Premature cardiovascular disease in chronic renal failure (CRF): A model for an advanced ageing process

Statins in Chronic Kidney Disease-Effects on Atherosclerosis and Cellular Senescence

Chronic kidney disease (CKD) is a serious health problem that can affect various systems in the human body. Renal failure promotes mechanisms of premature cellular aging and also features of generalized inflammation in the body, which translates into a close relationship between kidney dysfunction and cardiovascular disease (CVD). As kidney function deteriorates, cardiovascular risk and mortality increase in this group of patients. Oxidative stress and inflammation are two closely related processes that initiate a vicious cycle by activating each other. Together with aging, they represent the key factors that cause and exacerbate CVD in CKD. Patients with CKD are particularly vulnerable to the accumulation of aging endothelial cells, vascular smooth muscle and macrophages, increasing the risk of atherosclerosis. Several mechanisms are known that can lead to the progression of the aforementioned problems, such as the accumulation of uremic toxins, persistent inflammation, impaired lipid and electrolyte metabolism, nitric oxide (NO) deficiency, the increased production of reactive oxygen species (ROS) and damage to deoxyribonucleic acid (DNA) and mitochondria. According to research, we can distinguish a group of drugs that effectively counteract the negative effects of CKD-statins. This is a group of drugs that inhibit 3-hydroxy-3-methylglutaryl-coenzyme-A (HMG-CoA) reductase and affect a number of cellular processes and pathways, resulting in the overall slowing of atherosclerosis and cellular aging.

Coenzyme Q10: Clinical Applications in Cardiovascular Diseases

Coenzyme Q₁₀ (CoQ₁₀) is a ubiquitous factor present in cell membranes and mitochondria, both in its reduced (ubiquinol) and oxidized (ubiquinone) forms. Its levels are high in organs with high metabolism such as the heart, kidneys, and liver because it acts as an energy transfer molecule but could be reduced by aging, genetic factors, drugs (e.g., statins), cardiovascular (CV) diseases, degenerative muscle disorders, and neurodegenerative diseases. As CoQ₁₀ is endowed with significant antioxidant and anti-inflammatory features, useful to prevent free radical-induced damage and inflammatory signaling pathway activation, its depletion results in exacerbation of inflammatory processes. Therefore, exogenous CoQ₁₀ supplementation might be useful as an adjuvant in the treatment of cardiovascular diseases such as heart failure, atrial fibrillation, and myocardial infarction and in associated risk factors such as hypertension, insulin resistance, dyslipidemias, and obesity. This review aims to summarize the current evidences on the use of CoQ₁₀ supplementation as a therapeutic approach in cardiovascular diseases through the analysis of its clinical impact on patients' health and quality of life. A substantial reduction of inflammatory and oxidative stress markers has been observed in several randomized clinical trials (RCTs) focused on several of the abovementioned diseases, even if more RCTs, involving a larger number of patients, will be necessary to strengthen these interesting findings.

Klotho: A Major Shareholder in Vascular Aging Enterprises

Accelerated vascular aging is a condition that occurs as a complication of several highly prevalent inflammatory conditions such as chronic kidney disease, cancer, HIV infection and diabetes. Age-associated vascular alterations underlie a continuum of expression toward clinically overt cardiovascular disease. This has contributed to the striking epidemiologic transition whereby such noncommunicable diseases have taken center stage as modern-day global epidemics and public health problems. The identification of α-Klotho, a remarkable protein that confers powerful anti-aging properties has stimulated significant interest. In fact, emerging data have provided fundamental rationale for Klotho-based therapeutic intervention for vascular diseases and multiple other potential indications. However, the application of such discoveries in Klotho research remains fragmented due to significant gaps in our molecular understanding of Klotho biology, as well as hurdles in clinical research and experimental barriers that must first be overcome. These advances will be critical to establish the scientific platform from which future Klotho-based interventional trials and therapeutic enterprises can be successfully launched.

Early Vascular Ageing and Cellular Senescence in Chronic Kidney Disease

Chronic kidney disease (CKD) is a clinical model of premature ageing characterized by progressive vascular disease, systemic inflammation, muscle wasting and frailty. The predominant early vascular ageing (EVA) process mediated by medial vascular calcification (VC) results in a marked discrepancy between chronological and biological vascular age in CKD. Though the exact underlying mechanisms of VC and EVA are not fully elucidated, accumulating evidence indicates that cellular senescence - and subsequent chronic inflammation through the senescence-associated secretary phenotype (SASP) - plays a fundamental role in its initiation and progression. In this review, we discuss the pathophysiological links between senescence and the EVA process in CKD, with focus on cellular senescence and media VC, and potential anti-ageing therapeutic strategies of senolytic drugs targeting cellular senescence and EVA in CKD.

