Proximal tubule hypertrophy and hyperfunction: a novel pathophysiological feature in disease states.

The role of proximal tubules (PTs), a major component of the renal tubular structure in the renal cortex, has been examined extensively. Along with its physiological role in the reabsorption of various molecules, including electrolytes, amino acids and monosaccharides, transcellular transport of different hormones and regulation of homeostasis, pathological events affecting PTs may underlie multiple disease states. PT hypertrophy or a hyperfunctioning state, despite being a compensatory mechanism at first in response to various stimuli or alterations at tubular transport proteins, have been shown to be critical pathophysiological events leading to multiple disorders, including diabetes mellitus, obesity, metabolic syndrome and congestive heart failure. Moreover, pharmacotherapeutic agents have primarily targeted PTs, including sodium-glucose cotransporter 2, urate transporters and carbonic anhydrase enzymes. In this narrative review, we focus on the physiological role of PTs in healthy states and the current understanding of the PT pathologies leading to disease states and potential therapeutic targets.

Physical exercise in haemodialysis patients: which type of exercise is more convenient?

Randomized intra-haemodialysis and home-based exercise trials have demonstrated similar efficacy in improving physical performance, particularly in increasing walking distance. During dialysis sessions, patients can engage in structured, supervised activities such as cycling or resistance exercises, ensuring safety and immediate feedback from healthcare professionals. This structured nature can significantly enhance adherence, making exercise a regular part of the patient's treatment schedule. Home-based exercise offers flexibility and convenience. Patients can incorporate activities like walking, stretching or using resistance bands into their daily lives. This flexibility allows patients to exercise at their own pace and according to their preferences, fostering independence and self-management. By continuing physical activity at home, patients can maintain continuity in their exercise regimen, which is crucial for long-term health benefits. Combining both intra-haemodialysis and home-based exercises has the potential to improve overall adherence to exercise programs. Strategies such as patient education, customized plans, monitoring and feedback, and support systems can help combine these two exercise types. By integrating these two modalities, healthcare providers can create a comprehensive and balanced exercise regimen that enhances adherence, promotes independence and maximizes health benefits for dialysis patients, fostering long-term health and well-being through sustained physical activity. However, this dual approach, which caters to both the need for medical supervision and the desire for personal autonomy, has yet to be tested in randomized trials.

Plasma levels of myeloperoxidase and resistin independently predict mortality in dialysis patients.

BACKGROUND: In patients with kidney failure (KF) undergoing dialysis, neutrophils are dysfunctionally activated. Such chronic activation does not correspond to increased protection against infections and is thought to cause direct vascular damage accounting for the higher incidence of cardiovascular (CV) events. We hypothesized that circulating levels of neutrophil degranulation products (i.e. myeloperoxidase (MPO) and resistin) can predict overall and CV-specific mortality in dialysis patients. METHODS: MPO and resistin levels were assessed in plasma samples from n = 1182 dialysis patients who were followed-up for median 2.9 years (IQR: 1.7-4.2). RESULTS: Patients were 65 ± 14 (SD) years old and 36 % women. Median value of MPO and resistin were 78 ng/mL (IQR: 54 - 123) and 72 ng/mL (IQR: 46 - 110), respectively. MPO and resistin levels correlated with biomarkers of organ damage, nutritional status and inflammation. Both MPO and resistin levels predicted all-cause mortality even after adjustment for traditional risk factors and inflammation, nutritional and KF-related indexes (MPO, HRfor 1 ln unit increase: 1.26, 95 %CI 1.11 - 1.42, P < 0.001; Resistin, HRfor 1 ln unit increase: 1.25, 95 %CI 1.09 - 1.44, P = 0.001). Similarly, their predictive ability held true also for CV death (MPO, HRfor 1 ln unit increase: 1.19, 95 %CI 1.01 - 1.41, P = 0.04; Resistin, HRfor 1 ln unit increase: 1.29, 95 %CI 1.07 - 1.56, P = 0.007). CONCLUSION: Plasma levels of MPO and resistin correlate with prospective overall and CV-specific mortality risk in KF patients undergoing dialysis and might be useful prognostic tools. Mediators of inflammation may be potential target to improve survival of those patients.

When impact trials are not feasible: alternatives to study the impact of prediction models on clinical practice.

