Association of environmental cadmium exposure with inflammation and malnutrition in maintenance haemodialysis patients

Citrate Dialysate with and without Magnesium Supplementation in Hemodiafiltration: A Comparative Study Versus Acetate

The choice of dialysate buffer in hemodialysis is crucial, with acetate being widely used despite complications. Citrate has emerged as an alternative because of its favorable effects, yet concerns persist about its impact on calcium and magnesium levels. This study investigates the influence of citrate dialysates (CDs) with and without additional magnesium supplementation on CKD-MBD biomarkers and assesses their ability to chelate divalent metals compared to acetate dialysates (ADs). A prospective crossover study was conducted in a single center, involving patients on thrice-weekly online hemodiafiltration (HDF). The following four dialysates were compared: two acetate-based and two citrate-based. Calcium, magnesium, iPTH, iron, selenium, cadmium, copper, zinc, BUN, albumin, creatinine, bicarbonate, and pH were monitored before and after each dialysis session. Seventy-two HDF sessions were performed on eighteen patients. The CDs showed stability in iPTH levels and reduced post-dialysis total calcium, with no significant increase in adverse events. Magnesium supplementation with CDs prevented hypomagnesemia. However, no significant differences among dialysates were observed in the chelation of other divalent metals. CDs, particularly with higher magnesium concentrations, offer promising benefits, including prevention of hypomagnesemia and stabilization of CKD-MBD parameters, suggesting citrate as a viable alternative to acetate. Further studies are warranted to elucidate long-term outcomes and optimize dialysate formulations. Until then, given our results, we recommend that when a CD is used, it should be used with a 0.75 mmol/L Mg concentration rather than a 0.5 mmol/L one.

Mediation analysis of urinary metals and stroke risk by inflammatory markers

BACKGROUND

The association between metals and stroke has been reported, but the mediating role of inflammation between metals and stroke remains unclear.

METHODS

We included 9326 adults from the National Health and Nutrition Examination Survey in this study. Through least absolute selection and shrinkage operator (LASSO) regression, weighted quantile sum (WQS) regression, logistic regression, linear regression, restricted cubic spline analysis, and mediation analysis, we explored the association between metals and stroke, as well as the association between metals and inflammatory indicators, and further evaluated the mediating effect of inflammatory indicators on the association between selected metals and stroke risk.

RESULTS

The results of the present study suggested positive associations between mixed metals, cadmium and uranium and stroke risk. There is a positive correlation and dose‒response relationship between cadmium and C-reactive protein (CRP). Moreover, CRP mediates 10.1% of the association between cadmium and stroke.

CONCLUSIONS

At the epidemiological level, CRP mediates the association between cadmium and stroke risk, suggesting that inflammation may be a potential mechanism for metal-induced stroke.

Do trace elements play a role in coronary artery calcification in hemodialysis patients?

PURPOSE

Abnormalities of trace elements have previously been linked to inflammatory processes in hemodialysis (HD) patients. We aimed to establish the trace element status of maintenance HD patients, to investigate the relationship between coronary artery calcification scores (CACs) and whole blood levels of trace elements.

METHODS

Patients undergoing HD in three times a week for > 6 months and age-and sex-matched controls were included from October 2015 to June 2016. Data were collected from patient files. All subjects' whole blood levels of trace elements were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). CACs for patients were assessed by multi-detector computed tomography.

RESULTS

The 35 patients (male, 60%) with a mean age of 45.7 ± 10.4 years and 35 controls were included. HD patients showed significantly lower levels of selenium and uranium and higher cadmium (Cd), cobalt, lithium, manganese, nickel, lead, platinum, tin, strontium, and thallium levels compared to controls. Coronary artery calcification (CAC) was present in 21 patients (60%), and median CACs were 14.2 (IQR 0-149). Patients with CACs > median were significantly older, had a higher prevalence of hypertension and lower ALP levels than patients with CACs ≤ median. No significant differences in whole blood levels of trace elements were found between patients with CACs > median and patients with CACs ≤ median. A near significance was noted in median whole blood levels of Cd between these groups (P = 0.096). According to multivariate analysis, age was the only independent determinant for CAC development.

