Zinc sulfate inhibits the enterohepatic cycling of unconjugated bilirubin in subjects with Gilbert's syndrome

The effect of oral zinc sulfate supplementation on hospitalized infants with hyperbilirubinemia: a double-blind randomized clinical trial

Previous investigations on the impact of oral zinc sulfate treatment on newborns' serum bilirubin levels have produced conflicting results. As a result, the goal of this clinical study was to evaluate how oral zinc sulfate affected the levels of serum bilirubin in term infants who were admitted to the neonatal intensive care unit. The study was conducted at the Neonatal Care Unit of Besat Hospital in Sanandaj, Kurdistan Province, as a double-blind randomized controlled trial. The participants included term infants (37-42 weeks of gestation) who required phototherapy and were admitted to the neonatal intensive care unit. A total of 290 infants were enrolled and randomly divided into two groups. The intervention group received oral zinc sulfate supplementation at a dosage of 1 mg/kg per day in addition to phototherapy, while the placebo group received an equivalent amount of placebo daily. Bilirubin measurements were obtained at the initiation of the intervention and subsequently every 24 h until discharge. The collected data were analyzed using STATA software version 17. After the infants were randomly allocated to the zinc-sulfate and placebo groups, the study outcomes, including the average changes in bilirubin levels after intervention, the hours of phototherapy, and the number of days of hospitalization, were analyzed and compared for a total of 160 infants in the zinc sulfate group and 130 infants in the placebo group. The reduction in bilirubin levels in infants receiving zinc sulfate was (- 3.75 ± 0.19 CI 95% - 4.12, - 3.37) and for placebo group was (- 1.81 ± 0.15 CI 95% - 2.12, - 1.50) 24 h after the intervention. Furthermore, 48 and 72 h following the intervention, bilirubin levels in the intervention group demonstrated a more substantial decline. The zinc sulfate group had a shorter hospital stay (2.13 ± 0.04 vs. 2.83 ± 1.42) and required less phototherapy hours than the placebo group (6.21 ± 2.16 vs. 8.78 ± 1.40).           Conclusions: Oral zinc sulfate supplementation in term neonates with hyperbilirubinemia decreased the level of bilirubin levels, duration of phototherapy, and hospital stay.           Trial registration: IRCT, IRCT20220806055625N1. Study Registered 25 December 2022, http://irct.ir/trial/66,722 .

Effects of dietary zinc chloride hydroxide and zinc methionine on the immune system and blood profile of healthy adult horses and ponies

The effects of dietary zinc on the immune function of equines have not been evaluated in detail so far. In the present study, eight healthy adult ponies and two healthy adult horses were fed a diet supplemented with either zinc chloride hydroxide or zinc methionine in six feeding periods of four weeks each (according to maintenance zinc requirement, 120 mg zinc/kg dry matter, and 240 mg zinc/kg dry matter, for both dietary zinc supplements, respectively). All animals received the six diets, with increasing amounts of zinc chloride hydroxide in the feeding periods 1-3, and with increasing amounts of zinc methionine in the feeding periods 4-6. At the end of each feeding period, blood samples were collected for a blood profile and the measurement of selected immune variables. Increasing dietary zinc chloride hydroxide doses increased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the erythrocyte lysate, decreased the numbers of total leukocytes and granulocytes in the blood, and also decreased the interleukin-2 concentrations in the plasma of the animals. The dietary supplementation of increasing doses of zinc methionine enhanced the mitogen-stimulated proliferative activity of peripheral blood mononuclear cells, and decreased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the plasma of the animals. The percentage of blood monocytes with oxidative burst after in vitro stimulation with E. coli decreased with increasing dietary zinc concentrations, independently of the zinc compound used. The blood profile demonstrated effects of the zinc supplements on the red blood cells and the bilirubin metabolism of the horses and ponies, which require further investigation. Overall, high doses of dietary zinc modulate the equine immune system, for the most part also depending on the zinc compound used.

