Plasma Fibroblast Growth Factor 23 Is Elevated in Pediatric Primary Hypertension

Decreased FGF23 inhibits placental angiogenesis via the ERK1/2-EGR-1 signaling pathway in preeclampsia

PURPOSE

This study aimed to investigate the expression of fibroblast growth factor 23 (FGF23) in pregnant women with preeclampsia and elucidate its role in promoting placental angiogenesis through the ERK1/2-EGR-1 signaling pathway.

METHODS

Serum FGF23 levels were measured by ELISA in healthy pregnant women and patients with preeclampsia during the first, second, and third trimesters of pregnancy. Wound healing, Transwell, and tube formation assays were performed to investigate the effects of FGF23 on cell migration, invasion and tube formation. The expression of vascular endothelial growth factor A (VEGF-A) and its upstream signaling molecules, p-ERK, and EGR-1, in placental tissues was detected by RT-qPCR and western blotting. Additionally, the effect of FGF23 on VEGF-A, p-ERK, and EGR-1 expression was further explored in vitro.

RESULTS

Serum FGF23 levels increased with gestational age. During the third trimester, the control group exhibited a more pronounced increase in FGF23 levels than the preeclampsia group. Administering exogenous FGF23 promoted trophoblast cell migration, invasion and enhanced tube formation in vascular endothelial cells. The expression levels of VEGF-A, p-ERK, and EGR-1 in the placental tissues were significantly lower in the preeclampsia group than in the control group. In vitro experiments confirmed that FGF23 up-regulated VEGF-A expression through the p-ERK/EGR-1 signaling pathway.

CONCLUSION

The serum level of FGF23 decreased in pregnant women with preeclampsia, inhibiting the ERK1/2-EGR-1 pathway and resulting in decreased expression of VEGF-A, thereby inhibiting placental angiogenesis. This could be a potential mechanism involved in the progression of preeclampsia.

Efficacy of fosinopril and amlodipine in pediatric primary hypertension: a single-center observational study

Objective

Fosinopril and amlodipine are commonly prescribed as first-line pharmacotherapeutic agents for pediatric hypertension, but there is a lack of comparative studies regarding the efficacy of these two drugs. We aimed to evaluate and compare the efficacy of fosinopril and amlodipine monotherapy in pediatric primary hypertension.

Methods

This was a single-center, bidirectional observational study. A total of 175 children and adolescents with primary hypertension receiving antihypertensive monotherapy from July 2020 to February 2023 were enrolled. According to antihypertensive drugs, they were divided into the fosinopril group (n = 96) and the amlodipine group (n = 79). Subgroup analysis was performed to compare the efficacy of the two groups in terms of blood pressure (BP) control rates and reductions following a 4-week treatment.

Results

After 4 weeks of treatment, both groups achieved significant reductions in systolic BP (SBP) and diastolic BP (DBP) by more than 18 mmHg and 6 mmHg, respectively, with BP control rates of 61.5% in the fosinopril group and 59.5% in the amlodipine group, revealing no significant differences in the antihypertensive efficacy between the two groups except for DBP control rate (FDR adjusted P > 0.05). Further subsequent subgroup analyses revealed that the reductions in SBP and DBP in the fosinopril group were significantly greater than those in the amlodipine group in patients of females and hypo-HDL-cholesterolemia (FDR adjusted P < 0.05), and there was a trend of difference, although not significant, in patients with central obesity and insulin resistance (IR) (FDR adjusted 0.05 < P ≤ 0.1). However, there were no significant differences in treatment efficacy in patients without these characteristics. Furthermore, hypertriglyceridemia did not exhibit a significant association with the difference in treatment efficacy between the two medications (FDR adjusted P > 0.05).

Conclusions

Fosinopril and amlodipine monotherapy were both effective in pediatric primary hypertension during a short-term follow-up. Fosinopril may be particularly effective in reducing BP in hypertensive patients of females, central obesity, IR, and hypo-HDL-cholesterolemia. These findings indicate that optimizing antihypertensive medication selection based on the individualized characteristics of children with hypertension may improve the efficacy of antihypertensive treatment.

Kidney outcomes in early adolescence following perinatal asphyxia and hypothermia-treated hypoxic-ischaemic encephalopathy

BACKGROUND

Acute kidney injury (AKI) remains common among infants with hypothermia-treated hypoxic-ischaemic encephalopathy (HIE). Little is known about long-term kidney outcomes following hypothermia treatment. We recently reported that 21% of survivors of hypothermia-treated HIE had decreased estimated glomerular filtration rate (eGFR) based on plasma creatinine in early adolescence. Here, we assessed kidney functions more comprehensively in our population-based cohort of children born in Stockholm 2007-2009 with a history of hypothermia-treated HIE.

