Exploring the implications of blocking renin-angiotensin-aldosterone system and fibroblast growth factor 23 in early left ventricular hypertrophy without chronic kidney disease

Background

Whether fibroblast growth factor 23 (FGF23) directly induces left ventricular hypertrophy (LVH) remains controversial. Recent studies showed an association between FGF23 and the renin-angiotensin-aldosterone system (RAAS). The aim of this study was to investigate changes in FGF23 levels and RAAS parameters and their influences on LVH.

Methods

In the first experiment, male C57BL/6J mice were divided into sham and transverse aortic constriction (TAC) groups. The TAC group underwent TAC at 8 weeks of age. At 1, 2, 3, and 4 weeks after TAC, the mice were sacrificed, and blood and urine samples were obtained. Cardiac expressions of FGF23 and RAAS-related factors were evaluated, and cardiac histological analyses were performed. In the second experiment, the sham and TAC groups were treated with vehicle, angiotensin-converting enzyme (ACE) inhibitor, or FGF receptor 4 (FGFR4) inhibitor and then evaluated in the same way as in the first experiment.

Results

In the early stage of LVH without chronic kidney disease, serum FGF23 levels did not change but cardiac FGF23 expression significantly increased along with LVH progression. Moreover, serum aldosterone and cardiac ACE levels were significantly elevated, and cardiac ACE2 levels were significantly decreased. ACE inhibitor did not change serum FGF23 levels but significantly decreased cardiac FGF23 levels with improvements in LVH and RAAS-related factors, while FGFR4 inhibitor did not change the values.

Conclusions

Not serum FGF23 but cardiac FGF23 levels and RAAS parameters significantly changed in the early stage of LVH without chronic kidney disease. RAAS blockade might be more crucial than FGF23 blockade for preventing LVH progression in this condition.

Ambulatory blood pressure monitoring in children: A retrospective single-center study

OBJECTIVES

(1) Compare 24-hour ambulatory blood pressure monitoring (ABPM) diagnoses in a pediatric population with the new 2022 guidelines to the original diagnoses with the 2014 guidelines. (2) Determine whether findings of hypertension from ABPM could be predicted from prior patient data. (3) Determine whether ABPM readings could predict left ventricular mass index (LVMI) in patients who obtained an echocardiogram (ECHO).

STUDY DESIGN

Single-center retrospective study on patients referred to Pediatric Nephrology Clinic for evaluation of elevated blood pressure who underwent ABPM from 2015 to 2018. Predictions of hypertension were obtained using a logistic regression model, and predictions of LVMI were performed using regression models including (a) the wake systolic and diastolic BP indices, or (b) additionally including the standard deviation (SD) of wake SBP and DBP.

RESULTS

With the change in 2022 to new ABPM guidelines from the AHA, comparing the old and new guidelines led to 70% of previous pre-hypertensive diagnoses now meeting criteria for diagnosis of hypertension, and a rise from 21% of the ABPMs meeting criteria for hypertension to 51% now meeting criteria. In a logistic regression model, prior patient data were not predictive of a diagnosis of hypertension from ABPM (Nagelkerke's R ² = 0.04). Among the individual variables studied, none were statistically significant. For prediction of LVMI, the SD of wake SBP and DBP were significantly associated with increased LVMI, but the wake SBP and DBP indices were not.

CONCLUSIONS

In our patient population, the new ABPM guidelines led to a significant increase in diagnoses of hypertension. Prior patient data was not sufficient to predict a diagnosis of hypertension by ABPM, supporting the need for evaluation by ABPM as the gold standard. Our analysis of the relationship between ABPM readings and LVMI supports the hypothesis that BP variability contributes to increased LVMI. These data are consistent with growing evidence in the adult literature that BP variability detected by ABPM is associated with left-ventricular hypertrophy.