Evaluation of Serum Zinc Levels in Hyperbilirubinemic Neonates Before and After Phototherapy

Background

The existing therapeutic methods for neonatal jaundice are costly, time-consuming and potentially risky. Zinc salts can reduce phototherapy duration by precipitating unconjugated bilirubin in the intestine (bilirubin and zinc can form a complex in physiologic pH); however, zinc toxicity is an issue that must be considered since theoretically bilirubin reduction by phototherapy may increase serum zinc levels, making additional zinc supplementation the potential cause of zinc toxicity.

Objectives

So, our purpose was evaluating the serum zinc level alterations before and after phototherapy, in hyperbilirubinemic newborns.

Materials and Methods

A prospective cohort study was performed at the children’s medical center of Tehran University of Medical Sciences from 2012 to 2014. Healthy, full-term exclusively breast fed newborns with non-hemolytic jaundice were enrolled in the study. Participants were divided into two groups based on serum bilirubin levels (TSB < 18 mg/dL and TSB ≥ 18 mg/dL) at admission. Pre- and post-phototherapy total serum zinc level was measured before and 12 - 24 hours after termination of phototherapy.

Results

Phototherapy was associated with a significant increase in the serum zinc level in neonates with severe hyperbilirubinemia (TSB ≥ 18 mg/dL) but not in those with mild-moderate hyperbilirubinemia (TSB < 18 mg/dL). In addition, phototherapy caused a significant increase in the rate of zinc with potentially toxic levels (zinc > 200) in only neonates with severe hyperbilirubinemia.

Conclusions

Phototherapy increases serum zinc level by reducing bilirubin level so that additional supplementation of this element can lead potentially to zinc toxicity.

Oral zinc for the prevention of hyperbilirubinaemia in neonates

BACKGROUND

Between 6% and 15% of neonates develop hyperbilirubinaemia requiring treatment. Successful management of neonatal hyperbilirubinaemia relies on prevention and early treatment, with phototherapy being the mainstay of treatment. Oral zinc has been reported to decrease the serum total bilirubin (STB), presumably by decreasing the enterohepatic circulation.

OBJECTIVES

To determine the effect of oral zinc supplementation compared to placebo or no treatment on the incidence of hyperbilirubinaemia in neonates during the first week of life and to assess the safety of oral zinc in enrolled neonates.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2014, Issue 1), MEDLINE (1966 to November 30, 2014), and EMBASE (1990 to November 30, 2014).

SELECTION CRITERIA

Randomised controlled trials were eligible for inclusion if they enrolled neonates (term and preterm) to whom oral zinc, in a dose of 10 to 20 mg/day, was initiated within the first 96 hours of life, for any duration until day seven, compared with no treatment or placebo.

DATA COLLECTION AND ANALYSIS

We used the standard methods of The Cochrane Collaboration and its Neonatal Review Group for data collection and analysis.

MAIN RESULTS

Only one study met the criteria of inclusion in the review. This study compared oral zinc with placebo. Oral zinc was administered in a dose of 5 mL twice daily from day 2 to day 7 postpartum. The drug was administered into the mouth of the infant by the plastic measure provided with the bottle or with a spoon. Incidence of hyperbilirubinaemia, defined as serum total bilirubin (STB) ≥ 15 mg/dL, was similar between groups (N = 286; risk ratio (RR) 0.94, 95% confidence interval (CI) 0.58 to 1.52). Mean STB levels, mg/dL, at 72 ± 12 hours were comparable in both the groups (N = 286; mean difference (MD) -0.20; 95% CI -1.03 to 0.63). Although the duration of phototherapy in the zinc group was significantly shorter compared to the placebo group (N = 286; MD -12.80, 95% CI -16.93 to -8.67), the incidence of need for phototherapy was comparable across both the groups (N = 286; RR 1.20; 95% CI 0.66 to 2.18). Incidences of side effects like vomiting (N = 286; RR 0.65, 95% CI 0.19 to 2.25), diarrhoea (N = 286; RR 2.92, 95% CI 0.31 to 27.71), and rash (N = 286; RR 2.92, 95% CI 0.12 to 71.03) were found to be rare and statistically comparable between groups.

