Determination of creatinine-related molecules in saliva by reversed-phase liquid chromatography with tandem mass spectrometry and the evaluation of hemodialysis in chronic kidney disease patients.

The serum concentrations of creatinine (Cre) and urea are used for the determination of the renal function. However, the use of blood is not always suitable due to the invasive, hygienic and infection problems during its sample collection and handling. In contrast, saliva is relatively clean and the samples can be quickly and noninvasively collected and easily stored. Therefore, the simultaneous determination of Arginine (Arg), creatine (Cr) and Cre in the saliva of chronic kidney disease (CKD) patients was performed by UPLC-ESI-MS/MS together with the saliva of healthy volunteers. The evaluation of hemodialysis of CKD patients was also carried out by the determinations before and after the dialysis. An HS-F5 column was used for the simultaneous determination of Arg, Cr and Cre in the saliva. These molecules were rapidly separated within 4 min and sensitively determined by the multiple reaction monitoring (MRM) of the precursor ion [M+H](+) â†’ product ions (m/z 175.1 â†’ 70.1 for Arg; m/z 132.0 â†’ 44.1 for Cr; m/z 114.0 â†’ 44.1 for Cre). The concentration of Cre in the CKD patients was higher than that in the healthy persons. The concentrations of Cre in the saliva of the patients before hemodialysis were moderately correlated with the serum Cre concentrations (R(2) = 0.661). Furthermore, the concentration in the saliva obviously decreased after hemodialysis (before 0.73 mg/dL, after 0.25 mg/dL; p < 0.02). Thus, the proposed detection method using saliva by UPLC-MS/MS is useful for the evaluation of the renal function in CKD patients. The present method offers a new option for monitoring the hemodialysis of CKD patients.

Hypersensitivity reactions to acetate in the bicarbonate dialysate in a patient undergoing pre-dilution online hemodiafiltration.

A 63-year-old male patient first experienced recurrent hypotensive episode during the dialysis session just after switching the mode from hemodialysis to online hemodiafiltration (OL-HDF) with infusion in pre-dilution of the bicarbonate dialysate containing 9.2 mEq/L of acetate. Peripheral eosinophil count and serum IgE were both elevated to 16,440/µL and 2000 IU/L. The reactions promptly dissolved with substitution of acetate-free solution. This case illustrated that pre-dilution OL-HDF can induce an occult hypersensitivity to acetate in the standard bicarbonate dialysate.

Effects of change in the formulation of lanthanum carbonate on laboratory parameters.

Lanthanum carbonate (LC) is available in the two formulations of chewable tablets and granules. In this study, we changed the formulation of LC from chewable tablet to granules, and compared the laboratory parameters for 3 months before and after changing formulation in 58 hemodialysis (HD) patients. We also surveyed patients about their preferences for the two formulations. The mean serum phosphorus (P) levels decreased significantly (P < 0.01) from 6.7 mg/dL to 6.4 mg/dL after the change. The levels for serum albumin and geriatric nutritional risk index increased significantly (P < 0.01). Serum calcium levels also increased significantly (P < 0.01), while serum intact parathyroid hormone levels decreased significantly (P < 0.01). In the survey, approximately half of the patients responded that the granules were easier to take than the chewable tablets. These findings suggest that changing the formulation of LC to granules may reduce serum P levels of the HD patients in clinical practices.

A comparison of systemic inflammation-based prognostic scores in patients on regular hemodialysis.