Markers of endothelial damage in patients with chronic kidney disease on hemodialysis

Patients with Stage 5 chronic kidney disease who are on hemodialysis (HD) remain in a chronic inflammatory state, characterized by the accumulation of uremic toxins that induce endothelial damage and cardiovascular disease (CVD). Our aim was to examine microvesicles (MVs), monocyte subpopulations, and angiopoietins (Ang) to identify prognostic markers in HD patients with or without diabetes mellitus (DM). A total of 160 prevalent HD patients from 10 centers across Spain were obtained from the Biobank of the Nephrology Renal Network (Madrid, Spain): 80 patients with DM and 80 patients without DM who were matched for clinical and demographic criteria. MVs from plasma and several monocyte subpopulations (CD14²⁺/CD16⁺, CD14⁺/CD16²⁺) were analyzed by flow cytometry, and the plasma concentrations of Ang1 and Ang2 were quantified by ELISA. Data on CVD were gathered over the 5.5 yr after these samples were obtained. MV level, monocyte subpopulations (CD14⁺/CD16²⁺ and CD14²⁺/CD16⁺), and Ang2-to-Ang1 ratios increased in HD patients with DM compared with non-DM patients. Moreover, MV level above the median (264 MVs/µl) was associated independently with greater mortality. MVs, monocyte subpopulations, and Ang2-to-Ang1 ratio can be used as predictors for CVD. In addition, MV level has a potential predictive value in the prevention of CVD in HD patients. These parameters undergo more extensive changes in patients with DM.

Mechanisms of vascular calcification in CKD-evidence for premature ageing?

Ageing is a potent, independent risk factor for cardiovascular disease. Calcification of the vascular smooth muscle cell (VSMC) layer of the vessel media is a hallmark of vascular ageing. Young patients with chronic kidney disease (CKD) exhibit an extremely high cardiovascular mortality, equivalent to that seen in octogenarians in the general population. Even children on dialysis develop accelerated medial vascular calcification and arterial stiffening, leading to the suggestion that patients with CKD exhibit a 'premature ageing' phenotype. It is now well documented that uraemic toxins, particularly those associated with dysregulated mineral metabolism, can drive VSMC damage and phenotypic changes that promote vascular calcification; epidemiological data suggest that some of these same risk factors associate with cardiovascular mortality in the aged general population. Importantly, emerging evidence suggests that uraemic toxins may promote DNA damage, a key factor driving cellular ageing, and moreover, that these ageing mechanisms may reiterate some of those seen in patients with genetically induced progeric syndromes caused by nuclear lamina disruption. This new knowledge should pave the way for the development of novel therapies that target tissue-specific ageing mechanisms to treat vascular decline in CKD.

Age ≥ 60 years was an independent risk factor for diabetes-related complications despite good control of cardiovascular risk factors in patients with type 2 diabetes mellitus

Providing effective medical care for older patients with type 2 diabetes mellitus (T2D) that may contribute to their active aging has always been challenging. We examined the independent effect of age ≥ 60 years on disease control and its relationship with diabetes-related complications in patients with T2D in Malaysia. This was a cross-sectional study using secondary data from the electronic diabetes registry database Adult Diabetes Control and Management (ADCM). A total of 303 centers participated and contributed a total of 70,889 patients from May 2008 to the end of 2009. Demographic data, details on diabetes, hypertension, dyslipidemia and their treatment modalities, various risk factors and complications were updated annually. Independent associated risk factors were identified using multivariate regression analyses. Fifty-nine percent were female. Malay comprised 61.9%, Chinese 19% and Indian 18%. There were more Chinese, men, longer duration of diabetes and subjects that were leaner or had lower BMI in the older age group. Patients aged ≥ 60 years achieved glycemic and lipid targets but not the desired blood pressure. After adjusting for duration of diabetes, gender, ethnicity, body mass index, disease control and treatment, a significantly higher proportion of patients ≥ 60 years suffered from reported diabetes-related complications. Age ≥ 60 years was an independent risk factor for diabetes-related complications despite good control of cardiovascular risk factors. Our findings caution against the currently recommended control of targets in older T2D patients with more longstanding diseases and complications.