CONCLUSION

Age is independently associated with coronary vascular calcification. High Cd levels might play a role in CAC development in HD patients.

Association of blood heavy metal levels with osteocalcin abnormality and incidence of osteoporosis in Saudi subjects

Serum toxic metals have been implicated in development of many diseases. This study investigated the association between blood levels of lead and cadmium with abnormal bone mineral density (BMD) and incidence of osteoporosis. Sixty Saudi male adults age matching were assigned into two groups: A healthy control group (n = 30) and osteoporosis patients diagnosed according to T-score (n = 30). Serum calcium, vitamin D, osteocalcin, lead, cadmium were measured. Osteoporotic group showed a highly significant elevation of blood lead and cadmium levels compared to the control group (p <0.001). BMD was negatively correlated with serum osteocalcin level compared with control. There was a significant negative correlation between the cadmium and lead levels (r=-0.465 and p-value = 0.01) and calcium (p < 0.004). Our findings suggested that high cadmium and lead were negative correlated to BMD and increased the risk factor for osteoporosis.

Exposure to heavy metals and the risk of osteopenia or osteoporosis: a systematic review and meta-analysis

The relationship between heavy metal exposure and risk of osteopenia or osteoporosis has biological plausibility, yet it remains inconclusive; therefore, we conducted a systematic review and meta-analysis to evaluate the associations between exposure to heavy metals (i.e., cadmium, lead, and mercury) and the risk of osteopenia or osteoporosis. Databases of MEDLINE, Embase, Scopus, and Web of Science were searched through November 2019, to identify studies that evaluated the relationship between exposure to cadmium, lead, and mercury and risk of osteopenia or osteoporosis in adults. Fourteen eligible studies were included. Effect sizes expressed as pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated using weighted random-effect models. Exposure to cadmium (OR = 1.35; 95% CI: 1.17 to 1.56; P ≤ 0.001) and lead (OR = 1.15; 95% CI: 1.00 to 1.32; P = 0.05) was associated with an increased risk of osteopenia or osteoporosis, unlike mercury. Subgroup analyses showed cadmium exposure increased the risk of osteopenia or osteoporosis in older (> 65 yrs.; OR = 1.43; 95%CI: 1.08 to 1.88, P = 0.01) compared with younger (18-65 yrs.; OR = 1.24; 95% CI: 1.02 to 1.52, P = 0.03) adults. Also, lead exposure increased the risk in men (OR = 1.55; 95% CI: 1.15 to 2.09, P = 0.007) unlike in women. By contrast to urinary levels, blood (OR = 1.26; 95% CI: 1.08 to 1.47, P = 0.003) and dietary (OR = 1.46; 95% CI: 1.28 to 1.67, P < 0.001) levels of cadmium were associated with an increased risk of osteopenia or osteoporosis. Exposure to cadmium and lead may be associated with an increased risk of osteopenia or osteoporosis, although high heterogeneity was detected.

Chronic cadmium exposure induced hepatic cellular stress and inflammation in aged female mice

Previous studies have revealed that acute cadmium (Cd) exposure led to inflammation in different organs through an oxidative stress mechanism. However, whether chronic Cd exposure induces inflammation in liver and the mechanistic link between inflammation and cell stress remains unclear. In the present study, we investigated the effects of chronic Cd exposure on hepatic cellular stress and inflammatory responses. Female CD1 mice were administrated with CdCl₂ (10 and 100 mg/L) in drinking water for 57 weeks. Our results showed that the mRNA levels of Inos and the protein content of HO-1, markers of oxidative stress, were markedly increased in Cd-treated mice. In addition, the protein level of GRP78, the chaperone of endoplasmic reticulum (ER) stress, was significantly increased in Cd-treated mice. The expression of the proteins CHOP and peIF2α, two proteins downstream of ER stress, was also upregulated in the Cd-100 mg/L and Cd-10 mg/L group, respectively. Moreover, there were increased inflammatory cells existing in liver after Cd administration. Besides, there was a significant elevation in the mRNA level of Mip-2, Il-10 and Il-12 in the Cd-100 mg/L group. The mRNA level of Tgf-β was also upregulated in Cd-treated mice. Moreover, we also found that the number of Ki67-positive hepatic cells was increased in the Cd-10 mg/L group. Hence, our results indicated that chronic Cd exposure induced oxidative stress, ER stress, inflammatory responses and proliferation in the liver of aged female mice.

