CK (Creatine Kinase) Is Associated With Cardiovascular Hemodynamics: The HELIUS Study

The ATP-regenerating enzyme CK (creatine kinase) is strongly associated with blood pressure, which lowers upon experimental CK inhibition. The enzyme is thought to affect cardiovascular hemodynamics through enhanced systemic vascular resistance, stroke volume, and cardiac contractility, but data on these parameters are lacking. We hereby report hemodynamics by CK levels in the multiethnic, cross-sectional HELIUS study (Healthy Life in an Urban Setting). Physical examination included sitting brachial blood pressure and noninvasively assessed supine systemic vascular resistance, stroke volume, cardiac output, and cardiac contractility, which we associated with resting plasma CK. Data from 14 937 men and women (mean age, 43.3; SD, 12.9) indicated that per log CK increase, blood pressure increased with 20.2 (18.9-21.4) mm Hg systolic/13.0 (12.2-13.7) diastolic, an odds ratio for hypertension of 6.1 (5.1-7.2). Outcomes were similar by sex, body mass index, and ancestry, although higher blood pressures in men, with overweight/obesity, and West-African ancestry were partially explained by higher CK, with an adjusted increase in systolic/diastolic pressure of 10.5 (10.0-10.9)/6.4 (6.0-6.7) mm Hg per log CK increase. Systemic vascular resistance, stroke volume, cardiac output, and cardiac contractility (n=7876), increased by respectively 20%, 39%, 14%, and 23% SD per log CK increase. This study indicates that the association of CK with blood pressure likely results from an increase in systemic vascular resistance and stroke volume. These data expand the knowledge on the nature of hypertension associated with CK and may inform further experiments on CK inhibition as a means to lower blood pressure.

The risk of hypertension and cardiovascular disease in women with uterine fibroids

Women with fibroids have a notably high hypertension risk. However, adjusted data regarding other cardiovascular disease (CVD) risk factors are scarce. In this cross-sectional study, CVD risk factors, hemodynamic parameters, and asymptomatic organ damage were analyzed between women with uterine fibroids and controls in a multi-ethnic population. In total, 104 women with self-reported fibroids and 624 controls were included. Women with fibroids had significantly higher odds to have hypertension (OR 3.4; 95% CI 2.2-5.2), diabetes (1.7; 1.0-2.9), and hypercholesterolemia (1.8; 1.1-3.2). After adjustment for confounders, only the odds ratio for hypertension was significant (1.8; 1.1-3.1). Asymptomatic organ damage occurred significantly more often in women with fibroids (66.7%; 95% CI 55.8%-77.6% vs 42.9%; 38.0-47.8 in controls), especially in the younger age group (respectively 48.5%; 31.1%-65.9% vs 22.1%; 17.0-27.2). In this study, women with fibroids had a remarkably high hypertension risk compared to controls, with more asymptomatic organ damage, in particular young women.

Creatine kinase and renal sodium excretion in African and European men on a high sodium diet

Creatine kinase (CK) rapidly regenerates ATP for Na⁺ /K⁺ -ATPase driven sodium retention throughout the kidney. Therefore, we assessed whether resting plasma CK is associated with sodium retention after a high sodium diet. Sixty healthy men (29 European and 31 African ancestry) with a mean age of 37.2 years (SE 1.2) were assigned to low sodium intake (< 50 mmol/d) during 7 days, followed by 3 days of high sodium intake (> 200 mmol/d). Sodium excretion (mmol/24-h) after high sodium was 260.4 (28.3) in the high CK tertile versus 415.2 (26.3) mmol/24-h in the low CK tertile (P < .001), with a decrease in urinary sodium excretion of 98.4 mmol/24-h for each increase in log CK, adjusted for age and African ancestry. These preliminary results are in line with the energy buffering function of the CK system, but more direct assessments of kidney CK will be needed to further establish whether this enzyme enhances sodium sensitivity.

Body composition measures and cardiovascular risk in high-risk ethnic groups

BACKGROUND & AIMS

Cardiovascular disease (CVD) is highly prevalent in Suriname, a middle-income country with predominantly people of African and Asian ancestry. We examined whether the more comprehensive body composition measures determined by bioelectrical impedance analysis (BIA) are superior to the more traditional BMI and waist measures in relation to cardiovascular risk.