Patients with kidney disease have an uncertain future with prognosis varying greatly per patient. To get a better idea of what the future holds and tailor interventions to the individual patient, prediction models can be of great value. Before a prediction model can be applied in practice, its performance should be measured in target populations of interest (i.e., external validation) and whether it helps improve clinical practice (i.e., whether it impacts clinical practice) should be determined. The impact would ideally be determined using an impact trial, but such a trial is often not feasible, and the impact of prediction models is therefore rarely assessed. As a result, prediction models that may not be so impactful may end up in clinical practice and impactful models may not be implemented due to a lack of impact studies. Ultimately, many prediction models end up never being implemented, resulting in much research waste. To allow researchers to get an indication of a prediction model's impact on clinical practice, alternative methods to assess a prediction model's impact are important. In this paper, we discuss several alternatives, including interviews, case-based surveys, decision comparisons, outcome modelling, before-after analyses, and decision curve analyses. We discuss the general idea behind these approaches, including what information can be gathered from such studies and important pitfalls. Lastly, we provide examples of the different alternatives.

Antihypertensive drug treatment and the risk for intra-hemodialysis hypotension.

BACKGROUND: Antihypertensive medications are often prescribed to manage hypertension in hemodialysis (HD) patients, and intradialytic hypotension (IDH) is a common complication in these patients. We investigated the risk of IDH in incident HD patients who initiated treatment with antihypertensive drugs in monotherapy. METHODS: The study was conducted as an emulation of a randomized clinical trial in 4072 incident HD patients who started anti-hypertensive drug treatment between January 2016 to December 2019. The primary outcome was the occurrence of IDH during HD sessions. The Gener alised Estimating Equation (GEE) analysis was adjusted by inverse probability treatment weighting (IPTW). RESULTS: Calcium channel blocker (CCB) use was associated with an IDH incidence rate of 7.4 events per person-year (95% CI: 6.2-8.6). Compared to CCB use, use of beta and alpha-beta blockers was strongly associated with a higher likelihood of IDH (OR [95% CI] 2.27 [1.50-3.43]). Use of angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (OR [95% CI] 1.71 [1.14-2.57]) and diuretics (OR [95% CI] 1.52 [1.07-2.16]) were also associated with higher likelihood of IDH compared to CCB use. CONCLUSION: The study suggests that using beta and alpha-beta blockers, ACE inhibitors or angiotensin II receptor blockers, and diuretics may increase the risk of IDH in HD patients compared to CCB use.

Impact of COVID-19 vaccines in patients on hemodialysis: an Italian multicentre cohort study.

BACKGROUND: The aim of this study was to evaluate the impact on the national health system of COVID-19 infection in vaccinated patients undergoing haemodialysis. METHODS: From the cohort of vaccinated dialysis patients enrolled in 118 dialysis centres, we calculated hospitalisation incidence in COVID-19-infected subjects. COVID-19-related hospitalisations and ICU admissions were analysed over two time periods (prior to administration of the third dose and following administration of the third dose of vaccine) and adjusted for several co-variates. Using the general population as the reference, we then calculated the Standardized Incidence Ratio (SIR) of hospitalisation. RESULTS: Eighty-two subjects out of 1096 infected patients were hospitalised (7.5%) and sixty-four hospitalisations occurred among the 824 infected persons after the third dose. Age ≥ 60 years (Adj RR 2.91; 95% CI 1.34-6.30) and lung disease (Adj RR = 2.45; 95% CI 1.32-4.54) were the only risk factors associated with hospitalisation. The risk of ICU admission in the second time period (Time 2) was reduced by 86% (RR = 0.14; 95% CI 0.03-0.71) compared to the first time period (Time 1). The SIR of hospitalisation (SIR 14.51; 95% CI 11.37-17.65) and ICU admission (SIR 14.58; 95% CI 2.91-26.24) showed an increase in the number of events in dialysis patients compared to the general population. CONCLUSIONS: Our analysis revealed that while the second variant of the virus increased infection rates, it was concurrently associated with mitigated severity of infections. Dialysis patients exhibited a higher susceptibility to both COVID-19 hospitalisation and ICU admission than the general population throughout the pandemic.

Genetic biomarkers of cognitive impairment and dementia of potential interest in CKD patients.

