Association between serum alkaline phosphatase and primary resistance to erythropoiesis stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

Response to oral iron therapy in children with anemia of chronic kidney disease

BACKGROUND

Anemia is a common complication of chronic kidney disease (CKD) and oral iron is recommended as initial therapy. However, response to iron therapy in children with non-dialysis CKD has not been formally assessed.

METHODS

We reviewed medical records of pediatric patients with stages II-IV CKD followed in two New York metropolitan area medical centers between 2010 and 2020 and identified subjects who received oral iron therapy. Response to therapy at follow-up visits was assessed by improvement of hemoglobin, resolution of anemia by the 2012 KDIGO definition, and changes in iron status. Potential predictors of response were examined using regression analyses (adjusted for age, sex, eGFR, and center).

RESULTS

Study criteria were met by 65 children (median age 12 years, 35 males) with a median time between visits of 81 days. Median eGFR was 44 mL/min/1.73 m2, and 40.7% had glomerular CKD etiology. Following iron therapy, hemoglobin improved from 10.2 to 10.8 g/dL (p < 0.001), hematocrit from 31.3 to 32.8% (p < 0.001), serum iron from 49 to 66 mcg/dL (p < 0.001), and transferrin saturation from 16 to 21.4% (p < 0.001). There was no significant change in serum ferritin (55.0 to 44.9 ng/mL). Anemia (defined according to KDIGO) resolved in 29.3% of children. No improvement in hemoglobin/hematocrit was seen in 35% of children, and no transferrin saturation improvement in 26.9%. There was no correlation between changes in hemoglobin and changes in transferrin saturation/serum iron, but there was an inverse correlation between changes in hemoglobin and changes in ferritin. The severity of anemia and alkaline phosphatase at baseline inversely correlated with treatment response.

CONCLUSIONS

Anemia was resistant to 3 months of oral iron therapy in ~ 30% of children with CKD. Children with more severe anemia at baseline had better treatment response, calling for additional studies to refine approaches to iron therapy in children with anemia of CKD and to identify additional predictors of treatment response.

Liver Function Enzymes are Potential Predictive Markers for Kidney Allograft Dysfunction

Introduction

Biopsy of the allograft is the gold standard for assessing kidney allograft dysfunction. The aim of our pilot study was to identify serum biomarkers that could obviate the need for biopsy.

Materials and Methods

We conducted a study to identify the biomarkers in the serum from different groups of chronic kidney disease (CKD) patients and kidney transplanted patients vs. healthy individuals. The four groups (n=25 in each group) were as follows: 1) Patients with unstable kidney allograft transplants requiring biopsy for cause, 2) Patients with stable kidney allograft transplants, 3) Patients with CKD not on immunosuppressive therapy and, 4) healthy subjects. We measured the activity and level of serum alkaline phosphatase (ALP) and other liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) as potential serum biomarkers in acute allograft dysfunction.

Results

We found that ALP correlated with allograft biopsy findings, liver function, and clinical outcomes and possibly graft survival. Additionally, AST and ALT were higher in patients with graft rejection compared to non-rejected and stable kidney transplants. Moreover, the low Pearson correlations (r- values) between ALP level with age (r=0.179), gender, body mass index (r=0.236), creatinine (r=0.044) or estimated glomerular filtration rate (r=0.048) suggest that ALP may be an independent biomarker which is relatively unaffected by other individual-level variables.

Conclusion

ALP may be a putative biomarker to predict kidney allograft function and rejection. Data also indicated that liver function plays an important role for the overall success of kidney transplantation.

Exploring the association of Bone Alkaline Phosphatases And Hearing Loss

Hearing loss becomes increasingly common with age and affects quality of life. Recently, scientists have published articles about the relationship between metabolic disease and hearing loss. Metabolic disease was previously found to be highly related to an increase in alkaline phosphatase. Thus, there may be an indirect relationship between alkaline phosphatase (ALP) and hearing loss. In this paper, we will demonstrate the relationship between ALP and hearing loss. We included 3877 National Health and Nutrition Examination Survey (NHANES) participants, who represent the noninstitutionalized civilian population in the United States from age 20 to age 69, and examined the association between ALP and frequency distributions of pure-tone air-condition (PTAC) thresholds. After adjusting for pertinent variables, the subjects who belonged to the higher quartiles of ALP tended to have worse hearing thresholds (pure tone average at high and low frequencies) than the first quartile of ALP (p < 0.001). The results showed a positive correlation between ALP and hearing loss, in both males and females (p < 0.001) and in subjects whose body mass indices (BMI) were less than 30 (p < 0.001). In conclusion, ALP may play a role in detecting hearing loss.

