Gut microbiome in hemodialysis patients treated with calcium acetate or treated with sucroferric oxyhydroxide: a pilot study

Purpose It has been proved that the gut microbiome is altered in patients with chronic kidney disease. This contributes to chronic inflammation and increases cardiovascular risk and mortality, especially in those undergoing hemodialysis. Phosphate binders may potentially induce changes in their microbiome. This trial aimed to compare the changes in the gut microbiome of hemodialysis patients treated with calcium acetate to those treated with sucroferric oxyhydroxide. Methods Twelve hemodialysis patients were distributed to receive calcium acetate or sucroferric oxyhydroxide for 5 months. Blood samples (for biochemical analysis) and stool samples (for microbiome analysis) were collected at baseline, 4, 12, and 20 weeks after treatment initiation. Fecal DNA was extracted and a 16S rRNA sequencing library was constructed targeting the V3 and V4 hypervariable regions. Results Regarding clinical variables and laboratory parameters, no statistically significant differences were observed between calcium acetate or sucroferric oxyhydroxide groups. When analyzing stool samples, we found that all patients were different (p = 0.001) among themselves and these differences were kept along the 20 weeks of treatment. The clustering analysis in microbial profiles grouped the samples of the same patient independently of the treatment followed and the stage of the treatment. Conclusion These results suggest that a 5-month treatment with either calcium acetate or sucroferric oxyhydroxide did not modify baseline diversity or baseline bacterial composition in hemodialysis patients, also about the high-variability profiles of the gut microbiome found among these patients.

Effect of CKD-MBD therapies on the gastrointestinal expression of phosphate transporters

Background: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is prevalent and encompasses biochemical abnormalities, bone alterations, and vascular calcifications. CKD-MBD treatments include phosphate binders and calcimimetics that effectively lower phosphorus and PTH, respectively, but the impact of these treatments on phosphate transporters in the gastrointestinal tract is still unknown. NaPi2B is considered the primary intestinal phosphate transporter. However, NaPi2B inhibition shows limited effectiveness, thus the importance of PIT1 and PIT2 requires further investigation. Methods: We tested the effects phosphate binders (ferric citrate (FC) and calcium gluconate (Ca)) and the calcimimetic KP2326 (KP) in (Cy/+ male rat; CKD) and untreated normal littermates (NL). Treatments lasted 10 weeks until euthanasia at 28 weeks (moderate-to-advanced CKD), where we collected mucosa samples from duodenum, jejunum, and ileum. Blood was collected for biochemistry measurements. Total RNA was isolated, and qPCR performed to assess phosphate transporters expression (NaPi2B, PIT1, PIT2) normalized to b-actin. Results were analyzed via 2-way ANOVA. Results: As expected, CKD had abnormal plasma concentrations of phosphorus, PTH, and FGF23. FC and KP effectively lowered phosphorus. KP and Ca lowered PTH, but Ca increased FGF23. NaPi2B was expressed in the duodenum and jejunum but not in the ileum, and its expression was upregulated with FC compared to NL. PIT1 was expressed in all segments, but the expression was the highest in the ileum, while PIT2 was constitutively expressed in all segments. Ca led to higher PIT1 and PIT2 expression in the duodenum and jejunum compared to NL, CKD, or KP. KP led to higher expression of PIT1 in the ileum compared to CKD, FC, and Ca. Conclusions: CKD-MBD therapies differentially impacted biochemistries and phosphate transporters expression. The effect of Ca on gastrointestinal expression of PIT1 and PIT2 may explain the higher plasma phosphorus and should be further explored.