This review discusses genetic variants associated with cognitive dysfunction in chronic kidney disease (CKD) patients, emphasising the limited research in this area. Four studies have explored genetic markers of cognitive dysfunction in CKD, with findings suggesting shared genetic biomarkers between Alzheimer's Disease and CKD.Because of the limited specific research on genetic markers of cognitive dysfunction and dementia in CKD, we extracted data from the current literature studies on genetic markers in the general population that may be relevant to the CKD population. These markers include Apolipoprotein E (APOE), Complement Receptor 1 (CR1), Clusterin (CLU), Sortilin-related receptor 1 (SORL1), Catechol-O-methyltransferase (COMT), and Brain-derived neurotrophic factor (BDNF), all of which are known to be associated with cognitive dysfunction and dementia in other populations. These genes play various roles in lipid metabolism, inflammation, Aß clearance, and neuronal function, making them potential candidates for studying cognitive decline in CKD patients.CKD-specific research is needed to understand the role of these genetic markers in CKD-related cognitive dysfunction. Investigating how these genes influence cognitive decline in CKD patients could provide valuable insights into early detection, targeted interventions, and personalised treatment strategies. Overall, genetic studies to enhance our understanding and management of cognitive dysfunction in CKD represent a clinical research priority in this population.

The impact of population ageing on the burden of chronic kidney disease.

The burden of chronic kidney disease (CKD) and its risk factors are projected to rise in parallel with the rapidly ageing global population. By 2050, the prevalence of CKD category G3-G5 may exceed 10% in some regions, resulting in substantial health and economic burdens that will disproportionately affect lower-income countries. The extent to which the CKD epidemic can be mitigated depends largely on the uptake of prevention efforts to address modifiable risk factors, the implementation of cost-effective screening programmes for early detection of CKD in high-risk individuals and widespread access and affordability of new-generation kidney-protective drugs to prevent the development and delay the progression of CKD. Older patients require a multidisciplinary integrated approach to manage their multimorbidity, polypharmacy, high rates of adverse outcomes, mental health, fatigue and other age-related symptoms. In those who progress to kidney failure, comprehensive conservative management should be offered as a viable option during the shared decision-making process to collaboratively determine a treatment approach that respects the values and wishes of the patient. Interventions that maintain or improve quality of life, including pain management and palliative care services when appropriate, should also be made available.

Soft tissue sarcomas of the proximal adductor area of the thigh: Indications, results and complications at medium follow-up in a series of 43 surgically treated patients.

Introduction: When Soft Tissue Sarcomas are localized in the groin area, they pose specific challenges due to their proximity to important structures. These tumors exhibit elevated complication rates and a higher local recurrence rate compared to their locations in other limbs. The objective of this paper is to analyze a series of patients affected by soft tissue sarcomas in the adductor area of the proximal thigh. The analysis aims to elucidate the epidemiology, diagnostic and therapeutic approaches, complications, and outcomes. Additionally, the study seeks potential prognostic factors and to determine patients at a heightened risk of postoperative complications. Patients and methods: all patients who underwent surgeries for primary soft tissue sarcomas of the adductor area between October 2006 and March 2022 in a tertiary research hospital were valued. Epidemiology, tumor characteristics and therapeutic approaches were analyzed to identify risk factors for complications and local recurrences; survival was considered a secondary outcome. Results: The series comprised 43 patients, 26 males and 17 females, with an average age of 63.3 years. The most frequent histology was liposarcoma, followed by undifferentiated forms. All patients reported the presence of masses, with associated pain in 27.9% of cases. Limb-sparing surgery was performed in 86.0% of cases. Early and late complications were experienced by 34.9% and 20.0% of patients, respectively, with wound dehiscence being the most frequent problem. The recurrence rate was 9.3%, with no recurrences observed in low-grade patients. At an average follow-up of 51 months, 18 patients (41.9%) were alive, two of which with distant metastases. Conclusion: The present series provides evidence that when Soft Tissue Sarcomas localized in the groin area are managed in specialized centers, the rates of recurrence and complications are not significantly different from those observed in other anatomical sites.

Biomarkers in clinical epidemiology studies.