BACKGROUND/AIMS: Systemic inflammation-based prognostic scores have prognostic power in patients with cancer, independently of tumor stage and site. Although inflammatory status is associated with mortality in hemodialysis (HD) patients, it remains to be determined as to whether these composite scores are useful in predicting clinical outcomes. METHODS: We calculated the 6 prognostic scores [Glasgow prognostic score (GPS), modified GPS (mGPS), neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), prognostic index (PI) and prognostic nutritional index (PNI), which have been established as a useful scoring system in cancer patients. We enrolled 339 patients on regular HD (age: 64 ± 13 years; time on HD: 129 ± 114 months; males/females = 253/85) and followed them for 42 months. The area under the receiver-operating characteristics curve was used to determine which scoring system was more predictive of mortality. RESULTS: Elevated GPS, mGPS, NLR, PLR, PI and PNI were all associated with total mortality, independent of covariates. If GPS was raised, mGPS, NLR, PLR and PI were also predictive of all-cause mortality and/or hospitalization. GPS and PNI were associated with poor nutritional status. Using overall mortality as an endpoint, the area under the curve (AUC) was significant for a GPS of 0.701 (95% CI: 0.637-0.765; p < 0.01) and for a PNI of 0.616 (95% CI: 0.553-0.768; p = 0.01). However, AUC for hypoalbuminemia (<3.5 g/dl) was comparable to that of GPS (0.695, 95% CI: 0.632-0.759; p < 0.01). CONCLUSION: GPS, based on serum albumin and highly sensitive C-reactive protein, has the most prognostic power for mortality prediction among the prognostic scores in HD patients. However, as the determination of serum albumin reflects mortality similarly to GPS, other composite combinations are needed to provide additional clinical utility beyond that of albumin alone in HD patients.

Brachial-ankle pulse wave velocity and the cardio-ankle vascular index as a predictor of cardiovascular outcomes in patients on regular hemodialysis.

Brachial-ankle pulse wave velocity (baPWV) and the cardio-ankle vascular index (CAVI) are both used to evaluate arterial stiffness. The aim of the present study is to determine whether baPWV or CAVI is superior as a marker of arterial stiffness in hemodialysis (HD) patients. Of 194 patients, 59 patients had been excluded from the study due to advanced age over 76 years old (n = 29), or abnormal ankle-brachial pressure index (ABI) (<0.90 or ≥1.30) (n = 30). We then followed the 135 patients (age: 60 ± 11 years, time on HD: 110 ± 93 months) for the 63 ± 4 (55-70) months. Thirty-two (23.7%) patients had expired, 22 of them of cardiovascular (CV) causes. There were 37 fatal and non-fatal CV events. Kaplan-Meier analysis revealed that the patients with the highest tertile of baPWV (≥16.6 m/s) had a significantly lower survival rate (P < 0.01) when compared with the second (13.4 ≤ baPWV < 16.6 m/s) and the lowest tertiles (<13.4 m/s). Cox hazards analysis after adjustment for comorbid risk factors revealed that the top tertile of baPWV was a determinant of CV death (hazards ratio [HR]: 16.9 [1.1-251.8], P < 0.05) In contrast, CAVI did not associate with CV mortality or events. These findings suggest that baPWV is superior to CAVI as a predictor of CV outcomes in patients on regular HD.

Association of HCV core antigen seropositivity with long-term mortality in patients on regular hemodialysis.

Anti-hepatitis C virus (HCV) antibody seropositivity is independently associated with poor prognosis in hemodialysis (HD) patients. However, anti-HCV antibody cannot distinguish between patients with active infection and those who have recovered from infection. We therefore aimed in this study to examine the association of HCV core antigen (HCVcAg) seropositivity with mortality in HD patients. We first measured serum HCVcAg using an immunoradiometric assay and anti-HCV antibody in 405 patients on regular HD, and followed them for 104 months. There were 82 patients (20.2%) who had been positive for anti-HCV antibodies; 57 (69.5%) of these were positive for HCVcAg. During the follow-up, 29 patients were excluded, so we tested the association of HCVcAg seropositivity with all-cause, cardiovascular (CV) and non-CV mortalities in 376 patients. A total of 209 patients (55.6%) had expired during the observational period, 92 out of them due to CV causes. After adjusting for comorbid parameters, HCVcAg was independently associated with overall mortality (HR 1.61, 95% CI 1.05-2.47, p < 0.05). HCV infection was significantly related to liver disease-related mortality. Past HCV infection also contributed to CV mortality (HR 2.63, 95% CI 1.27-5.45, p < 0.01). In contrast, anti-HCV antibody and HCVcAg seropositivities did not associate with infectious disease-related and cancer-related (expect for hepatocellular carcinoma) mortality. It follows from these findings that HCVcAg serology is associated with all-cause and CV mortality in HD patients.

Influence of the assay for measuring serum albumin on corrected total calcium in chronic hemodialysis patients.

