Homocysteine levels and decline in physical function: MacArthur Studies of Successful Aging

PURPOSE: To test whether elevated homocysteine levels are associated with an increased risk of decline in physical function in older persons. METHODS: We performed a prospective cohort study of 499 highly functioning men and women aged 70 to 79 years who were enrolled in the MacArthur Studies of Successful Aging. We measured total homocysteine levels and performance-based physical function at baseline; physical function measures were repeated an average of 28 months later. A summary measure of physical performance from tests of balance, gait, lower body strength and coordination, and manual dexterity was developed, and a change score was calculated as the difference in scores from 1988 to 1991. RESULTS: The mean (+/-SD) homocysteine level was 11.6 +/- 4.3 micromol/L. With each SD increase in homocysteine, there was an increased risk of being in the worst quartile of decline in physical function (odds ratio = 1.5; 95% confidence interval: 1.2 to 1.9) in analyses that adjusted for age, sex, baseline physical performance, smoking status, vitamin B(12) levels, and incident stroke. Similar results were seen when change in physical performance was treated as a continuous variable. CONCLUSION: Older persons with elevated plasma homocysteine levels are at an increased risk of decline in physical function.     

Predicting cognitive impairment in high-functioning community-dwelling older persons: MacArthur Studies of Successful Aging

OBJECTIVES: To examine whether simple cognitive tests, when applied to cognitively intact older persons, are useful predictors of cognitive impairment 7 years later. DESIGN: Cohort study. SETTING: Durham, North Carolina; East Boston, Massachusetts; and New Haven, Connecticut, areas that are part of the National Institute on Aging Established Populations for Epidemiological Studies of the Elderly. PARTICIPANTS: Participants, aged 70 to 79, from three community-based studies, who were in the top third of this age group, based on physical and cognitive functional status. MEASUREMENTS: New onset of cognitive impairment as defined by a score of less than 7 on the Short Portable Mental Status Questionnaire (SPMSQ) in 1995. RESULTS: At 7 years, 21.8% (149 of 684 subjects) scored lower than 7 on the SPMSQ. Using multivariate logistic regression, three baseline (1988) cognitive tests predicted impairment in 1995. These included two simple tests of delayed recall-the ability to remember up to six items from a short story and up to 18 words from recall of Boston Naming Test items. For each story item missed, the adjusted odds ratio (AOR) for cognitive impairment was 1.44 (95% confidence interval (CI) = 1.16-1.78, P <.001). For each missed item from the word list, the AOR was 1.20 (95% CI = 1.09-1.31, P <.001). The Delayed Recognition Span, which assesses nonverbal memory, also predicted cognitive impairment, albeit less strongly (odds ratio = 1.06 per each missed answer, 95% CI = 1.003-1.13, P =.04). CONCLUSIONS: This study identifies measures of delayed recall and recognition as significant early predictors of subsequent cognitive decline in high-functioning older persons. Future efforts to identify those at greatest risk of cognitive impairment may benefit by including these measures.     

叶酸、维生素B6、维生素B12对大鼠同型半胱氨酸水平及动脉损伤的影响

目的 :观察补充叶酸、维生素 B6 和维生素 B1 2 对高蛋氨酸 (Met)喂饲所引起高同型半胱氨酸 (Hcy)血症及动脉损伤的影响。　　方法 :Wistar大鼠 30只随机分成 3组 :对照组、高 Met组和给药组 ,每组 10只 ,分别喂以普通鼠饲料、普通鼠饲料添加 1% Met、普通饲料添加 1% Met同时每只鼠每天添加叶酸 0 .5 mg、维生素 B6 2 .5 mg和维生素 B1 2 5 0 μg,喂养 3个月。测定血浆总 Hcy(t Hcy)浓度、血清叶酸浓度及红细胞超氧化物歧化酶 (SOD)和谷胱甘肽过氧化物酶 (GPX)活力。光镜、电镜检测主动脉组织学改变。　　结果 :实验前 ,血浆 t Hcy、血清叶酸浓度 3组间无明显差异。实验后 ,给药组血清叶酸浓度明显高于实验前和高 Met组及对照组 (P<0 .0 1) ,血浆 t Hcy断食 2 h和 7h均低于高 Met组 (P<0 .0 1) ,且断食 7h降至对照组水平 (P>0 .0 5 ) ,但断食 2 h仍高于对照组。实验后红细胞 SOD活力高 Met组明显升高 ,给药组较高 Met组明显减低 ,与对照组无明显差异。红细胞 GPX活力 3组间无差异。组织学检测发现给药组主动脉损伤程度明显轻于高 Met组。　　结论 :补充叶酸、维生素 B6 和维生素 B1 2 可降低高 Met摄入所致高 Hcy血症 ,削弱后者引起的过氧化应激 ,减轻动脉损伤程度     