This paper discusses the use of biomarkers in clinical practice and biomedical research. Biomarkers are measurable characteristics that can be used to indicate the presence or absence of a disease or to track the progression of a disease. They can also be used to predict how a patient will respond to a particular treatment. Biomarkers have enriched clinical practice and disease prognosis by providing measurable characteristics that indicate biological processes. They offer valuable insights into disease susceptibility, progression, and treatment response, aiding drug development and personalized medicine. However, developing and implementing biomarkers come with challenges that must be addressed. Rigorous testing, standardization of assays, and consideration of ethical factors are crucial in ensuring the reliability and validity of biomarkers. Reliability is vital in biomarker research. It ensures accurate measurements by preventing biases and facilitating robust correlations with outcomes. Conversely, validation examines which and how many biomarkers correspond to theoretical constructs and external criteria, establishing their predictive value. Multiple biomarkers are sometimes necessary to represent the complex relationship between exposure and disease outcomes accurately. Susceptibility factors are pivotal in disease states' complex interaction among genetic and environmental factors. Gaining a comprehensive understanding of these factors is essential for effectively interpreting biomarker data and maximizing their clinical usefulness. Using well-validated biomarkers can improve diagnoses, more effective treatment evaluations, and enhanced disease prediction. This, in turn, will contribute to better patient outcomes and drive progress in medicine.

Socioeconomic Status and Clinical Outcomes in Chronic Kidney Disease: Bootstrap Validation of a Simple Indicator.

Background: Chronic Kidney Disease (CKD) is a complex health condition that interacts significantly with socioeconomic determinants, particularly income status and education. This study developed a simple indicator of socioeconomic status (SES), which is composed of income status and education in CKD patients, and evaluated its impact on health outcomes in this population. Methods: This study was conducted on 561 CKD patients, stages 2-5. The composite SES score was developed by combining the regression coefficients of income and education as predictors of the study endpoint in a multivariable Cox model, normalizing these coefficients to derive weights, and then using these weights to calculate an individual percentage score based on each person's income and education. The composed SES indicator was internally validated through bootstrap analysis. Over a median follow-up time of 36 months, we tracked all-cause death and non-fatal cardiovascular events. Results: Both lack of income (p = 0.020) and low educational level (p = 0.034) were independently related to the combined endpoint. Based on these covariates' regression coefficients, a composite socioeconomic score considering income and educational level was generated. In a Cox regression model, a 10% increase in this composite risk score entailed a 25% increase in the hazard ratio (HR) of the combined endpoint [HR (10% increase): 1.25], and the internally validated 95% CI ranged from 1.14 to 1.41 (p < 0.001). Conclusions: This study underscores the significant impact of a simple, bootstrap-validated composite SES indicator on CKD patients' health outcomes. These findings highlight the importance of considering education and socioeconomic factors in managing and treating CKD patients and inform future research and policy considerations for this population.

IL-6 inhibition with clazakizumab in patients receiving maintenance dialysis: a randomized phase 2b trial.

Inflammation mediated by interleukin-6 (IL-6) is strongly associated with cardiovascular risk. Here we evaluated clazakizumab, a monoclonal antibody targeting the IL-6 ligand, in a phase 2b dose-finding study. Adults with cardiovascular disease and/or diabetes receiving maintenance dialysis with high-sensitivity C-reactive protein (hs-CRP) ≥ 2 mg l-1 at baseline were randomized to receive clazakizumab (2.5 mg, 5 mg or 10 mg, n = 32 per dose group) or placebo (n = 31) every 4 weeks. The primary endpoint was the change from baseline in hs-CRP to week 12, expressed as the geometric mean ratio. Clazakizumab treatment signficantly reduced serum hs-CRP concentrations at week 12 by 86%, 90% and 92% relative to placebo in patients randomized to 2.5 mg, 5 mg or 10 mg clazakizumab, respectively (all P < 0.0001), meeting the primary outcome. With regard to secondary endpoints, clazakizumab treatment reduced serum fibrinogen, amyloid A, secretory phospholipase A2, and lipoprotein(a) concentrations, as well as increased mean serum albumin concentrations at 12 weeks, relative to placebo. The proportion of patients who achieved hs-CRP < 2.0 mg l-1 was 79%, 82% and 79% in the 2.5 mg, 5 mg and 10 mg clazakizumab groups, respectively, compared with 0% of placebo-treated patients. With regard to safety, no cases of sustained grade 3 or 4 thrombocytopenia or neutropenia were observed. Serious infections were seen with similar frequency in the placebo, clazakizumab 2.5 mg and clazakizumab 5 mg groups, but were numerically more frequent in the clazakizumab 10 mg group. The results of this trial indicate that in patients receiving maintenance dialysis, clazakizumab reduced inflammatory biomarkers associated with cardiovascular events. ClinicalTrials.gov registration: NCT05485961 .