The Effect of Phosphate Binders in Patients With End Stage Kidney Disease Undergoing Hemodialysis: a Prospective Observational Study

To compare the clinical efficacy of sevalamer carbonate and lanthanum carbonate in chronic hemodialysis patients. This prospective observational study included 80 patients randomly divided into two groups were followed from December 2019 to December 2020. After 12 months of maintenance hemodialysis treatment with sevalamer carbonate or lanthanum carbonate, serum phosphorus, serum calcium, alkaline phosphatase(ALP), parathyroid hormone (iPTH), low-density lipoprotein(LDL), hemoglobin(HGB), triglycerides(TG) and albumin(ALB) were evaluated. The adequacy of dialysis, the effective rate of treatment and the incidence of adverse reactions were compared as well. After treatment, In lanthanum carbonate group, serum phosphorus and iPTH decreased and albumin increased, the difference was significant(P < 0.05). In sevalamer carbonate group, serum phosphorus and LDL decreased and albumin increased after treatment, the difference was significant(P < 0.05). There was no significant difference in the dialysis adequacy and total effective rate between the two groups (P>0.05). However, the incidence of gastrointestinal adverse reactions in the sevalamer carbonate group was lower than in the lanthanum carbonate group and the difference was significant (P < 0.05). The two phosphate binders are safe and effective for the treatment of hyperphosphatemia in patients with ESKD undergoing maintenance hemodialysis. Nevertheless, sevalamer carbonate seems to be superior with lowering the incidence of gastrointestinal adverse reactions and improving lipid metabolism.

The Effect of Phosphate Binders in Patients With End Stage Kidney Disease Undergoing Hemodialysis: a Prospective Observational Study

The authors have requested that this preprint be removed from Research Square.

Very Few Interventions after Tumor Lysis Monitoring in Patients with Chronic Lymphocytic Leukemia Who Are Started on Venetoclax in the Real-World Setting- Suggests Less Intensive Monitoring Maybe Safe for Low-Risk Patients

Background: Chronic lymphocytic leukemia (CLL) is one of the most common lymphoid malignancies in adults. Venetoclax, an orally administered B-cell lymphoma 2 (BCL2) inhibitor, is a FDA approved therapy offering durable responses. Due to risk of tumor lysis syndrome (TLS) upon venetoclax initiation, a strict dose escalation schedule with frequent laboratory monitoring is recommended in the package insert (PI). Real world data reflecting adherence to this schedule and frequency of interventions resulting from intense monitoring are not described. Methods: Retrospective review of the Levine Cancer Institute database identified 73 consecutive patients with CLL who were initiated on venetoclax between July 2017 and March 2021. This included those initiated at the central academic site and regional academic-hybrid community sites. In the first two weeks of venetoclax, ramp up dosing and TLS labs (creatinine, potassium, calcium, phosphorous and uric acid) were evaluated for compliance consistent with the PI. Compliance required labs to be performed pre-dose, and at 6-8 hours and 24 hours after the initial 20 mg and 50 mg doses on weeks 1 and 2. The consequent interventions within these first 2 weeks, based on TLS labs, were then recorded. Patients who strictly adhered to all these laboratory checks at the various timepoints were considered compliant. Those who missed even a single lab or time point were considered non-compliant. Tumor lysis was measured by standard criteria using the Cairo-Bishop definition. The following Interventions were recorded: rasburicase administration, renal replacement therapy, ED visits, unplanned hospitalizations, ICU admissions, unplanned administration of IV fluids, the use of calcium supplementation, phosphate binders, treatment for hyperkalemia, dose reduction or holding of venetoclax. Baseline patient, disease, and treatment characteristics were summarized and described; rates of compliance were compared between tumor burden categories using Fisher's Exact test. Results : Baseline characteristics of the 73 identified patients were: 64% male, 79% white and 19% black, median age at venetoclax initiation was 67 (44 - 84). There were 49% of patients in the low tumor burden category, 44% in the medium tumor burden category and 6% in the high tumor burden category. Compliance with TLS labs during the first 2 weeks was 66% overall (n=48), with compliance between the tumor burden categories being 75% in high, 66% in medium and 67% in low (P&gt;0.99). Interventions occurred in 6 (8%) of the patients, with all interventions occurring in the medium or high tumor burden group. These interventions included administration of IV fluids (n=2), calcium supplementation (n=1), phosphate binders (n=2) and holding of venetoclax (n=1). None of these 6 patients requiring an intervention had clinical or laboratory TLS. None of the 73 patients required rasburicase administration, renal replacement therapy, ED visits, unplanned hospitalizations, or ICU admissions during this 2 week ramp up period. Of the 6 patients requiring interventions, 4 patients had TLS labs performed by the PI versus 2 patients who did not. Clinical and laboratory TLS in the PI-compliant group was recorded. None of these patients had clinical TLS and 1 patient met the criteria for laboratory criteria TLS based on a 25% change from baseline in phosphorus and uric acid, however, labs remained in normal range. There were no deaths during the venetoclax ramp up. Conclusion: Compliance with the strict TLS lab monitoring during venetoclax initiation is not universal, likely due to real world patient and institutional barriers. The intervention rates during the first 2 weeks were low, with no patients in the low tumor burden category requiring an intervention. These results suggest that a less strict laboratory monitoring schedule may be safe in patients with low tumor burden CLL. If the safety is confirmed prospectively, it would make the venetoclax initiation less cumbersome and result in increased access to venetoclax for patients with low burden CLL. Disclosures Hu: Kite: Membership on an entity's Board of Directors or advisory committees; BeiGene: Membership on an entity's Board of Directors or advisory committees; Cellectar: Membership on an entity's Board of Directors or advisory committees. Moyo: Seattle Genetics: Consultancy. Park: Teva: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; G1 Therapeutics: Consultancy; Morphosys: Membership on an entity's Board of Directors or advisory committees; Rafael Pharma: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Gilead: Speakers Bureau; Seattle Genetics: Research Funding, Speakers Bureau; Takeda: Research Funding. Copelan: Amgen: Consultancy. Avalos: Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; BMJ Best Practice: Patents & Royalties: Royalties from a co-authored article on evaluation of neutropenia. Symanowski: Carsgen: Consultancy; Immatics: Consultancy, Other: DSMB Member; Eli Lilly: Consultancy, Other: DSMB Member. Jacobs: AbbVie: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; TG Therapeutics: Research Funding, Speakers Bureau; Verastem: Consultancy; ADC Therapeutics: Consultancy; Adaptive Biotechnologies: Consultancy; MEI Pharma: Research Funding; TeneoBio: Research Funding; SecuraBio: Consultancy, Speakers Bureau; Genentech: Consultancy; Jannsen: Speakers Bureau. Ghosh: Genmab: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; Adaptive Biotech: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; AbbVie: Honoraria, Speakers Bureau; Karyopharma: Consultancy, Honoraria; Genentech: Research Funding.