The Japanese Society for Dialysis Therapy guideline for secondary hyperparathyroidism recommends the use of albumin-corrected serum Ca as a therapeutic target in chronic hemodialysis patients; however, the assay used for albumin measurement may affect the corrected Ca level. In this study, we examined the impact of the albumin assay on corrected Ca levels in hemodialysis patients. We measured serum albumin using bromocresol green (BCG) and modified bromocresol purple (BCP) assays, and corrected Ca for albumin using Payne's formula in 422 hemodialysis patients (age 66±13 years; time on hemodialysis 116±111 months). Serum albumin values were 3.7±0.4 (1.4-4.6) g/dL by BCG and 3.3±0.4 (1.0-4.3) g/dL by modified BCP, with the differences between the two assays ranging from 0.0 to 0.6 with a mean of 0.35±0.09 g/dL. Serum C-reactive protein and globulin values were significantly higher in patients with differences in albumin greater than 0.5 g/dL (P<0.01). Based on the BCG method, 71 patients (16.8%) were classified with hypocalcemia, 51 (12.1%) with hypercalcemia, and 300 (70.0%) as normocalcemic. In contrast, when using modified BCP, 33 patients (7.9%) were labeled as hypocalcemic, while 92 (21.8%) were hypercalcemic. Depending on the use of either BCG or modified BCP, a discrepancy of classification was observed in 79 patients (18.7%): 41 patients were re-classified from normocalcemic to hypercalcemic, and 38 patients were re-classified from hypocalcemic to normocalcemic by selecting the modified BCP assay. These findings suggest that the type of assay used for albumin measurement has an impact on albumin-corrected Ca levels.

Association of abdominal visceral adiposity and thigh sarcopenia with changes of arteriosclerosis in haemodialysis patients.

BACKGROUND: In haemodialysis (HD) patients, abdominal visceral fat is accumulated while lean body mass is decreased irrespective of their body mass indexes (BMI). However, it is poorly understood which changes of fat and muscle masses are more associated with changes of arteriosclerosis. We aimed at examining the associations of abdominal visceral fat and thigh muscle masses with markers of arteriosclerosis in chronic HD patients in a cross-sectional fashion. PATIENTS AND METHODS: We measured abdominal visceral fat mass area (AVFA), abdominal subcutaneous fat mass area (ASFA), thigh muscle area (TMA) and TMA standardized for femoral shaft area (TMA/FSA) by computed tomography (CT) in 161 HD patients (age: 61 ± 11 years, time on HD: 12 ± 10 years, male/female = 113/48, non-diabetes/diabetes = 127/34). We also investigated carotid artery intima-media thickness (CA-IMT) using the ultrasound instrument, and brachial-ankle pulse wave velocity (baPWV), cardio-ankle vascular index (CAVI) and ankle-brachial pressure index (ABI) using the waveform device (CAVI-VaSera VS-1000). RESULTS: AVFA was significantly and positively related to CA-IMT in both non-diabetic (r = 0.23, P < 0.05) and diabetic HD patients (r = 0.38, P < 0.05). There was a significant and positive correlation between AVFA and hs-CRP in all patients (r = 0.26, P < 0.01). ASFA was also significantly correlated with CA-IMT (r = 0.53, P < 0.01) in diabetic HD patients. TMA/SFA ratio was negatively associated with CA-IMT (r = - 0.21, P < 0.05), while positively with ABI (r = 0.28, P < 0.01) in non-diabetic patients. TMA/SFA ratio was inversely related to baPWV (r = - 0.41, P < 0.01) and CAVI (r = - 0.41, P < 0.05) in diabetic HD patients. Multiple regression analysis revealed that AVFA was a significant determinant of CA-IMT. TMA/AFA was also significantly associated with CA-IMT, baPWV, CAVI and ABI. CONCLUSION: Accumulated abdominal visceral fat is associated with CA-IMT. In addition, reduced thigh muscle mass area is independently related to CA-IMT, baPWV, CAVI and ABI, suggesting that sarcopenia in the leg is closely associated with systemic changes of arteriosclerosis in HD patients.

Relationship between an increased serum kynurenine/tryptophan ratio and atherosclerotic parameters in hemodialysis patients.