AUTHORS' CONCLUSIONS

The limited evidence available has not shown that oral zinc supplementation given to infants up to one week old reduces the incidence of hyperbilirubinaemia or need for phototherapy.

Zinc supplementation for neonatal hyperbilirubinemia: a randomized controlled trial

OBJECTIVE

To determine the efficacy of oral zinc for treatment of idiopathic neonatal hyperbilirubinemia in near-term and term (35-41 weeks) neonates.

DESIGN

Randomized placebo-controlled trial.

SETTING

Tertiary-care teaching hospital.

PARTICIPANTS

Eighty newborns with idiopathic neonatal hyperbilirubinemia.

INTERVENTION

Neonates were randomized to receive either oral zinc sulfate (10 mg/d) or placebo for 7 days.

MAIN OUTCOME MEASURES

Primary: total serum bilirubin levels at 48 (±12) h, 96 (±12) h and 144 (±12) h after intervention. Secondary: duration of phototherapy, and serum zinc and copper levels.

RESULTS

Baseline mean (SD) total serum bilirubin levels were 14.8 (3.8) and 14.4 (3.5) mg/dL in zinc and placebo groups, respectively. No significant differences were observed in total bilirubin levels between the two groups after the intervention. Mean (SD) total serum bilirubin levels in zinc and placebo groups were 13.9 (2.5) vs. 13.4 (1.9) mg/dL (mean difference 0.566; 95% CI -0.535, 1.668, P=0.038) at 48 h, 13.1 (2.7) vs. 12.8 (2.3) mg/dL (mean difference 0.234; 95% CI -1.011, 1.479, P =0.708) at 96 h and 8.0 (2.0) vs. 8.6 (1.2) mg/dL (mean difference -0.569, 95% CI -1.382, 0.242, P=0.166) at 144 h. Although the mean duration of phototherapy in the zinc group was less by 21.3 h (95% CI 11.6, 30.9, P=0.052), the difference was not significant. Post-intervention, serum zinc levels were significantly higher in the zinc-supplemented group while serum copper levels were comparable between the two groups.

CONCLUSIONS

Oral zinc sulfate, in a dose of 10 mg/day, is not effective in the management of idiopathic neonatal hyperbilirubinemia.

Coadministration of atazanavir-ritonavir and zinc sulfate: impact on hyperbilirubinemia and pharmacokinetics

Atazanavir (ATV) causes an elevation of unconjugated hyperbilirubinemia (HBR) as a result of UDP glucuronyltransferase (UGT) 1A1 inhibition. Zinc sulfate (ZnSO4) reduces unconjugated hyperbilirubinemia in individuals with Gilbert's syndrome. We assessed the changes in total, conjugated, and unconjugated bilirubin and the effect on ATV pharmacokinetics (PK) after single and 14-day dosing of ZnSO(4). HIV patients, stable on ATV/ritonavir (ATV/r)-containing regimens with a total bilirubin level of >25 mmol/liter received 125 mg daily of ZnSO(4) as Solvazinc tablets for 14 days. ATV/r and bilirubin concentrations were measured pre-ATV/r dose and 2, 4, 6, 8, and 24 h post-ATV/r dose; before ZnSO4 initiation (phase 1), after a single dose (phase 2) and after 14 days (phase 3). Changes in bilirubin and ATV/r concentrations in the absence or presence of ZnSO4 were evaluated by geometric mean ratios (GMRs) and 90% confidence intervals (CIs; we used phase 1 as a reference). Sixteen male patients completed the study maintaining virologic suppression; ZnSO(4) was well tolerated. Statistically significant declines in total bilirubin C(max) and AUC(0-24) of 16 and 17% were seen in phase2 and 20% in phase 3. Although there were no significant changes in conjugated bilirubin, unconjugated bilirubin Cmax and AUC(0-24) of were lower (17 and 19%, phase 2; 20 and 23% during phase 3). The ATV GMRs (90% CI) for C(trough), C(max), and AUC(0-24) were 0.74 (0.62 to 0.89), 0.82 (0.70 to 0.97), and 0.78 (0.70 to 0.88). Intake of ZnSO(4) decreases total and unconjugated bilirubin and causes modest declines in ATV exposure. ZnSO(4) supplementation may be useful in management of ATV-related HBR in selected patients.

