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Adhikari A, Bhutani VK, Mondal S, Das M, Darbar S, Ghosh R, Polley N, Das AK, Bhattacharya SS, Pal D, Mallick AK, Pal SK. Chemoprevention of bilirubin encephalopathy with a nanoceutical agent. Pediatr Res 2023; 93:827-837. [PMID: 35794251 DOI: 10.1038/s41390-022-02179-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/08/2022] [Accepted: 06/19/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Targeted rapid degradation of bilirubin has the potential to thwart incipient bilirubin encephalopathy. We investigated a novel spinel-structured citrate-functionalized trimanganese tetroxide nanoparticle (C-Mn3O4 NP, the nanodrug) to degrade both systemic and neural bilirubin loads. METHOD Severe neonatal unconjugated hyperbilirubinemia (SNH) was induced in neonatal C57BL/6j mice model with phenylhydrazine (PHz) intoxication. Efficiency of the nanodrug on both in vivo bilirubin degradation and amelioration of bilirubin encephalopathy and associated neurobehavioral sequelae were evaluated. RESULTS Single oral dose (0.25 mg kg-1 bodyweight) of the nanodrug reduced both total serum bilirubin (TSB) and unconjugated bilirubin (UCB) in SNH rodents. Significant (p < 0.0001) UCB and TSB-degradation rates were reported within 4-8 h at 1.84 ± 0.26 and 2.19 ± 0.31 mg dL-1 h-1, respectively. Neural bilirubin load was decreased by 5.6 nmol g-1 (p = 0.0002) along with improved measures of neurobehavior, neuromotor movements, learning, and memory. Histopathological studies confirm that the nanodrug prevented neural cell reduction in Purkinje and substantia nigra regions, eosinophilic neurons, spongiosis, and cell shrinkage in SNH brain parenchyma. Brain oxidative status was maintained in nanodrug-treated SNH cohort. Pharmacokinetic data corroborated the bilirubin degradation rate with plasma nanodrug concentrations. CONCLUSION This study demonstrates the in vivo capacity of this novel nanodrug to reduce systemic and neural bilirubin load and reverse bilirubin-induced neurotoxicity. Further compilation of a drug-safety-dossier is warranted to translate this novel therapeutic chemopreventive approach to clinical settings. IMPACT None of the current pharmacotherapeutics treat severe neonatal hyperbilirubinemia (SNH) to prevent risks of neurotoxicity. In this preclinical study, a newly investigated nano-formulation, citrate-functionalized Mn3O4 nanoparticles (C-Mn3O4 NPs), exhibits bilirubin reduction properties in rodents. Chemopreventive properties of this nano-formulation demonstrate an efficacious, efficient agent that appears to be safe in these early studies. Translation of C-Mn3O4 NPs to prospective preclinical and clinical trials in appropriate in vivo models should be explored as a potential novel pharmacotherapy for SNH.
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Affiliation(s)
- Aniruddha Adhikari
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Vinod K Bhutani
- Department of Neonatal and Developmental Medicine, Lucile Packard Children's Hospital, Stanford University, 750 Welch Road, Palo Alto, CA, 94304, USA
| | - Susmita Mondal
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Monojit Das
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India
- Department of Zoology, Vidyasagar University, Rangamati, Midnapore, 721102, India
| | - Soumendra Darbar
- Research and Development Division, Dey's Medical Stores (Mfg.) Pvt. Ltd., 62 Bondel Road, Ballygunge, Kolkata, 700019, India
| | - Ria Ghosh
- Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Nabarun Polley
- Physical Chemistry - innoFSPEC, University of Potsdam, Am Mühlenberg 3, Golm, 14476, Potsdam, Germany
| | - Anjan Kumar Das
- Department of Pathology, Coochbehar Govt. Medical College and Hospital, Silver Jubilee Road, Coochbehar, 736101, India
| | | | - Debasish Pal
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India
| | - Asim Kumar Mallick
- Department of Pediatric Medicine, Nil Ratan Sirkar Medical College and Hospital, 138 AJC Bose Road, Sealdah, Rajabazar, Kolkata, 700014, India
| | - Samir Kumar Pal
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India.
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India.
- Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India.