Chronic kidney disease: a clinical model of premature aging

Premature aging is a process associated with a progressive accumulation of deleterious changes over time, an impairment of physiologic functions, and an increase in the risk of disease and death. Regardless of genetic background, aging can be accelerated by the lifestyle choices and environmental conditions to which our genes are exposed. Chronic kidney disease is a common condition that promotes cellular senescence and premature aging through toxic alterations in the internal milieu. This occurs through several mechanisms, including DNA and mitochondria damage, increased reactive oxygen species generation, persistent inflammation, stem cell exhaustion, phosphate toxicity, decreased klotho expression, and telomere attrition. Because recent evidence suggests that both increased local signaling of growth factors (through the nutrient-sensing mammalian target of rapamycin) and decreased klotho expression are important modulators of aging, interventions that target these should be tested in this prematurely aged population.

Out of control: accelerated aging in uremia

Next to a high morbidity, patients with end-stage renal failure (ESRD) suffer from a complex spectrum of clinical manifestations. Both the phenotype of patients with ESRD as well as the pathophysiology of uremia show interesting parallels with the general aging process. Phenotypically, patients with ESRD have an increased susceptibility for both cardiovascular as well as infectious disease and show a reduction in functional capacity as well as muscular mass (sarcopenia), translating into a high prevalence of frailty also in younger patients. Pathophysiologically, the immune dysfunction, telomere attrition and the presence of low-grade inflammation in uremic patients also show parallels with the aging process. System models of aging, such as the homeodynamic model and reliability theory of Gavrilov may also have relevance for ESRD. The reduction in the redundancy of compensatory mechanisms and the multisystem impairment in ESRD explain the rapid loss of homeodynamic/homeostatic balance and the increased susceptibility to external stressors in these patients. System theories may also explain the relative lack of success of interventions focusing on single aspects of renal disease. The concept of accelerated aging, which also shares similarities with other organ diseases, may be of relevance both for a better understanding of the uremic process, as well as for the design of multidimensional interventions in ESRD patients, including an important role for early rehabilitation. Research into processes akin to both aging and uremia may result in novel therapeutic approaches.

'Time and time again': oscillatory and longitudinal time patterns in dialysis patients

Oscillatory and longitudinal time patterns play a major role in human physiology. In chronic hemodialysis patients, abnormalities in both time patterns have been observed, while time patterns can also influence the response of patients to the treatment. Abnormal oscillatory patterns have been observed for ultradian rhythms (cycle time <20 h), such as an impaired heart rate variability and circadian rhythms, as reflected by reduced day-night blood pressure differences. Conversely, the circadian rhythm of body temperature may influence the hemodynamic tolerance to the dialysis treatment. With regard to infradian (cycle time >28 h) rhythms, large seasonal differences in mortality, but also in blood pressure and interdialytic weight gain, have been observed in dialysis patients. The most important longitudinal pattern is the general reduction of life span in dialysis patients. One explanation of this phenomenon relates to the concept of accelerated aging in dialysis patients, for which there are various supportive arguments. From a phenomenological point of view, this concept translates into the high prevalence of frailty, even in young dialysis patients. A multidimensional approach appears necessary to adequately address this problem. In this review, the relevance of disturbed time patterns in dialysis patients is discussed. The changes may reflect an impairment or reduction in homeostatic/homeodynamic control in dialysis patients and also may have important prognostic and therapeutic implications.

Cardiovascular Biomarkers in Chronic Kidney Disease

Cardiovascular morbidity and mortality are markedly increased in chronic renal failure patients. Although it cannot be regarded as a cardiovascular disease risk equivalent, kidney dysfunction is considered an independent predictor of increased cardiovascular risk that increases with deteriorating kidney function. The association is a very complex one, and the term cardiorenal syndrome is now widely used. Cardiovascular disease in chronic kidney disease patients usually manifests as ischemic heart disease (in the form of angina, acute coronary syndrome or sudden cardiac death), cerebrovascular disease, peripheral vascular disease, and congestive heart failure. Vascular disease includes atherosclerosis and vascular calcifications, and cardiomyopathy comprises left ventricular hypertrophy, cardiac fibrosis and left ventricular systolic and diastolic dysfunction. In addition to the well-established traditional risk factors such as hypertension, hyperlipidemia, insulin resistance and diabetes mellitus, the association is supported by synergistic action of non-traditional risk factors such as excessive calcium-phosphorus load, hyperparathyroidism, anemia, hemodynamic overload, malnutrition, inflammation, hyperhomocysteinemia, altered nitric oxide synthase and increased oxidative stress. This paper summarizes the current understanding of the significance of specific uremic retention solutes, natriuretic peptides, biochemical markers of disorders in calcium-phosphorus homeostasis, systemic inflammation, oxidative stress, and dyslipidemia.