Sevelamer hydrochloride dose-dependent increase in prevalence of severe acidosis in hemodialysis patients: analysis of nationwide statistical survey in Japan

Gut Microbiota and Renal Injury

Renal injury, especially chronic kidney disease (CKD), is closely associated with gut microbiota. It is well known that renal injury development could cause enteric microbial compositional disruption. On the other hand, gut microbial composition, as well as their function, would directly influence the renal disease progression. Here, in the present chapter, we will summarize the crosstalk between intestinal microbiota and renal disease and discuss some potential therapeutic approaches based on this topic.

Use of lanthanum for water treatment A matter of concern?

Among several other eutrophication management tools, Phoslock®, a lanthanum modified bentonite (LMB) clay, is now frequently used. Concerns have been raised as to whether exposure to Phoslock®-treated water may lead to lanthanum accumulation/toxicity in both animals and humans. In the present experimental study, rats were administered lanthanum orally as either lanthanum carbonate, lanthanum chloride or Phoslock® at doses of either 0.5 or 17 mg/L during 10 weeks. Controls received vehicle. The gastrointestinal absorption and tissue distribution of lanthanum was investigated. Extremely strict measures were implemented to avoid cross-contamination between different tissues or animals. Results showed no differences in gastrointestinal absorption between the different compounds under study as reflected by the serum lanthanum levels and concentrations found in the brain, bone, heart, spleen, lung, kidney and testes. At sacrifice, significant but equally increased lanthanum concentrations versus vehicle were observed in the liver for the highest dose of each compound which however, remained several orders of magnitude below the liver lanthanum concentration previously measured after long-term therapeutic administration of lanthanum carbonate and for which no hepatotoxicity was noticed in humans. In conclusion, (i) the use of LMB does not pose a toxicity risk (ii) gastrointestinal absorption of lanthanum is minimal and independent on the type of the compound, (iii) with exception of the liver, no significant increase in lanthanum levels is observed in the various organs under study, (iv) based on previous studies, the slightly increased liver lanthanum levels observed in a worst case scenario do not hold any risk of hepatotoxicity.

Bicarbonate levels in hemodialysis patients switching from lanthanum carbonate to sucroferric oxyhydroxide

AIM

To examine possible alterations in acid-base parameters in patients switching from lanthanum carbonate (LanC) to sucroferric oxyhydroxide (SFOH).

METHODS

Fifteen stable hemodialysis patients were switched from LanC to SFOH. Only nine continued on SFOH, three returned to LanC and the other three switched to sevelamer carbonate. The later six patients served as a control group to the SFOH group of nine patients. Blood was sampled on the 3-d and the last 2-d interval of the week prior to switching and six weeks after. Bicarbonate levels (HCO₃^-), pH, pO₂, pCO₂ were measured, and the mean of the two measurements (3-d and 2-d interval) was calculated.

RESULTS

Comparing pre-switching to post-switching measurements in the SFOH group, no statistically significant differences were found in any of the parameters studied. The mean pre-switching HCO₃^- was 22.41 ± 1.66 mmol/L and the mean post-switching was 22.62 ± 2.25 mmol/L (P = 0.889). Respectively, the mean pH= 7.38 ± 0.03 vs 7.39 ± 0.03 (P = 0.635), mean pCO₂= 38.41 ± 3.29 vs 38.37 ± 3.62 mmHg (P = 0.767), and Phosphate = 1.57 ± 0.27 vs 1.36 ± 0.38mmol/L (P = 0.214). There were not any significant differences when we performed the same analyses in the control group or between the SFOH group and control group. No correlations were found, either between pre-switching LanC daily dose or between post-switching daily dose of the new binder and the measured parameters.

CONCLUSION

In our small study, switching from LanC to SFOH did not have any significant effect on blood bicarbonate levels and gas analysis, indicating that there is no need to change hemodialysis prescription regarding these parameters.