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Wiedmeier SE, Bahr TM, Ohls RK, Christensen TR, Baer VL, Ilstrup SJ, Cail K, Christensen RD. Exchange transfusion for hemolytic hyperbilirubinemia: could some be averted by emergent administration of an inhibitor of bilirubin production? J Perinatol 2021; 41:860-864. [PMID: 32669646 DOI: 10.1038/s41372-020-0736-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/01/2020] [Accepted: 07/07/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVES The objective of this study is to explore the hypothetical number of neonates where an exchange transfusion (ET) could be prevented by emergency administration of an inhibitor of bilirubin production. STUDY DESIGN We identified all neonates who received an ET in our NICUs during the past 12 years. We reviewed the indications for ET and recorded the time between ordering and beginning the exchange. RESULTS Forty-six neonates underwent ET, 37 (80.4%) for hemolytic hyperbilirubinemia (36.9 ± 2.9 weeks gestation and 2.5 ± 2.1 days old at ET). The mean delay period was 7.5 ± 3.5 h. Nine (19.6%) had ET not involving bilirubin. CONCLUSIONS A trial testing compounds that can inhibit bilirubin production would have about three eligible neonates/years in our system. Since our births are 1% of national, up to 300 neonates/years might qualify for such a study.
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Affiliation(s)
- Susan E Wiedmeier
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
| | - Timothy M Bahr
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA.
| | - Robin K Ohls
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
| | | | - Vickie L Baer
- Women and Newborns Research, Intermountain Healthcare, Salt Lake City, UT, USA
| | - Sarah J Ilstrup
- Department of Pathology, Intermountain Medical Center, Murray, UT, USA
| | - Kelly Cail
- ARUP Laboratories, Salt Lake City, UT, USA
| | - Robert D Christensen
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA.,Women and Newborns Research, Intermountain Healthcare, Salt Lake City, UT, USA.,Division Hematology/Oncology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
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Combined iron sucrose and protoporphyrin treatment protects against ischemic and toxin-mediated acute renal failure. Kidney Int 2016; 90:67-76. [PMID: 27165818 DOI: 10.1016/j.kint.2016.01.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/08/2016] [Accepted: 01/14/2016] [Indexed: 01/07/2023]
Abstract
Tissue preconditioning, whereby various short-term stressors initiate organ resistance to subsequent injury, is well recognized. However, clinical preconditioning of the kidney for protection against acute kidney injury (AKI) has not been established. Here we tested whether a pro-oxidant agent, iron sucrose, combined with a protoporphyrin (Sn protoporphyrin), can induce preconditioning and protect against acute renal failure. Mice were pretreated with iron sucrose, protoporphyrin, cyanocobalamin, iron sucrose and protoporphyrin, or iron sucrose and cyanocobalamin. Eighteen hours later, ischemic, maleate, or glycerol models of AKI were induced, and its severity was assessed the following day (blood urea nitrogen, plasma creatinine concentrations; post-ischemic histology). Agent impact on cytoprotective gene expression (heme oxygenase 1, hepcidin, haptoglobin, hemopexin, α1-antitrypsin, α1-microglobulin, IL-10) was assessed as renal mRNA and protein levels. AKI-associated myocardial injury was gauged by plasma troponin I levels. Combination agent administration upregulated multiple cytoprotective genes and, unlike single agent administration, conferred marked protection against each tested model of acute renal failure. Heme oxygenase was shown to be a marked contributor to this cytoprotective effect. Preconditioning also blunted AKI-induced cardiac troponin release. Thus, iron sucrose and protoporphyrin administration can upregulate diverse cytoprotective genes and protect against acute renal failure. Associated cardiac protection implies potential relevance to both AKI and its associated adverse downstream effects.
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Zager RA. Marked protection against acute renal and hepatic injury after nitrited myoglobin + tin protoporphyrin administration. Transl Res 2015; 166:485-501. [PMID: 26117289 PMCID: PMC4609608 DOI: 10.1016/j.trsl.2015.06.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/02/2015] [Indexed: 01/30/2023]
Abstract
The phenomenon known as renal "ischemic preconditioning," whereby an initial ischemic insult induces resistance against subsequent kidney damage, has been well established in the experimental literature. However, a clinically applicable way to safely recapitulate this state has not been defined. We hypothesized that a unique combination of agents (nitrited myoglobin [N-Mgb] + tin protoporphyrin [SnPP]) can achieve these ends safely and synergistically, increasing cytoprotective proteins (eg, heme oxygenase 1 [HO-1], interleukin 10 [IL-10], and haptoglobin) in kidney cells. To test this hypothesis, CD-1 mice received 1 mg of N-Mgb and 1 μmol of SnPP, either alone or in combination. Renal cortical HO-1, haptoglobin, and IL-10 gene expressions (messenger RNA [mRNA], protein levels) were determined 4 and 18 hours later. Cytoresistance to 3 forms of acute kidney injury (AKI; glycerol-induced rhabdomyolysis, maleate nephrotoxicity, and postischemic AKI progression to chronic kidney disease [CKD]) was assessed. To ascertain whether cytoresistance might emerge in extrarenal organs, hepatic HO-1, IL-10, and haptoglobin levels were also measured, and resistance to 25 minutes of hepatic ischemia-reperfusion injury and hepatotoxicity (intraperitoneal glycerol injection) was sought. N-Mgb + SnPP induced additive or synergistic increases in renal HO-1, haptoglobin, and IL-10 mRNA and protein levels (up to 20-fold) without inducing any apparent renal or extrarenal damage. After 18 hours of post-treatment, marked or complete protection against glycerol-induced AKI, maleate-induced AKI, and postischemic AKI progression to CKD had emerged. Combined N-Mgb + SnPP was more protective than either agent alone (assessed in glycerol model). N-Mgb + SnPP also upregulated cytoprotective pathways in liver and induced marked protection against both hepatic ischemia-reperfusion and toxic liver damage. In conclusion, we posit that "preconditioning" with combined administration of N-Mgb + SnPP represents a promising approach for protecting against diverse forms of renal and nonrenal (hepatic) forms of tissue damage.
