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Chang EI, Zárate MA, Rabaglino MB, Richards EM, Keller-Wood M, Wood CE. Ketamine suppresses hypoxia-induced inflammatory responses in the late-gestation ovine fetal kidney cortex. J Physiol 2015; 594:1295-310. [PMID: 26497972 DOI: 10.1113/jp271066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/28/2015] [Indexed: 01/04/2023] Open
Abstract
Acute fetal hypoxia is a form of fetal stress that stimulates renal vasoconstriction and ischaemia as a consequence of the physiological redistribution of combined ventricular output. Because of the potential ischaemia-reperfusion injury to the kidney, we hypothesized that it would respond to hypoxia with an increase in the expression of inflammatory genes, and that ketamine (an N-methyl-D-aspartate receptor antagonist) would reduce or block this response. Hypoxia was induced for 30 min in chronically catheterized fetal sheep (125 ± 3 days), with or without ketamine (3 mg kg(-1)) administered intravenously to the fetus 10 min prior to hypoxia. Gene expression in fetal kidney cortex collected 24 h after the onset of hypoxia was analysed using ovine Agilent 15.5k array and validated with qPCR and immunohistochemistry in four groups of ewes: normoxic control, normoxia + ketamine, hypoxic control and hypoxia + ketamine (n = 3-4 per group). Significant differences in gene expression between groups were determined with t-statistics using the limma package for R (P ≤ 0.05). Enriched biological processes for the 427 upregulated genes were immune and inflammatory responses and for the 946 downregulated genes were metabolic processes. Ketamine countered the effects of hypoxia on upregulated immune/inflammatory responses as well as the downregulated metabolic responses. We conclude that our transcriptomics modelling predicts that hypoxia activates inflammatory pathways and reduces metabolism in the fetal kidney cortex, and ketamine blocks or ameliorates this response. The results suggest that ketamine may have therapeutic potential for protection from ischaemic renal damage.
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Affiliation(s)
- Eileen I Chang
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, 32610-0274, USA
| | - Miguel A Zárate
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, 32610-0274, USA
| | - Maria B Rabaglino
- Department of Animal Reproduction, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Elaine M Richards
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610-0487, USA
| | - Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610-0487, USA
| | - Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, 32610-0274, USA
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Derderian SC, Jeanty C, Fleck SR, Cheng LS, Peyvandi S, Moon-Grady AJ, Farrell J, Hirose S, Gonzalez J, Keller RL, MacKenzie TC. The many faces of hydrops. J Pediatr Surg 2015; 50:50-4; discussion 54. [PMID: 25598092 PMCID: PMC4315667 DOI: 10.1016/j.jpedsurg.2014.10.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 10/06/2014] [Indexed: 12/26/2022]
Abstract
PURPOSE Fetal hydrops arises from multiple disease processes and can portend a grim prognosis. We reviewed our experience with hydropic fetuses to understand relevant antenatal anatomic and physiologic predictors of survival. METHODS We reviewed fetal ultrasounds and echocardiograms of hydropic fetuses evaluated from 1996 to 2013. RESULTS Overall neonatal survival in 167 fetuses was 44% (range, 0-75%) and was influenced by the underlying disease process. The anatomic distribution of fluid varied and was not significantly different between survivors and nonsurvivors. Univariate analysis indicated that resolution of hydrops and delivery at a later gestational age were predictive of survival (OR: 5.7 (95% CI: 2.5-13.2) and OR: 1.3 (95% CI: 1.1-1.4), respectively). Fetal intervention also improved survival in some diseases. Echocardiograms were reviewed to group fetuses with similar cardiac physiology and defined categories with high or low/normal cardiothoracic ratio (CTR). Among patients with a high CTR, the cardiovascular profile score was predictive of survival (p=0.009). CONCLUSION Survival in hydrops depends on the underlying disease, available fetal therapies to resolve hydrops, and the gestational age of delivery and not on the specific anatomic manifestations of hydrops. In hydropic fetuses with high CTRs, the cardiovascular profile score may be a useful prognostic indicator.
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Affiliation(s)
- S Christopher Derderian
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Surgery, The University of California, San Francisco, CA
| | - Cerine Jeanty
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Surgery, The University of California, San Francisco, CA
| | - Shannon R Fleck
- Department of Pediatrics, The University of California, San Francisco, CA
| | - Lily S Cheng
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Surgery, The University of California, San Francisco, CA
| | - Shabnam Peyvandi
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Pediatrics, The University of California, San Francisco, CA
| | - Anita J Moon-Grady
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Pediatrics, The University of California, San Francisco, CA
| | - Jody Farrell
- Fetal Treatment Center, The University of California, San Francisco, CA
| | - Shinjiro Hirose
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Surgery, The University of California, San Francisco, CA
| | - Juan Gonzalez
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Obstetrics and Gynecology, The University of California, San Francisco, CA
| | - Roberta L Keller
- Fetal Treatment Center, The University of California, San Francisco, CA
,Department of Pediatrics, The University of California, San Francisco, CA
| | - Tippi C MacKenzie
- Fetal Treatment Center, The University of California, San Francisco, CA, United States; Department of Surgery, The University of California, San Francisco, CA, United States.
