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Abstract
Drug delivery using a surfactant vehicle has the potential to prevent systemic side effects by delivering therapeutic agents directly to the respiratory system. The inherent chemical properties of surfactant allows it to readily distribute throughout the respiratory system. Therapeutic agents delivered by surfactant can primarily confer additional benefits but have potential to improve surfactant function. It is critically important that additional agents do not interefere with the innate surface tension lowering function of surfactant. Systemic evaluation through benchtop, translational and human trials are required to translate this potential technique into clinical practice.
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Affiliation(s)
- Arun Sett
- Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Department of Obstetrics, Gynaecology and Newborn Health, The University of Melbourne, Melbourne, Australia; Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia; Newborn Services, Joan Kirner Women's and Children's, Sunshine Hospital, Victoria, Australia.
| | - Charles C Roehr
- Newborn Services, Southmead Hospital, North Bristol NHS Trust Bristol, Bristol, UK; Faculty of Health Sciences, University of Bristol, Bristol, UK; Oxford Population Health, National Perinatal Epidemiology Unit, Medical Sciences Division, University of Oxford, Oxford, UK
| | - Brett J Manley
- Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Department of Obstetrics, Gynaecology and Newborn Health, The University of Melbourne, Melbourne, Australia; Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia
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Rao S, Bartle D, Patole S. Current and future therapeutic options for persistent pulmonary hypertension in the newborn. Expert Rev Cardiovasc Ther 2010; 8:845-62. [PMID: 20528642 DOI: 10.1586/erc.09.186] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is a potentially life-threatening condition that is characterized by supra-systemic pulmonary vascular resistance causing right-to-left shunting through the ductus arteriosus and/or foramen ovale, leading to a vicious cycle of hypoxemia, acidosis and further pulmonary vasoconstriction. Advances in neonatology including surfactant instillation, high-frequency ventilation, extracorporeal membrane oxygenation and, most importantly, inhaled nitric oxide (INO), have revolutionized the management of PPHN. However, given that INO does not improve oxygenation in a significant proportion (30-40%) of cases, there is an urgent need to consider other therapeutic options for PPHN. The issue is more important for developing nations with a higher PPHN-related health burden and limited resources. This article discusses the evidence about INO in term and preterm neonates in brief, and focuses mainly on the potential alternative drugs in the management of PPHN.
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Affiliation(s)
- Shripada Rao
- Department of Neonatal Paediatrics, KEM Hospital for Women, Bagot road, Subiaco, Perth 6008, Western Australia, Australia
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Liu J, Morton J, Miedzyblocki M, Lee TF, Bigam DL, Fok TF, Chen C, Lee SK, Davidge ST, Cheung PY. Sodium tanshinone IIA sulfonate increased intestinal hemodynamics without systemic circulatory changes in healthy newborn piglets. Am J Physiol Heart Circ Physiol 2009; 297:H1217-24. [DOI: 10.1152/ajpheart.00477.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In traditional Chinese medicine, tanshinone IIA is a lipid-soluble component of Danshen that has been widely used for various cardiovascular and cerebrovascular disorders, including neonatal asphyxia. Despite promising effects, little is known regarding the hemodynamic effects of tanshinone IIA in newborn subjects. To examine the dose-response effects of sodium tanshinone IIA sulfonate (STS) on systemic and regional hemodynamics and oxygen transport, 12 newborn piglets were anesthetized and acutely instrumented for the placement of femoral arterial and venous, pulmonary arterial catheters to measure mean arterial, central venous, and pulmonary arterial pressures, respectively. The blood flow at the common carotid, renal, pulmonary, and superior mesenteric (SMA) arteries were continuously monitored after treating the piglets with either STS (0.1–30 mg/kg iv) or saline treatment ( n = 6/group). To further delineate the underlying mechanisms for vasorelaxant effects of STS, in vitro vascular myography was carried out to compare its effect on rat mesenteric and carotid arteries ( n = 4–5/group). STS dose-dependently increased the SMA blood flow and the corresponding oxygen delivery with no significant effect on systemic and pulmonary, carotid and renal hemodynamic parameters. In vitro studies also demonstrated that STS selectively dilated rat mesenteric but not carotid arteries. Vasodilation in mesenteric arteries was inhibited by apamin and TRAM-34 (calcium-activated potassium channel inhibitors) but not by meclofenamate (cyclooxygenase inhibitor) or N-nitro-l-arginine methyl ester hydrochloride (nitric oxide synthase inhibitor). In summary, without significant hemodynamic effects on newborn piglets, intravenous infusion of STS selectively increased mesenteric perfusion in a dose-dependent manner, possibly via an endothelium-derived hyperpolarizing factor vasodilating pathway.