Essential amino acid tryptophan (Trp) is mainly catabolized by indoleamine 2,3-dioxygenase, which leads to the formation of kynurenine (Kyn). In this study, we reexamined whether an increased indoleamine 2,3-dioxygenase activity, as estimated by the Kyn/Trp ratio (µM/mM), is associated with atherosclerotic parameters in hemodialysis (HD) patients. Serum Trp and Kyn were measured in 243 HD patients by liquid chromatography/electrospray ionization tandem mass spectrometry. We measured carotid artery intima-medial thickness, brachial-ankle pulse wave velocity, ankle-brachial pressure index, and the cardio-ankle vascular index. Log-transformed Kyn/Trp ratio was significantly correlated with log-transformed time on HD (ρ=0.28, P<0.01), log-transformed highly sensitive C-reactive protein (ρ=0.20, P<0.01), and peripheral total lymphocyte count (ρ=-0.13, P<0.05). A significant association was found between log-transformed Kyn/Trp ratio and mean carotid artery intima-medial thickness (ρ=0.18, P<0.01). Mean carotid artery intima-medial thickness was significantly higher in the lowest quartile of Kyn/Trp ratio (<165) (0.62±0.12 mm) when compared with the highest quartile (≥304) (0.68±0.15 mm) (P<0.01). Ankle-brachial pressure index was lower in the second quartile (1.01±0.20), the third quartile (1.01±0.19), and the fourth quartile (1.03±0.15) compared with that in the first quartile (1.09±0.13) (P<0.05). It follows from these findings that the Kyn/Trp ratio increases with time on HD, and is associated with advanced atherosclerotic changes in chronic HD patients.

Comparison of serum albumin, C-reactive protein and carotid atherosclerosis as predictors of 10-year mortality in hemodialysis patients.

Serum albumin, C-reactive protein (CRP), and the intima-medial thickness of the common carotid artery (CA-IMT) are associated with clinical outcomes in hemodialysis (HD) patients. However, it remains unclear which parameters are more reliable as predictors of long-term mortality. We measured serum albumin, CRP, and CA-IMT in 206 HD patients younger than 80 years old, and followed them for the next 10 years. One hundred sixty-eight patients (age: 57 +/- 11 years, time on HD: 11 +/- 7 years) were enrolled in the analyses. We divided all patients into three tertiles according to their albumin levels, and conducted multivariate analyses to examine the impact on 10-year mortality. Seventy-three (43.5%) patients had expired during the follow-up. Serum albumin was significantly lower in the expired patients than in the surviving patients (3.8 +/- 0.3 vs. 4.0 +/- 0.3, P<0.01), while CRP (4.7 +/- 5.0 vs. 2.8 +/- 3.5 g/L, P=0.01) and CA-IMT (0.70 +/- 0.15 vs. 0.59 +/- 0.11 mm, P<0.01) were significantly higher in the expired group. The multivariate analysis revealed that there was a significantly higher risk for total mortality in HD patients with serum albumin <3.8 g/dL (odds ratio 5.04 [95% CI: 1.30-19.60], P=0.02) when compared with those with albumin >4.1 g/dL. In contrast, CRP and CA-IMT did not associate with total death. It follows from these findings that serum albumin is more superior as a mortality predictor compared with CRP and CA-IMT in HD patients.

A small reduction in the ankle-brachial index is associated with increased mortality in patients on chronic hemodialysis.

BACKGROUND: High pulse wave velocity (PWV) and a low ankle-brachial index (ABI) are associated with mortality in hemodialysis (HD) patients. Recently, the cardio-ankle vascular index (CAVI) was developed as a novel index of arterial stiffness independent of blood pressure. METHODS: We compared brachial-ankle PWV (baPWV), the ABI and the CAVI as predictors of mortality in 194 HD patients (age 64 +/- 12 years; time on HD 111 +/- 96 months) during a follow-up period of 39 +/- 4 months (range 31-46). RESULTS: The ABI was significantly positively correlated with serum albumin and negatively with log-transformed highly sensitive C-reactive protein (p < 0.01), while baPWV and the CAVI were not. Of 194 patients, 39 patients (20.1%) died during the follow-up, 25 (64.1%) of cardiovascular causes. Kaplan-Meier analysis revealed that the patients with an ABI in the lowest tertile (<1.0) had a significantly lower survival rate (p < 0.01). Cox hazards analysis after adjustment for the conventional risk factors revealed that an ABI value in the lowest tertile was a determinant of total mortality when compared with ABI values in the highest tertile [>1.1; hazard ratio 3.50 (95% confidence interval 1.20-10.20); p = 0.02]. In contrast, baPWV and the CAVI were not associated with mortality. CONCLUSION: These findings suggest that a small reduction in the ABI (<1.0) is an independent predictor of all-cause mortality in chronic HD patients.