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Affiliation(s)
- Richard A Zager
- Fred Hutchinson Cancer Research Center, Seattle, Wash; Department of Medicine, University of Washington, Seattle, Wash.
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Schulz S, Wong RJ, Vreman HJ, Stevenson DK. Metalloporphyrins - an update. Front Pharmacol 2012; 3:68. [PMID: 22557967 PMCID: PMC3337460 DOI: 10.3389/fphar.2012.00068] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 04/03/2012] [Indexed: 11/13/2022] Open
Abstract
Metalloporphyrins are structural analogs of heme and their potential use in the management of neonatal hyperbilirubinemia has been the subject of considerable research for more than three decades. The pharmacological basis for using this class of compounds to control bilirubin levels is the targeted blockade of bilirubin production through the competitive inhibition of heme oxygenase (HO), the rate-limiting enzyme in the bilirubin production pathway. Ongoing research continues in the pursuit of identifying ideal metalloporphyrins, which are safe and effective, by defining therapeutic windows and targeted interventions for the treatment of excessive neonatal hyperbilirubinemia.
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Affiliation(s)
- Stephanie Schulz
- Division of Neonatal and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine Stanford, CA, USA
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Vlahakis JZ, Lazar C, Roman G, Vukomanovic D, Nakatsu K, Szarek WA. Heme oxygenase inhibition by α-(1H-imidazol-1-yl)-ω-phenylalkanes: effect of introduction of heteroatoms in the alkyl linker. ChemMedChem 2012; 7:897-902. [PMID: 22431362 DOI: 10.1002/cmdc.201100602] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 01/25/2012] [Indexed: 11/10/2022]
Abstract
Several α-(1H-imidazol-1-yl)-ω-phenylalkanes were synthesized and evaluated as novel inhibitors of heme oxygenase (HO). These compounds were found to be potent and selective for the stress-induced isozyme HO-1, showing mostly weak activity toward the constitutive isozyme HO-2. The introduction of an oxygen atom in the alkyl linker produced analogues with decreased potency toward HO-1, whereas the presence of a sulfur atom in the linker gave rise to analogues with greater potency toward HO-1 than the carbon-containing analogues. The most potent compounds studied contained a five-atom linker between the imidazolyl and phenyl moieties, whereas the most HO-1-selective compounds contained a four-atom linker between these groups. The compounds with a five-atom linker containing a heteroatom (O or S) were found to be the most potent inhibitors of HO-2; 1-(N-benzylamino)-3-(1H-imidazol-1-yl)propane dihydrochloride, with a nitrogen atom in the linker, was found to be inactive.
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Affiliation(s)
- Jason Z Vlahakis
- Department of Chemistry, Queen's University, Kingston, ON, Canada
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Stevenson DK, Wong RJ. Metalloporphyrins in the management of neonatal hyperbilirubinemia. Semin Fetal Neonatal Med 2010; 15:164-8. [PMID: 20006567 PMCID: PMC2859976 DOI: 10.1016/j.siny.2009.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neonatal jaundice in the first week of life is a common problem in newborns. It is due to an imbalance of bilirubin production and its elimination, which can lead to significantly elevated levels of circulating bilirubin or hyperbilirubinemia. Use of phototherapy and/or exchange transfusion are the current modes for treating neonatal hyperbilirubinemia and preventing any neurologic damage. These strategies, however, only remove bilirubin that has already been formed. Preventing the production of excess bilirubin may be a more logical approach. Synthetic heme analogs, metalloporphyrins, are competitive inhibitors of heme oxygenase, the rate-limiting enzyme in bilirubin production, and their use has been proposed as an attractive alternative strategy for preventing or treating severe hyperbilirubinemia.