METHODS

At 10-12 years of age, we measured cystatin C (cyst C) to estimate GFR. Children with decreased cyst C eGFR also underwent iohexol clearance examination. We measured urine-albumin/creatinine ratio, blood pressure (BP) and kidney volume on magnetic resonance imaging. Fibroblast growth factor 23 (FGF 23) levels in plasma were assessed by enzyme-linked immunosorbent assay (ELISA). Outcomes were compared between children with and without a history of neonatal AKI.

RESULTS

Forty-seven children participated in the assessment. Two children (2/42) had decreased cyst C eGFR, for one of whom iohexol clearance confirmed mildly decreased GFR. One child (1/43) had Kidney Disease Improving Global Outcomes (KDIGO) category A2 albuminuria, and three (3/45) had elevated office BP. Subsequent ambulatory 24-h BP measurement confirmed high normal BP in one case only. No child had hypertension. Kidney volume and FGF 23 levels were normal in all children. There was no difference in any of the parameters between children with and without a history of neonatal AKI.

CONCLUSION

Renal sequelae were rare in early adolescence following hypothermia-treated HIE regardless of presence or absence of neonatal AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Calcium, Its Regulatory Hormones, and Their Causal Role on Blood Pressure: A Two-Sample Mendelian Randomization Study

CONTEXT

Vitamin D (Vit-D), parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23) are the major calciotropic hormones involved in the regulation of blood calcium levels from the intestine, kidney, and bone through a tight endocrine feedback loop system. Altered levels of calcium itself or through the effect of its regulatory hormones could affect blood pressure (BP), but the exact mechanisms remain unclear.

OBJECTIVE

To evaluate whether a causal relationship exists between serum calcium level and/or the regulatory hormones involved in its homeostasis with BP, we performed a two-sample Mendelian randomization (MR) study.

METHODS

From 4 large genome-wide association studies (GWAS) we obtained independent (r2 < 0.001) single nucleotide polymorphisms (SNPs) associated with serum calcium (119 SNPs), Vit-D (78 SNPs), PTH (5 SNPs), and FGF23 (5 SNPs), to investigate through MR their association with systolic BP (SBP) and diastolic BP (DBP) in a Swedish urban-based study, the Malmö Diet and Cancer study (n = 29 298). Causality was evaluated by the inverse variance weighted method (IVW) and weighted median, while MR Egger and MR-PRESSO were used as sensitivity analyses.

RESULTS

Genetically predicted serum calcium level was found to be associated with DBP (IVW: beta = 0.10, SE = 0.04, P = 0.007) and SBP (IVW: beta = 0.07, SE = 0.04, P = 0.04). Genetically predicted Vit-D and PTH showed no association with the traits, while FGF23 was inversely associated with SBP (IVW: beta = -0.11, SE = 0.04, P = 0.01), although this association lost statistical significance in sensitivity analysis.

CONCLUSION

Our study shows a direct association between genetically predicted calcium level and DBP, and a weaker association with SBP. No such clear association was found for genetically predicted calciotropic hormone levels. It is of interest to detect which target genes involved in calcium homeostasis mediate the effect of calcium on BP, particularly for improving personalized intervention strategies.

Plasma Fibroblast Growth Factor 23 as a Predictor for Fosinopril Therapeutic Efficacy in Pediatric Primary Hypertension

Background

Plasma fibroblast growth factor 23 (FGF23) has been reported to be a predictive biomarker for therapeutic effectiveness of angiotensin‐converting enzyme inhibitors in heart failure. Higher plasma FGF23 levels have been shown in pediatric primary hypertension, but the predictive value of FGF23 for angiotensin‐converting enzyme inhibitors’ effectiveness in pediatric primary hypertension has not been documented.

Methods and Results

This is a prospective study. An exploratory study with 139 patients was first conducted to determine the cutoff value of FGF23 for the prediction of treatment responsiveness. After receiving fosinopril for 4 weeks, of all 139 patients, 91 responded, while 48 did not respond to the treatment, and the responders had a significantly higher baseline plasma FGF23 level than nonresponders (P<0.01). Multiple regression analysis revealed a significant impact of baseline plasma FGF23 levels on fosinopril responsiveness (P<0.05). The receiver operating characteristic curve analysis showed that the plasma FGF23 predicted the effectiveness of fosinopril treatment with an area under the curve of 0.784 (95% CI, 0.704–0.863) for a sensitivity and a specificity of 67.0% and 89.6%, respectively, for a cutoff value of 62.08 RU/mL. Subsequently, another group of 40 patients were recruited for validation. The blood pressure control rate in those (n=22) with baseline plasma FGF23 >62.08 RU/mL was significantly higher than that in children (n=18) with FGF23 ≤62.08 RU/mL (P<0.05).