The Effect of Phosphate Binders in Patients With End Stage Kidney Disease Undergoing Hemodialysis: a Prospective Cohort Study

Background: To compare the clinical efficacy of sevalamer carbonate and lanthanum carbonate in chronic hemodialysis patients. Methods: This prospective observational study included 76 patients with follow-up from September 2019 to December 2020. After 15 months of maintenance hemodialysis treatment with sevalamer carbonate or lanthanum carbonate, serum phosphorus, serum calcium, alkaline phosphatase(ALP), parathyroid hormone (iPTH), low-density lipoprotein(LDL), hemoglobin(HGB), triglycerides(TG) and albumin(ALB) were evaluated. The adequacy of dialysis, the effective rate of treatment and the incidence of adverse reactions were compared as well. Results: After treatment, In lanthanum carbonate group, serum phosphorus and iPTH decreased and albumin increased, the difference was significant(P < 0.05). In sevalamer carbonate group, serum phosphorus and LDL decreased and albumin increased after treatment, the difference was significant(P < 0.05). There was no significant difference in the dialysis adequacy and total effective rate between the two groups (P>0.05). However, the incidence of adverse reactions in the sevalamer carbonate group was lower than in the lanthanum carbonate group and the difference was significant (P < 0.05). Conclusion: The two phosphate binders are safe and effective for the treatment of hyperphosphatemia in patients with ESKD undergoing maintenance hemodialysis. Nevertheless, sevalamer carbonate seems to be superior with lowering the incidence of gastrointestinal adverse reactions and improving lipid metabolism.

