The association between TMAO, CMPF, and clinical outcomes in advanced chronic kidney disease: results from the European QUALity (EQUAL) Study

BACKGROUND

Trimethylamine N-oxide (TMAO), a metabolite from red meat and fish consumption, plays a role in promoting cardiovascular events. However, data regarding TMAO and its impact on clinical outcomes are inconclusive, possibly due to its undetermined dietary source.

OBJECTIVES

We hypothesized that circulating TMAO derived from fish intake might cause less harm compared with red meat sources by examining the concomitant level of 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), a known biomarker of fish intake, and investigated the association between TMAO, CMPF, and outcomes.

METHODS

Patients were recruited from the European QUALity (EQUAL) Study on treatment in advanced chronic kidney disease among individuals aged ≥65 y whose estimated glomerular filtration rate (eGFR) had dropped for the first time to ≤20 mL/min per 1.73 m2 during the last 6 mo. The association between TMAO, CMPF, and outcomes including all-cause mortality and kidney replacement therapy (KRT) was assessed among 737 patients. Patients were further stratified by median cutoffs of TMAO and CMPF, suggesting high/low red meat and fish intake.

RESULTS

During a median of 39 mo of follow-up, 232 patients died. Higher TMAO was independently associated with an increased risk of all-cause mortality (multivariable HR: 1.46; 95% CI: 1.17, 1.83). Higher CMPF was associated with a reduced risk of both all-cause mortality (HR: 0.79; 95% CI: 0.71, 0.89) and KRT (HR: 0.80; 95% CI: 0.71, 0.90), independently of TMAO and other clinically relevant confounders. In comparison to patients with low TMAO and CMPF, patients with low TMAO and high CMPF had reduced risk of all-cause mortality (adjusted HR: 0.49; 95% CI: 0.31, 0.73), whereas those with high TMAO and high CMPF showed no association across adjusted models.

CONCLUSIONS

High CMPF conferred an independent role in health benefits and might even counteract the unfavorable association between TMAO and outcomes. Whether higher circulating CMPF concentrations are due to fish consumption, and/or if CMPF is a protective factor, remains to be verified.

MO194: A Rare Case of Secondary Haemolytic Uremic Syndrome after ANTI-SARS-COV-2 Vaccination

BACKGROUND AND AIMS

Haemolytic uremic syndrome (HUS) is a rare disease characterized by macroangiopathic haemolytic anaemia, thrombocytopaenia and severe AKI, belonging to the thrombotic microangiopathies (TMAs). It is divided into typical and atypical HUS: the first one occurs most frequently in children within the first 5 years of life and it is associated with Shiga-like toxin producing Escherichiacoli infection; the second one (aHUS) is less common (10%) and it is due to complement abnormalities with coexisting disease or trigger such as autoimmunity, transplantation, cancer, infection, certain cytotoxic drugs or pregnancy. There is an increasing interest in SARS-CoV-2 infection as new trigger for complement activation. Nine cases of aHUS were recently associated with COVID-19, most of them occurring within 1 month from the infection. Available data suggest that SARS-CoV-2 is a potential trigger for aHUS: it can induce an over inflammatory state and to activate coagulation and complement pathway. Likewise, mRNA-based vaccines against COVID-19 inducing the expression of SARS-CoV-2 spike protein to stimulate immune recognition and antibody response could be a suitable trigger for HUS.

METHOD

We report the case of a 17-year-old woman, who presented at our emergency department with fever, dyspnoea, acute kidney injury AKI III with anuria, hypertension, severe anaemia, no diarrhoea, severe thrombocytopaenia and myocarditis, about 2 weeks after the first administration of SARS-CoV-2 vaccine (Comirnaty) and recent exposition to SARS-CoV-2 positive individual. SARS-CoV-2 nasal PCR swab was negative (as well as successive ones) and she was immediately admitted to paediatric intensive care unit and treated with transfusions and haemodialysis. Laboratory exams suggested a thrombotic microangiopathy with normal ADAMTS-13 activity and no E. coli infection. She underwent a renal biopsy that confirmed our hypothesis of aHUS: wrinkled capillaries, subendothelial expansion, mesangiolysis and rare thrombi in capillaries lumen. Arterioles had intimal proliferation with mucoid oedema who gave rise to onionskin like lesion that obliterates lumens. One glomerulus showed extracapillary proliferation (crescent), and there was interstitial lymphomonocytic inflammatory infiltration in the nearby. Also signs of acute tubular injury and atrophy were reported. Positive stain to fibrinogen in the arterioles at immunohistology was noted. She immediately performed genetic exams for aHUS-related complement mutations and she started immunosuppression with corticosteroids and eculizumab infusions. After 2 months of eculizumab, she was still oliguric, requiring renal replacement therapy. Genetic analysis showed no mutations. Therefore, she was examined for other genetic causes of thrombotic microangiopathies.