METHODS

Data from the cross-sectional Healthy Life in Suriname (HELISUR) study were used to calculate BMI, waist-hip ratio, waist-to-height ratio, and waist circumference. BIA was used to estimate fat percentage, fat-free mass index, and fat-to-fat-free mass ratio. High cardiovascular risk was defined as 1) a 10-year Framingham coronary heart disease risk score ≥10% in African-Surinamese and ≥12% in Asian-Surinamese, and 2) an increased arterial stiffness (pulse wave velocity >10 m/s). Using logistic regression analysis, we pre-selected the strongest correlate (i.e. lowest p-value below 0.05) of all body composition items for both outcomes of cardiovascular risk separately, and subsequently, used forward logistic regression modelling to determine whether other measures added value to the initial model with the strongest correlate (-2 log-likelihood (-2LL) of initial model minus -2LL of new model, χ-square statistic >3.841, 1 df). Analyses were adjusted for sex, age and ethnicity.

RESULTS

We examined 691 participants (65% women; 48% African-Surinamese) with a mean age of 42 (SD 14) years. Waist circumference was the strongest correlate for high 10-year CVD risk in the total group, in men and African-Surinamese. In Asian-Surinamese, fat-free mass index was the strongest correlate of high 10-year CVD risk. Increased arterial stiffness was most strongly related with waist-to-height ratio in the total group and in African-Surinamese, and with BMI in men. None of the measures were significantly associated in women (for both outcomes) and Asian-Surinamese (for increased arterial stiffness). Forward selection showed that only BMI added value next to waist-to-height ratio in the total group in relation to increased arterial stiffness.

CONCLUSIONS

Waist measures, in particular waist circumference and waist-to-height ratio, and BMI should be used in African and Asian-Surinamese to identify who is at increased cardiovascular risk. Overall, we found little advantage in using BIA measures rather than simple anthropometric measures.

Hypertension and Cardiovascular Risk Profile in a Middle-Income Setting: The HELISUR Study

BACKGROUND

Hypertension is the leading risk factor responsible for premature death worldwide, but its burden has shifted to low- and middle-income countries. Therefore, we studied hypertension and cardiovascular risk in the population of Suriname, a middle-income country with a predominantly urban population of African and Asian ancestry.

METHODS

A random sample of 1,800 noninstitutionalized men and women aged 18-70 years was selected to be interviewed at home and examined at the local hospital for cardiovascular risk factors, asymptomatic organ damage, and cardiovascular disease.

RESULTS

The 1,157 participants examined (37% men) were mainly of self-defined Asian (43%) or African (39%) ancestry, mean age 43 years (SD 14). The majority of the population (71%) had hypertension or prehypertension, respectively, 40% and 31%. Furthermore, 72% was obese or overweight, while 63% had diabetes or prediabetes. Only 1% of the adult population had an optimal cardiovascular risk profile. Hypertension awareness, treatment, and control were respectively 68%, 56%, and 20%. In line with this, 22% of the adult population had asymptomatic organ damage, including increased arterial stiffness, left ventricular hypertrophy, microalbuminuria, or asymptomatic chronic kidney disease.

CONCLUSIONS

In this first extensive cardiovascular assessment in the general population of this middle-income Caribbean country, high prevalence of hypertension with inadequate levels of treatment and control was predominant. The findings emphasize the need for collaborative effort from national and international bodies to prioritize the implementation of affordable and sustainable public health programs that combat the escalating hypertension and cardiovascular risk factor burden.

The acute effect of beta-guanidinopropionic acid versus creatine or placebo in healthy men (ABC-Trial): A randomized controlled first-in-human trial

Aims

Increasing evidence indicates that the ATP‐generating enzyme creatine kinase (CK) is involved in hypertension. CK rapidly regenerates ATP from creatine phosphate and ADP. Recently, it has been shown that beta‐guanidinopropionic acid (GPA), a kidney‐synthesized creatine analogue and competitive CK inhibitor, reduced blood pressure in spontaneously hypertensive rats. To further develop the substance as a potential blood pressure‐lowering agent, we assessed the tolerability of a sub‐therapeutic GPA dose in healthy men.

Methods

In this active and placebo‐controlled, triple‐blind, single‐centre trial, we recruited 24 healthy men (18–50 years old, BMI 18.5–29.9 kg m⁻²) in the Netherlands. Participants were randomized (1:1:1) to one week daily oral administration of GPA 100 mg, creatine 5 g, or matching placebo. The primary outcome was the tolerability of GPA, in an intent‐to‐treat analysis.