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Affiliation(s)
- David K. Stevenson
- Corresponding author. Tel.: +1 650-723-5711; fax: +1 650-725-8351., (D. Stevenson)
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Yu Z, Han S, Guo X, Gao C, Ji C. Chinese herbal medicines for the treatment of neonatal jaundice. Hippokratia 2010. [DOI: 10.1002/14651858.cd008434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zhangbin Yu
- Nanjing Maternal and Child Health Hospital of Nanjing Medical University; Department of Pediatrics, Section of Neonatology; No. 123 Tian Fei Xiang Mo Chou Road Nanjing China 210004
| | - Shuping Han
- Nanjing Maternal and Child Health Hospital of Nanjing Medical University; Department of Pediatrics, Section of Neonatology; No. 123 Tian Fei Xiang Mo Chou Road Nanjing China 210004
| | - Xirong Guo
- Nanjing Maternal and Child Health Hospital of Nanjing Medical University; Department of Pediatrics, Section of Neonatology; No. 123 Tian Fei Xiang Mo Chou Road Nanjing China 210004
| | - Chunlin Gao
- Nanjing Maternal and Child health Hospital of Nanjing Medical University; Department of Pediatrics; No. 123 Tian Fei Xiang Mo Chou Road Nanjing China 210004
| | - Chenbo Ji
- Nanjing Maternal and Child Health Hospital of Nanjing Medical University; Department of Pediatrics; No. 123 Tian Fei Xiang Mo Chou road Nanjing China 210004
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Wu J, Su W, Jin Y, Shi Y, Li C, Zhong W, Zhang X, Zhang Z, Xia Z. Targeted suppression of heme oxygenase-1 by small interference RNAs inhibits the production of bilirubin in neonatal rat with hyperbilirubinemia. BMC Mol Biol 2009; 10:77. [PMID: 19646271 PMCID: PMC2726144 DOI: 10.1186/1471-2199-10-77] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 08/01/2009] [Indexed: 11/13/2022] Open
Abstract
Background Excessive accumulation of bilirubin contributes to neonatal hyperbilirubinemia in rats. Heme oxygenase (HO) is one of the rate-limiting enzymes in catabolizing heme to bilirubin. In the present study, we investigated whether suppression of rat HO-1 (rHO-1) expression by small interference RNAs (siRNAs) reduces bilirubin levels in hyperbilirubinemic rats. Results Four pairs of siRNA targeting rHO-1 mRNA were introduced into BRL cells and compared for their inhibitory effect on the expression of rHO-1 gene and production of rHO-1 protein. The siRNA exhibiting the most potent effect on HO-1 expression and activity was then administered intraperitoneally to 7 to 9-day-old rats with hyperbilirubinemia. The siRNA distributed mostly in the liver and spleen of neonatal rat. Serum bilirubin levels and hepatic HO-1 expression were further evaluated. Systemic treatment of siRNA targeting rHO-1 reduced hepatic HO-1 expression and decreased the serum bilirubin levels in a time- and dose-dependent manner, and siRNA decreased the indirect bilirubin levels more effectively than Sn-protoporphyrin (SnPP), an HO-1 inhibitor. Conclusion siRNA targeting rHO-l attenuates hepatic HO-1 expression and serum bilirubin levels. Thus this study provides a novel therapeutic rationale for the prevention and treatment of neonatal hyperbilirubinemia.
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Affiliation(s)
- Jinyong Wu
- Ruijin Hospital Affiliated to School of Medicine, Shanghai Jiao Tong University, Shanghai, PR China.