RESULTS

Finally, came to light that she had high levels of homocysteine, and she was diagnosed with secondary HUS associated with cobalamin C deficiency, which manifests with methylmalonic aciduria and homocystinuria due to a recessive mutation in the MMACHC gene, causing a cobalamin C type deficiency, which is the common functional variant of vitamin B12. After metabolic therapy with hydroxocobalamin, she gradually recovered diuresis and partially renal function without need for replacement therapy.

CONCLUSION

Reports from immunization programs show as myocarditis and thrombotic thrombocytopaenia are considered among main serious complications caused by COVID-19 vaccines, representing 12.6 cases per million doses and 0.73 cases per 100 000, respectively.

This interesting case probably supports data about the role of mRNA-based anti-SARS-CoV-2 vaccines like a precipitant factor for TMAs. Moreover, our patient turned out to be an extremely rare case of HUS secondary to cobalamin C deficiency, that is generally diagnosed in early infancy and show typically neurological symptoms (absent in our case). Probably, the mRNA-based vaccine acted like ‘a second hit’, but existing predisposition should always be investigated including also the less frequent forms.

Associations between depressive symptoms and disease progression in older patients with chronic kidney disease: results of the EQUAL study

Background

Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex.

Methods

CKD patients (≥65 years; estimated glomerular filtration rate ≤20 mL/min/1.73 m²) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off ≤70; 0–100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders.

Results

Overall kidney function decline in 1326 patients was –0.12 mL/min/1.73 m²/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03–1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality).

Conclusions

There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men.

The relationship between uremic toxins and symptoms in older men and women with advanced chronic kidney disease

Background

Patients with stage 4/5 chronic kidney disease (CKD) suffer from various symptoms. The retention of uremic solutes is thought to be associated with those symptoms. However, there are relatively few rigorous studies on the potential links between uremic toxins and symptoms in patients with CKD.

Methods

The EQUAL study is an ongoing observational cohort study of non-dialyzed patients with stage 4/5 CKD. EQUAL patients from Germany, Poland, Sweden and the UK were included in the present study (n = 795). Data and symptom self-report questionnaires were collected between April 2012 and September 2020. Baseline uric acid and parathyroid hormone and 10 uremic toxins were quantified. We tested the association between uremic toxins and symptoms and adjusted P-values for multiple testing.

Results

Symptoms were more frequent in women than in men with stage 4/5 CKD, while levels of various uremic toxins were higher in men. Only trimethylamine N-oxide (TMAO; positive association with fatigue), p-cresyl sulfate (PCS) with constipation and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (negative association with shortness of breath) demonstrated moderately strong associations with symptoms in adjusted analyses. The association of phenylacetylglutamine with shortness of breath was consistent in both sexes, although it only reached statistical significance in the full population. In contrast, TMAO (fatigue) and PCS and phenylacetylglutamine (constipation) were only associated with symptoms in men, who presented higher serum levels than women.

Conclusion

Only a limited number of toxins were associated with symptoms in persons with stage 4/5 CKD. Other uremic toxins, uremia-related factors or psychosocial factors not yet explored might contribute to symptom burden.

MO852MANAGEMENT OF PATIENTS UNDERGOING CHRONIC HEMODIALYSIS DURING THE COVID-19 PANDEMIC: FONDAZIONE POLICLINICO A. GEMELLI’S EXPERIENCE

Background and aim

COVID-19 (COronaVIrus Disease 19) is an acute respiratory disease caused by SARS CoV 2 virus. The correlation between SARS-CoV2 infection and comorbidities is complex; patients with multiple comorbidities present often with the most severe symptoms that could potentially lead to death. Patients undergoing hemodialysis are generally frail and immunodeficient. This leads to a greater risk of contracting infectious diseases. In the literature, the estimated incidence of SARS-CoV2 infection is 3.24% in chronic hemodialysis patients.

Method

Fondazione Policlinico A. Gemelli is a COVID hospital. During the pandemic patients from several dialysis centers converged in our hospital. FPG has two dialysis centers, one for outpatients and one for inpatients. Patients admitted for COVID-19 infection have been treated in three different settings: 1. isolation room within the dialysis center; 2. Bedside; 3. In a COVID-19 dialysis center. We retrospectively collected data of patients treated from March 2020 to January 2021 and analyzed the SARS-CoV2 incidence in our center’s chronic hemodialysis patients.