Renal toxicity of heavy metals (cadmium and mercury) and their amelioration with ascorbic acid in rabbits

Cadmium and mercury are among the most toxic and dangerous environmental pollutants that may cause fatal implications. Vitamin C is an important chain-breaking antioxidant and enzyme co-factor against heavy metals. The objective of the present study was to evaluate the toxicological effects of cadmium chloride, mercuric chloride, and their co-administration on biochemical parameters of blood serum and metal bioaccumulation in kidneys and also to elucidate the protective effect of vitamin C in rabbits against these metals. In the current research, cadmium chloride (1.5 mg/kg), mercuric chloride(1.2 mg/kg), and vitamin C (150 mg/kg of body weight) were orally administered to eight treatment groups of the rabbits (1, control; 2, vitamin; 3, CdCl₂; 4, HgCl₂; 5, vitamin + CdCl₂; 6, vitamin + HgCl₂; 7, CdCl₂ + HgCl₂, and 8, vitamin + CdCl₂ + HgCl₂). After the biometric measurements of all experimental rabbits, biochemical parameters viz. creatinine, cystatin C, uric acid, and alkaline phosphatase (ALP) and metal bioaccumulation were determined using commercially available kits and atomic absorption spectrophotometer, respectively. The levels of creatinine (28.3 ± 1.1 μmol/l), cystatin C (1932.5 ± 38.5 ηg/ml), uric acid (4.8 ± 0.1 mg/day), and ALP (51.6 ± 1.1 IU/l) were significantly (P < 0.05) increased due to administration of mercuric chloride but in the presence of vitamin C, the effects of mercuric chloride on creatinine (21.9 ± 1.4 μmol/l), cystatin C (1676.2 ± 42.2 ηg/ml), uric acid (3.9 ± 0.1 mg/day), and ALP (43.3 ± 0.8 IU/l) were less as compared to metal-exposed specimens. Similar results were found in rabbits treated with cadmium chloride and vitamin C and also with co-administration of both metals and vitamin C. Because of the bio-accumulative nature of cadmium chloride and mercuric chloride, these metals were accumulated in kidneys of rabbits, which might lead to deleterious effects. The results of the present study provide an insight into the toxicity of the cadmium chloride, mercuric chloride, and/or their combination on biochemical parameters as well as kidneys of the rabbits and the ameliorating potential of vitamin C against these metals is also evaluated.

High Serum Alkaline Phosphatase, Hypercalcaemia, Race, and Mortality in South African Maintenance Haemodialysis Patients

Objective. To determine the association between serum total alkaline phosphatase (TAP) and mortality in African maintenance haemodialysis patients (MHD). Patients and Methods. The study enrolled a total of 213 patients on MHD from two dialysis centers in Johannesburg between January 2009 and March 2016. Patients were categorized into a low TAP group (≤112 U/L) versus a high TAP group (>112 U/L) based on a median TAP of 112 U/L. Results. During the follow-up period of 7 years, there were 55 (25.8%) deaths. After adjusting for cofounders such as age, other markers of bone disorder, and comorbidity (diabetes mellitus), patients in the high TAP group had significantly higher risk of death compared to patients in the low TAP group (hazard ratio, 2.50; 95% CI 1.24-5.01, P = 0.01). Similarly, serum calcium >2.75 mmol/L was associated with increased risk of death compared to patients within levels of 2.10-2.37 mmol/L (HR 6.34, 95% CI 1.40-28.76; P = 0.02). The HR for death in white patients compared to black patients was 6.88; 95% CI 1.82-25.88; P = 0.004. Conclusion. High levels of serum alkaline phosphatase, hypercalcaemia, and white race are associated with increased risk of death in MHD patients.