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Morioka I, Wong RJ, Abate A, Vreman HJ, Contag CH, Stevenson DK. Systemic effects of orally-administered zinc and tin (IV) metalloporphyrins on heme oxygenase expression in mice. Pediatr Res 2006; 59:667-72. [PMID: 16627879 DOI: 10.1203/01.pdr.0000215088.71481.a6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Some metalloporphyrins (Mps) inhibit heme oxygenase (HO), the rate-limiting enzyme in the production of bilirubin, and are potential compounds for the treatment of neonatal jaundice. We studied the safety and efficacy of Mps following oral administration. Adult HO-1-luc reporter mice were administered 30 micromol/kg body weight of tin mesoporphyrin (SnMP), zinc bis glycol deuteroporphyrin (ZnBG), or zinc protoporphyrin (ZnPP), or vehicle by oral gavage. Bilirubin production was measured as total body carbon monoxide (CO) excretion (VeCO). HO activity was quantitated via CO measurements by gas chromatography. HO-1 protein was determined by Western blot. HO-1 transcription levels were assessed by in vivo bioluminescence imaging. A significant 28% decrease in bilirubin production occurred within 3 h of SnMP treatment and persisted beyond 48 h. Bilirubin production decreased 15% and 9% by 3 h after administration of ZnBG and ZnPP, respectively, but returned to baseline within 48 h. Maximal inhibition of liver, spleen, and intestine HO activity was seen at 3 h with inhibitory effects decreasing in the order: SnMP > or = ZnBG > or = ZnPP. After SnMP treatment, HO-1 transcription increased 5.7-fold after 24 h. Furthermore, liver and spleen HO-1 protein significantly increased 3.7- and 2.0-fold, respectively, after 24 h. HO-1 transcription and protein were not affected in ZnBG- or ZnPP-treated mice. We conclude that the three Mps are absorbed at different rates in the mouse and affect bilirubin production and HO-1 expression in a tissue- and time-dependent manner.
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Affiliation(s)
- Ichiro Morioka
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305-5208, USA
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DeSandre GH, Wong RJ, Morioka I, Contag CH, Stevenson DK. The effectiveness of oral tin mesoporphyrin prophylaxis in reducing bilirubin production after an oral heme load in a transgenic mouse model. Neonatology 2005; 89:139-46. [PMID: 16205054 DOI: 10.1159/000088717] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Accepted: 08/12/2005] [Indexed: 01/06/2023]
Abstract
BACKGROUND Neonatal jaundice is commonly encountered and rarely associated with morbidity and mortality. Nonetheless, infants with glucose-6-phosphate dehydrogenase deficiency often have hemolysis (a heme load) caused by an environmental oxidant trigger, thus increasing their risk for serious morbidity. The use of tin mesoporphyrin (SnMP) has been proposed for interdicting the development of severe hyperbilirubinemia in a variety of conditions. OBJECTIVES We studied the in vivo effects of prophylactic oral SnMP on heme oxygenase (HO) activity and bilirubin production, as indexed by the excretion rate of carbon monoxide (VeCO), following a subsequent oral heme load. METHODS Adult mice were exposed serially to heme and assessed for in vivo bilirubin production rates, HO-1 transcription and protein, and HO activity. The effect of prophylaxis with a single oral dose of SnMP prior to an oral heme load was assessed by measuring VeCOand tissue HO activities. RESULTS After serial heme exposures, VeCO, HO-1 transcription and protein, and liver and spleen HO activities increased incrementally. After pretreatment with oral SnMP, bilirubin production decreased in response to an oral heme load. Also, heme-mediated increases in liver, spleen, and intestine HO activities were significantly dampened. CONCLUSIONS A single oral dose of SnMP results in durable inhibition of bilirubin production and HO activity for at least 24 h in a mouse model of oral heme loading. Further studies are needed to fully elucidate the duration of this protection against hyperbilirubinemia due to a delayed heme load and any long-term consequences of prophylaxis with SnMP on HO-1 transcription and HO-1 protein.
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Affiliation(s)
- Glenn H DeSandre
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94306, USA
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Abstract
PURPOSE OF REVIEW To evaluate the safety and efficacy of metalloporphyrins for the treatment of neonatal hyperbilirubinemia. RECENT FINDING Since the 1980s and 1990s, there have been no publications on trials to determine the efficacy of metalloporphyrins in the treatment of neonatal jaundice. In the past year, a single case report was presented on the compassionate use of tin mesoporphyrin in a very low birth weight infant with intrauterine growth retardation who did not respond to phototherapy. Subcutaneous administration of a single dose of tin mesoporphyrin at 46 hours of life was associated with a greater than 25% reduction in serum bilirubin. This further supports existing evidence that tin mesoporphyrin is efficacious in lowering bilirubin production. In the laboratory, most metalloporphyrins were shown to induce heme oxygenase, and in addition, metalloporphyrins modulate cardiac cell function in vitro. These observations suggest that the therapeutic benefits may be obviated if such considerations hold true in humans. SUMMARY Recent case reports and previous evidence from larger clinical trials conducted in Greece and Argentina in the 1980s and 1990s demonstrate that tin mesoporphyrin is useful in the treatment of neonatal jaundice. Its long-term safety is not well understood but will be important to determine, before its widespread or prophylactic use in neonates with hyperbilirubinemia can be recommended.
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Affiliation(s)
- Phyllis A Dennery
- Department of Pediatrics, University of Pennsylvania School of Medicine, and Children's Hospital of Philadelphia, Division of Neonatology, Philadelphia, Pennsylvania 19104, USA.
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