Results

66 hemodialysis patients affected by COVID-19 have been treated in our hospital from March 2020 to January 2021, 60 patients undergoing chronic dialysis and 6 patients diagnosed with acute kidney injury (AKI) stage III non-intensive care unit. Among chronic patients, 64 underwent chronic hemodialysis and 2 patients underwent peritoneal dialysis. Median age was 68.19 (46 males, 20 females), all patients had multiple comorbidities: 37.8% of patients had diabetes mellitus; 72.7% cardiovascular diseases and 16.6% a positive clinical history for cancer. Among the 6 AKI cases, 3 patients regained total kidney function; the other 3 had to continue renal replacement therapy. The mean hospital stay length was 18.5 days with a mean time of COVID-19 infection of 21.23 days. The overall mean Charlson Comorbidty Index was 6.21. Among the 66 treated patients, 43 were diagnosed with COVID-19-related pneumonia, 14 had the infection, no pulmonary involvement, but presented with other complications, and 5 patients resulted positive although asymptomatic. Among the 116 hemodialysis outpatients, only 4 presented with SARS-CoV2 infection, 3 were contacts of a positive family member and 1 resulted positive during a hospital stay for Clostridium Difficile infection. All patients required hospitalization. 14 (21%) patients died. Among the deceased patients, the mean age was 76.90 years (9 males, 3 females), mean Charlson Comorbidity Index was 7.3, mean hospital stay length was 9 days. Among patients who survived the disease the mean age was 76.92 years (34 males, 14 females), mean Charlson Comorbidty Index was 5.87 and mean hospital stay length was 19.47 days. Statistical significance was reached for age (p value 0.005) and Charlson Comorbidty Index (p value 0.39), but not for mean hospital stay length (p value 0.13). All COVID-19 patients were treated with bicarbonate hemodialysis and a Theranova 400 Baxter® filter. This filter was chosen for its efficiency on medium-size molecules removal (between 25 kDa and 60 kDa) that may be associated with inflammation. Bedside treatments were performed using the Genius© Fresenius system. Each treatment lasted 180 minutes, in order to reduce the time of exposure to COVID-19 of medical staff and the risk of virus spread on one hand, but still ensuring an optimal and complication-free treatment to patients.

Conclusion

Our experience seems to confirm the national data collected so far, both in terms of patients’ outcomes and mortality rate. Our study confirms that age is a risk factor for mortality. How to properly manage chronic hemodialysis patients affected by COVID-19 remains a challenging and burdensome question. However, there is the need of new flexible solutions that guarantee the patients and the medical staff’s safety on one hand and a personalized management on the other.

MO794EVALUATION OF THE BONE ELASTIC STRUCTURE IN PERSONS WITH AND WITHOUT CHRONIC KIDNEY DISEASE ON DIALYSIS

Background and Aims

Chronic kidney disease is a frequent condition, characterized, especially in its more advanced stages, by an array of derangements in bone structure and density, resulting in a higher rate of bone fractures. Current strategies to monitor the bone status and assess the risk of bone fractures in CKD patients are limited.

The Bone Elastic Structure (BES) test is a recently-developed non-invasive tool that measures the elastic characteristics of the trabecular bone by simulating the application of loads on a virtual biopsy obtained from radiographic images of the proximal epiphyses in the patient’s hand fingers. The simulation results are combined to obtain a parameter defined Bone Structure Index (BSI). The aim of our study is to explore whether the BES test could be a useful monitoring tool of bone status in patients with CKD on dialysis by exploring whether such patients have different BSI values compared with persons without CKD.

Method

The BES test was performed on a sample of 41 patients undergoing chronic hemodialysis (HD) and the BSI compared with a group of 374 persons with normal renal function who had undergone the BES test in previous studies. Differences in BSI and 95% confidence intervals (CIs) between the two groups were obtained and tested for statistical significance with a linear regression model including BSI as the dependent variable and kidney status (HD vs no HD) as the independent variable, adjusted for age and sex. Subgroup effects were explored by including interaction terms (age x kidney status, age x sex, kidney status x sex) in the model. Finally, to further remove the potential confounding by age and sex, each HD patient was individually matched with up to 4 non-HD participants based on sex and age (with a 5-year caliper) and a matched analysis was conducted on BSI values.

Results

Average (SD) age was 64 (17) years in the HD group and 60 (12) years in the non-HD group, with a prevalence of males of 49% and 16%, respectively.