Efficacy of zinc in reducing hyperbilirubinemia among at-risk neonates: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the efficacy of oral zinc salt on the incidence of hyperbilirubinemia and need for phototherapy between 25 and 168 h of age in term and late-preterm at-risk neonates cared at a tertiary care hospital in New Delhi, India.

METHODS

In all neonates born at ≥35 wks' gestation, serum total bilirubin (STB) was assayed at 24 ± 6 h of age. At-risk neonates, neonates with STB levels ≥6 mg/dL, were given either 10 mg of zinc gluconate salt (n = 148) or placebo (n = 146) in twice daily doses till day seven of age. Jaundice was assessed clinically and STB was measured by spectrophotometry. Neonates were followed up until day seven of age. Primary outcome measure was incidence of hyperbilirubinemia (STB ≥ 15 mg/dl). Secondary outcome measures were mean STB level at 72 ± 12 h of age, proportion of infants requiring phototherapy, and duration there of.

RESULTS

Risk factors for hyperbilirubinemia, including male gender, gestational age, birth-weight, incidence of birth trauma, ABO incompatibility, hyperbilirubinemia in previous sib, etc. were comparable in zinc and placebo groups. The incidence of hyperbilirubinemia was comparable in both the groups (17.9% vs 19.1% in zinc and placebo groups respectively; OR = 0.95, 95% CI: 0.50 to 1.67; P = 0.92). The requirement of phototherapy (14.5% and 12.0% in zinc and placebo groups respectively; OR = 1.24, 95% CI: 0.95 to 2.6; P = 0.54) was comparable in both the groups; however, duration of phototherapy was shorter in zinc group (duration in hours, 22.8 ± 19.4 vs 35.6 ± 16.1 in zinc and placebo group respectively; mean difference = -12.8, 95% CI: -24.73 to -0.92; P = 0.04). There was no difference in the mean STB levels at 72 ± 12 h of age between zinc and placebo groups (mean difference in mg/dL: 0.20, 95% CI: 1.0 to -0.64). No significant adverse effects related to oral zinc administration were noted.

CONCLUSIONS

Twice daily administration of oral zinc in a dose of 10 mg/day does not reduce the incidence of hyperbilirubinemia in at-risk term and late-preterm neonates during first wk of age.

Effective treatment of unconjugated hyperbilirubinemia with oral bile salts in Gunn rats

BACKGROUND & AIMS

We tested the hypothesis that oral administration of bile salts, which are known to increase the biliary excretion of unconjugated bilirubin (UCB), decreases unconjugated hyperbilirubinemia in the Gunn rat model.

METHODS

Adult Gunn rats were fed a standard diet or the same diet supplemented with 0.5 weight % ursodeoxycholic acid (UDCA) or cholic acid (CA) for 1 or 6 weeks. UCB and urobilinoids, a family of intestinal UCB breakdown products, were determined in plasma, feces, or both. After 6 weeks of treatment, tracer 3H-UCB was administered intravenously to determine steady-state UCB kinetics over the next 60 hours.

RESULTS

One-week treatment with UDCA or CA decreased plasma UCB concentrations by 21% and 30%, respectively (each P < .01). During the first 4 days of treatment, both UDCA and CA increased the combined fecal excretion of UCB and urobilinoids (+52% and +32%, respectively; each P < .01). Prolongation of treatment to 6 weeks caused a persistent decrease in plasma UCB concentrations to approximately 40% below baseline (each bile salt P < .001). (3)H-UCB kinetic studies showed that UDCA and CA administration decreased UCB pool size (-33% and -32%, respectively; each P < .05) and increased UCB fractional turnover (+33% and +25%, respectively; each P < .05).