Comprehensive bioinformatics analysis identifies LAPTM5 as a potential blood biomarker for hypertensive patients with left ventricular hypertrophy

Left ventricular hypertrophy (LVH) is a pivotal manifestation of hypertensive organ damage associated with an increased cardiovascular risk. However, early diagnostic biomarkers for assessing LVH in patients with hypertension (HT) remain indefinite. Here, multiple bioinformatics tools combined with an experimental verification strategy were used to identify blood biomarkers for hypertensive LVH. GSE74144 mRNA expression profiles were downloaded from the Gene Expression Omnibus (GEO) database to screen candidate biomarkers, which were used to perform weighted gene co-expression network analysis (WGCNA) and establish the least absolute shrinkage and selection operator (LASSO) regression model, combined with support vector machine-recursive feature elimination (SVM-RFE) algorithms. Finally, the potential blood biomarkers were verified in an animal model. A total of 142 hub genes in peripheral blood leukocytes were identified between HT with LVH and HT without LVH, which were mainly involved in the ATP metabolic process, oxidative phosphorylation, and mitochondrial structure and function. Notably, lysosomal associated transmembrane protein 5 (LAPTM5) was identified as the potential diagnostic marker of hypertensive LVH, which showed strong correlations with diverse marker sets of reactive oxygen species (ROS) and autophagy. RT-PCR validation of blood samples and cardiac magnetic resonance imaging (CMRI) showed that the expression of LAPTM5 was significantly higher in the HT with LVH model than in normal controls, LAPTM5 demonstrated a positive association with the left ventricle wall thickness as well as electrocardiogram (ECG) parameters widths of the QRS complex and QTc interval. In conclusion, LAPTM5 may be a potential biomarker for the diagnosis of LVH in patients with HT, and it can provide new insights for future studies on the occurrence and the molecular mechanisms of hypertensive LVH.

Left Ventricular Hypertrophy in Diabetic Cardiomyopathy: A Target for Intervention

Heart failure is an important manifestation of diabetic heart disease. Before the development of symptomatic heart failure, as much as 50% of patients with type 2 diabetes mellitus (T2DM) develop asymptomatic left ventricular dysfunction including left ventricular hypertrophy (LVH). Left ventricular hypertrophy (LVH) is highly prevalent in patients with T2DM and is a strong predictor of adverse cardiovascular outcomes including heart failure. Importantly regression of LVH with antihypertensive treatment especially renin angiotensin system blockers reduces cardiovascular morbidity and mortality. However, this approach is only partially effective since LVH persists in 20% of patients with hypertension who attain target blood pressure, implicating the role of other potential mechanisms in the development of LVH. Moreover, the pathophysiology of LVH in T2DM remains unclear and is not fully explained by the hyperglycemia-associated cellular alterations. There is a growing body of evidence that supports the role of inflammation, oxidative stress, AMP-activated kinase (AMPK) and insulin resistance in mediating the development of LVH. The recognition of asymptomatic LVH may offer an opportune target for intervention with cardio-protective therapy in these at-risk patients. In this article, we provide a review of some of the key clinical studies that evaluated the effects of allopurinol, SGLT2 inhibitor and metformin in regressing LVH in patients with and without T2DM.

Left atrial dysfunction in patients with obstructive sleep apnea: a combined assessment by speckle tracking and real-time three-dimensional echocardiography

BACKGROUND

At present, little research concerning the assessment of left atrial (LA) dysfunction in patients with obstructive sleep apnea (OSA) using a combined assessment by speckle tracking (STE) and real-time three-dimensional echocardiography (RT3DE) is available. The objective of this study was to evaluate the LA volume and function by STE and RT3DE in patients with OSA.

METHODS

In our cohort study, ninety-two OSA patients and 50 healthy individuals were enrolled. According to the apnea hypopnea index (AHI), patients (AHI >15/h) classified as having moderate and severe OSA were included. The patients were divided into 2 subgroups according to the left ventricular mass index (LVMI): the left ventricular hypertrophy (LVH) group in which patients had LVH (n=30), and the nonLVH group in which patients did not have LVH (n=62). All subjects underwent LA function assessment by conventional techniques and the combination of STE and RT3DE.