Preparation and study of thermostable composites based on solid magnesium phosphate and calcium phosphate binders

Thermostable composite materials based on solid magnesium phosphate and calcium phosphate, as well as hybrid calcium magnesium phosphate binders have been developed and investigated. Thermal and phase transformations of the phosphate composites have been studied. Strength characteristics of composite materials have been determined in the temperature range of 20–1000 °C. It is shown that the obtained phosphate composites have high strength properties (compressive strength reaches 120–130 MPa) and are characterised by high thermal stability in the temperature range up to 1000 °С. The low weight loss of the studied composites (no more than 10 %) and the absence of significant thermal effects indicate that they are promising for use as a thermostable matrix for obtaining functional composite materials.

Biomarkers of heart and vascular lesions in the framework of mineral and bone disorders in chronic kidney disease, correction possibilities

Сardiovascular disease (СVD) is the most common complication of chronic kidney disease (СKD). In patients with the earlier stages of CKD, the risk of death from CVD greatly exceeds the risk of progression to end-stage renal disease. In recent years, accumulated data suggest that chronic kidney disease — mineral and bone disorders (CKD-MBD) are strongly associated with cardiovascular events and mortality. Among cardiovascular damage in CKD, both, the progressive cardiac remodeling and vascular calcifi cation, contribute immensely, and lead to an urgently high cardiovascular mortality in patients with CKD. Clarifi cation of CKD progression mechanisms and possible early markers of CVD has led to interest in studying the identifi ed factors such as fi broblast growth factor-23 (FGF-23), Klotho and sclerostin in recent years. Results of studies show that disorders in the system of FGF-23–Klotho–sclerostin correlate with the frequency and severity of hypertension, cardiac remodeling, vascular calcifi cation, anaemia, malnutrition, infl ammation, and strongly aggravate cardiovascular risk in CKD. This review represents an analysis of the available data showing the potential association of СVD with established (phosphate, parathyroid hormone (PTH), Vitamin D) and newer (FGF-23, Klotho, sclerostin) СKD-MBD biomarkers. In addition, it has been shown that renoprotective therapy, including renin-angiotensin blockers, low-protein diet with amino/keto acid supplementation, phosphate binders, erythropoiesis stimulators, vitamin D metabolites used to reach the target levels of blood pressure, serum phosphorus, haemoglobin, PTH and nutritional status disorders, can aff ect CKD-MBD biomarkers and reduce the risk of cardiovascular events in CKD patients.

Small Intestinal Phosphate Absorption: Novel Therapeutic Implications

<b><i>Background:</i></b> Chronic kidney disease (CKD) affects approximately 15% of adults in the USA. As CKD progresses, urinary phosphate excretion decreases and results in phosphate retention and, eventually, hyperphosphatemia. As hyperphosphatemia is associated with numerous adverse outcomes, including increased cardiovascular mortality, reduction in phosphorus concentrations is a guideline-recommended, established clinical practice. Dietary phosphate restriction, dialysis, and phosphate binders are currently the only options for phosphate management. However, many patients with hyperphosphatemia have phosphorus concentrations &#x3e;5.5 mg/dL, despite treatment. <b><i>Summary:</i></b> This review pre­sents recent advances in the understanding of intestinal phosphate absorption and therapeutic implications. Dietary phosphate is absorbed in the intestine through two distinct pathways, paracellular absorption and transcellular transport. Recent evidence indicates that the paracellular route accounts for 65–80% of total phosphate absorbed. Thus, the paracellular pathway is the dominant mechanism of phosphate absorption. Tenapanor is a first-in-class, non-phosphate binder that inhibits the sodium-hydrogen exchanger 3 or solute carrier family 9 member 3 (SLC9A3) encoded by the SLC9A3 gene, and blocks paracellular phosphate absorption. <b><i>Key Messages:</i></b> Targeted inhibition of sodium-hydrogen exchanger 3 effectively reduces paracellular permeability of phosphate. Novel therapies that target the paracellular pathway may improve phosphate control in chronic kidney disease.