Cadmium modulates hematopoietic stem and progenitor cells and skews toward myelopoiesis in mice

The heavy metal cadmium (Cd) is known to modulate immunity and cause osteoporosis. However, how Cd influences on hematopoiesis remain largely unknown. Herein, we show that wild-type C57BL/6 (B6) mice exposed to Cd for 3months had expanded bone marrow (BM) populations of long-term hematopoietic stem cells (LT-HSCs), common myeloid progenitors (CMPs) and granulocyte-macrophage progenitors (GMPs), while having reduced populations of multipotent progenitors (MPPs) and common lymphoid progenitors (CLPs). A competitive mixed BM transplantation assay indicates that BM from Cd-treated mice had impaired LT-HSC ability to differentiate into mature cells. In accordance with increased myeloid progenitors and decreased lymphoid progenitors, the BM and spleens of Cd-treated mice had more monocytes and/or neutrophils and fewer B cells and T cells. Cd impaired the ability of the non-hematopoietic system to support LT-HSCs, in that lethally irradiated Cd-treated recipients transplanted with normal BM cells had reduced LT-HSCs after the hematopoietic system was fully reconstituted. This is consistent with reduced osteoblasts, a known critical component for HSC niche, observed in Cd-treated mice. Conversely, lethally irradiated control recipients transplanted with BM cells from Cd-treated mice had normal LT-HSC reconstitution. Furthermore, both control mice and Cd-treated mice that received Alendronate, a clinical drug used for treating osteoporosis, had BM increases of LT-HSCs. Thus, the results suggest Cd increase of LT-HSCs is due to effects on HSCs and not on osteoblasts, although, Cd causes osteoblast reduction and impaired niche function for maintaining HSCs. Furthermore, Cd skews HSCs toward myelopoiesis.

Impact of dialyzer membrane flux on metal clearance in hemodialysis patients

Deficiency of essential trace elements (such as Cu or Zn) and accumulation of potentially toxic trace elements (as Cd or Pb) are both known to have adverse effects in hemodialysis (HD) patients. Up to our knowledge, no studies about the permeability of low and high flux polysulfone membranes on metal ions during hemodialysis are available. Therefore, the aim of the present study was to address this issue. Forty one hemodialysis patients (19 were using high flux polysulfone membrane while the remaining were using low flux one) participated in the study. Blood levels of Cu, Zn, Cd and Pb were determined by graphite furnace atomic absorption spectrometry among HD patients, before and after dialysis session, as well as among matched 40 healthy persons. Blood concentrations of Cu and Zn in the whole hemodialysis group was significantly lower than those of the healthy control group, on the other hand the toxic metals (Cd and Pb) levels were observed to be significantly higher among HD patients compared to the normal persons. Among the hemodialysis group, there were no significant differences between the low and high flux dialyzer groups in terms of pre-dialysis blood levels of Cu, Zn, Cd and Pb. In addition, significantly decreased levels of all metal ions were observed after dialysis sessions using either low or high flux membranes. An exception was Pb which did not show any difference between pre-dialysis and post-dialysis values in the low flux groupIn conclusion Zn and Cu deficiencies should be considered in the treatment of these patients. High flux membranes are more efficient than low flux ones in removing excess Cd and Pb. Therefore, when high flux membranes are used, chelation therapy might not be required for Cd and Pb overload.