RESULTS

OSA patients showed impaired LA global longitudinal strain during early diastole (LA S-E) and systole (LA S-S) but increased LA global longitudinal strain during late diastole (LA S-A) compared with controls (all P<0.05). In addition, OSA patients with LVH had lower LA S-S and LA S-E than patients without LVH (all P<0.05). With regard to parameters obtained from RT3DE, indexed LA maximum, minimum, and preatrial contraction volumes (LAVi-max, LAVi-min, LAVi-preA) and the LA active emptying fraction (LAAEF) were significantly higher, whereas the LA passive emptying fraction (LVPEF) was significantly lower in OSA patients in comparison with controls (all P<0.05). The LA total emptying fraction (LVTEF) and the LA expansion index were significantly lower in OSA patients with LVH than in controls (all P<0.05). Additionally, OSA patients with LVH had higher LAVi-min, LAVi-preA and LAAEVi but lower LAPEF than patients without LVH (all P<0.05).

CONCLUSIONS

OSA is associated with LA remodeling and dysfunction that occurs in the subclinical stage before the development of LVH and left ventricular diastolic dysfunction, and it will be further aggravated along with the development of LVH and OSA severity. The process can be detected with a detailed evaluation of active and passive functions of the LA using the STE and RT3DE method.

Characteristics of the Electrocardiogram in Japanese Fabry Patients Under Long-Term Enzyme Replacement Therapy

Objective: An electrocardiogram (ECG) is an important tool for demonstrating cardiac manifestations in various heart diseases. The present study clarified the characteristics of ECG parameters in Japanese Fabry patients under long-term enzyme replacement therapy (ERT).

Methods: We analyzed the ECGs of 40 Fabry patients (male, n = 17; female, n = 23) before and after treatment with ERT. To evaluate the atrio-ventricular conduction, the PQ interval, corrected PQ and PQ minus P-wave in lead II (Pend-Q) were calculated. The QRS duration, QTc, Sokolow-Lyon index, and strain pattern were also examined.

Results: At the baseline, the shortening of the PQ interval, corrected PQ and Pend-Q was identified in 7.5, 25.0, and 47.5% of cases, respectively. The prolongation of QRS duration and QTc was found in 7.5 and 40.0% of cases, respectively. The strain pattern was mainly identified in female patients, irrespective of left ventricular hypertrophy (LVH). During long-term ERT, the PQ interval, corrected PQ and Pend-Q did not change significantly. The QRS duration was significantly prolonged in both genders, whereas the QTc was significantly prolonged only in male patients. A subgroup analysis revealed that the prolongation of the QRS duration and QTc only occurred in male patients with LVH and only occurred in female patients with the classical type mutation. The prevalence of the strain was significantly increased only in male patients with LVH.

Conclusions: These results suggest that the shortening of the Pend-Q is a specific finding in Japanese Fabry patients, and the strain pattern without LVH in female patients can be considered Fabry disease. During long-term ERT, prolongation of the QRS duration and QTc can indicate the progression of myocardial damage in male patients with LVH and in female patients with the classical type mutation.

Social Determinants of Cardiovascular Health in African American Children With CKD: An Analysis of the Chronic Kidney Disease in Children (CKiD) Study

RATIONALE & OBJECTIVE

To identify differences in socioeconomic factors (SES) and subclinical cardiovascular disease (CVD) markers by race among Chronic Kidney Disease in Children (CKiD) participants and determine whether differences in CVD markers persist after adjusting for SES.

STUDY DESIGN

Analysis of 3,103 visits with repeated measures from 628 children (497 White participants; 131 African American participants) enrolled in the CKiD study.

SETTING & PARTICIPANTS

Children with mild-moderate CKD with at least 1 cardiovascular (CV) parameter (ambulatory blood pressure, left ventricular mass index [LVMI], or lipid profile) measured.

EXPOSURE

African American race.