The individual values of BSI divided by kidney status and sex in Figure. The multivariate linear regression model showed that, after adjustment for age and sex, the BSI in the HD group was significantly lower compared with the non-HD group (HD 145, 95% CI 140, 154; non-HD 179, 95% CI 177, 181; absolute difference −32, 95% CI −40, −25; p-value < 0.001). There was no significant interaction between age, sex and kidney status on BSI values (all p-values > 0.05).

Individual matching was successful for 36 out of 41 HD patients, who were matched to 127 non-HD participants; matched analysis confirmed the results (absolute difference −31, 95% CI −40, −23; p-value < 0.001).

Conclusion

The output of a non-invasive tool to determine the bone elastic structure appeared to be strongly associated with kidney function after control for differences in age and sex. Further studies are needed to determine the potential application of the BES test in patients with CKD.

Serum sodium variability and acute kidney injury: a retrospective observational cohort study on a hospitalized population

Aim of our study was to analyze the association between serum sodium (Na) variability and acute kidney injury (AKI) development. We performed a retrospective observational cohort study on the inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 1, 2010 and December 31, 2014 with inclusion of adult patients with ≥ 2 Na and ≥ 2 serum creatinine measurements. We included only patients with ≥ 2 Na measurements before AKI development. The outcome of interest was AKI. The exposures of interest were hyponatremia, hypernatremia and Na fluctuations before AKI development. Na variability was evaluated using the coefficient of variation (CV). Multivariable Cox proportional hazards and logistic regression models were fitted to obtain hazard ratios (HRs), odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the exposures of interest and AKI. Overall, 56,961 patients met our inclusion criteria. During 1541 person-years of follow-up AKI occurred in 1450 patients. In multivariable hazard models, patients with pre-existent dysnatremia and those who developed dysnatremia had a higher risk of AKI compared with patients with normonatremia. Logistic models suggested a higher risk for AKI in the 3rd (OR 1.41, 95% CI 1.18, 1.70, p < 0.001) and 4th (OR 1.53, 95% CI 1.24, 1.91, p < 0.001) highest quartiles of Na CV with a significant linear trend across quartiles (p trend < 0.001). This association was also independent from Na highest and lowest peak value. Dysnatremia is a common condition and is positive associated with AKI development. Furthermore, high Na variability might be considered an independent early indicator for kidney injury development.

Seasonality of acute kidney injury in a tertiary hospital academic center: an observational cohort study

BACKGROUND

The aim of our study was to describe seasonal trends of acute kidney injury (AKI) and its relationship with weather conditions in a hospitalized population.

METHODS

We retrospectively collected demographic (age, sex), clinical (ICD-9-CM codes of diagnosis discharge) and laboratory data (creatinine values) from the inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 2010 and December 2014 with inclusion of all patients ≥18 years with at least two values available for creatinine. The outcome of interest was AKI development, defined according to creatinine kinetics criteria. The exposures of interest were the months and seasons of the year; air temperature and humidity level were also evaluated. Log-binomial regression models adjusted for age, sex, eGFR, comorbidities, Charlson/Deyo index score, year of hospitalization were used to estimate risk ratios (RR) and 95% confidential intervals (CI).

RESULTS

A total of 64,610 patients met the inclusion criteria. AKI occurred in 2864 (4.4%) hospital admissions. After full adjustment, winter period was associated with increased risk of AKI (RR 1.16, 95% CI 1.05, 1.29, p=0.003). Lower air temperature and higher humidity level were associated with risk of AKI, however in multivariable-adjusted models only higher humidity level showed a significant and independent association.

CONCLUSIONS

AKI is one of the most common complications of hospitalized populations with a defined seasonal pattern and a significant increase in incidence during wintertime; weather conditions, particularly higher humidity level, are independent predictors of AKI and could partially justify the observed seasonal variations.

Hyperchloremia and acute kidney injury: a retrospective observational cohort study on a general mixed medical-surgical not ICU-hospitalized population

The aim of this observational retrospective cohort study was to analyze the association between hyperchloremia and serum chloride variation with in-hospital acute kidney injury (AKI) and mortality in a general, no-ICU hospitalized population. We performed a retrospective study on inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 2010 and December 2014 with inclusion of adult patients with at least two values available for chloride, sodium and creatinine. Hyperchloremia was defined as serum chloride concentration ≥ 108 mmol/L (moderate hyperchloremia: chloremia between 108-110 mmol/L, severe hyperchloremia: chloremia > 110 mmol/L). According to the time of onset of the electrolyte disturbance, hyperchloremia was then classified as hospital acquired (HA) and community acquired (CA). In patients with HA-hyperchloremia, chloride variation (ΔCl) was calculated. In-hospital AKI was defined according to creatinine kinetics criteria occurring 48 h after hospital admission. Logistic regression analysis was used to evaluate the association between the exposures of interest and in-hospital AKI and mortality. A total of 24,912 hospital admissions met the inclusion criteria. Regression analyses showed that only severe HA-hyperchloremia was associated with increased risk of in-hospital AKI [odds ratio (OR) 2.60, 95% confidence interval (CI) 1.58, 4.30, p value < 0.001] and death (OR 3.89, 95% CI 2.11, 7.18, p value < 0.001). With increasing ΔCl, the OR of in-hospital AKI increased progressively (p value for trend = 0.005). In conclusion, severe hyperchloremia is an independent predictor for in-hospital AKI and mortality; HA-hyperchloremia is more detrimental for patient outcome; higher ΔCl from hospital admission is associated with increased risk of AKI.