Blood homocysteine and risk of depression in the elderly

We studied whether increased blood homocysteine is a predictor for incident depression in a population-based cohort aged ≥65. A total of 240 men and 217 women were identified at baseline and were assessed 4 years later for depression (Geriatric Depression Scale, GDS ≥10 or use of antidepressants). Risk of incident depression was estimated for the highest gender-specific tertile of baseline plasma homocysteine compared to the other tertiles combined in a reference group. As deficiencies of B₁₂ and folate are the main determinant of increased blood homocysteine in old age, serum concentrations of these vitamins were also measured. In women only, the highest homocysteine tertile was associated with incident depression. However, women with combined serum B₁₂/folate deficiency had the highest blood homocysteine but also a lower depression risk than vitamin-replete women. In conclusion, the data only moderately support the hypothesis that blood homocysteine is a predictor of depression.     

Vitamin B12 and folate concentrations during pregnancy and insulin resistance in the offspring: the Pune Maternal Nutrition Study

Aims/hypothesis Raised maternal plasma total homocysteine (tHcy) concentrations predict small size at birth, which is a risk factor for type 2 diabetes mellitus. We studied the association between maternal vitamin B₁₂, folate and tHcy status during pregnancy, and offspring adiposity and insulin resistance at 6 years. Methods In the Pune Maternal Nutrition Study we studied 700 consecutive eligible pregnant women in six villages. We measured maternal nutritional intake and circulating concentrations of folate, vitamin B₁₂, tHcy and methylmalonic acid (MMA) at 18 and 28 weeks of gestation. These were correlated with offspring anthropometry, body composition (dual-energy X-ray absorptiometry scan) and insulin resistance (homeostatic model assessment of insulin resistance [HOMA-R]) at 6 years. Results Two-thirds of mothers had low vitamin B₁₂ (<150 pmol/l), 90% had high MMA (>0.26 μmol/l) and 30% had raised tHcy concentrations (>10 μmol/l); only one had a low erythrocyte folate concentration. Although short and thin (BMI), the 6-year-old children were relatively adipose compared with the UK standards (skinfold thicknesses). Higher maternal erythrocyte folate concentrations at 28 weeks predicted higher offspring adiposity and higher HOMA-R (both p < 0.01). Low maternal vitamin B₁₂ (18 weeks; p = 0.03) predicted higher HOMA-R in the children. The offspring of mothers with a combination of high folate and low vitamin B₁₂ concentrations were the most insulin resistant. Conclusions/interpretation Low maternal vitamin B₁₂ and high folate status may contribute to the epidemic of adiposity and type 2 diabetes in India. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

The Cardiac Effects of Prolonged Vitamin B12 and Folate Deficiency in Rats

In the recent past, hyperhomocysteinemia (HHCY) has been linked to chronic heart failure. Folate and vitamin B12 deficiencies are the common causes of HHCY. The impact of these vitamins on cardiac function and morphology has scarcely been investigated. The aim of this study was to conduct an analysis of the cardiac effect of folate and vitamin B12 deficiency in vivo. Two groups of rats, a control (Co, n = 10) and a vitamin-deficient group (VitDef, n = 10), were fed for 12 weeks with a folate and vitamin B12-free diet or an equicaloric control diet. Plasma and tissue concentrations of HCY, S-adenosyl-homocysteine (SAH), S-adenosyl-methionine (SAM), and brain natriuretic peptide (BNP) were measured. Moreover, echocardiographic and histomorphometric analyses were performed. VitDef animals developed a significant HHCY (Co vs VitDef: 6.8 ± 2.7 vs 61.1 ± 12.8 μmol/l, P < 0.001). Fractional shortening, left ventricular dimension at end-diastole and end-systole, posterior wall thickness, perivascular collagen, mast cell number, and BNP tissue levels were comparable in VitDef and Co animals. Interstitial collagen (Co vs VitDef: 6.8 ± 3.0 vs 4.5 ± 2.1%, P < 0.05), plasma BNP (Co vs VitDef: 180 ± 80 vs 70 ± 60 ng/l, P < 0.05), and tissue HCY (Co vs VitDef: 0.13 ± 0.07 vs 0.07 ± 0.04 μmol/g protein, P < 0.05) were lower in VitDef animals. Folate and vitamin B₁₂ deficiency do not affect cardiac function and morphology.     