OUTCOMES

Ambulatory hypertension, LVMI, triglycerides, high-density lipoprotein cholesterol.

ANALYTICAL APPROACH

Due to increased CV risks of glomerular disease, the analysis was stratified by CKD cause. Inverse probability weighting was used to adjust for SES (health insurance, household income, maternal education, food insecurity, abnormal birth history). Linear and logistic regression were used to evaluate association of race with CV markers.

RESULTS

African American children were disproportionately affected by adverse SES. African Americans with nonglomerular CKD had more instances of ambulatory hypertension and higher LVMI but more favorable lipid profiles. After adjustment for SES, age, and sex, the magnitude of differences in these CV markers was attenuated but remained statistically significant. Only LVMI differed by race in the glomerular CKD group, despite adjustment for SES.

LIMITATIONS

Study design limits causal inference.

CONCLUSION

African American children with CKD are disproportionately affected by socioeconomic disadvantages compared with White children. The degree to which CV markers differ by race is influenced by disease etiology. African Americans with nonglomerular CKD have increased LVMI, more ambulatory hypertension, and favorable lipid profile, but attenuation in magnitude after adjustment for SES was observed. African Americans with glomerular CKD had increased LVMI, which persisted after SES adjustment. As many social determinants of health were not captured, future research should examine effects of systemic racism on CV health in this population.

Hemodynamic and Non-Hemodynamic Components of Cardiac Remodeling in Primary Aldosteronism

OBJECTIVES

Patients with primary aldosteronism (PA) have cardiac remodeling due to hemodynamic and non-hemodynamic causes. However, component analysis of cardiac remodeling and reversal in PA patients is lacking. We investigated components of cardiac remodeling and reversal after adrenalectomy in patients with aldosterone-producing adenoma (APA).

METHODS

This study prospectively enrolled 304 APA patients who received adrenalectomy and 271 with essential hypertension (EH). Clinical, biochemical and echocardiographic data were collected in both groups and 1 year after surgery in the APA patients. The hemodynamic and non-hemodynamic components of left ventricular (LV) remodeling were represented by predicted left ventricular mass index (LVMI) (pLVMI) and inappropriately excessive LVMI (ieLVMI, defined as LVMI-pLVMI).

RESULTS

After propensity score matching, 213 APA and 213 EH patients were selected. APA patients had higher hemodynamic (pLVMI) and non-hemodynamic (ieLVMI) components of LV remodeling than EH patients. In multivariate analysis, baseline pLVMI was correlated with systolic blood pressure (SBP) and serum potassium, whereas ieLVMI was correlated with log plasma aldosterone concentration but not blood pressure. Post-operative echocardiography was available in 207 patents and showed significant decreases in both pLVMI and ieLVMI after adrenalectomy. In multivariate analysis, ΔpLVMI was correlated with SBP, ΔSBP, and pre-operative pLVMI, whereas ΔieLVMI was correlated with Δlog aldosterone-to-renin ratio (ARR) and pre-operative ieLVMI.

CONCLUSIONS

This study concluded that extensive cardiac remodeling in APA patients occurs through hemodynamic and non-hemodynamic causes. Adrenalectomy can improve both hemodynamic and non-hemodynamic components of LV remodeling. Regressions of pLVMI and ieLVMI were correlated with decreases in blood pressure and ARR, respectively.

Adiposity, Sex, and Cardiovascular Disease Risk in Children With CKD: A Longitudinal Study of Youth Enrolled in the Chronic Kidney Disease in Children (CKiD) Study

RATIONALE & OBJECTIVE

Traditional and nontraditional cardiovascular disease risk factors are highly prevalent in children with chronic kidney disease (CKD). We examined the longitudinal association of adiposity with cardiac damage among children with CKD and explored whether this association was modified by sex.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Children with mild-to-moderate CKD enrolled in the Chronic Kidney Disease in Children (CKiD) Study at 49 pediatric nephrology centers across North America.

EXPOSURE

Age- and sex-specific body mass index (BMI) z score.

