scholarly journals Establishment of the Variation of Vitamin K Status According to Vkorc1 Point Mutations Using Rat Models

Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2076 ◽  
Author(s):  
Jean Valéry Debaux ◽  
Abdessalem Hammed ◽  
Brigitte Barbier ◽  
Thomas Chetot ◽  
Etienne Benoit ◽  
...  

Vitamin K is crucial for many physiological processes such as coagulation, energy metabolism, and arterial calcification prevention due to its involvement in the activation of several vitamin K-dependent proteins. During this activation, vitamin K is converted into vitamin K epoxide, which must be re-reduced by the VKORC1 enzyme. Various VKORC1 mutations have been described in humans. While these mutations have been widely associated with anticoagulant resistance, their association with a modification of vitamin K status due to a modification of the enzyme efficiency has never been considered. Using animal models with different Vkorc1 mutations receiving a standard diet or a menadione-deficient diet, we investigated this association by measuring different markers of the vitamin K status. Each mutation dramatically affected vitamin K recycling efficiency. This decrease in recycling was associated with a significant alteration of the vitamin K status, even when animals were fed a menadione-enriched diet suggesting a loss of vitamin K from the cycle due to the presence of the Vkorc1 mutation. This change in vitamin K status resulted in clinical modifications in mutated rats only when animals receive a limited vitamin K intake totally consistent with the capacity of each strain to recycle vitamin K.

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5861 ◽  
Author(s):  
Ignacio Fernández-Fígares ◽  
Jose Miguel Rodríguez-López ◽  
Lucrecia González-Valero ◽  
Manuel Lachica

Most valuable cured products from Iberian pigs come from pure bred animals raised for a final grazing-fattening period where pigs eat mainly acorns, a low protein energy rich fruit. This is a nutritional challenge for animals fed equilibrated diets from weaning. The aim of the study was to determine net portal appearance (NPA) of metabolites in gilts fed acorns and evaluate adaptational changes after one week of feeding. Two sampling periods were carried out (after one day and after one week of acorn feeding) with six gilts (34 kg average BW) set up with three catheters: in carotid artery and portal vein for blood sampling, and ileal vein for para-aminohippuric acid (PAH) infusion to measure portal plasma flow (PPF). Pigs were fed at 2.5 × ME for maintenance a standard diet in two portions, at 09:00 (0.25) and 15:00 h (the remaining 0.75). On the day prior to the first sampling period, pigs were fed 2.4 kg of oak acorns. After feeding 0.25 of ration a 6 h serial blood collection was initiated. Following an identical protocol, a second sampling session was performed 1 week later. Adaptation to acorn consumption decreased NPA of ammonia (47%,P < 0.001). Although there was a transfer of urea from the gastrointestinal tract to the circulation in both sampling periods, no differences in NPA of urea was found (P > 0.05). NPA of glucose was not influenced by sampling period (P > 0.05), but NPA of lactate was greatly increased (231%,P < 0.001). There was a negative NPA of albumin although adaptation to acorn feeding did not alter it. Although NPA of triglycerides and cholesterol were unchanged, a subtle increase in arterial and portal cholesterol was noticed (9.6%,P < 0.01). Pigs fed a protein deficient diet for one week adapted decreasing NPA of ammonia for saving metabolic energy as less ammonia would become available for conversion to urea.


Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3231-3232 ◽  
Author(s):  
Leon J. Schurgers ◽  
Hermann Aebert ◽  
Cees Vermeer ◽  
Burkhard Bültmann ◽  
Jan Janzen

Abstract Calcification is a common complication in cardiovascular disease and may affect both arteries and heart valves. Matrix γ-carboxyglutamic acid (Gla) protein (MGP) is a potent inhibitor of vascular calcification, the activity of which is regulated by vitamin K. In animal models, vitamin K antagonists (oral anticoagulants [OACs]) were shown to induce arterial calcification. To investigate whether long-term OAC treatment may induce calcification in humans also, we have measured the grade of aortic valve calcification in patients with and without preoperative OAC treatment. OAC-treated subjects were matched with nontreated ones for age, sex, and disease. Calcifications in patients receiving preoperative OAC treatment were significantly (2-fold) larger than in nontreated patients. These observations suggest that OACs, which are widely used for antithrombotic therapy, may induce cardiovascular calcifications as an adverse side effect.