Pharmacotherapy in chronic kidney disease hyperphosphatemia – effects on vascular calcification and bone health

Hyperphosphatemia (HP) in patients with chronic kidney disease (CKD) leads to complications such as renal osteodistrophy, cardiovascular calcification and hemodynamic abnormalities, all of them having a serious impact on the survival rate and quality of life. Also, HP is a key pathogenic factor in the development of secondary hyperparathyroidism (SHPT) in CKD. Having in regard the significance of controlling serum phosphorus levels (Pi), in this paper, the needs and obstacles to successful pharmacological management of HP in CKD are presented, with an overview of major classes of phosphate binders (PBs) and other drugs affecting Pi level, such as active vitamin D sterols and calcimimetics (CMs). In addition, their effects on progression of cardiovascular calcification and bone health are elaborated. In this regard, a PubMed search was carried out to capture all abstracts and articles relevant to the topic of CKD, HP and mineral metabolism, bone disorders and vascular/valvular calcification (VC), published from January 2007 to August 2017. The search was limited to English language, with the search terms including drug name AND hyperphosphatemia or cardiovascular calcification or bone disorder. Comparative studies, clinical studies/trials and meta-analyses related to different classes/representatives of PBs, vitamin D analogues and CMs were reviewed and research data related to their efficacy and safety compared. Keywords: chronic kidney disease, hyperphosphatemia, phosphate binders, active vitamin D sterols, calcimimetics, bone disorders, cardiovascular calcification

Practical use of sevelamer in chronic kidney disease patients on dialysis in People's Republic of China

Hyperphosphatemia is a common complication of dialysis patients. Only 38.5% of Chinese dialysis patients met the Kidney Disease Outcomes Quality Initiative defined targets for serum phosphate. Sevelamer is a high molecular weight cationic hydrogel polymer that prevents absorption of dietary phosphate by binding it in the gastrointestinal tract. In Chinese trials, it was confirmed that sevelamer had better efficacy than calcium carbonate in terms of reducing the serum level of phosphorus and calcium-phosphate product. Sevelamer can also reduce the levels of lipid parameters and improve the micro-inflammatory state. When sevelamer was combined with other treatments, it elicited superior effects on calcium phosphorus metabolism, secondary hyperparathyroidism, and renal osteodystrophy. Combination treatment of sevelamer and traditional Chinese medicine has the unique advantage. However, sevelamer is associated with a high incidence of gastrointestinal adverse effects in Chinese patients. Although more effective, the practical use of sevelamer is not very common because it is expensive and not paid by medical insurance. This article provides a comprehensive review of the practical use of sevelamer in chronic kidney disease patients on dialysis in People's Republic of China.

Niacin as a drug repositioning candidate for hyperphosphatemia management in dialysis patients

Nearly all patients with end-stage renal disease develop hyperphosphatemia. These patients typically require oral phosphate binders for life-long phosphorus management, in addition to dietary restrictions and maintenance dialysis. Recently, niacin, a traditional antilipemic agent, drew attention as an experimental treatment for hyperphosphatemia. The purpose of this article was to report on new findings regarding niacin’s novel effects and to review the possibility of repurposing niacin for hyperphosphatemia treatment in dialysis patients by elucidating its safety and efficacy profiles along with its synergistic clinical benefits. Following approval from the Institutional Review Board, we tracked the yearly trends of order frequency of niacin in comparison with statins and sevelamer in a tertiary care hospital. Also, a Cochrane Library and PubMed literature search was performed to capture prospective clinical trials on niacin’s hypophosphatemic effects in dialysis patients. Niacin use in clinical settings has been on the wane, and the major contribution to that originates from the wide use of statins. Niacin use rates have further plummeted following a trial failure which prompted the suspension of the niacin-laropiprant (a flushing blocker) combination product in the global market. Our literature search identified ten relevant articles. Overall, all studies demonstrated that niacin or nicotinamide (the metabolite form) reduced serum phosphorus levels as well as Ca-P products significantly. Additive beneficial effects on lipid parameters were also observed. Sevelamer appeared superior to niacin in a comparative study, but the study design had several limitations. The intervention dosage for niacin ranged from 375 to 1,500 mg/day, with the average daily dose of approximately 1,000–1,500 mg. Niacin can be a patient-convenient and inexpensive alternative or adjunctive therapy for phosphorus management in dialysis patients. Further well-designed, large-scale, long-term, comparative trials are needed to successfully repurpose niacin for the new indication.