Proprotein convertase subtilisin/kexin type 9 (PCSK9) and clinical outcomes in dialysis patients.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9), a factor accelerating the degradation of LDL receptors, was associated with a gender-dependent risk for cardiovascular (CV) events in the general population and with all-cause and CV mortality in two relatively small studies in black Africans and South Korean haemodialysis patients. The effect modification by gender was untested in these studies. METHODS: The study enrolled 1188 dialysis patients from the Prospective Registry of The Working Group of Epidemiology of Dialysis Region Calabria (PROGREDIRE) cohort. PCSK9 was measured by colorimetric enzyme-linked immunosorbent assay. The primary outcomes were all-cause and CV mortality. Statistical analysis included Cox regression analysis and effect modification analysis. RESULTS: During a median 2.9-year follow-up, out of 494 deaths, 278 were CV-related. In unadjusted analyses, PCSK9 levels correlated with increased all-cause (HRfor1ln unit increase: 1.23, 95% CI 1.06-1.43, p =.008) and CV mortality (HRfor1ln unit increase: 1.26, 95% CI 1.03-1.54, p =.03). After multivariate adjustment, these associations were no longer significant (all-cause mortality, HRfor 1 ln unit increase: 1.16, 95% CI .99-1.36, p =.07; CV mortality, HRfor1ln unit increase: 1.18, 95% CI .95-1.46, p =.14). However, in fully adjusted interaction analyses, a doubling in the risk of this outcome in women was registered (Women, HRfor1ln unit increase: 1.88, 95% CI 1.27-2.78, p =.002; Men, HRfor1ln unit increase: 1.07, 95% CI .83-1.38, p =.61; p for effect modification: .02). CONCLUSIONS: PCSK9 levels are unrelated to all-cause mortality in haemodialysis patients but, like in studies of the general population, independently of other risk factors, entail a doubling in the risk of CV events in women in this population.

A new era in the science and care of kidney diseases.

Notable progress in basic, translational and clinical nephrology research has been made over the past five decades. Nonetheless, many challenges remain, including obstacles to the early detection of kidney disease, disparities in access to care and variability in responses to existing and emerging therapies. Innovations in drug development, research technologies, tissue engineering and regenerative medicine have the potential to improve patient outcomes. Exciting prospects include the availability of new drugs to slow or halt the progression of chronic kidney disease, the development of bioartificial kidneys that mimic healthy kidney functions, and tissue engineering techniques that could enable transplantable kidneys to be created from the cells of the recipient, removing the risk of rejection. Cell and gene therapies have the potential to be applied for kidney tissue regeneration and repair. In addition, about 30% of kidney disease cases are monogenic and could potentially be treated using these genetic medicine approaches. Systemic diseases that involve the kidney, such as diabetes mellitus and hypertension, might also be amenable to these treatments. Continued investment, communication, collaboration and translation of innovations are crucial to realize their full potential. In addition, increasing sophistication in exploring large datasets, implementation science, and qualitative methodologies will improve the ability to deliver transformational kidney health strategies.

En-bloc spondylectomy in the lumbar spine: indications, results and complications in a series of 47 patients affected by primary malignant bone tumors.

INTRODUCTION: Wide Surgery is the reference treatment for malignant and aggressive benign primary bone tumors in the spine. When located in the lumbar spine, En-Bloc Spondylectomy (EBS) remains a complex challenge. Moreover, surgery is complicated by the presence of the diaphragm in the thoracolumbar junction and the hinderance of the iliac wings at the lumbosacral levels. Therefore, EBS in the lumbar spine frequently requires combined approaches. The purpose of this study is to describe clinical presentation, tumor characteristics and results of a series of 47 consecutive patients affected by malignant primary bone tumors of the lumbar spine who underwent EBS. MATERIALS AND METHODS: 47 patients were reviewed. Complications were distinguished in early and late whether they occurred before or after 30 days from surgery. Overall survival (OS), disease-free survival (DFS) and local recurrence-free survival (LRFS) were calculated by the Kaplan-Meier product-limit method from surgery until relapse or death. RESULTS: 27 patients presented to observation after a first intralesional approach in a non-specialized center. Chordoma was the most represented histotype. Vertebrectomies were: 23 one-level, 10 two-level, 12 three-level and 2 four-level. Reconstructions were always carried out with screws and rods. The main postoperative complication was blood loss, while hardware failure was the main long-term complication. The 5-year LRFS was 75.5%, the 5-year DFS was 54.3%, and 5-year OS was 63.6%. CONCLUSIONS: The surgical margin obtained during the index surgery was statistically associated with Local Recurrence, DFS and OS, underlining the importance of treating patients in reference centers.