Association Between Blood Cadmium Levels and Mortality in Peritoneal Dialysis

The negative impact of environmental exposure of cadmium has been well established in the general population. However, the effect of cadmium exposure in chronic peritoneal dialysis (PD) patients remains uncertain.A total of 306 chronic PD patients were included in this 36-month observational study. Patients were stratified into 3 groups by the tertile of baseline blood cadmium levels (BCLs): high (>0.244 μg/L, n = 101), middle (0.130-0.244 μg/L, n = 102), and low (<0.130 μg/L, n = 103) for cross-sectional analyses. Mortality rates and cause of death were recorded for longitudinal analyses.Patients in the high-BCL group were older, more likely to have diabetes mellitus, had lower levels of serum albumin and lower percentage of lean body mass than patients in the low-BCL group. A multivariate logistic regression analysis revealed that logarithmic transformed BCL was independently associated with a higher risk of low turnover bone disease (odds ratio = 3.8, P = 0.005). At the end of the 36-month follow-up, 66 (21.6%) patients died. Mortality rates increased with higher BCLs (P for trend = 0.005). A Cox multivariate analysis showed that, using the low-BCL group as the reference, the high-BCL group had increased hazard ratios (HR) for all-cause mortality in chronic PD patients after adjusting for related variables (HR = 2.469, 95% confidence interval = 1.078-5.650, P = 0.043).In conclusion, BCL showed significant association with malnutrition and low turnover bone disease in chronic PD patients. Furthermore, BCL is an important determinant of mortality. Our findings suggest that avoiding environmental exposure to cadmium as much as possible is warranted in chronic PD patients.

Effect of Blood Cadmium Level on Mortality in Patients Undergoing Maintenance Hemodialysis

Previous studies of general populations indicated environmental exposure to low-level cadmium increases mortality. However, the effect of cadmium exposure on maintenance hemodialysis (MHD) patients is unclear.A total of 937 MHD patients from 3 centers in Taiwan were enrolled in this 36-month observational study. Patients were stratified by baseline blood cadmium level (BCL) into 3 groups: high BCL (>0.521 μg/L; n = 312), intermediate BCL (0.286-0.521 μg/L; n = 313), and low BCL (<0.286 μg/L; n = 312). The mortality rates and causes of death were analyzed.The analytic results demonstrated patients in the high BCL group had a significantly higher prevalence of malnutrition and inflammation than patients in the low and intermediate BCL groups. After 3 years of follow-up, 164 (17.5%) patients died and the major cause of death was cardiovascular disease. A Cox multivariate analysis indicated the high BCL group had increased hazard ratios (HRs) for all-cause mortality (HR = 1.72; 95% confidence interval [CI]: 1.14-2.63; P = 0.018), cardiovascular-related mortality (HR = 1.85; 95% CI: 1.09-3.23; P = 0.032), and infection-related mortality (HR = 2.27; 95% CI: 1.12-4.55; P = 0.035). A Cox multivariate analysis of MHD patients who never smoked (n = 767) indicated the high BCL group had increased HRs for all-cause mortality (HR = 1.67; 95% CI: 1.04-2.63; P = 0.048) and cardiovascular-related mortality (HR = 2.08; 95% CI: 1.08-4.00; P = 0.044).In conclusion, BCL is an important determinant of mortality in MHD patients. Therefore, MHD patients should avoid cadmium exposure as much as possible, such as tobacco smoking and eating cadmium-containing foods.

Comparing gene expression during cadmium uptake and distribution: untreated versus oral Cd-treated wild-type and ZIP14 knockout mice

The nonessential metal cadmium (Cd) is toxic only after entering the cell. Proteins possibly relevant to intracellular Cd accumulation include the divalent metal transporter-1 (DMT1) and all 14 zinc-like iron-like protein (ZIP) importers, 10 zinc transporter (ZnT) exporters, and metallothionein chaperones MT1 and MT2. Comparing oral Cd-treated ZIP14 knockout (KO) with wild-type (WT) mice, we predicted Cd uptake and distribution would be diminished in the KO-because ZIP14 is very highly expressed in GI tract and liver; this was indeed observed for Cd content in liver. However, the reverse was found in kidney and lung from 6 or 12 h through 10 days of Cd exposure; at these times, Cd accumulation was unexpectedly greater in KO than WT mice; mRNA levels of the 27 above-mentioned genes were thus examined in proximal small intestine (PSI) versus kidney to see if these paradoxical effects could be explained by substantial alterations in any of the other 26 genes. PSI genes highly expressed in untreated WT animals included seven ZIP and five ZnT transporters, DMT1, MT1, and MT2; kidney genes included 11 ZIP and 7 ZnT transporters, DMT1, MT1, and MT2. Over 10 days of oral Cd, a bimodal response was seen for Cd content in PSI and for various mRNAs; initially, acute effects caused by the toxic metal; subsequently, the up- or down-regulation of important genes presumably to combat the sustained adversity. These data underscore the complex interplay between the gastrointestinal tract and renal proteins that might be relevant to Cd uptake and distribution in animals exposed to oral Cd.