Living Kidney Donation in a Type 1 Dent's Disease Patient from His Mother

INTRODUCTION

Dent's disease is a rare X-linked recessive disorder that manifests in childhood or early adulthood and can lead to end-stage renal disease (ESRD). It occurs in males, who are hemizygous. In patients who develop ESRD, a deceased donor kidney transplant cures the disease. Females are obligate carriers of the mutated gene, and some show a mild Dent's disease phenotype. There may be reason for concern when considering a female obligate carrier (i.e., the mother) for kidney donation because of the risk of kidney function deterioration.

CASE PRESENTATION

We describe the first successful kidney transplantation involving a patient with type 1 Dent's disease and ESRD given a kidney by an obligate carrier of the gene mutation, his mother.

CONCLUSIONS

After careful assessment of the female obligate carriers, intrafamilial kidney donation in Dent's disease type 1 is feasible. No deteriorating renal function in the donor was observed.

Sodium Fluctuations and Mortality in a General Hospitalized Population

Background/Aims: Aim of our study was to describe the association between natremia (Na) fluctuation and hospital mortality in a general population admitted to a tertiary medical center. Methods: We performed a retrospective observational cohort study on the patient population admitted to the Fondazione Policlinico A. Gemelli IRCCS Hospital between January 2010 and December 2014 with inclusion of adult patients with at least 2 Na values available and with a normonatremic condition at hospital admission. Patients were categorized according to all Na values recorded during hospital stay in the following groups: normonatremia, hyponatremia, hypernatremia, and mixed dysnatremia. The difference between the highest or the lowest Na value reached during hospital stay and the Na value read at hospital admission was used to identify the maximum Na fluctuation. Cox proportional hazards models were used to estimate hazard ratios (HRs) for in-hospital death in the groups with dysnatremias and across quartiles of Na fluctuation. Covariates assessed were age, sex, highest and lowest Na level, Charlson/Deyo score, cardiovascular diseases, cerebrovascular diseases, dementia, congestive heart failure, severe kidney disease, estimated glomerular filtration rate, and number of Na measurements during hospital stay. Results: 46,634 admissions matched inclusion criteria. Incident dysnatremia was independently associated with in-hospital mortality (hyponatremia: HR 3.11, 95% CI 2.53, 3.84, p < 0.001; hypernatremia: HR 5.12, 95% CI 3.94, 6.65, p < 0.001; mixed-dysnatremia: HR 4.94, 95% CI 3.08, 7.92, p < 0.001). We found a higher risk of in-hospital death by linear increase of quartile of Na fluctuation (p trend <0.001) irrespective of severity of dysnatremia (HR 2.34, 95% CI 1.55, 3.54, p < 0.001, for the highest quartile of Na fluctuation compared with the lowest). Conclusions: Incident dysnatremia is associated with higher hospital mortality. Fluctuation of Na during hospital stay is a prognostic marker for hospital death independent of dysnatremia severity.

[The pathway of vasopressin as a pharmacological target in nephrology: a narrative review]

ADH is a hormone secreted by neurohypophysis that plays different roles based on the target organ. At the renal level, this peptide is capable of causing electrolyte-free water absorption, thus playing a key role in the hydro-electrolytic balance. There are pathologies and disorders that jeopardize this balance and, in this field, ADH receptor inhibitors such as Vaptans could play a key role. By inhibiting the activation pathway of vasopressin, they are potentially useful in euvolemic and hypervolemic hypotonic hyponatremia. However, clinical trials in heart failure have not given favourable results on clinical outcomes. Even in SIADH, despite their wide use, there is no agreement by experts on their use. Since vaptans inhibit the cAMP pathway in tubular cells, their use has been proposed to inhibit cystogenesis. A clinical trial has shown favourable effects on ADPKD progression. Because vaptans have been shown to be effective in models of renal cysts disorders other than ADPKD, their use has been proposed in diseases such as nephronophthisis and recessive autosomal polycystic disease. Other possible uses of vaptans could be in kidney transplantation and cardiorenal syndrome. Due to the activity of ADH in coagulation and haemostasis, ADH's activation pathway by Desmopressin Acetate could be a useful strategy to reduce the risk of bleeding in biopsies in patients with haemorrhagic risk.

