Efficacy and safety of nicotinamide on phosphorus metabolism in hemodialysis patients: A systematic review and meta-analysis

Physiological Associations between Vitamin B Deficiency and Diabetic Kidney Disease

The number of people living with chronic kidney disease (CKD) is growing as our global population continues to expand. With aging, diabetes, and cardiovascular disease being major harbingers of kidney disease, the number of people diagnosed with diabetic kidney disease (DKD) has grown concurrently. Poor clinical outcomes in DKD could be influenced by an array of factors-inadequate glycemic control, obesity, metabolic acidosis, anemia, cellular senescence, infection and inflammation, cognitive impairment, reduced physical exercise threshold, and, importantly, malnutrition contributing to protein-energy wasting, sarcopenia, and frailty. Amongst the various causes of malnutrition in DKD, the metabolic mechanisms of vitamin B (B1 (Thiamine), B2 (Riboflavin), B3 (Niacin/Nicotinamide), B5 (Pantothenic Acid), B6 (Pyridoxine), B8 (Biotin), B9 (Folate), and B12 (Cobalamin)) deficiency and its clinical impact has garnered greater scientific interest over the past decade. There remains extensive debate on the biochemical intricacies of vitamin B metabolic pathways and how their deficiencies may affect the development of CKD, diabetes, and subsequently DKD, and vice-versa. Our article provides a review of updated evidence on the biochemical and physiological properties of the vitamin B sub-forms in normal states, and how vitamin B deficiency and defects in their metabolic pathways may influence CKD/DKD pathophysiology, and in reverse how CKD/DKD progression may affect vitamin B metabolism. We hope our article increases awareness of vitamin B deficiency in DKD and the complex physiological associations that exist between vitamin B deficiency, diabetes, and CKD. Further research efforts are needed going forward to address the knowledge gaps on this topic.

[Research Progress in Niacinamide in the Prevention and Treatment of Mouth and Systemic Diseases]

Nicotinamide (NAM) is the amide form of niacin and one of the precursors of nicotinamide adenine dinucleotide (NAD +). NAM can be used as a dietary supplement or clinical therapeutic drug to replenish NAD + levels in the human body and participate in key bodily functions such as cellular metabolism and DNA repair. NAM has the advantage of low cost, wide availability, and sound biosafety. It also has multiple biological functions, including antibacterial effect, anti-inflammatory effect, and modulation of cellular immunity, producing significant ameliorative effects on skin and neurodegenerative diseases. However, most studies on NAM are still at the laboratory stage. Herein we reviewed the role and mechanism of NAM in the prevention and treatment of oral and systemic diseases, explored its potential as clinical therapeutic medication, provided some basis and references for the clinical application of nicotinamide in the prevention and treatment of various diseases, and discussed its prospects for future research and application.

NAD+ Metabolism and Interventions in Premature Renal Aging and Chronic Kidney Disease

Premature aging causes morphological and functional changes in the kidney, leading to chronic kidney disease (CKD). CKD is a global public health issue with far-reaching consequences, including cardio-vascular complications, increased frailty, shortened lifespan and a heightened risk of kidney failure. Dialysis or transplantation are lifesaving therapies, but they can also be debilitating. Currently, no cure is available for CKD, despite ongoing efforts to identify clinical biomarkers of premature renal aging and molecular pathways of disease progression. Kidney proximal tubular epithelial cells (PTECs) have high energy demand, and disruption of their energy homeostasis has been linked to the progression of kidney disease. Consequently, metabolic reprogramming of PTECs is gaining interest as a therapeutic tool. Preclinical and clinical evidence is emerging that NAD⁺ homeostasis, crucial for PTECs' oxidative metabolism, is impaired in CKD, and administration of dietary NAD⁺ precursors could have a prophylactic role against age-related kidney disease. This review describes the biology of NAD⁺ in the kidney, including its precursors and cellular roles, and discusses the importance of NAD⁺ homeostasis for renal health. Furthermore, we provide a comprehensive summary of preclinical and clinical studies aimed at increasing NAD⁺ levels in premature renal aging and CKD.

