Maintenance of Elevated Blood Levels of Vitamin B12 in Human Subjects

Trauma-related disorders, such as posttraumatic stress disorder (PTSD) are remarkably common and debilitating, and are often characterized by dysregulated threat responses. Across numerous epidemiological studies, females have been found to have an approximately twofold increased risk for PTSD and other stress-related disorders. Understanding the biological mechanisms of this differential risk is of critical importance. Recent data suggest that the pituitary adenylate cyclase-activating polypeptide (PACAP) pathway is a critical regulator of the stress response across species. Moreover, increasing evidence suggests that this pathway is regulated by both stress and estrogen modulation and may provide an important window into understanding mechanisms of sex differences in the stress response. We have recently shown that PACAP and its receptor (PAC1R) are critical mediators of abnormal processes after psychological trauma. Notably, in heavily traumatized human subjects, there appears to be a robust sex-specific association of PACAP blood levels and PAC1R gene variants with fear physiology, PTSD diagnosis, and symptoms, specifically in females. The sex-specific association occurs within a single-nucleotide polymorphism (rs2267735) that resides in a putative estrogen response element involved in PAC1R gene regulation. Complementing these human data, the PAC1R messenger RNA is induced with fear conditioning or estrogen replacement in rodent models. These data suggest that perturbations in the PACAP-PAC1R pathway are regulated by estrogen and are involved in abnormal fear responses underlying PTSD.

Download Full-text

Association of blood levels of homocysteine, vitamin B12, and serum cholesterol with age related macular degeneration in the elderly population of India

Egyptian Journal of Ophthalmology, (Mansoura Ophthalmic Center) ◽

10.21608/ejomos.2021.75761.1019 ◽

2021 ◽

Vol 1 (3) ◽

pp. 121-127

Author(s):

Anushree Gupta

Keyword(s):

Vitamin B12 ◽

Macular Degeneration ◽

Serum Cholesterol ◽

Elderly Population ◽

The Elderly ◽

Age Related Macular Degeneration ◽

Blood Levels ◽

Age Related

Download Full-text

Supplemented Creatine Induces Changes in Human Metabolism of Thiocompounds and One- and Two-Carbon Units

Physiological Research ◽

10.33549/physiolres.931588 ◽

2010 ◽

pp. 431-442

Author(s):

T Navrátil ◽

E Kohlíková ◽

M Petr ◽

D Pelclová ◽

M Heyrovský ◽

...

Keyword(s):

Urinary Excretion ◽

Vitamin B12 ◽

Metabolic Pathways ◽

Blood Levels ◽

Redox Processes ◽

Human Metabolism ◽

Metabolic Disturbances ◽

Creatinine Excretion ◽

Thiodiglycolic Acid ◽

The Last Man

The administration of creatine (5 g/day for one month) to 11 young active sportsmen affected their urinary excretion of creatine, creatinine, and thiodiglycolic acid (TDGA) as well as blood levels of homocysteine, vitamin B12 and folates. The probands were divided into four groups, according to the amount of creatine found in urine, and of folates and vitamin B12 determined in blood. The changes of folates and vitamin B12 were mutually reciprocal. Each group utilized CR as donor of one- and two-carbon (1C and 2C) units by means of homocysteine (HoCySH), folates, and vitamin B12, in different metabolic pathways. In 10 men the creatine administration was accompanied by an increase of HoCySH level in blood, while in the last man, with accidentally discovered hyperhomocysteinemia, the HoCySH level dropped by 50 %. Differences between initial and terminal TDGA levels indicate that creatine affects equilibria of redox processes. Creatinine excretion into urine changed in the dependence on the extent of metabolic disturbances.

Download Full-text

Elevated blood levels of soluble tumor necrosis factor receptors in nasopharyngeal carcinoma: correlation with humoral immune response to lytic replication of Epstein-Barr virus.

International Journal of Oncology ◽

10.3892/ijo.15.1.167 ◽

1999 ◽

Cited By ~ 1

Author(s):

P Feng ◽

S H Chan ◽

E E Ooi ◽

M Y Soo ◽

K S Loh ◽

...

Keyword(s):

Tumor Necrosis ◽

Epstein Barr Virus ◽

Lytic Replication ◽

Blood Levels ◽

Elevated Blood ◽

Tumor Necrosis Factor Receptors ◽

Humoral Immune ◽

Barr Virus ◽

Epstein Barr ◽

Necrosis Factor

Download Full-text

Effect of a Klamath algae product (“AFA-B12”) on blood levels of vitamin B12 and homocysteine in vegan subjects: a pilot study

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.79.2.117 ◽

2009 ◽

Vol 79 (2) ◽

pp. 117-123 ◽

Cited By ~ 8

Author(s):

Luciana Baroni ◽

Stefano Scoglio ◽

Serena Benedetti ◽

Chiara Bonetto ◽

Silvia Pagliarani ◽

...