OUTCOME

Age- and sex-specific left ventricular mass index (LVMI) z score and left ventricular hypertrophy (LVH).

ANALYTICAL APPROACH

Longitudinal analyses using mixed-effects models to estimate sex-specific associations of BMI z scores with LVMI z score and with LVH, accounting for repeated measurements over time.

RESULTS

Among 725 children with 2,829 person-years of follow-up, median age was 11.0 years and median estimated glomerular filtration rate was 52.6mL/min/1.73m2. Nearly one-third of both boys and girls were overweight or obese, median LVMI z score was 0.18 (IQR: -0.67, 1.08), and 11% had LVH. Greater BMI z scores were independently associated with greater LVMI z scores and greater odds of LVH. For each 1-unit higher BMI z score, LVMI z score was 0.24 (95% CI, 0.17-0.31) higher in boys and 0.38 (95% CI, 0.29-0.47) higher in girls (Pinteraction = 0.01). For each 1-unit higher BMI z score, the odds of LVH was 1.5-fold (95% CI, 1.1-2.1) higher in boys and 3.1-fold (95% CI, 1.8-4.4) higher in girls (Pinteraction = 0.005).

LIMITATIONS

Not all children had repeated measurements. LVH is a surrogate and not a hard cardiac outcome. The observational design limits causal inference.

CONCLUSIONS

In children, adiposity is independently associated with the markers of cardiac damage, LVMI z score and LVH. This association is stronger among girls than boys. Pediatric overweight and obesity may therefore have a substantial impact on cardiovascular risk among children with CKD.

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA), previously known as senile cardiac amyloidosis: clinical presentation, diagnosis, management and emerging therapies

Cardiac amyloidosis is thought to be a rare group of diseases caused by extracellular deposition of misfolded proteins in the extracellular cardiac matrix resulting in heart failure with preserved ejection fraction (HFpEF). This review focuses on the similarities and differences between the pathophysiology, clinical presentation and diagnostic tests of wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) compared to immunoglobulin light chain amyloidosis and hereditary cardiac amyloidosis. We address some obstacles to timely diagnosis and opportunities for management of the clinical symptoms as well as possibility of future novel disease modifying therapies.

A comparison of Cornell and Sokolow-Lyon electrocardiographic criteria for left ventricular hypertrophy in a military male population in Taiwan: the Cardiorespiratory fitness and HospItalization Events in armed Forces study

BACKGROUND

The Cornell and Sokolow-Lyon electrocardiography (ECG) criteria have been widely used for diagnosing left ventricular hypertrophy (LVH) in patients with hypertension. However, the correlations of these ECG criteria with LVH were rarely compared in military members who received rigorous training, particularly of the Asian male population.

METHODS

We compared the Cornell voltage and product criteria with the Sokolow-Lyon criteria for the echocardiographic LVH in 539 military male members, ages 18-50 years and free of hypertension in the Cardiorespiratory fitness and HospItalization Events in armed Forces (CHIEF) study in Taiwan. Pearson's correlation coefficient was used to determine the association of each ECG criterion with the index of left ventricular mass (LVM, g)/height (m)^2.7. The sensitivities and specificities were estimated using a receiver-operating characteristics (ROC) curve in relation to the echocardiographic LVH which was defined as LVM index ≥49 g/m^2.7.

RESULTS

The correlations of the Cornell voltage and product criteria (r=0.24 and 0.26 respectively, both P<0.0001) were stronger than that of the Sokolow-Lyon criteria (r=0.049 and 0.095, and P=0.26 and 0.03 respectively) with the LVM index. Similarly the performances of the Cornell voltage and product criteria for the echocardiographic LVH [area under curve (AUC): 0.66 and 0.68, both P<0.0001] were superior to that of the Sokolow-Lyon criteria (AUC: 0.54 and 0.53, both P>0.1) in the area under the ROC curve analysis.

CONCLUSIONS

The Cornell ECG criteria for the echocardiographic LVH had better performance than the Sokolow-Lyon criteria in a young military male cohort in Taiwan.