The efficacy and safety of niacin on hyperphosphatemia in ESRD patients undergoing hemodialysis: randomized controlled trial

Background

Hyperphosphatemia is a common complication of end-stage renal disease (ESRD) and particularly affects hemodialysis (HD) patients. Elevated serum phosphorus contributes to the development of secondary hyperparathyroidism, chronic kidney disease–mineral bone disorder (CKD-MBD), metastatic calcifications and calcific uremic arteriolopathy. There is a significant association between hyperphosphatemia and increased morbidity and mortality in ESRD patients including cardiovascular morbidity and mortality, and it is also associated with prolonged hospitalization of HD patients. This study aim to evaluate the serum phosphorus lowering effect of niacin in HD patients.

Results

There was a decrease in phosphate values during the first 3 months of the study in the niacin group, with a significant change in phosphate level at the third month (5.90 ± 0.52 vs. 6.42 ± 0.65 (mEq/l); P <  0.001) and at the sixth month (5.12 ± 0.41 vs. 5.76 ± 0.47 (mEq/l); P <  0.001) compared to the control group. It was noted that both groups had an insignificant difference regarding baseline parathormone (PTH), though the PTH showed a significantly lower level at the third month (192.39 ± 78.85 vs. 388.27 ± 263.10 pg/ml; P <  0.001) and at the sixth month (127.56 ± 90.87 vs. 249.85 ± 97.69 pg/ml; P <  0.001) in the niacin group.

Conclusion

Niacin caused a statistically significant decrease in levels of phosphate and PTH in dialysis patients.

Trial registration

Registered at ClinicalTrials.gov NCT03163576. Trial registration date: 22 May 2017. Date of first patient’s enrolment: 1 October 2018. Date of the ethical committee approval: 29 March 2017. Number of the ethical committee approval: 17100040.

Extension of use of nicotinamide riboside chloride as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of an extension of use of the novel food (NF) nicotinamide riboside chloride (NRC) pursuant to Regulation (EU) 2015/2283. The assessment addresses the use of NRC in ‘meal replacement products’ and ‘nutritional drink mixes’ at levels up to 300 mg/day for the general population, and in food for special medical purposes (FSMP) and total diet replacement for weight control (TDRWC) (as per Regulation (EU) No 609/2013) at levels up to 500 mg/day in adults. Benchmark dose modelling was carried out on data from the 90‐day oral toxicity studies in rats relevant to the safety assessment. Considering the lack of tolerable upper intake level (UL) for nicotinamide in infants and the narrow margin of exposure between the estimated intake in infants and the lower confidence bound of the benchmark doses (BMDL₀₅) estimated by the models, the Panel concludes that the safety of the NF has not been established for use in ‘meal replacement products’ and ‘nutritional drink mixes’ under the proposed conditions of use. For FSMP and TDRWC, the proposed maximum use level corresponds to an intake of 210 mg nicotinamide per day, which is below the current UL for nicotinamide of 900 mg/day for adults. The Panel considers that the NF is as safe as pure nicotinamide for use in FSMP and TDRWC. The Panel, however, notes experimental data which indicate several pathways by which intakes of nicotinamide (or its precursors), at levels that are substantially higher than the physiological requirement, might cause adverse effects. The Panel considers that further investigations are required and that a re‐evaluation of the UL for nicotinamide may be warranted.

Intestinal Phosphorus Absorption in Moderate CKD and Healthy Adults Determined Using a Radioisotopic Tracer

BACKGROUND

Reducing intestinal phosphorus absorption is a cornerstone in CKD-MBD management. Yet, knowledge gaps include how CKD pathophysiology affects intestinal phosphorus absorption. In vivo rodent studies suggest that intestinal phosphorus absorption remains inappropriately normal in early-moderate CKD, despite declining 1,25-dihydroxyvitamin D (1,25D). We measured intestinal phosphorus absorption in patients with moderate CKD versus healthy adults using a direct radiotracer method.