Association between blood cadmium levels and malnutrition in peritoneal dialysis

Background

Malnutrition is associated with an increased risk of cardiovascular death and may cause protein-energy wasting in individuals with chronic kidney disease. A previous study demonstrated that blood cadmium levels (BCLs) were associated with malnutrition in maintenance hemodialysis (MHD) patients. However, the correlation between cadmium exposure and malnutrition remains unclear in chronic peritoneal dialysis (CPD) patients. This study examined the possible adverse effects of environmental cadmium exposure in CPD patients.

Methods

A total of 301 CPD patients were enrolled and divided into 3 study groups based on the following BCL tertiles: low (<0.19 μg/L), middle (0.19–0.39 μg/L), and high (>0.39 μg/L). Demographic, hematological, biochemical, and dialysis-related data were obtained for analysis. The analysis also included values of nutritional and inflammatory markers.

Results

The BCLs of CPD patients were lower than those of MHD patients. At baseline, patients in the high BCL group were older and had a higher prevalence of diabetes mellitus but lower serum albumin, creatinine, and phosphate levels than the patients in the other 2 groups. After adjusting for potential variables, stepwise backward multiple linear regression analysis revealed that age and alanine aminotransferase levels were positively associated with logarithmic transformation of BCLs (log BCLs), while serum albumin levels were negatively associated with log BCLs in CPD patients. The log BCLs were a significant determinant (beta coefficient ± standard error = -0.185 ± 0.074; P = 0.013) of nutritional status and significantly associated with the presence of malnutrition (odds ratio = 2.64; 95% confidence interval: 1.07–6.48; P = 0.035) in CPD patients after adjustment for related variables.

Conclusions

BCL is significantly associated with nutritional status and malnutrition in CPD patients. Therefore, it is important for CPD patients to avoid environmental exposure to cadmium such as through smoking and consumption of cadmium-rich foods.

Elemental concentrations in scalp hair, nutritional status and health-related quality of life in hemodialysis patients

Elemental concentrations in hair from hemodialysis (HD) patients have not been well investigated. We examined the relationships between the elemental concentrations in scalp hair and health-related quality of life (HRQOL) and nutritional status in HD patients. Twenty six elemental concentrations were measured in scalp hair samples from 60 male HD patients using inductively-coupled plasma mass spectrometry. To evaluate HRQOL, the Short Form 36 item health survey (SF36) was used. As indices of nutritional status, body mass index, serum parameters, and geriatric nutritional risk index (GNRI) were used. Phosphorus correlated positively with serum creatinine, blood urea nitrogen (BUN), GNRI and the physical domains of the SF36. Zinc correlated positively with serum creatinine, BUN and the physical domains of the SF36. Mercury and arsenic correlated positively with BUN. Cadmium correlated negatively with serum albumin, BUN and GNRI. Copper correlated positively with the physical domains of the SF36. Iodine correlated negatively with the physical domains of the SF36. Selenium correlated negatively with the mental domains of the SF36. In conclusion, phosphorus and zinc concentrations in scalp hair can be additional biomarkers of HRQOL and/or nutritional status in HD patients. Cadmium accumulation correlated with malnutrition. Iodine and selenium accumulation may adversely affect HRQOL. Further investigation is necessary to determine precisely how these elements affect these measures.

Serum cadmium levels are independently associated with endothelial function in hemodialysis patients

OBJECTIVE

Hemodialysis (HD) patients are at risk of deficiency of essential trace elements and excess of toxic trace elements. The aim of the study was to evaluate the relation between the serum levels of some trace elements and heavy metals (iron, zinc, manganese, copper, magnesium, cobalt, cadmium, and lead) and endothelial function in HD patients.

METHODS

Forty-eight chronic HD patients without known atherosclerotic disease and 42 age- and sex-matched healthy individuals were included in the study. The serum levels of trace elements (iron, zinc, manganese, copper, and magnesium) and heavy metals (cobalt, cadmium, and lead) were measured by Atomic Adsorption Spectrophotometer (UNICAM-929).