Nutrients ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 100 ◽  
Author(s):  
Liv M. Vossen ◽  
Abraham A. Kroon ◽  
Leon J. Schurgers ◽  
Peter W. de Leeuw

Vascular calcification is an independent predictor of cardiovascular disease, and therefore, inhibition or regression of this processes is of clinical importance. The standard care regarding prevention and treatment of cardiovascular disease at this moment mainly depends on drug therapy. In animal and preclinical studies, various forms of cardiovascular drug therapy seem to have a positive effect on vascular calcification. In particular, calcium channel blockers and inhibitors of the renin–angiotensin–aldosteron system slowed down arterial calcification in experimental animals. In humans, the results of trials with these drugs are far less pronounced and often contradictory. There is limited evidence that the development of new atherosclerotic lesions may be retarded in patients with coronary artery disease, but existing lesions can hardly be influenced. Although statin therapy has a proven role in the prevention and treatment of cardiovascular morbidity and mortality, it is associated with both regression and acceleration of the vascular calcification process. Recently, nutritional supplements have been recognized as a potential tool to reduce calcification. This is particularly true for vitamin K, which acts as an inhibitor of vascular calcification. In addition to vitamin K, other dietary supplements may also modulate vascular function. In this narrative review, we discuss the current state of knowledge regarding the pharmacological and nutritional possibilities to prevent the development and progression of vascular calcification.


1982 ◽  
Vol 242 (6) ◽  
pp. F699-F704 ◽  
Author(s):  
N. Brautbar ◽  
R. Baczynski ◽  
C. Carpenter ◽  
S. Moser ◽  
P. Geiger ◽  
...  

The effects of phosphate depletion (PD) of 4, 8, and 12 wk duration on myocardial energy metabolism were studied in rats fed a phosphate-deficient diet and compared with rats pair-fed a normal phosphate diet. Myocardial biopsies were examined for high-energy phosphate bonds. The results show that PD causes a significant reduction in myocardial concentration of inorganic phosphorus at 4 wk of PD and creatine phosphate at 8 wk of PD, while adenine nucleotides were significantly reduced only after 12 wk of PD. The changes in cellular inorganic phosphorus and creatine phosphate displayed a significant correlation with serum phosphorus levels. Mitochondrial respiration was impaired early in PD. Total cellular, mitochondrial, and myofibrillar creatine kinase activities were significantly reduced at 4 wk of PD and fell further at 8 and 12 wk. These data show that chronic PD is associated with reduced mitochondrial capacity to produce ATP, impaired transport via the creatine phosphate shuttle, and reduced myofibrillar ability to utilize ATP. These abnormalities indicate that all steps of myocardial energetics are impaired in PD and provide the molecular basis for the altered myocardial function seen in PD.


1993 ◽  
Vol 61 ◽  
pp. 298
Author(s):  
Takashi Tomiuga ◽  
Masatoshi Kobayashi ◽  
Yoshikage Nakajima ◽  
Motoaki Bessho ◽  
Kuniko Hara ◽  
...  

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Asen Kamenov ◽  
Stoyanka Georgieva ◽  
Dobrina Mlachkova ◽  
Daniela Valentinova Monova

Abstract Background and Aims In patients with chronic kidney disease (CKD), arterial calcification (AC) is a potential mechanism for the progression of cardiovascular disease. AC is common in CKD patients and is a consequence of mineral-bone disorders. Indirect anticoagulants or vitamin K deficiency lead to matrix γ-carboxyglutamate decarboxylation, which may potentiate vascular calcification formation. The impaired renal function and indirect anticoagulants intake may lead to vitamin K deficiency and increased AC. The aim of this study is to determine if oral intake of Acenocoumarol has influence on abdominal aorta calcium score (AACS) and the AC relation with atrial fibrillation (AF) and / or ischemic heart disease (IHD) morbidity. Method We observe 129 patients with CKD (glomerular filtration rate below 44 ml/min/1,73 m2, MDRD formula calculated). X - ray of the lateral abdominal aorta is performed for the AACS assessment according to L. I. Kauppila et al. method. The assessment of calcium score is formed by the involvement grade of each segment on the anterior and posterior wall of the vessel along the first four lumbar vertebrae. Calcification affecting less than 1/3 of the anterior wall of the aorta along the lumbar vertebral body receives 1 score and calcification extending over ½ of the vertebral body length receives 3 scores (total score - 24). The patients are distributed into three groups: I group with calcium score from 0 to 7, II - from 8 to 15 and III group - from 16 to 24. The data from assessed AACS are compared with Acenocoumarol intake and the presence/absence of AF and/or IHD. The results are processed with χ2 statistical analysis. Results One hundred twenty nine patients with CKD (95 males and 34 females) are included in the study. The patients data (mean, percentages, degrees, etc.) are summarized in tabl.1 and tabl. 2. Clinically significant is the correlation between the grades of AACS and Acenocoumarol intake (p &lt; 0,05). With the calcium score increasing, the patients percentage treated with Acenocoumarol also increases (fig. 1). There is a moderate correlation (Cramer’s coefficient is 0,39) between the AACS grades and heart morbidity from AF and / or IHD (p &lt; 0,05). The data shows that the higher calcium score is related with increased patients percentage with AF and / or IHD morbidity (fig. 2). In our study, vascular calcifications are found in the abdominal aorta walls in all of the observed patients. We found that a higher AACS is associated with an Acenocoumarol intake in CKD patients and corresponds to an increased morbidity of AF and / or IHD. Acenocoumarol intake may lead to increased AACS. The higher calcium score is associated with a higher incidence of AF and / or IHD morbidity. Conclusion The study outcome supported the hypothesis that the increased AC formation and cardiovascular morbidity high risk could be a reason for the limited vitamin K antagonists (acenocoumarol) use in CKD patients. Furthermore, vitamin K2 supplementation is reasonable and may reduce the progression of AC.