[Hemodialysis treatment as a trigger cause of cryoglobulinemic purpura: a case report]

We describe the clinical case of a patient who developed mixed cryoglobulinemia syndrome after hemodialysis treatment with dialysate temperature lower than 36°C despite the negativization of the viral genome for HCV after eradication therapy.

Living kidney donation from people at risk of nephrolithiasis, with a focus on the genetic forms

Deciding whether to accept a donor with nephrolithiasis is a multifaceted task because of the challenge of finding enough suitable donors while at the same time ensuring the safety of both donors and recipients. Until not long ago, donors with a history of renal stones or with stones emerging during screening on imaging were not considered ideal, but recent guidelines have adopted less stringent criteria for potential donors at risk of stones. This review goes through the problems that need to be approached to arrive at a wise clinical decision, balancing the safety of donors and recipients with the need to expand the organ pool. The risk of declining renal function and worsening stone formation is examined. Documents (consensus statements, guidelines, etc.) on this issue released by the most important medical societies and organizations are discussed and compared. Specific problems of living kidney donation associated with certain systemic (chronic hypercalcemia due to CYP24A1 gene mutations, primary hyperoxaluria, APRT deficiency) and renal (medullary sponge kidney, cystinuria, distal renal tubular acidosis, Dent's disease, Bartter syndrome, familial hypomagnesemia with hypercalciuria and nephrocalcinosis) Mendelian disorders that cause nephrolithiasis are also addressed.

[Recurrent Kidney Stones in a patient with Malabsorption Syndrome]

Enteric hyperoxaluria is one of the most frequent complications of bariatric surgery. In this setting the prevalence of kidney stones is increased. Currently the treatment of enteric hyperoxaluria is based not only on the reduction of urinary oxalate but even controlling other lithogenic risk factors, like urinary volume and urinary citrate levels. This case report suggests a possible benefit using magnesium citrate in addition to calcium supplementation, in the treatment of hyperoxaluria caused by enteric malabsorption.

Cardiac Calcium Evaluation in Hemodialysis Patients with Multisection Spiral Computed Tomography

Aim

The aim of this study is cardiac calcium content evaluation in hemodialysis patients by a new technique, based on ultrafast multisection CT (MTC).

Methods

The study was carried out on 30 HD patients, 14F and 16 M, average age 57.7±13.9 years, average HD age 57.3±47.4 months. The intact PTH levels were 625.4±571 pg/mL. Serum calcium, phosphate and CaxP product were 9.75±0.84 mg/mL, 6.21±1.01 mg/dL and 60.2±10.7 mg2/dL2, respectively.

Results

The values obtained with the MTC technique were reported in terms of Agatson scores. Score values frankly in the pathologic range (>100) were found in 24 patients (80%). Correlation analysis has shown positive and significant correlation coefficients of the score with patients’ age (p=0.003), serum calcium (p=0.012), CaxP (p=0.015), iPTH (=0.049), and borderline, to HD age (p=0.06).

Conclusion

Risk factors for cardiac calcification are mainly age, degree of hyperparathyroidism, increased CaxP and serum calcium levels. A control of calcium phosphate parameters in hemodialysis patients seems to be mandatory to avoid increased severity of coronary artery disease.

A novel CYP24A1 genotype associated to a clinical picture of hypercalcemia, nephrolithiasis and low bone mass

Mutations of the CYP24A1 gene, encoding for the enzyme 25(OH)D-24-hydroxylase, can cause hypercalcemia, hypercalciuria, nephrolithiasis and nephrocalcinosis. We report the case of a 22-year-old male patient with recurrent nephrolithiasis, nephrocalcinosis, hypercalcemia with low parathyroid hormone levels, hypercalciuria and low bone mass. Gene sequencing showed that the patient had compound heterozygous mutations including a novel genotype of the CYP24A1 gene. Genetic CYP24A1 testing and biochemical analyses were offered to other family members; the father was heterozygous for the same novel genotype and was also affected with recurrent nephrolithiasis.

Temporal trend of cadmium exposure in the United States population suggests gender specificities

BACKGROUND

Over the years, environmental cadmium exposure has been linked to increased mortality. Over the years, the use of cadmium has generally decreased.

