Fat-Soluble Vitamins
Luke R. Bucci in Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Like other fat-soluble vitamins, vitamin K exists as a series of compounds with the same biological activity.562–566 Vitamin K is the generic term for menadione, menaquinone, and phylloquinone. As 1,4-naphthoquinone ring compounds, vitamin K vitamers are lipophilic (fat-soluble) and subject to oxidation-reduction (redox) reactions in tissues. The chief role of vitamin K is as a cofactor for enzymes that convert protein-bound glutamyl residues to γ-carboxyglutamyl residues.562–566 Prothrombin activity is dependent upon gamma carboxylation of glutamyl residues, and, thus, vitamin K is associated with antihemorrhagic and blood clotting properties. Recently, vitamin K-dependent gamma carboxylation of bone-associated proteins (osteocalcin and others) has been confirmed, and another role of vitamin K has been added: regulation of bone mineral formation.562–566 All gamma carboxylated proteins bind calcium ions in a specific manner that allows for specific functions for each protein.
Haematological conditions
David M. Luesley, Mark D. Kilby in Obstetrics & Gynaecology, 2016
If there is likely to be a significant delay before investigations are complete or the index of suspicion is high, anticoagulation should be started until the diagnosis is confirmed or refuted. The anticoagulant of choice is LMWH.31,32 Meta-analyses have shown that, in comparison with unfractionated heparin (UFH), LMWH is equally efficacious and has a reduced risk of haemorrhagic complications33 and lower overall mortality. The risk of heparin-induced thrombocytopenia and osteoporosis is also significantly less. Vitamin K antagonists should not be used in pregnancy, as they are teratogenic in the first trimester and associated with haemorrhagic complications and central nervous system (CNS) anomalies at all stages of pregnancy.
Cognitive Disorders and Lifestyle Change
Gia Merlo, Kathy Berra in Lifestyle Nursing, 2023
Clinical evidence supports the role of micronutrients and the role they play on cognition. Thiamine (B1) deficiency has been linked to cognitive impairment (Gibson et al., 2016), intake of pyridoxine (vitamin B6) has been linked to improved cognitive function, and B12 deficiency has been linked to impaired cognition (Smith, 2016). Intake of folic acid (vitamin B6) has been linked with improved cognition (Fortune et al., 2019). Cognitive decline has been linked to decreased vitamin A levels (Shahar et al., 2013). Vitamin A deficiency may be a predictor of mild cognitive impairment. An increased intake of carotenoids was shown to decrease the risk of poor cognitive function. Increased vitamin K intake was associated with better cognitive function in older adults (Soutif-Veillon et al., 2016). Maintaining adequate vitamin D levels during aging may delay the onset of dementia and reduce the risk of cognitive decline (Jia et al., 2019). Additionally, according to the US National Health and Nutrition Examination Survey, better cognitive function was directly correlated to a high intake of magnesium and adequate intake of vitamin D (Peeri et al., 2020). A decrease in mild cognitive impairment was seen in individuals with high vitamin C levels (Beydoun et al., 2015). Higher vitamin E levels were associated with higher scores on memory, recall, and better language/verbal fluency (Farina et al., 2017). Circulating and brain selenium concentrations have been noted to be lower in Alzheimer’s disease (Varikasuvu et al., 2018).