RESULTS

The serum levels of iron, zinc, and manganese were lower, and levels of copper, magnesium, cobalt, cadmium, and lead were higher in HD patients compared to controls. Flow-mediated dilatation (FMD %) in HD patients was lower than that in the control group (7.27 ± 0.76 vs. 11.29 ± 0.82, P < 0.001). There was a significant negative correlation between FMD % and serum levels of cobalt (r = -0.313, P = 0.03) and cadmium (r = -0.524, P < 0.01). A linear regression analysis showed that serum cadmium levels were still significantly and negatively correlated with FMD % (regression coefficient = -0.526, P < 0.001).

CONCLUSION

We first demonstrated that serum cadmium levels independently predict endothelial function in HD patients without known atherosclerotic disease.

High incidence and recurrence of transitional cell carcinoma in Taiwanese patients with end-stage renal disease

AIM

This study examines the epidemiology of transitional cell carcinoma (TCC) in end-stage renal disease (ESRD) population from Taiwan, the area with the highest incidence and prevalence of ESRD.

METHODS

A total of 98 out of 10,890 ESRD patients were referred for management of TCC between 2000 and 2008. Demographic, clinical and laboratory data were collected and patient mortality and tumour recurrence rates were analyzed.

RESULTS

TCC patients were aged 61.4 ± 10.2 years and 66.3% were female. The average time from initiation of dialysis to tumour detection was 51.2 ± 36.4 months. Hypertensive nephrosclerosis, diabetes mellitus, chronic glomerulonephritis and unknown aetiology accounted for 25.5%, 20.4%, 22.4% and 31.6% of the causes of renal failure, respectively. The aetiology of renal failure for the 31.6% of patients was unclear, but chronic tubulointerstitial nephritis following long-term consumption of Chinese herbs (19.4%) or analgesic compounds (3.1%) was considered in some patients. Almost all (98.0%) patients presented with gross haematuria. Most TCC were in early stage (stage 0, 3.1%; stage I, 56.1%) during diagnosis. At the end of this study, 17 of 98 (17.3%) patients died. Multivariate Cox regression analysis found that age (odds ratio =1.140, 95% confidence interval = 1.049-1.239, P = 0.002) and tumour pain (odds ratio = 0.234, 95% confidence interval = 0.057-0.961, P = 0.044) were significant risk factors for all-cause mortality. Furthermore, 35.7% of TCC recurred during follow up. The 5 year patient and tumour-free survival rates were 72.4% and 14.4%, respectively.

CONCLUSION

The data shows that Taiwanese patients with ESRD had high incidence (0.9%) and recurrence (35.7%) of TCC.

White blood cell count predicts all-cause, cardiovascular disease-cause and infection-cause one-year mortality of maintenance hemodialysis patients

Elevated white blood cell (WBC) counts predict coronary heart disease and all-cause mortality in the general population. Chronic inflammation and malnutrition are associated with increased risk of cardiovascular death in individuals with chronic kidney disease. In this study, we investigated the association between WBC count with inflammation, malnutrition, and mortality in maintenance hemodialysis (MHD) patients. A total of 959 MHD patients were stratified into four equal sized groups based on WBC count. Demographic, hematological, nutritional and inflammatory markers, and biochemical and dialysis-related data were obtained for cross-sectional analysis. All patients were followed for one year to investigate the risks for mortality. The mean WBC count was 6.4 ± 1.8 × 10(3)/µL (range: 2.3-16.3 × 10(3)/µL). Stepwise multiple linear regression analysis indicated a positive correlation between WBC count and inflammation (high-sensitivity C-reactive protein > 3 mg/L). Forty-five patients (4.7%) died within the 1-year study period. Cox multivariate regression analysis demonstrated that total WBC count significantly predicts 1-year mortality due to all-cause (hazard ratio (HR): 1.228, 95% confidence interval (CI): 1.095-1.378; P < 0.001), due to cardiovascular disease (HR: 1.242, 95% CI: 1.046-1.475; P = 0.013) and due to infection (HR: 1.252, 95% CI: 1.066-1.470; P = 0.006). These findings suggest that total WBC count should be measured in future studies that evaluate the clinical outcome of MHD patients and that dialysis patients with elevated WBC counts require further medical attention to reduce risks of mortality.