Correlation between dietary polyunsaturated fatty acids and plasma homocysteine concentration in vitamin B6-deficient rats

BACKGROUND AND AIM: Vitamin B6 as cofactor of Delta6 desaturase is involved in polyunsaturated fatty acid metabolism; moreover, it is a cofactor of the trans-sulfuration pathway of homocysteine. Some studies report that low concentrations of pyridoxine, by increasing homocysteine levels, are associated with coronary artery disease, and carotid and arterial lesions. The aim of this study was to verify whether different dietary amounts of polyunsaturated fatty acids associated with low content of vitamin B6 could modulate homocysteinemia. METHODS AND RESULTS: Thirty-two rats were divided into two groups, one fed a diet with adequate vitamin B6 content the other a diet containing low amount of the same vitamin. Within each group, rats were divided into two subgroups differing in the polyunsaturated fatty acid content of the diet (63 and 33%, respectively). The vitamin B6-deficient diet induced an increase in homocysteine concentration compared to the vitamin B6-normal diet. This increase was tenfold in the subgroup fed high polyunsaturated fatty acid levels and twofold in the other subgroup. The fatty acid composition of liver phospholipids showed a lower arachidonic acid relative molar content and a lower 20:4/18:2 ratio in vitamin B6-deficient groups compared with B6-normal groups. CONCLUSIONS: On the basis of the different biological functions of pyridoxine and considering that some factors closely related to atherosclerosis are vitamin B(6) dependent, adequate pyridoxine availability could be necessary to assure a normal long chain fatty acid metabolism and to reduce the risk linked to hyperhomocysteinemia.     

叶酸和维生素B6、B12对不稳定型心绞痛并高同型半胱氨酸患者预后的影响

近年来的研究表明,高同型半胱氨酸（homocys—teine,Hcy）血症可导致心血管疾病发病率和死亡率增高,与高脂血症、高血压、高血糖等因素同等重要,是动脉粥样硬化发生、发展的一个独立危险因素。     

High urinary catecholamine excretion predicts mortality and functional decline in high-functioning, community-dwelling older persons: MacArthur Studies of Successful Aging

PURPOSE: Catecholamine release is a marker of stress, and high plasma norepinephrine levels have been associated with increased mortality. The predictive value of high urinary catecholamine excretion for functional decline and mortality in healthier older persons has not been determined. SUBJECTS AND METHODS: We used data from the MacArthur Studies of Successful Aging to determine the effects of high urinary catecholamine excretion on 3- and 7-year mortality and functional decline. In 1988, 765 high-functioning older subjects provided complete overnight urine samples for norepinephrine and epinephrine, and 199 of these provided repeat samples in 1991. Subjects who were in the top tertile of urinary norepinephrine or epinephrine excretion in 1988 were considered high excreters; those in the top tertile in both 1988 and 1991 were considered sustained high excreters. We used bivariate and multivariate analysis to examine the relations between high catecholamine excretion and mortality and Rosow-Breslau functional decline in 1991 and 1995. RESULTS: In multivariate analyses, subjects with high baseline urinary excretion of epinephrine, norepinephrine, or either catecholamine were at higher risk for mortality and functional decline at 3 and 7 years, although the magnitude of risk (adjusted odds-ratios ranged from 1.1 to 3.1) varied depending upon specific catecholamine and outcome measure. Subjects who had sustained high urinary norepinephrine excretion were also at increased risk for 4-year mortality or functional decline. CONCLUSIONS: High urinary catecholamine excretion in high-functioning, community-dwelling older persons likely reflects subclinical sympathetic stimulation and is a marker of increased risk for functional decline and mortality.     