Keyword(s):

Vitamin B12 ◽

Blood Concentration ◽

Control Period ◽

Vegan Diet ◽

Blood Levels ◽

Intervention Period ◽

Natural Sources ◽

Reliable Source ◽

Preliminary Study ◽

Reliable Marker

Vitamin B12 is a critical nutrient that is often inadequate in a plant-based (vegan) diet, thus the inclusion of a reliable vitamin B12 source in a vegan diet is recommended as essential. Unfortunately, many natural sources of vitamin B12 have been proven to contain biologically inactive vitamin B12 analogues, inadequate for human supplementation. The aim of this non-randomized open trial was to determine whether supplementation with a natural Klamath algae-based product (“AFA-B12”, Aphanizomenon flos-aquae algae plus a proprietary mix of enzymes) could favorably affect the vitamin B12 status of a group of 15 vegan subjects. By assessing blood concentration of vitamin B12, folate, and more importantly homocysteine (Hcy, a reliable marker in vegans of their B12 absorption), the vitamin B12 status of the participants at the end of the 3-month intervention period, while receiving the Klamath-algae supplement (T2), was compared with their vitamin B12 status at the end of the 3-month control period (T1), when they were not receiving any supplement, having stopped taking their usual vitamin B12 supplement at the beginning of the study (T0). Compared to the control period, in the intervention period participants improved their vitamin B12 status, significantly reducing Hcy blood concentration (p=0.003). In conclusion, the Klamath algae product AFA-B12 appears to be, in a preliminary study, an adequate and reliable source of vitamin B12 in humans.

Download Full-text

Folic Acid and Vitamin B12 Administration in CKD, Why Not?

Nutrients ◽

10.3390/nu11020383 ◽

2019 ◽

Vol 11 (2) ◽

pp. 383 ◽

Cited By ~ 17

Author(s):

Irene Capelli ◽

Giuseppe Cianciolo ◽

Lorenzo Gasperoni ◽

Fulvia Zappulo ◽

Francesco Tondolo ◽

...

Keyword(s):

Risk Factors ◽

Folic Acid ◽

Cardiovascular Risk ◽

Vitamin B12 ◽

Therapeutic Target ◽

Direct Action ◽

Blood Levels ◽

Traditional Risk Factors ◽

Stage Renal Disease ◽

End Stage

Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Since traditional risk factors cannot fully explain such increased cardiovascular risk, interest in non-traditional risk factors, such as hyperhomocysteinemia and folic acid and vitamin B12 metabolism impairment, is growing. Although elevated homocysteine blood levels are often seen in patients with CKD and ESRD, whether hyperhomocysteinemia represents a reliable cardiovascular and mortality risk marker or a therapeutic target in this population is still unclear. In addition, folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. The purpose of this review was to highlight homocysteine, folic acid and vitamin B12 metabolism impairment in CKD and ESRD and to summarize available evidences on hyperhomocysteinemia, folic acid and vitamin B12 as cardiovascular risk markers, therapeutic target and risk factors for CKD progression.

Download Full-text

“Saturation” Studies with Vitamin B12 in Human Subjects

American Journal of Clinical Nutrition ◽

10.1093/ajcn/6.5.535 ◽

1958 ◽

Vol 6 (5) ◽

pp. 535-541 ◽

Cited By ~ 1

Author(s):

WALTER C. UNGLAUB ◽

O. NEAL MILLER ◽

GRACE A. GOLDSMITH

Keyword(s):

Vitamin B12 ◽

Human Subjects

Download Full-text

Hydroxocobalamin. I. Blood Levels and Urinary Excretion of Vitamin B12 in Man After a Single Parenteral Dose of Aqueous Hydroxocobalamin, Aqueous Cyanocobalamin and Cyanocobalamin Zinc-Tannate Complex

Blood ◽

10.1182/blood.v18.5.511.511 ◽

1961 ◽

Vol 18 (5) ◽

pp. 511-521 ◽

Cited By ~ 23

Author(s):

GEORGE B. JERZY GLASS ◽

HELEN R. SKEGGS ◽

DUK HO LEE ◽

E. LINN JONES ◽

WILLIAM W. HARDY

Keyword(s):

Urinary Excretion ◽

Vitamin B12 ◽

Blood Level ◽

Intramuscular Injection ◽

Serum Vitamin ◽

Blood Levels ◽

Parenteral Dose ◽

Single Intramuscular Injection

Abstract A single intramuscular injection of 500 or 1000 µg. of hydroxocobalamin to 17 individuals resulted in a 1.8- to 4.1-times higher mean serum vitamin B12 blood level, respectively, 5 hours after injection; a 4.6- and 12.8-times higher level 24 hours after injection; a 2.4- and 5.2-times higher level 72 hours after injection, and a 1.6- and 2.4-times higher level by the 2nd through the 4th week after injection than identical doses of cyanocobalamin administered to 19 individuals. The vitamin B12 blood levels following i.m. administration of 500 or 1000 µg. of hydroxocobalamin were significantly higher during the first 24 and 48 hours, respectively, than they were after a cyanocobalamin zinc-tannate complex given to 17 individuals at identical doses. After a single i.m. injection of 500 or 1000 µg. of hydroxocobalamin, an average of only 16 per cent and 27 per cent, respectively, of the vitamin B12 was lost in the 72-hour urines, as compared to 60 per cent and 69 per cent, respectively, after identical doses of cyanocobalamin. These differences, again, were highly significant statistically. The results of these studies give evidence of a slower rate of urinary excretion of hydroxocobalamin as compared to that of cyanocobalamin, and of its ability to build up consistently higher and more prolonged vitamin B12 levels in the blood.

Download Full-text