2020 ◽  
Vol 14 ◽  
Author(s):  
Carmen Diaz ◽  
Luis Puelles

The hypothalamus is a heterogeneous rostral forebrain region that regulates physiological processes essential for survival, energy metabolism, and reproduction, mainly mediated by the pituitary gland. In the updated prosomeric model, the hypothalamus represents the rostralmost forebrain, composed of two segmental regions (terminal and peduncular hypothalamus), which extend respectively into the non-evaginated preoptic telencephalon and the evaginated pallio-subpallial telencephalon. Complex genetic cascades of transcription factors and signaling molecules rule their development. Alterations of some of these molecular mechanisms acting during forebrain development are associated with more or less severe hypothalamic and pituitary dysfunctions, which may be associated with brain malformations such as holoprosencephaly or septo-optic dysplasia. Studies on transgenic mice with mutated genes encoding critical transcription factors implicated in hypothalamic-pituitary development are contributing to understanding the high clinical complexity of these pathologies. In this review article, we will analyze first the complex molecular genoarchitecture of the hypothalamus resulting from the activity of previous morphogenetic signaling centers and secondly some malformations related to alterations in genes implicated in the development of the hypothalamus.


1938 ◽  
Vol 67 (6) ◽  
pp. 911-920 ◽  
Author(s):  
H. P. Smith ◽  
E. D. Warner ◽  
K. M. Brinkhous ◽  
W. H. Seegers

In biliary fistula dogs the plasma prothrombin falls eventually to low levels and bleeding commonly occurs. Faulty absorption of vitamin K from the intestine in these animals is an important causative factor. Feeding bile permits absorption of the traces of this vitamin normally present in mixed diets, and as a result a slow rise in prothrombin level is observed. If a standard diet is supplemented with large amounts of vitamin K concentrate the prothrombin rise is rapid, provided bile or bile salt is supplied to aid in the absorption. Variations in the rate of prothrombin depletion in biliary fistula dogs kept on constant diet indicate the existence of additional factors which require further study. Our experience indicates that vitamin A and vitamin D supplements do not correct the prothrombin deficiency in biliary fistula animals.


2006 ◽  
Vol 96 (11) ◽  
pp. 602-610 ◽  
Author(s):  
Ravinay Bhindi ◽  
Paul Witting ◽  
Aisling McMahon ◽  
Levon Khachigian ◽  
Harry Lowe

SummaryAnimal models of cardiovascular pathology contribute towards understanding and treatment of a broad range of conditions. Specifically in the context of acute myocardial infarction (AMI), rat models have been commonly used in studies of pathogenesis, investigation and novel therapies, although there has often been difficulty in translating experimental findings to clinical benefit. However, recent years have seen two important changes to our clinical approaches to AMI. First, there is increasing recognition that the pathophysiology of human AMI is a process occurring at many levels, not just within the epicardial coronary artery, but also within the microvasculature and the myocardium. Second, contemporary treatments are shifting away from thrombolytic dissolution of epicardial coronary thrombus to direct mechanical approaches using angioplasty and stents. These changes in our understanding of AMI have implications for the relevance of these animal models. The following discussion therefore reviews and examines the current rat models of AMI, places them in a clinical context, discusses their advantages and limitations, and outlines likely future developments, providing an overview of the place of these important models of AMI.


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