非酒精性脂肪肝患者同型半胱氨酸浓度及叶酸与维生素B12浓度变化及相关性

目的:探讨非酒精性脂肪性肝病(NAFLD)患者同型半胱氨酸浓度、叶酸与维生素B_(12)浓度变化及其关系.方法:对199例健康体检人群行B超检查,其中NAFLD 67例,正常对照组132例,分别检测血浆Hcy、叶酸与维生素B_(12)浓度并进行相关性分析.结果:NAFLD患者血Hcy水平高于正常对照组(18.64±11.2μmol/L vs 12.49±6.4μmol/L,P<0.01),并且Hcy与叶酸、维生素B_(12)呈直线负相关(r=-0.381,P<0.01;r=-0.561,P<0.001)结论:NAFLD患者血Hcy增高,高Hcy血症可能是NAFLD一个新的危险因素.     

Measuring holotranscobalamin II, an early indicator of negative vitamin B12 balance, by radioimmunoassay in patients with ischemic cerebrovascular disease

Circulating homocysteine is a risk factor of cardiovascular and cerebrovascular events. Hyperhomocysteinemia may be an early indicator for vitamin B₁₂ disorders because cobalamin is a cofactor in the remethylation process of homocysteine. Serum holotranscobalamin (holoTC II) becomes decreased before the development of metabolic dysfunction. In this study, we assessed circulating holoTC II to estimate the diagnosis of vitamin B₁₂ deficiency in the first ischemic cerebrovascular attack. We also compared the efficacy of the measurement of plasma holoTC II with the other standard biochemical and hematological markers used to reach the diagnosis of cobalamin deficiency. Forty-five patients (age 71 years (range 35–90), 16 men/29 women) within the first ischemic cerebrovascular event were included in this prospective study. All the enrolled patients have been administered vitamin B₁₂ 1 mg intramuscular injection once a day for 10 days. At the baseline and on the tenth day of treatment, plasma levels of holoTC II and the proper biochemical and hematological markers in diagnosing cobalamin deficiency were measured. After admission, anemia and diminished serum vitamin B₁₂ levels were determined to be only 20% (9/45) and 44% (20/45), respectively; 78% (35/45) of the patients had low serum holoTC II (<37 pmol/l). Serum homocysteine was higher in patients (49% of them) who had previously suffered a stroke. Thrombocytopenia, hypersegmentated neutrophils, and indirect hyperbilirubinemia were observed in 20% of the patients. Leukopenia and macrocytosis were not evident in any of them. In 18 of 27 patients (67%) that had low holoTC II levels after joining the study and who remained in the study until the end of cobalamin treatment, serum holoTC II levels returned to normal values. Cobalamin deficiency should be considered in patients with cerebrovascular diseases, even if anemia, elevated mean cell volume, depression of the serum cobalamin, or other classic hematological and/or biochemical abnormalities are lacking. Furthermore, measurement of serum holoTC II looks promising as a first-line of tests for diagnosing early vitamin B₁₂ deficiency.     

Pancreatic Extract and the Intestinal Uptake of Vitamin B12

Pancreatic extract (PE) contained small-molecular, thermo-stable as well as macro-molecular, thermo-labile factors capable of reducing the uptake of ⁵⁷CoB₁₂ bound to rat intrinsic factor by perfused rat intestinal segments (p<0.01 and p<0.01). Neither non-radioactive vitamin B₁₂ nor non-pancreatic protein reduced the ⁵⁷CoB₁₂-uptake (p>0.5 and p>0.1). Crystalline trypsin and trypsinogen, but not chymotrypsin, also inhibited the uptake (p<0.05, p<0.02 and p>0.05). The tryptic inhibition was abolished by soybean trypsin inhibitor (p>0.05).     

Association of homocysteine,vitamin B<Subscript>12</Subscript>, folic acid,and MTHFR C677T in patients with a thrombotic event or recurrent fetal loss