Microarray analysis of gene expression patterns in human proximal tubule cells over a short and long time course of cadmium exposure

Numerous studies showed that renal proximal tubules cells are the cell type critically affected by chronic exposure to cadmium (Cd(2+)). The aim of the present study was to apply global gene expression technology and a human renal epithelial cell culture model (HPT) to determine whether time of exposure to Cd(2+) exerts a major influence on the resulting pattern of global gene expression. HPT cells were exposed to Cd(2+) for a short, 1-d, period of exposure (9, 27, and 45 μM) versus a longer, 13-d, period (4.5, 9, and 27 μM), with the hypothesis being that the stress response of the cells would be more active during the short time of exposure. The results showed that the differential expression of genes was very extensive for HPT cells exposed to Cd(2+) for 1 d, with more than 1848 genes displaying alterations compared to control and with the major categories of genes being involved in stress responses; cell death; checkpoint arrest, DNA repair, and the cell cycle; inflammatory responses; and cell adhesion, motion and differentiation. In contrast, HPT cells exposed to Cd(2+) for 13 d showed 923 genes to be differentially expressed, with a marked reduction in the number of differentially expressed stress response genes and a significant increase in the number of genes involved in development and differentiation. There were 387 differentially expressed genes common to both times of exposure. Data suggest that unless one is actively seeking to study the acute stress response, global gene expression technology should not be applied within an early time course of toxicant exposure.

Association between body mass and mortality in maintenance hemodialysis patients

A total of 959 Taiwanese patients undergoing maintenance hemodialysis-102 underweight (BMI < 18.5 kg/m(2)), 492 normal weight (BMI 18.5-22.9 kg/m(2)), 187 overweight (BMI 23.0-24.9 kg/m(2)), and 178 obese (BMI >or= 25 kg/m(2)) were recruited into this three-year, multicenter longitudinal study. It was found initially that the underweight group had more females, longer hemodialysis durations, less use of a biocompatible membrane (BCM) dialyzer, higher erythropoietin doses and Kt/V(urea), and lower white blood cell counts, hemoglobin, serum creatinine and phosphate, and high sensitivity C-reactive protein (hsCRP) than other groups (P < 0.001). Furthermore, a chi(2)-test demonstrated that underweight patients had poorer nutrition (P = 0.023), but less systemic inflammation (P < 0.001) than other groups. A stepwise multiple linear regression analysis established that age, sex, diabetes mellitus, hemodialysis duration, use of BCM dialyzer, Kt/V(urea), creatinine, high-density lipoprotein cholesterol, and hsCRP were significant risk factors associated with BMI (P < 0.001-0.002). After three years, 149 (15.5%) patients had died, including 22 of 102 (21.6%) underweight patients, 64 of 492 (13.0%) normal weight patients, 38 of 187 (20.3%) overweight patients, and 25 of 178 (15.5%) obese patients. The primary causes of mortality were cardiovascular (52.3%) and infection (39.6%). A multivariate Cox regression analysis revealed that age, diabetes mellitus, BMI, albumin, hsCRP, and cardiothoracic ratio were significant risk factors associated with all-cause mortality over three years (P < 0.001-0.022). Finally, Kaplan-Meier analysis confirmed that underweight patients suffer higher mortality than other groups (Log rank, P = 0.0392); therefore, the data have demonstrated a survival disadvantage of low BMI in Taiwanese patients undergoing maintenance hemodialysis.

High-calcium dialysate: a factor associated with inflammation, malnutrition and mortality in non-diabetic maintenance haemodialysis patients

AIM

Chronic inflammation, which is common in dialysis patients, often causes malnutrition and even protein-energy wasting. However, the association of high-calcium dialysate with malnutrition and/or inflammation in non-diabetic maintenance haemodialysis patients remains unclear. This study investigated the possible adverse effects of high-calcium dialysate and mortality in this population.