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Affiliation(s)
- Jiangqin Liu
- Department of 1Pediatrics, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Children's Hospital of Fudan University, Shanghai; and
| | - Jude Morton
- Department of 3Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Tze Fun Lee
- Department of 1Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - David L. Bigam
- Department of 4Surgery, University of Alberta, Edmonton, Alberta, Canada
| | - Tai Fai Fok
- Department of Pediatrics, the Chinese University of Hong Kong, Hong Kong, China
| | - Chao Chen
- Department of Pediatrics, Children's Hospital of Fudan University, Shanghai; and
| | - Shoo K. Lee
- Department of 1Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Sandra T. Davidge
- Department of 3Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | - Po-Yin Cheung
- Department of 1Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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Tessler R, Wu S, Fiori R, Macgowan CK, Belik J. Sildenafil acutely reverses the hypoxic pulmonary vasoconstriction response of the newborn pig. Pediatr Res 2008; 64:251-5. [PMID: 18458659 DOI: 10.1203/pdr.0b013e31817d9b93] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Sildenafil is a pulmonary vasodilator shown to be effective in neonates, but conflicting data exist regarding its effect on arterial oxygenation. To address this issue, we tested the sildenafil effect on the piglet's hypoxic pulmonary vasoconstriction (HPV) response. A segmental lung atelectasis was created by obstructing the corresponding bronchus. Total pulmonary and specific flows to the atelectatic and contra-lateral lobes were measured by magnetic resonance (MR) before and 30-min post sildenafil (0.2 and 1 mg/kg i.v.) or saline administration. Flow was reduced (p < 0.01) in the atelectatic and increased in the contra-lateral lobe indicating an effective HPV response. Sildenafil at both doses significantly (p < 0.01) increased flow solely to the atelectatic lobe. At a dose of 1 mg/kg, sildenafil induced a decrease in Pao2 from 285 +/- 37 to 161 +/- 22 mm Hg (p < 0.01). We conclude that the HPV response in the newborn is capable of almost completely reducing blood flow to nonventilated lung units and is reversed following sildenafil i.v. administration in a dose-dependent manner. In the presence of lung parenchymal disease, the use of i.v. sildenafil as a pulmonary vasodilator may worsen arterial oxygenation by reversing the HPV response in nonventilated lung units.
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Affiliation(s)
- Rogerio Tessler
- Department of Pediatrics, Pontifícia Universidade Católica do Rio Grande do Sul, Rio Grande do Sul, Brazil
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Herrera EA, Ebensperger G, Krause BJ, Riquelme RA, Reyes RV, Capetillo M, González S, Parer JT, Llanos AJ. Sildenafil reverses hypoxic pulmonary hypertension in highland and lowland newborn sheep. Pediatr Res 2008; 63:169-75. [PMID: 18091352 DOI: 10.1203/pdr.0b013e31815ef71c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Perinatal exposure to chronic hypoxia induces sustained hypertension and structural and functional changes in the pulmonary vascular bed. We hypothesized that highland newborn lambs (HLNB, 3600 m) have a higher pulmonary arterial pressure (PAP) due in part to a higher activity/expression of phosphodiesterase 5 (PDE5). We administered sildenafil, a PDE5 inhibitor, during basal and hypoxic conditions in the pulmonary hypertensive HLNB and compared them to lowland newborn lambs (LLNB, 580 m). Additionally, we compared the vasodilator responses to sildenafil in isolated small pulmonary arteries and the PDE5 mRNA expression and evaluated the vascular remodeling by histomorphometric analysis in these newborn lambs. Under basal conditions, HLNB had a higher PAP and cardiac output compared with LLNB. Sildenafil decreased the PAP during basal conditions and completely prevented the PAP increase during hypoxia in both groups. HLNB showed a greater contractile capacity and a higher maximal dilation to sildenafil. PDE5 mRNA expression did not show significant differences between HLNB and LLNB. The distal pulmonary arteries showed an increased wall thickness in HLNB. Our results showed that HLNB are more sensitive to sildenafil and therefore could be useful for treatment of pulmonary hypertension in high-altitude neonates.
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Affiliation(s)
- Emilio A Herrera
- Program in Pathophysiology, University of Chile, CP 6640871, Santiago, Chile
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Been JV, Zimmermann LJI. What's new in surfactant? A clinical view on recent developments in neonatology and paediatrics. Eur J Pediatr 2007; 166:889-99. [PMID: 17516084 PMCID: PMC7102086 DOI: 10.1007/s00431-007-0501-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 04/18/2007] [Indexed: 11/29/2022]
Abstract
UNLABELLED Surfactant therapy has significantly changed clinical practice in neonatology over the last 25 years. Recent trials in infants with respiratory distress syndrome (RDS) have not shown superiority of any natural surfactant over another. Advancements in the development of synthetic surfactants are promising, yet to date none has been shown to be superior to natural preparations. Ideally, surfactant would be administered without requiring mechanical ventilation. An increasing number of studies investigate the roles of alternative modes of administration and the use of nasal continuous positive airway pressure to minimise the need for mechanical ventilation. Whether children with other lung diseases benefit from surfactant therapy is less clear. Evidence suggests that infants with meconium aspiration syndrome and children with acute lung injury/acute respiratory distress syndrome may benefit, while no positive effect of surfactant is seen in infants with congenital diaphragmatic hernia. However, more research is needed to establish potential beneficial effects of surfactant administration in children with lung diseases other than RDS. Furthermore, genetic disorders of surfactant metabolism have recently been linked to respiratory diseases of formerly unknown origin. It is important to consider these disorders in the differential diagnosis of unexplained respiratory distress although no established treatment is yet available besides lung transplantation for the most severe cases. CONCLUSION Research around surfactant is evolving and recent developments include further evolution of synthetic surfactants, evaluation of surfactant as a therapeutic option in lung diseases other than RDS and the discovery of genetic disorders of surfactant metabolism. Ongoing research is essential to continue to improve therapeutic prospects for children with serious respiratory disease involving disturbances in surfactant.
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Affiliation(s)
- Jasper V Been
- Department of Paediatrics, Research Institute Growth and Development, Maastricht University Hospital, Maastricht, The Netherlands.
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