Results

Twenty‐four randomized participants received the allocated intervention and 23 completed the study. One participant in the placebo arm dropped out for personal reasons. GPA was well tolerated, without serious or severe adverse events. No abnormalities were reported with GPA use in clinical safety parameters, including physical examination, laboratory studies, or 12‐Lead ECG. At day 8, mean plasma GPA was 213.88 (SE 0.07) in the GPA arm vs. 32.75 (0.00) nmol l⁻¹ in the placebo arm, a mean difference of 181.13 (95% CI 26.53–335.72).

Conclusion

In this first‐in‐human trial, low‐dose GPA was safe and well‐tolerated when used during 1 week in healthy men. Subsequent studies should focus on human pharmacokinetic and pharmacodynamic assessments with different doses.

Abstract P131: The Acute Effect of the Creatine Kinase Inhibitor Beta-GPA in Healthy Man (ABC-Trial): A Randomized Placebo Controlled First-in-human Trial

Aim: Increasing evidence indicates that the ATP-generating enzyme creatine kinase is involved in hypertension. Creatine kinase rapidly regenerates ATP from creatine phosphate and ADP. Recently, we showed that beta-guanidinopropionic acid (GPA), a kidney-synthesized creatine analogue and competitive inhibitor of creatine kinase, effectively and safely reduced blood pressure in spontaneously hypertensive rats. To further develop the substance as a potential blood pressure-lowering agent, we assessed the tolerability of a sub-therapeutic GPA dose in healthy men.

Methods: In this active and placebo-controlled, triple-blind, single-center trial, we recruited 24 healthy men (18 to 50 years old, BMI 18.5 to 29.9 kg/m 2 ) in the Netherlands. Participants were randomized (1:1:1) to one week daily oral administration of GPA 100 mg, creatine 5 gram, or matching placebo. The primary outcome was the tolerability of GPA, in an intent-to-treat analysis.

Results: Twenty four randomized participants received the allocated intervention and 23 completed the study. One participant in the placebo arm dropped out for personal reasons. GPA was well tolerated, without serious or severe adverse events. No abnormalities were reported with GPA use in clinical safety parameters, including physical examination, laboratory studies, or 12-Lead ECG (Table1).

At day 8, mean plasma GPA was 213.88 (SE 0.07) in the GPA arm vs. 32.75 (0.00) nmol/L in the placebo arm, a mean difference of 181.13 (95% CI 26.53 to 335.72).

Conclusion: In this first-in-human trial, low-dose GPA was safe and well-tolerated when used during 1 week in healthy men. Therefore, GPA is suitable for dose escalation trials

Health literacy in Suriname

BACKGROUND

Low health literacy is an independent predictor of cardiovascular mortality. However, data on health literacy in low- and middle-income countries are scarce. Therefore, we assessed the level of health literacy in Suriname, a middle-income country with a high cardiovascular mortality.

METHODS

We estimated health literacy in a convenience sample at an urban outpatient center in the capital and at a semirural health center, using the validated Rapid Estimate of Adult Literacy in Medicine adapted for the Dutch language (REALM-D) instrument. REALM-D scores vary from 0 to 66 (all correct). The primary outcome was the level of health literacy. Furthermore, we assessed the effect of age, sex, ethnicity, disease history, research location, and level of education on health literacy with multivariable linear regression.

RESULTS

We included 99 volunteers (52% men; 51% urban research location) with a mean age of 44.9 years (SD 13.4). The mean REALM-D score was moderate: 48.6 (SD 8.1). Greater health literacy was associated with male sex, an urban research location, and a higher educational level.

CONCLUSION

Health literacy was moderate in these Surinamese participants. Health care workers should take health literacy into account, and targeted interventions should be developed to improve health literacy in Suriname.

Creatine kinase as a marker of obesity in a multi-ethnic population

OBJECTIVE

Creatine kinase (CK), the central regulatory enzyme of energy metabolism, is particularly high in type II skeletal muscle fibers, which are associated with insulin resistance and obesity. As resting plasma CK is mainly derived from skeletal muscle, we assessed whether plasma CK is associated with markers of obesity.

METHODS

In this cross-sectional study, we analyzed a random sample of the multi-ethnic population of Amsterdam, the Netherlands, consisting of 1444 subjects aged 34-60 years. The primary outcome was the independent association between plasma CK after rest and waist circumference. Other outcomes included waist-to-hip ratio and body mass index.