METHODS

Patients with CKD and healthy adults matched for age, sex, and race were enrolled in this 8-day controlled diet study: the first 6 days outpatient and the final 2 days inpatient. Oral and intravenous doses of 33P and serial blood and urine sampling determined intestinal phosphorus absorption during the final 2 days. Secondary outcomes included fasting biochemistries and 24-hour urine phosphorus (uP).

RESULTS

In total, n=8 patients with CKD (eGFR=29-55 ml/min per 1.73 m2) and n=8 matched healthy controls completed the study. On a controlled diet, no difference in fractional intestinal phosphorus absorption was detected between patients with CKD and healthy adults (0.69 versus 0.62, respectively; P=0.52), and this was similar for 24-hour uP (884 versus 935 mg/d, respectively; P=0.70). Fractional intestinal phosphorus absorption was not significantly related to 24-hour uP. Patients with CKD had higher serum intact PTH and intact FGF23 and lower 1,25D. The relationship between 1,25D and fractional intestinal phosphorus absorption was not statistically significant.

CONCLUSIONS

Intestinal phosphorus absorption with typical dietary intake did not differ in patients with moderate CKD compared with controls, despite lower serum 1,25D levels. In this setting, a relationship between 24-hour uP and fractional or absolute intestinal absorption was not evident. Further investigation is needed to determine what factors influence intestinal phosphorus absorption in CKD and the apparent lack of compensation by the intestine to limit phosphorus absorption in the face of declining kidney function and reduced 1,25D. Whether this is evident across a range of dietary phosphorus intakes, as well as CKD severity, also needs to be determined.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Phosphorus Absorption in Healthy Adults and in Patients with Moderate Chronic Kidney Disease, NCT03108222.

Randomized controlled trials for comparison of laparoscopic versus conventional open catheter placement in peritoneal dialysis patients: a meta-analysis

Background

The application of laparoscopic catheterization technology in peritoneal dialysis (PD) patients has recently increased. However, the advantages and disadvantages of laparoscopic versus conventional open PD catheter placement are still controversial. The aim of this meta-analysis is to assess the complications of catheterization in PD patients and to provide a reference for choosing a PD-catheter placement technique in the clinic.

Methods

We searched numerous databases, including Embase, PubMed, CNKI and the Cochrane Library, for published randomized controlled trials (RCTs).

Results

Eight relevant studies (n = 646) were included in the meta-analysis. The pooled results showed a lower incidence of catheter migration (OR: 0.42, 95% CI: 0.19 to 0.90, P: 0.03) and catheter removal (OR: 0.41, 95% CI: 0.21 to 0.79, P: 0.008) but a higher incidence of bleeding (OR: 3.25, 95% CI: 1.18 to 8.97, P: 0.02) with a laparoscopic approach than with a conventional approach. There was no significant difference in the incidence of omentum adhesion (OR: 0.32, 95% CI: 0.05 to 2.10, P: 0.24), hernia (OR: 0.38, 95% CI: 0.09 to 1.68, P: 0.20), leakage (OR: 0.69, 95% CI: 0.38 to 1.26, P: 0.23), intestinal obstruction (OR: 0.96, 95% CI: 0.48 to 1.91, P: 0.90) or perforation (OR: 0.95, 95% CI: 0.06 to 15.42, P: 0.97). The statistical analysis showed no significant difference in early (OR: 0.44, 95% CI: 0.15 to 1.33, P: 0.15), late (OR: 0.89, 95% CI: 0.41 to 1.90, P: 0.76) or total (OR: 0.68, 95% CI: 0.42 to 1.12, P: 0.13) peritonitis infections between the 2 groups, and there are no no significant difference in early (OR: 0.39, 95% CI: 0.06 to 2.36, P: 0.30), late (OR: 1.35, 95% CI: 0.78 to 2.33, P: 0.16) or total (OR: 1.20, 95% CI: 0.71 to 2.02, P: 0.17) tunnel or exit-site infections between the 2 groups.

Conclusion

Laparoscopic catheterization and conventional open catheter placement in PD patients have unique advantages, but laparoscopic PD catheterization may be superior to conventional open catheter placement. However, this conclusion needs to be confirmed with further large-sample-size, multi-centre, high-quality RCTs.