Cystatin C and Cardiac Measures in Children and Adolescents With CKD

BACKGROUND

Cardiovascular disease (CVD) is highly prevalent among children with chronic kidney disease (CKD). Cystatin C is an established marker of kidney function and an emerging biomarker for CVD events. We quantified the relationship between cystatin C level and cardiac structure and function over time among children with CKD and assessed whether cystatin C level and diastolic function retained an association after accounting for kidney function.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

678 children and adolescents with mild to moderate CKD enrolled in the CKD in Children (CKiD) Study with 1,228 echocardiographically obtained cardiac structure and function measurements.

PREDICTOR

Serum cystatin C (mg/L) measured annually.

OUTCOMES

Cardiac structure (left ventricular mass index [g/m^2.7]) and cardiac function (shortening fraction; E/A, E'/A', E/E' ratios) measured every other year.

MEASUREMENTS

Demographics and anthropometrics, measured glomerular filtration rate (mGFR), heart rate, blood pressure, hemoglobin z score, serum albumin level, and calcium-phosphorus product.

RESULTS

Independent of time, each 1-mg/L increase in cystatin C level was independently associated with a concurrent 7.7% (95% CI, 5.3%-10.0%) increase in left ventricular mass index, a -4.7% (95% CI, -7.0% to -2.4%) change in E/A ratio, a -6.6% (95% CI, -9.0% to -4.2%) change in E'/A' ratio, and a 2.5% (95% CI, 0.3%-4.7%) increase in E/E' ratio. mGFR was also independently associated with E'/A' ratio. When cystatin C level and mGFR were included in the same model, cystatin C level remained independently associated with E'/A' ratio, whereas mGFR was not.

LIMITATIONS

24% of the cohort was missing data for outcomes of interest or measurements; study population includes only children and adolescents with mild to moderate CKD.

CONCLUSIONS

In this study of children and adolescents with mild to moderate CKD, cystatin C level was independently associated with cardiac structure and diastolic function. Cystatin C level remained able to predict diastolic function decline via E'/A' ratio even after adjusting for mGFR, suggesting that cystatin C level may have an independent role in CVD risk stratification among children and adolescents with CKD.

Estimated GFR and Subsequent Higher Left Ventricular Mass in Young and Middle-Aged Adults With Normal Kidney Function: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Left ventricular hypertrophy is common and is associated with cardiovascular events and death among patients with known chronic kidney disease. However, the link between reduced glomerular filtration rate (GFR) and left ventricular mass index (LVMI) remains poorly explored among young and middle-aged adults with preserved kidney function. In this study, we examined the association of cystatin C-based estimated GFR (eGFRcys) and rapid decline in eGFR with subsequent LVMI.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

We included 2,410 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort with eGFRcys > 60mL/min/1.73m(2) at year 15 and who had an echocardiogram obtained at year 25.

PREDICTOR

eGFRcys at year 15 and rapid decline in eGFRcys (defined as >3% per year over 5 years from years 15 to 20).

OUTCOME

LVMI measured at year 25.

MEASUREMENTS

We adjusted for age, sex, race, diabetes, body mass index, low- and high-density lipoprotein cholesterol levels, cumulative systolic blood pressure, and albuminuria.

RESULTS

Mean age was 40±4 (SD) years, 58% were women, and 43% were black. After 10 years of follow-up, mean LVMI was 39.6±13.4g/m(2.7). Compared with eGFRcys > 90mL/min/1.73m(2) (n = 2,228), eGFRcys of 60 to 75mL/min/1.73m(2) (n = 29) was associated with 5.63 (95% CI, 0.90-10.36) g/m(2.7) greater LVMI (P = 0.02), but there was no association of eGFRcys of 76 to 90mL/min/1.73m(2) (n = 153) with LVMI after adjustment for confounders. Rapid decline in eGFRcys was associated with higher LVMI compared with participants without a rapid eGFRcys decline (β coefficient, 1.48; 95% CI, 0.11-2.83; P = 0.03) after adjustment for confounders.