RESULTS

Mean waist circumference increased from the first through the third CK tertile, respectively 90.3 (SD 13.4), 93.2 (SD 14.3), and 94.4 (SD 13.3) cm (p < 0.001 for differences between tertiles). The increase in waist circumference was 8.91 (95% CI 5.35 to 12.47) cm per log CK increase after adjustment for age, sex, African ethnicity, educational level, physical activity and plasma creatinine. Similarly, CK was independently associated with waist-to-hip ratio and body mass index, with an increase of respectively 0.05 (95% CI 0.03 to 0.07) and 3.6 (95% CI 2.3 to 5.0) kg/m² per log CK increase.

CONCLUSIONS

Plasma CK is independently associated with measures of obesity in a multi-ethnic population. This is in line with the central role of type II skeletal muscle fibers in energy metabolism and obesity. Prospective studies should assess whether resting plasma CK could be an easy accessible marker of CK rich type II fiber predominance that helps identify individuals at risk for obesity.

Hypertension risk in Dutch women with symptomatic uterine fibroids

BACKGROUND

Female-specific risk factors for cardiovascular disease are understudied. We assessed whether women with uterine fibroids have a greater hypertension risk, independent of the shared risk factors for both conditions.

METHODS

Blood pressure was measured in women scheduled for fibroid surgery compared to women scheduled for nonfibroid gynecological surgery and women randomly sampled from the general population. We used multivariable binary logistic regression to assess whether hypertension was more common with surgically treated fibroids, independent of age, body mass index, and African ancestry.

RESULTS

We included 1,342 women (542 of African ancestry), of which 272 scheduled for fibroid surgery, 385 controls scheduled for nonfibroid gynecological surgery, and 685 random population controls, with a mean age (SD) of, respectively, 43.4 (6.6), 41.3 (10.2), and 45.1 (6.6) years; and a mean body mass index (SD) of, respectively, 27.4 (5.3), 25.7 (5.7), and 28.2 (5.6) kg/m(2). Hypertension was found more frequently with surgically treated fibroids, with an occurrence of 41.9% in women with fibroids vs. 27.5% in surgical controls, and 28.3% in population controls (P < 0.001 for fibroids vs. controls). The association with hypertension was independent of age, body mass index, and African ancestry (odds ratio, 2.4; 95% confidence interval, 1.7-3.4).

CONCLUSIONS

Hypertension risk is higher in Dutch women with surgically treated fibroids than in surgery or population controls, independent of age, body mass index, and African ancestry. Our data add to the body of evidence indicating that women with uterine fibroids are eligible for hypertension screening.

The acute effect of beta-guanidinopropionic acid versus creatine or placebo in healthy men (ABC Trial): study protocol for a randomized controlled trial

Background

Despite adequate treatment, up to 30% of treated antihypertensive patients with primary, uncomplicated hypertension remain uncontrolled. We proposed that high intracellular activity of the ATP regenerating enzyme creatine kinase (CK) increases pressor responses and hypertension risk. In line with this, we found that plasma CK activity after rest, a surrogate measure of tissue activity, is the main predictor of blood pressure levels and failure of antihypertensive therapy in the general population. In addition, the creatine analog and competitive oral creatine kinase inhibitor beta-guanidinopropionic acid effectively and safely reduced blood pressure in the spontaneously hypertensive rat. However, to our knowledge there are no human data on the safety of oral supplementation with this substance. Therefore, we will assess the tolerability of beta-guanidinopropionic acid in men, compared to creatine and placebo.

Methods/Design

This is a randomized, active and placebo controlled, triple blind, double dummy, single center clinical intervention trial in 24 healthy male volunteers, 18 to 50 years old, recruited in the Netherlands. The intervention consists of one week of daily oral administration of beta-guanidinopropionic acid 100 mg, creatine 5 gram, or placebo. The primary outcome is the tolerability of beta-guanidinopropionic acid as a descriptive measure, in an intent-to-treat analysis. Other outcomes include the placebo-adjusted differences with baseline in biochemical and hemodynamic parameters, including plasma markers of muscle tissue damage, urine sodium excretion, resting sitting systolic and diastolic brachial blood pressure, supine systolic and diastolic central blood pressure, pulse wave velocity and augmentation index, heart rate, cardiac contractility, cardiac output, and total peripheral resistance.

Discussion

There is an unfulfilled need for new conservative options to treat resistant hypertension. This study will provide first-in-men data on creatine kinase inhibition as a potential new class of antihypertensive drugs.

Trial registration

The Netherlands National Trial Register Trialregister.nl (identifier NTR 4444), registered 9 March 2014.