Vitamin K status and inflammation are associated with cognition in older Irish adults
Published in Nutritional Neuroscience, 2020
A. Kiely, G. Ferland, B. Ouliass, P.W. O’Toole, H. Purtill, E.M. O’Connor
Vitamin K is generally known for its role in blood coagulation and is the general term for a group of fat-soluble compounds.1 However in recent years, a number of potential health benefits beyond coagulation have been attributed to vitamin K. While green leafy vegetables provide phylloquinone (or vitamin K1), the most widely consumed dietary form of the vitamin,2 high levels of a menaquinone (vitamin K2) isoform called menaquinone-4 (MK-4) have been reported in brain tissues.3 At the biochemical level, vitamin K is implicated in the production of sphingolipids, a group of lipids that comprise the myelin sheath of neuronal tissue3,4 and that are now recognised as important bioactive mediators of cell interaction, proliferation, senescence, differentiation and transformation.5 The vitamin K-dependent protein (VKDP) Growth-arrest specific gene-6 (Gas6) is present in the brain where it performs cell regulatory and myelination functions. A role for vitamin K in memory consolidation has also been documented. Carrie and colleagues (2011) conducted a feeding study on female Sprague–Dawley rats fed a low, adequate and high phylloquinone diet to determine the effects on spatial memory (using the Morris water maze test). Animals exposed to a high or adequate phylloquinone diet required less visual assistance to complete the task than rats on the vitamin K depleted diet.6
Cefoperazone-sulbactam and risk of coagulation disorders or bleeding: a retrospective cohort study
Published in Expert Opinion on Drug Safety, 2020
Wen Wang, Yanmei Liu, Chuan Yu, Jing Tan, Weiyi Xiong, Duo Dong, Sheyu Li, Rui Zhang, Jijie Li, Yu Wu, Zhiyong Zong, Na Su, Kang Zou, Guizhi Wu, Xin Sun
However, the occurrence of adverse effects (i.e. hypoprothrombinemia) may differ among antibiotics containing the NMTT chain [18]. A study involving patients with hepatobiliary disorders found that treatment with cefotetan – an antibiotic containing the NMTT chain – may not induce hypoprothrombinemia or bleeding [18]. Similarly, a prospective study suggested that antibiotics containing NMTT chain (e.g. cefotetan) did not increase the risk of coagulation disorders among patients with critical illness [25]. In addition, the beta-lactamase inhibitor may exert effects on the coagulation disorder. Our study found that, unlike cefoperazone-tazobactam, cefoperazone-sulbactam increased the risk of PT prolongation and coagulation disorders compared with ceftazidime. However, the mechanism involved in this process remains unclear. Previous studies suggested that NMTT-containing antibiotics were not an independent risk. In contrast, the severity of illness, poor nutrition status, and failure to use vitamin K supplementation may be potential risk factors for developing hypoprothrombinemia and bleeding [6,11,25]. Another possible hypothesis is that sulbactam may exhibit a synergistic effect with cefoperazone on hypoprothrombinemia. Our findings suggested that the risk of coagulation disorders among patients treated with cefoperazone-sulbactam was significantly increased compared with that reported in patients receiving cefoperazone-tazobactam. Nevertheless, this hypothesis warrants further exploration.
Role of rivaroxaban in the prevention of atherosclerotic events
Published in Expert Review of Clinical Pharmacology, 2019
Marcelo Sanmartín, Sergi Bellmunt, Juan Cosín-Sales, Xavier García-Moll, Antoni Riera-Mestre, Manuel Almendro-Delia, José Luis Hernández, Francisco Lozano, Pilar Mazón, Carmen Suarez Fernández
Coagulation factors are essential in atherothrombosis [15,16]. Targeting the coagulation cascade for the prevention of cardiovascular thrombotic events had already been done with vitamin K antagonists. For example, it has been reported that among patients with a recent acute coronary syndrome, compared with aspirin in monotherapy, warfarin, alone or in combination with aspirin reduced the risk of cardiovascular events, but with an unacceptably higher bleeding risk [17]. In addition, vitamin K antagonists have many limitations, such as narrow therapeutic window, multiple interactions with food/drugs and many dose adjustments, that may have had a negative impact on these results [18]. Accordingly, it was hypothesized that the use of an anticoagulant agent at a lower dose could provide some beneficial effect on cardiovascular outcomes, but without a marked increased risk of bleeding. However, a fixed 1–3 mg low dose of warfarin offered no benefit, compared to aspirin alone in the multicenter, randomized, CARS trial [19].