AIMS

Although even relatively low levels of cadmium have been associated with increased mortality in the general population, whether this applies to blood cadmium is not well understood.

METHODS

The authors analysed data of the National Health and Nutrition Examination Survey to study the temporal trend of cadmium exposure in the period 1988-2006 and the risk of all-cause, cancer and cardiovascular mortality associated with blood cadmium levels.

RESULTS

Urinary cadmium decreased significantly over time in males (0.58 (0.01) mcg/g to 0.41 (0.01) mcg/g; P < 0.001) but not in females (0.71 (0.09) mcg/g to 0.63 (0.08) mcg/g; P= 0.66). All-cause mortality was significantly higher in the highest quartiles compared with the lowest quartile of blood cadmium in both males (hazard ratio 1.89, 95% confidence interval 1.22, 2.89; P= 0.005) and females (hazard ratio 2.03, 95% confidence interval 1.06, 3.89; P= 0.035) after adjustment for age, race/ethnicity, smoke status, alcohol intake, annual household income and body mass index. There was also a significant association with cardiovascular mortality in females (P= 0.025).

CONCLUSIONS

Our data show that elevated blood cadmium levels are associated with elevated mortality, that there seem to be gender differences in temporal trends of cadmium exposure and that blood cadmium is a proxy of chronic cadmium exposure.

[Hyponatremia: practical approach to diagnosis and treatment]

Hyponatremia is one of the most frequent ion and water disorders. It is generally due to disproportionate renal water retention. Severe hyponatremia (<125 mEq/L) is associated with well-known clinical symptoms and manifestations. However, even mild reductions in sodium blood levels have been shown to be associated with increased mortality and with the risk of falls and fractures. The diagnosis of hyponatremia, although requiring simple clinical and laboratory tests, may be complex and difficult. Treatment should be tailored to the clinical manifestations and severity of hyponatremia. Vaptans may be used in euvolemic or hypervolemic hyponatremia and particularly in SIADH.

[Pulmonary-renal syndromes]

Pulmonary-renal syndromes (PRS) are characterized by the simultaneous presence of diffuse alveolar hemorrhage and acute glomerulonephritis. The most common causes of PRS are ANCA-associated vasculitides, Goodpasture's syndrome and systemic lupus erythematosus. The clinical picture of PRS includes hemoptysis (not always present), acute-onset anemia and renal abnormalities ranging from isolated urinary abnormalities to rapidly progressive glomerulonephritis. The severity of the pulmonary involvement determines the mortality risk as well as the need for mechanical ventilation in intensive care. The diagnosis of PRS is based upon clinical, serological, radiological and histological findings. Immunosuppressive therapy, along with an adequate support therapy (especially aimed at avoiding microbial infection), needs to be started promptly and effectively to reduce both the mortality risk and long-term complications such as end-stage renal disease.

Low level exposure to cadmium increases the risk of chronic kidney disease: analysis of the NHANES 1999-2006

Background

Environmental factors have been associated with the outbreak of chronic kidney disease (CKD). We evaluated the association of Cadmium (Cd) exposure with the risk of CKD in U.S. adults who participated in the 1999-2006 National Health and Nutrition Examination Surveys (NHANES).

Methods

5426 subjects ≥ 20 years were stratified for values of urinary and blood Cd and a multivariate logistic regression was performed to test the association between blood and urinary Cd, CKD and albuminuria (ALB) after adjustment for age, gender, race/ethnicity, body mass index and smoking habits.

Results

Subjects with urinary Cd > 1 mcg/g and subjects with blood Cd > 1 mcg/L showed a higher association with ALB (OR 1.63, 95% CI 1.23, 2.16; P = 0.001). Subjects with blood Cd > 1 mcg/L showed a higher association with both CKD (OR 1.48, 95% CI 1.01, 2.17; P = 0.046) and ALB (OR 1.41, 95% CI 1.10, 1.82; P = 0.007). An interaction effect on ALB was found for high levels of urinary and blood Cd (P = 0.014).

Conclusions

Moderately high levels of urinary and blood Cd are associated with a higher proportion of CKD and ALB in the United States population.

