenile skeletons analysed exhibited a combination of porous and proliferative bone lesions consistent with the pathological alterations associated with nutritional stress. This paper describes a pathological lesion on the inferior surface of the basilar portion of the occipital bone, not previously reported in association with infantile scurvy, but which was exhibited by 90% (N=9) of the 10 scorbutic individuals identified during this study.