METHODS

A total of 717 non-diabetic haemodialysis patients participated in this 2 year prospective study. The subjects were categorized into three subgroups based on whether dialysate calcium concentrations were high (3.5 mEq/L), standard (3.0 mEq/L) or low (2.5 mEq/L). Demographic, haematological, nutritional and inflammatory markers, biochemical and dialysis-related data were obtained for cross-sectional analysis. Causes of death and mortality rates were also analyzed for each subgroup.

RESULTS

Patients with high-calcium dialysate (n = 82) had a higher incidence of malnutrition and inflammation (61.0% vs 44.1% and 43.9%, respectively) than those with standard- and low-calcium dialysate (n = 528 and 107). Backward stepwise multiple regression analysis revealed that high-calcium dialysate was negatively correlated with nutritional index, serum albumin levels, but positively associated with the inflammatory marker of serum ferritin levels. At the end of the 2 year follow up, 45 patients had died. Cox multivariate analysis demonstrated that high-calcium dialysate was a significant associated factor (relative risk 2.765; 95% confidence interval 1.429-5.352) for 2 year all-cause mortality in these patients.

CONCLUSION

The analytical results indicate that high-calcium dialysate is associated with malnutrition and inflammation as well as 2 year mortality in non-diabetic maintenance haemodialysis patients and the findings suggest that this population, even those with optimal mineral balance, should avoid high-calcium dialysate.

Blood cadmium level's association with 18-month mortality in diabetic patients with maintenance haemodialysis

BACKGROUND

Cadmium exposure is related to severity of diabetes and diabetes-related organ damage in diabetic patients. Elevated blood cadmium levels (BCLs) are well known in maintenance haemodialysis (MHD) patients but the clinical significance in diabetic MHD patients remains unknown.

METHODS

A total of 212 diabetic MHD patients were enrolled in this 18-month prospective study and were categorized into three equal groups according to the basal BCL: high (> 0.889 μg/L; n = 71), middle (0.373-0.889 μg/L; n = 70) and low (< 0.373 μg/L; n = 71) BCL groups. The mortality and cause of death were recorded and analysed longitudinally.

RESULTS

Patients with high BCL had trends of higher white blood cell counts, glycosylated haemoglobin, phosphate and blood lead levels than other group patients. At the end of the follow-up, 31 patients had died. Kaplan-Meier analysis showed that the high BCL group patients had a higher mortality than other group patients (log-rank test, P = 0.036). Cox multivariate analysis demonstrated that logarithmic BCL was associated with increased hazard ratios (HR) for the all-cause mortality (HR = 2.336, 95% confidence intervals [CI] = 1.099-4.964, P = 0.027) in diabetic MHD patients. Similarly, if the low BCL group was the reference, the high BCL was associated with increased HR for all-cause mortality (HR = 2.865, 95% CI = 1.117-7.353, P = 0.043) in these patients.

CONCLUSIONS

The study results first demonstrated that BCL is associated with increased HR for 18-month all-cause mortality in diabetic MHD patients. Avoiding smoking and high cadmium-containing food may be important in these patients.

Selenium, lead, and cadmium levels in renal failure patients in China

Whole blood and serum samples of Chinese stable chronic renal failure (CRF) patients (n = 81), hemodialysis patients (n = 135), posttransplant patients (n = 60), and subjects with normal renal function (NRF; N = 42) were collected, as well as water and dialysate samples from five dialysis centers. The concentration of selenium (Se), lead (Pb), and cadmium (Cd) was measured by atomic absorption spectrometry. The mean serum Se levels in patients with different degrees of renal failure were significantly lower than those of subjects with NRF (p < 0.01). Pb levels were not increased in renal failure patients, while the Cd levels in patients with various degrees of renal failure were higher than in subjects with NRF (p < 0.05). After correcting the results of Pb and Cd for hematocrit (Hct) however, Pb levels of dialysis patients were also increased. In the dialysis population under study, blood Pb and Cd levels were closely related to the time on dialysis, while contamination of the final dialysate may also contribute to the increased blood Cd and to a less extent Pb levels. Correction for Hct may be recommended to accurately compare blood Pb and Cd levels in dialysis patients and CRF patients with varying degrees of anemia to those of subjects with NRF.