Induction of tissue plasminogen activator secretion from rat heart microvascular cells by fM 1,25(OH)(2)D(3)

Association of Serum 25(OH) D Levels with Infarct Volumes and Stroke Severity in Acute Ischemic Stroke

BACKGROUND

The aim of this study is to investigate whether 25-hydroxyvitamin D [25(OH) D] is associated with initial stroke severity and infarct volume, using diffusion-weighted imaging (DWI) in patients with acute ischemic stroke.

METHODS

We studied a total of 235 patients who were admitted within 24 hours of acute ischemic stroke onset. Initial stroke severity was assessed using the NIH Stroke Scale (NIHSS) score. Infarct volume was measured using DWI. Multivariable linear and logistic regression analyses were used to test whether 25(OH) D represents an independent predictor of infarct volume and stroke severity (NIHSS score of ≥6).

RESULTS

Among 235 study patients, the median age was 64 years (IQR 56-75 years), and 125 (53.2%) were women. In multivariable models adjusted for other significant risk factors, 25(OH) D levels in the lowest and second interquartiles were associated with an increased risk of a NIHSS≥6 (with highest 25 (OH) D quartile as reference) with odd ratios (OR) 3.02(95% confidence interval [CI]:1.59-6.34) and 5.85(2.90-11.54). The median DWI infarct volumes for the serum 25(OH) D level quartiles (lowest to highest) were 12.35, 6.55, 2.44, and 1.59 ml. The median DWI infarct volume in the lowest serum 25(OH) D level quartile was larger than that in the other 3 quartiles (P<0.001). The median adjusted DWI infarct volume in the lowest serum 25(OH) D level quartile was statistically significantly larger than that in the other 3 quartiles (P<0.01).

CONCLUSION

In conclusion, reduced serum 25(OH) D levels in acute ischemic stroke are an early predictor of larger volumes of ischemic tissue and worse neurological deficit (assessed by the NIHSS).

Low Serum Vitamin D Is Independently Associated with Larger Lesion Volumes after Ischemic Stroke

BACKGROUND

Despite its high prevalence, known association with vascular disease and stroke incidence and fatality, little is known about the contribution of vitamin D status to a worse outcome after ischemic stroke. Therefore, we sought to assess whether low serum 25-hydroxyvitamin D (25[OH]D), a marker of vitamin D status, is predictive of the ischemic infarct volume and whether it relates to a worse outcome.

METHODS

We retrospectively analyzed prospective, consecutive acute ischemic stroke patients evaluated from January 2013 to January 2014 at a tertiary referral center. All patients (n = 96) had a magnetic resonance imaging-proven acute ischemic stroke. Multivariable linear and logistic regression analyses were used to test whether vitamin D represents an independent predictor of infarct volume and poor 90-day outcome (modified Rankin Scale score of >2).

RESULTS

In univariable analyses, lacunar infarct etiology, lower admission National Institutes of Health Stroke Scale, and higher serum 25(OH)D concentration were associated with smaller infarct volumes (P < .05). The association of 25(OH)D with ischemic infarct volume was independent of other known predictors of the infarct extent (P = .001). Multivariable analyses showed that the risk for a poor 90-day outcome doubled with each 10-ng/mL decrease in serum 25(OH)D.

CONCLUSIONS

Low serum 25(OH)D was independently associated with larger ischemic infarct volume, which may partially explain observed worse outcomes in ischemic stroke patients with poor vitamin D status. Although causality remains to be proven, our results provide the rationale to further explore vitamin D as a promising marker for cerebral ischemic vulnerability and to identify stroke patients at high risk for poor outcome.

Serum levels of vitamin D and haemostatic factors in healthy subjects: the Tromsø study

BACKGROUND

Receptors for vitamin D have been found in various tissues, including the vascular endothelium. The role of vitamin D in the haemostatic process is uncertain, but in vitro studies may indicate a pro-fibrinolytic effect.

METHODS

Two hundred and six subjects (105 males) were included in the study. The relations between indices of calcium metabolism and haemostatic factors [tissue plasminogen activator antigen (tPA Ag), plasminogen activator inhibitor 1 (PAI-1), prothrombin fragment 1+2, activated factor VII and total factor VII coagulant activity] and high-sensitivity C-reactive protein (HS-CRP) were examined.

RESULTS

There were significant and negative correlations between serum 25(OH) vitamin D and PAI-1 and tPA Ag, and between serum 1,25(OH)2 vitamin D and tPA Ag and HS-CRP. In a multiple linear regression model with age, gender, body mass index and smoking status as covariables, only the relation between 25(OH) vitamin D and tPA Ag was significant. There were no significant relations between any of the haemostatic factors tested and serum parathyroid hormone.

CONCLUSION

It appears that the serum level of vitamin D is related to fibrinolytic activity and to the integrity of the vascular endothelium, but the clinical importance of this observation remains to be determined.

Effects of dietary vitamin A intake on acrosin- and plasminogen-activator activity of ram spermatozoa

Acrosin and plasminogen activators are proteolytic enzymes of ram spermatozoa that play an essential role in the induction of the acrosome reaction, as well as the binding of spermatozoa to the oocyte and their penetration through the layers that surround the oocyte. Since vitamin A can alter gene expression in various tissues, testis included, this study was undertaken to evaluate the possible effect of vitamin A intake on acrosin- and plasminogen-activator activity. During a 20-week experiment, 15 rams of the Greek breed Karagouniki, divided to three groups, received different amounts of vitamin A per os in retinyl acetate capsules (group A, controls, 12,500 iu/animal per day; group B, 50,000 iu/animal per day; group C, 0 iu/animal per day up to the 13th week, then 150,000 iu/animal per day until the end of the experiment). Acrosin- and plasminogen-activator activity were determined by spectrophotometric methods. Vitamin A was determined in blood plasma by HPLC. No statistical differences were detected regarding the body weight of the rams or the qualitative and quantitative parameters of their ejaculate throughout the whole experiment. No statistically significant alterations of enzyme activity were detected in group B. In group C, both enzyme activities started declining in week 9. Compared with controls, maximum reduction for acrosin was 49% on week 11 and for plasminogen activators 51% in week 14. Activities returned to normal rates after vitamin A re-supplementation. To date, the main result of vitamin A deficiency was known to be arrest of spermatogenesis and testicular degeneration. A new role for vitamin A may be suggested, since it can influence factors related to male reproductive ability before spermatogenesis is affected.