Hyperhomocysteinemia (HHC) is a known risk factor for venous and arterial thrombosis. Thrombophilia workup includes the level of homocysteine and other related parameters such as: vitamin B₁₂, folic acid, and methylenetetrahydrofolate reductase (MTHFR) C677T genotype. As the levels of homocysteine, vitamin B₁₂, folic acid, and MTHFR C677T genotype are linked biochemically, we hypothesized that a statistical association will be found between them. The purpose of the present study was to assess the association between the four parameters in patients with a thrombotic event or recurrent fetal loss. The potential study population included 326 patients who were referred to the Thrombosis and Hemostasis Unit; 125 of these patients had at least one pathological test result of the four parameters. The correlations between homocysteine and vitamin B₁₂ as well as between homocysteine and folic acid were found to be weak (r = −0.236 and r = −0.209, respectively). No significant difference was revealed between the mean homocysteine level and the CC, CT, and TT MTHFR genotypes (p = 0.246). In conclusion, in the population studied, the association between homocysteine, vitamin B₁₂, folic acid, and MTHFR C677T is weak. The results raise doubt as to whether the current routine evaluation of HHC, as part of thrombophilia workup, truly reflects the increased risk of thrombosis.     

Serum Ferritin,Vitamin B<Subscript>12</Subscript>, Folate,and Zinc Levels in Children Infected with <Emphasis Type="Italic">Helicobacter pylori</Emphasis>

We sought to explore the relationship between Helicobacter pylori infection and serum ferritin, vitamin B₁₂, folate, and zinc status among children. Fifty patients aged 5–18 years who underwent upper gastrointestinal endoscopy because of dyspeptic symptoms, were studied, prospectively. Patients were grouped as H. pylori positive (group 1, n=32) or H. pylori negative (group 2, n=18) by histopathologic examination and rapid urease test. Fasting serum ferritin, vitamin B₁₂, folate, and zinc levels of patients were measured. Both groups were indifferent according to age, gender, height standard deviation score (H_SDS), and weight standard deviation score (W_SDS). Serum ferritin levels were 33±26 and 50±46 ng/mL (P=.098), vitamin B₁₂ levels were 303±135 and 393±166 pg/mL (P=.042), folate levels were 9.64±3.2 and 9.61±2.8 ng/mL (P=.979), and zinc levels were 95±48 and 87±31 μg/dL (P=.538), in groups 1 and 2, respectively. Ferritin levels of 14 (43.8%) patients in group 1 and 6 (33.3%) patients in group 2 were below the normal range (P=.470). Serum vitamin B₁₂ levels of 9 children (28%) in group 1 and 2 children (11%) in group 2 were below the normal range (P=.287). The findings of the present study suggest that H. pylori infection has a negative effect on serum ferritin and vitamin B₁₂ levels in children. This negative effect on vitamin B₁₂ levels is rather marked in contrast to that on ferritin levels. H. pylori infection has no significant effect on serum folate or zinc levels among children.     

Role of vitamins B6, B12 and folic acid on hyperhomocysteinemia in a Pakistani population of patients with acute myocardial infarction

BACKGROUND AND AIM: Pakistani people belong to an ethnic group which has the highest rate of coronary artery disease (CAD). We investigated the possible correlation between deficiency of vitamins B6, B12 or folic acid and hyperhomocysteinemia in Pakistani patients with acute myocardial infarction (AMI). A case-control study was carried out involving 224 AMI patients (age 30-70 years; 55 females and 169 males) and 126 normal healthy subjects (age 31-70 years; 35 females and 91 males). METHODS AND RESULTS: Fasting venous blood was obtained from cases and controls. Serum was analyzed for folic acid and B12 using radioassays. Plasma was analyzed for pyridoxal phosphate (PLP; coenzymic form of B6) using a radioenzymatic assay and for total homocysteine using a fluorescence polarization immunoassay. Mean serum B12 concentration in AMI patients was found to be significantly lower than the mean for controls (241+/-185 pg/ml vs 608+/-341 pg/ml; p < 0.001). Mean serum folate level in patients was also found to be lower than controls (3.35+/-3.78 ng/ml vs 4.93+/-2.93 ng/ml), however, the differences were not statistically significant. Similarly, mean PLP concentration in plasma of cases (19.4+/-24.4 nmol/l) was lower than the concentration in controls (23.2+/-17.6 nmol/l), but the difference was not statistically significant. Mean plasma homocysteine level in AMI cases (18+/-8.36 micromol/l) was higher than the mean level in controls (16.4+/-4.9 micromol/l), but not to a significant extent. However, this mean homocysteine concentration in normal healthy subjects was among the highest reported in the literature and was significantly more than mean values reported in most Eastern and Western studies. Compared to controls, there was significantly greater deficiency of folate (32.5% vs 67.1%), B12 (3.2% vs 63.4%) and PLP (49.2% vs 74.1%) in AMI patients. Deficiencies of folate, B12 and PLP were defined as serum folate levels less than 3.5 ng/ml, serum levels of B12 less than 200 pg/ml and plasma PLP levels less than 20 nmol/l. Mean plasma homocysteine levels in smokers were found to be significantly higher in both cases and controls. Similarly, mean serum folate levels in smokers (compared to nonsmokers) were significantly lower in both cases and controls. CONCLUSIONS: Substantial nutritional deficiencies of these three vitamins along with mild hyperhomocysteinemia, perhaps through an interplay with the classical cardiovascular risk factors (highly prevalent in this population), could be further aggravating the risk of CAD in the Pakistani population.     