Blood monocyte count is a predictor of total and cardiovascular mortality in hemodialysis patients.

An increase in white blood cell (WBC) count is an independent predictor of mortality in hemodialysis (HD) patients. However, few studies have assessed the association of specific WBC subtypes with mortality. We prospectively studied the predictive value of WBC subtypes for total and cardiovascular death in 333 HD patients (age 63 +/- 12 years; HD duration 129 +/- 109 months) during a 40-month of follow-up. There was a significant and positive correlation between highly sensitive C-reactive protein and neutrophil (r = 0.28, p < 0.01) and monocyte (r = 0.20, p < 0.01) counts by a non-parametric Spearman rank analysis. Blood monocyte counts were significantly correlated inversely with ankle-brachial pressure index (r = -0.24, p < 0.01). Kaplan-Meier analysis revealed that basal neutrophil (>4,060/microl) and monocyte (>270/microl) counts in the highest tertile had a significantly lower survival rate compared to the middle and the lowest tertiles, respectively (p < 0.03). Cox hazards analysis after adjustment for other conventional risk factors revealed that monocyte counts of >270/microl became a determinant of total death compared with those of <180/microl (hazards ratio 1.98 [1.10-3.57], p = 0.02). In contrast, neutrophil and lymphocyte counts were not associated with mortality. Our findings suggest that an increased blood monocyte count is an independent predictor of long-term mortality in chronic HD patients.

Association between seroprevalence of anti-chlamydial antibodies and long-term cardiovascular mortality in chronic hemodialysis patients.

Chlamydial infection has been suspected in the pathogenesis of ischemic heart disease. However, it remains undetermined if persistent chlamydial infection is related to cardiovascular mortality in regular hemodialysis (HD) patients. We measured Chlamydia pneumoniae (Cp) antibody seropositivity in 154 HD subjects (age 59 +/- 11 years, time on HD 13 +/- 7 years, male/female = 101/53), and prospectively examined an association between Cp antibody status and cardiovascular death for 56 months of follow-up. Seropositivity for Cp IgA and IgG antibodies at the entry of the study was 50.6 and 60.8%, respectively. There was no significant difference in age, time on HD, serum albumin, C-reactive protein (CRP) and interleukin-6 (IL-6) between those positive and negative for IgA antibodies. During follow-up over 56 months, 31 patients (20.1%) expired, 16 (55.2%) of them of cardiovascular causes. Serological IgA and IgG antibody positivity did not influence mortality, while multiple Cox proportional hazards analysis revealed that diabetes, ischemic changes on electrocardiogram, log-transformed CRP and intact parathyroid hormone were independent determinants of cardiovascular death. These observations suggest that serological Cp antibody status does not affect long-term cardiovascular mortality in chronic HD patients.

Impact of serum parathyroid hormone concentration and its regulatory factors on arterial stiffness in patients undergoing maintenance hemodialysis.

BACKGROUND: Cardiovascular mortality is extremely high in patients on hemodialysis. Among a variety of pathophysiological conditions, deranged calcium homeostasis including secondary hyperparathyroidism may be one of the factors contributing to cardiovascular disease in patients on hemodialysis. This study was designed to evaluate the role of the serum parathyroid hormone (PTH) concentration and its regulatory factors in serum on arterial stiffness in patients on maintenance hemodialysis. METHODS: Arterial stiffness was assessed by pulse wave velocity (PWV) in 73 non-diabetic patients undergoing maintenance hemodialysis. At the same time, serum concentrations of calcium, phosphate, and intact PTH were measured. RESULTS: Single regression analyses revealed that arterial PWV was positively correlated with age (r = 0.505, p < 0.0001), systolic blood pressure (r = 0.250, p = 0.043), and pulse pressure (r = 0.306, p = 0.012). It was inversely correlated with the serum phosphate concentration (r = -0.240, p = 0.041) and the duration of hemodialysis treatment (r = -0.343, p = 0.003), but not with serum concentrations of calcium and intact PTH or the calcium x phosphate product in serum. By multiple regression analysis age was found to be the most significant variable affecting arterial PWV, and the duration of hemodialysis treatment negatively influenced arterial PWV. CONCLUSION: Age is an independent risk factor for arterial stiffness in patients on maintenance hemodialysis, and the serum PTH concentration and its regulatory factors in the serum are not.