Is rasburicase an effective alternative to allopurinol for management of hyperuricemia in renal failure patients? A double blind-randomized study

Recent epidemiological studies provide a clear evidence that hyperuricemia is associated with hypertension, coronary heart disease, left ventricular hypertrophy and progression of renal disease. Aim of our study was to assess the effect of low dosage of recombinant urate oxidase on hyperuricemia in renal failure patients that already receiving allopurinol. Our study group consisted of 43 renal failure patients, 23 women and 20 men. The mean age was 74 years (range 36-90 years). The following variables were studied on admission: serum creatinine, blood urea nitrogen and serum uric acid. Intravenous rasburicase was administered at a dose of 0.02 mg/kg/day on 3 consecutive days in patients with serum uric acid between 8-10 mg/dl, on 5 consecutive days in patients with serum uric acid between 10-15 mg/dl and on 7 consecutive days in patients with serum uric acid > 15 mg/dl. Uric acid levels were assayed after 48 hours and 7 days after rasburicase treatment. Mean values of uric acid levels after 48 hours were 2.47 mg/dl (+/- 1.58) in men and 2.77 mg/dl (+/- 2.24) in woman, where'as mean values of uric acid levels after 7 days were 4.45 mg/dl (+/- 2.0) in men and 5.75 mg/dl (+/- 1.9) in woman. No significant relationship were found between uric acid and creatinine as before as well after therapy. There were no side effects in all patients included in the study. After 7 days, the rasburicase therapy showed more antihyperuricemic effect in men (59%) than in women (46%).

Cardiac calcifications: Fetuin-A and other risk factors in hemodialysis patients

Cardiac calcifications are a frequent finding in hemodialysis for chronic renal failure. Several factors may play a role in the intimal and medial calcification of coronary arteries such as age and some known atherogenetic factors. In addition, Fetuin-A has been proposed as a protective agent through solubilization of calcium phosphate salt. Fetuin-A is also a marker of inflammatory-nutritional state, and its changes could be an expression of this condition. The aim of this cross-sectional study is to evaluate the relative importance of risk factors of calcifications with special regard to Fetuin-A. The study was conducted with 132 hemodialysis patients. They were subjected to multislice computed tomography for evaluation of calcium deposits in the heart. In addition, the patients were sampled for evaluation of calcium-phosphate parameters, lipid profile, nutritional and inflammatory markers, and also Fetuin-A. There was a wide variability of the extent of calcium deposits expressed as Agatston score, with only 9.3% of patients without calcifications. Age, hemodialysis age, sex, calcium-phosphate parameters, and lipid profile were important risk factors, together with nutritional and inflammatory status of the patients. An inverse correlation between coronary calcium score and Fetuin-A emerged from a multiple regression analysis. However, there was no significant difference in serum Fetuin-A among different grades of calcium score. By dividing the patients in tertiles of serum Fetuin-A, an association between low levels of Fetuin-A and high calcification score was found. Fetuin-A as dependent variable was strictly linked to prealbumin serum levels. In addition, there was a clear link between cardiac calcification scores and inflammatory-nutritional markers. Serum calcium and treatment with calcitriol emerged as predictive variables of coronary score.Fetuin-A could be involved in the process of calcification both in the case of markedly low serum levels, due to decreased prevention of calcium phosphate precipitation, and also as a marker of inflammation, a well-known risk factor of atherogenesis. Treatment with intravenous calcitriol could marginally enhance cardiac calcifications, probably through its hypercalcemic effect.

Cardiac calcifications in hemodialysis patients assessed with spiral computed tomography

AIM

Cardiac disease is a major cause of mortality in uremic patients. The aim of this paper was to evaluate cardiac calcium content in uremic patients with multislice computed tomography (MSCT).

METHODS

The study has been carried out on 120 uremic and 28 nonuremic patients affected by cardiovascular disease. Serum calcium, phosphorus, calcium-phosphate product, intact PTH were assayed. Several lipidic and nutritional parameters were measured. Calcification values obtained with the MSCT were reported in terms of Agatson scores.

RESULTS

We found that the average score values in cohort on uremic was 10 times higher than in nonuremic patients (score values 3.389 vs 328). Cardiac calcification score was found to be correlated significantly to age (P=0.006), HD age (P=0.010), serum calcium (P=0.006), iPTH (P=0.004). Multiregression analysis (MRA) with the cardiac score as dependent variable selected the following variables (R(2) 0.612): age (P=0.002), HD age (P=0.010), serum cholesterol (P<0.000), triglycerides (P=0.001) and inversely HDL cholesterol (P=0.001) and non-HDL cholesterol (P=0.001) as predictive variables for cardiac score. By comparing patients with scores lower and higher than 400, the group with score <400 showed a significantly lower age (P=0.0001), HD vintage (P=0.01) and a significantly higher serum cholesterol (P=0.009), HDL cholesterol (P=0.05) and non-HDL cholesterol (P=0.05).

CONCLUSIONS

The MSCT could help in identifying and stratifying high-risk patients to implement preventive strategies. The control of mineral metabolism and of lipid levels is important in prevention of arterial calcification in uremic patients.