Conclusions

Plasma FGF23 might be a valuable biomarker to guide fosinopril therapy for primary hypertension in children.

The Correlation Between ABPM Parameters and Left Ventricular Hypertrophy in Pediatric Essential Hypertension

OBJECTIVE

To explore the association of dipping pattern and blood pressure load with left ventricular hypertrophy (LVH) in pediatric essential hypertension.

MATERIALS AND METHODS

Through an echocardiography monitor and an ambulatory blood pressure monitor of 425 children and adolescents diagnosed with essential hypertension with no treatment received, we identified 140 cases of LVH. Grouping patients according to LVH (LVH, N = 140; n-LVH, N = 285), we further evaluated their ambulatory blood pressure monitoring (ABPM) parameters by comparing dipping patterns between groups. A multivariable logistic regression analysis was used to determine the effect of blood pressure load on LVH.

RESULTS

No significant difference was found in systolic or diastolic blood pressure dipping patterns between groups (P = 0.161, P = 0.139). However, compared to the n-LVH group, the LVH group presented significant elevated nighttime systolic blood pressure (SBP) (P < 0.05), while nighttime DBP remained stable (P = 0.391), resulting in higher daytime and nighttime SBP loads, higher nighttime DBP load, and higher 24-h SBP load (P < 0.05). Notably, our multivariable logistic regression has shown that this trend of 24-h SBP load acts independently as a critical risk factor for LVH.

CONCLUSION

Collectively, we observed a correlation between BP load and LVH in pediatric hypertension. Our data demonstrated that SBP load has a more significant weight in LVH progression, and 24-h SBP load, in particular, acts as a critical early prognostic parameter for LVH in pediatric hypertension.

Update on the Crosstalk Between Adipose Tissue and Mineral Balance in General Population and Chronic Kidney Disease

Adipose tissue is nowadays considered as a major endocrine organ, which apart from controlling lipid metabolism, displays a significant role in energy expenditure, food intake and in the regulation of various systemic physiological processes. Adipose derived pro-inflammatory cytokines and adipokines, particularly leptin and adiponectin, provide inter-communication of adipose tissue with various metabolic pathways, ultimately resulting in a complex network of interconnected organ systems. Recent clinical and experimental research has been focused on exploring the direct interaction between adipokine profile and elements of mineral metabolism, including parathormone (PTH), fibroblast growth factor-23 (FGF23) and calcitriol. The emerging crosstalk between adipose tissue and calcium and phosphorus homeostasis suggests that metabolic disorders from one system may directly affect the other and vice versa. It is current knowledge that fat metabolism disturbance, commonly encountered in obese individuals, influences the expression of calciotriopic hormones in general population, while various clinical trials attempting to successfully achieve body fat loss by modulating mineral profile have been published. In chronic kidney disease (CKD) state, there is an increasing evidence suggesting that mineral disorders, influence adipose tissue and linked endocrine function. On the contrary, the impact of disturbed fat metabolism on CKD related mineral disorders has been also evocated in clinical studies. Recognizing the pathogenetic mechanisms of communication between adipose tissue and mineral balance is critical for understanding the effects of metabolic perturbations from the one system to the other and for identifying possible therapeutic targets in case of disrupted homeostasis in one of the two connected systems. To that end, this review aims to enlighten the recent advances regarding the interplay between mineral metabolism, fat mass and adipokine profile, based on in vitro, in vivo and clinical studies, in general population and in the course of CKD.

FGF23 and Phosphate-Cardiovascular Toxins in CKD

Elevated levels of fibroblast growth factor 23 (FGF23) and phosphate are highly associated with increased cardiovascular disease and mortality in patients suffering from chronic kidney disease (CKD). As the kidney function declines, serum phosphate levels rise and subsequently induce the secretion of the phosphaturic hormone FGF23. In early stages of CKD, FGF23 prevents the increase of serum phosphate levels and thereby attenuates phosphate-induced vascular calcification, whereas in end-stage kidney disease, FGF23 fails to maintain phosphate homeostasis. Both hyperphosphatemia and elevated FGF23 levels promote the development of hypertension, vascular calcification, and left ventricular hypertrophy by distinct mechanisms. Therefore, FGF23 and phosphate are considered promising therapeutic targets to improve the cardiovascular outcome in CKD patients. Previous therapeutic strategies are based on dietary and pharmacological reduction of serum phosphate, and consequently FGF23 levels. However, clinical trials proving the effects on the cardiovascular outcome are lacking. Recent publications provide evidence for new promising therapeutic interventions, such as magnesium supplementation and direct targeting of phosphate and FGF receptors to prevent toxicity of FGF23 and hyperphosphatemia in CKD patients.