LIMITATIONS

There were a limited number of participants with eGFRcys of 60 to 90mL/min/1.73m(2).

CONCLUSIONS

Among young and middle-aged adults with preserved kidney function, eGFRcys of 60 to 75mL/min/1.73m(2) and rapid decline in eGFRcys were significantly associated with subsequently higher LVMI. Further studies are needed to understand the mechanisms that contribute to elevated LVMI in this range of eGFRcys.

Levocarnitine Improves Cardiac Function in Hemodialysis Patients With Left Ventricular Hypertrophy: A Randomized Controlled Trial

BACKGROUND

Levocarnitine deficiency in hemodialysis patients is common. Although the effect of levocarnitine therapy on uremic anemia has been studied in small trials, its effects on cardiac function remain unclear.

STUDY DESIGN

Multicenter, prospective, open-label, parallel, randomized, controlled trial.

SETTING & PARTICIPANTS

Patients undergoing maintenance hemodialysis with carnitine deficiency (free carnitine plasma concentration < 40μmol/L) enrolled in 3 hemodialysis centers.

INTERVENTION

Random assignment to treatment for 12 months with oral levocarnitine therapy at a dose of 20mg/kg/d or control group (no levocarnitine therapy).

OUTCOMES & MEASUREMENTS

Cardiac function was assessed by echocardiography. The primary end point was change in ejection fraction from baseline at the end of the study. Secondary end points included changes in left ventricular mass index and clinical parameters from baseline at the end of the study.

RESULTS

222 patients were randomly assigned, of whom 148 patients (levocarnitine group, n=75; control group, n=73) were analyzed. Ejection fraction increased from baseline to the end of the study in the levocarnitine group by 5.43% (95% CI, 4.53%-6.32%), but not in the control group (change, -0.14%; between-group difference, 5.57% [95% CI, 4.48%-6.66%]; P<0.001). Left ventricular mass index decreased from baseline to the end of the study in the levocarnitine group (change of -8.89 [95% CI, -11.7 to -6.09] g/m(2)), but not in the control group (change of 1.62g/m(2); between-group difference, 10.50 [95% CI, 7.51 to 13.60] g/m(2); P<0.001). Levocarnitine therapy reduced N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and improved the erythropoietin responsiveness index, whereas no such effects were observed in the control group.

LIMITATIONS

Not a double-blinded study.

CONCLUSIONS

Levocarnitine therapy is useful for hemodialysis patients with carnitine deficiency; these patients may benefit from such therapy, with amelioration of cardiac function and reduction of left ventricular mass index.

Role of ubiquitin-proteasome system (UPS) in left ventricular hypertrophy (LVH)

Cardiac hypertrophy is a key compensatory mechanism acting in response to pressure or volume overload, involving some alterations in signaling transduction pathways and transcription factors-regulation. These changes result in enhanced proteins' synthesis leading to Left Ventricular Hypertrophy (LVH). It is known that the main function of Ubiquitin-Proteasome System (UPS) is to prevent accumulation of damaged, misfolded and mutant proteins by proteolysis. But emerging evidences suggest that UPS also attends to the cells' growth, favoring proteins' synthesis, subsequently evolving in LVH. The role of the proteasome in to favor cellular hypertrophy consists in upregulation of the catalytic proteasome subunit, with prevalence of proteins-synthesis on proteins degradation. It is also evident that UPS inhibition may prevent cells' growth opposing to the hypertrophy. In fact in several experimental models, UPS inhibition demonstrated to be able to prevent or reverse cardiac hypertrophy induced by abdominal aortic banding (AAB). That can happen with several proteasome inhibitors acting by multifactorial mechanisms. These evidences induce to hypothesize that, in the future, in patients with the increased volume overload by systemic hypertension, some proteasome-inhibitors could be used to antagonize or prevent LVH without reducing peripheral high blood pressure levels too.