CONCLUSIONS

Dietary bile salt administration induces a large, persistent decrease in plasma UCB concentrations in Gunn rats. Both UDCA and CA enhance UCB turnover by increasing its fecal disposal. These results support the application of oral bile salt treatment in patients with unconjugated hyperbilirubinemia.

Effective oral treatment of unconjugated hyperbilirubinemia in Gunn rats

We sought to develop an oral treatment for unconjugated hyperbilirubinemia. In the Gunn rat model of unconjugated hyperbilirubinemia, dietary supplementation with the lipase inhibitor orlistat (Orl) or with calcium phosphate (CaP) decreases plasma unconjugated bilirubin (UCB) levels. We determined whether Orl, CaP, or their combination is superior to phototherapy, the conventional treatment, and whether the effects of Orl and CaP are influenced by dietary fat content. Gunn rats were treated with Orl (200 mg/kg chow), CaP (20 g/kg chow), Orl + CaP, or continuous phototherapy (19 muW/cm(2)/nm) during a low-fat (LF) diet (13 energy%) or high-fat (HF) diet (35 energy%). Plasma UCB and fecal fat excretion were measured before, during, and/or at the end of treatment. Orl treatment for 2 weeks (HF diet) reduced plasma UCB concentrations similar to phototherapy (-34% and -28%, respectively); the combination of both was more effective than either treatment alone (-48%; P < .001). After 3 weeks of a HF diet, plasma UCB was 46% lower compared with the LF diet (P < .001). Plasma UCB concentrations were negatively correlated with fecal fat excretion (r = -0.96; P < .001). Irrespective of dietary fat content, 3 weeks of combined treatment (Orl + CaP) decreased plasma UCB by approximately 50% (P < .01) and was more effective than phototherapy (P < .05) at the intensity provided. In conclusion, plasma UCB concentrations in Gunn rats are negatively related to fecal fat excretion and dietary fat content. Orlistat is equally effective as phototherapy for the treatment of unconjugated hyperbilirubinemia in Gunn rats, and combined oral treatment with Orl + CaP is more effective than phototherapy. The present results support the feasibility of an efficient oral treatment of unconjugated hyperbilirubinemia.

The effect of zinc salts on serum bilirubin levels in hyperbilirubinemic rats

OBJECTIVES

Intestinal metabolism of bilirubin is implicated in the pathogenesis of neonatal jaundice and Crigler-Najjar syndrome. In the present study the authors investigated the effect of oral administration of zinc salts on serum bilirubin levels in hyperbilirubinemic rats.

METHODS

Bilirubin-binding activities of zinc sulfate and water-insoluble zinc methacrylate were determined in vitro. Congenitally hyperbilirubinemic Gunn rats and artificially hyperbilirubinemic Wistar rats were used in in vivo studies. Animals were fed a normal diet for 1 week and then a treatment diet of either zinc sulfate or zinc methacrylate for additional 2 weeks. Serum and fecal bile pigments were determined at the end of each phase. Biliary bilirubin secretion rates were determined in hyperbilirubinemic Wistar rats fed zinc methacrylate.

RESULTS

Substantial bilirubin-binding activities of zinc salts were demonstrated in in vitro experiments. Treatment with oral zinc salts significantly decreased serum bilirubin levels in Gunn rats (166 +/- 53 versus 123 +/- 38 and 206 +/- 34 versus 131 +/- 31 micromol/L, P < 0.05 for zinc methacrylate and zinc sulfate, respectively). A similar effect of zinc methacrylate was also observed in hyperbilirubinemic Wistar rats (102 +/- 10 versus 14 +/- 4 micromol/L, P < 0.0001). In accord, biliary bilirubin secretion decreased significantly in these animals (45 +/- 11 versus 28 +/- 4 nmol/h 100g body weight, P < 0.02). In contrast to zinc sulfate, treatment with zinc methacrylate did not lead to the elevation of serum zinc levels.

CONCLUSIONS

Oral administration of zinc salts efficiently decreased serum bilirubin levels in hyperbilirubinemic rats, presumably as a result of inhibition of enterohepatic circulation of bilirubin. This approach might be useful in the treatment of severe unconjugated hyperbilirubinemias.