Circulating heat shock protein 70 (Hsp70) in elderly members of a rural population from Cameroon: association with infection and nutrition

Hsp are highly conserved cytoprotective proteins which have been repeatedly portrayed at elevated levels in various infectious diseases, and there are suggestions that the presence of infectious agents may possibly be the root cause of Hsp induction. As organisms age the vulnerability to illnesses such as infection and inflammation increases and late complications due to infectious agents are mostly observed in the older part of the population. Although it is well known that environmental conditions can modulate the susceptibility to infection, and that poor nutritional status can increase the risk of contracting infection when exposed to an infectious agent, the effects of environmental conditions and nutritional status on the heat shock response have not been investigated. Therefore, we studied the heat shock response in a special elderly population living in a remote area in Cameroon, where infection and parasitosis are endemic. Our results indicate a significant increase in Hsp70 serum levels with increasing degree of inflammation. We found negative correlations between Hsp70 levels and micronutrients including vitamin D, vitamin B₁₂, as well as folate, which could be linked to the immune modulating effects of these vitamins.     

Polymorphisms of interleukin-1 gene complex, IL6 and tumour necrosis factor genes in chronic idiopathic neutropenia of adults

Chronic idiopathic neutropenia of adults (CINA) is a granulocytic disorder characterised by the unexplained decrease in the number of circulating neutrophils. Serum inflammatory cytokines and chemokines are increased in CINA. In addition, cytokines gene polymorphisms are associated with increased levels of respective products and related with inflammatory diseases. The aim of the present study was to investigate the association of polymorphisms of IL1B-511C/T and +3953C/T, IL1RN intron 2, IL6-174G/C and TNF-308G/A genes with CINA. We analysed 29 CINA and controls by polymerase chain reaction and restriction fragment length polymorphism. Statistical analyses were performed using ² test, and the Hardy–Weinberg equilibrium (HWE) was investigated. All alleles analysed were in HWE in both populations. Similar frequencies of IL1B-511C/T, IL1B+3953C/T, IL1RN, IL6-174G/C and TNF-308G/A genotypes were observed in CINA and controls. These results suggest that cytokine polymorphisms associated with control of gene expression and protein levels were not associated with occurrence of CINA and were not responsible for the increased cytokine in CINA patients.     

Knock-Out of Retrovirus Receptor Gene Tva in the Chicken Confers Resistance to Avian Leukosis Virus Subgroups A and K and Affects Cobalamin (Vitamin B12)-Dependent Level of Methylmalonic Acid

The chicken Tva cell surface protein, a member of the low-density lipoprotein receptor family, has been identified as an entry receptor for avian leukosis virus of classic subgroup A and newly emerging subgroup K. Because both viruses represent an important concern for the poultry industry, we introduced a frame-shifting deletion into the chicken tva locus with the aim of knocking-out Tva expression and creating a virus-resistant chicken line. The tva knock-out was prepared by CRISPR/Cas9 gene editing in chicken primordial germ cells and orthotopic transplantation of edited cells into the testes of sterilized recipient roosters. The resulting tva −/− chickens tested fully resistant to avian leukosis virus subgroups A and K, both in in vitro and in vivo assays, in contrast to their susceptible tva +/+ and tva +/− siblings. We also found a specific disorder of the cobalamin/vitamin B₁₂ metabolism in the tva knock-out chickens, which is in accordance with the recently recognized physiological function of Tva as a receptor for cobalamin in complex with transcobalamin transporter. Last but not least, we bring a new example of the de novo resistance created by CRISPR/Cas9 editing of pathogen dependence genes in farm animals and, furthermore, a new example of gene editing in chicken.