Role of soluble receptors for tumor necrosis factor alpha in the development of hypoalbuminemia in hemodialysis patients.

BACKGROUND: Hypoalbuminemia is a significant predictor of mortality in patients on hemodialysis (HD). The cause of hypoalbuminemia in HD patients, however, remains to be clarified. Recent studies have demonstrated that high blood concentrations of soluble receptors for tumor necrosis factor (sTNFRs) are associated with malnutrition in a variety of diseases and that the blood sTNFRs concentrations are elevated in HD patients. METHODS: The serum concentrations of tumor necrosis factor alpha, sTNFR (p55 and p80), and interleukin (IL) 6 were measured in 21 HD patients with low (equal to or less than 3.6 g/dl) and in 19 HD patients with normal (equal to or more than 4.0 g/dl) concentrations of serum albumin who were free from acute infection, malignancy, collagen diseases, liver diseases, or surgery. The correlation between these parameters and the degree of hypoalbuminemia was examined. RESULTS: The serum concentrations of sTNFR p80 and IL-6 were significantly higher in patients with hypoalbuminemia as compared with those with normoalbuminemia (sTNFR p80: 47.4 +/- 4.7 vs. 35.3 +/- 2.1 ng/ml, p < 0.05; IL-6: 10.8 +/- 2.0 vs. 6.3 +/- 0.5 pg/ml, p < 0.05). In contrast, there was no difference in the serum concentrations of tumor necrosis factor alpha and sTNFR p55 between the two groups. Multivariate regression analysis showed that sTNFR p80 but not IL-6 significantly influenced the serum albumin concentrations. There were no significant differences in body mass index, serum total cholesterol, and normalized protein catabolic rate between the two groups. CONCLUSIONS: Our results suggest the development of hypoalbuminemia in some HD patients who do not have any obvious cause of hypoalbuminemia and that high concentrations of sTNFR p80 might contribute to the development of hypoalbuminemia in patients on long-term HD.

Elevated erythropoietin receptor and transforming growth factor-beta1 expression in stenotic arteriovenous fistulae used for hemodialysis.

The issue of whether recombinant human erythropoietin (rhEPO) increases thrombosis of arteriovenous (AV) fistulae used for hemodialysis remains unclear. Thrombosis often occurs at stenotic segments of fistulae where there is marked intimal hyperplasia and extracellular matrix accumulation. Increased expression of transforming growth factor-beta1 (TGF-beta1) has been shown to be involved in the development of atherosclerotic lesions by promoting intimal hyperplasia and extracellular matrix accumulation. To clarify the role of rhEPO in the development of stenosis of AV fistulae, this study examined expression of the erythropoietin receptor (EPO-R), TGF-beta1, plasminogen activator inhibitor type 1 (PAI-1), cellular fibronectin containing an extra domain A (EDA+), and TGF-beta1 mRNA, and assessed in situ rhEPO binding in tissue specimens from seven cutaneous veins and eight patent and seven stenosed portions of AV fistulae of patients undergoing dialysis. Prominent intimal hyperplasia was evident in the stenosed segments. Significant elevation in expression of EPO-R and TGF-beta1 was noted in patent AV fistulae compared to the cutaneous veins. Significant enhancement of EPO-R and TGF-beta expression was detected in the stenotic fistulae. Fibronectin EDA+ and PAI-1 expression was increased in intimal hyperplasia compared to patent fistulae and cutaneous veins. Elevated EPO-R expression was further confirmed by in situ binding of biotin-labeled rhEPO in stenosed tissue specimens. It is hypothesized that increased rhEPO binding due to elevated EPO-R expression contributes to the development of AV fistula stenosis caused by intimal hyperplasia and extracellular matrix accumulation in response to increased TGF-beta1 expression in patients receiving hemodialysis.