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Does Maturity Affect Cephalic Perfusion and T/QRS Ratio during Prolonged Umbilical Cord Occlusion in Fetal Sheep? Obstet Gynecol Int 2014; 2014:314159. [PMID: 24693290 PMCID: PMC3945773 DOI: 10.1155/2014/314159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/18/2013] [Accepted: 12/31/2013] [Indexed: 11/17/2022] Open
Abstract
T/QRS ratio monitoring is used to help identify fetal asphyxia. However, immature animals have greater capacity to maintain blood pressure during severe asphyxia, raising the possibility that they may show an attenuated T/QRS increase during asphyxia. Chronically instrumented fetal sheep at 0.6 of gestation (0.6 GA; n = 12), 0.7 GA (n = 12), and 0.8 GA (n = 8) underwent complete umbilical cord occlusion for 30 min, 25 min, or 15 min, respectively. Cord occlusion was associated with progressive metabolic acidosis and initial hypertension followed by severe hypotension, with a more rapid fall in mean arterial blood pressure (MAP) and carotid blood flow (CaBF) with advancing gestation. T/QRS ratio rose after occlusion more rapidly at 0.8 GA than in immature fetuses, to a similar final peak at all ages, followed by a progressive fall that was slower at 0.8 GA than in the immature fetuses. The increase in T/QRS ratio correlated with initial hypertension at 0.8 GA (P < 0.05, R2 = 0.38), and conversely, its fall correlated closely with falling MAP in all gestational groups (P < 0.01, R2 = 0.67). In conclusion, elevation of the T/QRS ratio is an index of onset of severe asphyxia in the last third of gestation, but not of fetal compromise.
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Treiber M, Gorenjak M, Pecovnik Balon B. Serum cystatin-C as a marker of acute kidney injury in the newborn after perinatal hypoxia/asphyxia. Ther Apher Dial 2013; 18:57-67. [PMID: 24499085 DOI: 10.1111/1744-9987.12054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We evaluated cystatin-C (cysC) in the umbilical blood as a predictor of acute kidney injury (AKI) after perinatal hypoxia/asphyxia compared with creatinine (Cr). One hundred full-term newborns were enrolled in the study (50 in a group affected by perinatal hypoxia/asphyxia [AS] and 50 controls). CysC and Cr were measured in blood samples from the umbilical cord at birth (cysC-umb and Cr-umb) and from a peripheral vein 3 days later (cysC-3 and Cr-3). At birth, the mean level of cysC in healthy term babies was found to be 1.39 ± 0.19 mg/L and 1.34 ± 0.21 mg/L after 3 days of life, not significantly decreased (P = 0.137). The mean of cysC in the AS group was 2.12 ± 0.53 mg/L in cord blood and 1.56 ± 0.32 g/L in day 3 blood samples, also decreased (P < 0.001) and different from the control (P < 0.001). Cr levels, determined simultaneously at birth were different (P = 0.001) between the control (62.74 ± 12.84 μmol/L) and AS (72.60 ± 15.55 μmol/L) group, significantly decreased after 3 days in both groups (P < 0.001). The receiver-operating characteristic curve analysis, comparing AS and the control group, showed area under the curve for cysC-umb, cysC-3, Cr-umb and Cr-3 (0.918; 0.698; 0.692; 0.660). The highest diagnostic accuracy was achieved with a chosen cut-off for cysC-umb of 1.67 mg/L (sensitivity of 84.0%, specificity of 90.0%) or 1.69 mg/L (sensitivity of 82.0%, specificity of 94.0%). Our results indicate serum CysC is a more sensitive marker of glomerular filtration rate than Cr in the newborns.
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Affiliation(s)
- Milena Treiber
- Clinical Department of Gynecology and Perinatology, Unit of Neonatology, Maribor, Slovenia
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Çetinkaya M, Durmaz O, Büyükkale G, Ozbek S, Acar D, Kilicaslan I, Kavuncuoglu S. Neonatal Bartter syndrome and unilateral ectopic renal cyst as new renal causes of hydrops fetalis: two case reports and review of the literature. J Matern Fetal Neonatal Med 2013; 26:1147-50. [PMID: 23484775 DOI: 10.3109/14767058.2013.783803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Non-immune hydrops fetalis (NIHF) is a challenging entity as it represents the end stage of several different disorders. Renal and genitourinary causes of NIHF are rare and include congenital renal malformations, tumors and ureter-urethra disorders. Herein, two NIHF cases with different renal causes were presented. The first case that had antenatal NIHF was diagnosed neonatal Bartter syndrome. The second case of NIHF with antenatal large cyst in the surrenal gland area required surgery and ectopic renal cyst was diagnosed. To our best of knowledge, these are the first reports of NIHF associated with neonatal Bartter syndrome and ectopic renal cyst in neonates. Although it may be coincidental, these cases suggest that both neonatal Bartter syndrome and unilateral ectopic renal cyst may cause NIHF development in neonates by several different mechanisms. Therefore, these two rare entities should be suspected in cases of NIHF with similar findings.
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Affiliation(s)
- Merih Çetinkaya
- Department of Neonatology, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey.
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Karnak I, Atilla P, Müftüoğlu S. Effect of increased intra-abdominal pressure on urinary system development in fetal rabbits. J Pediatr Urol 2012; 8:535-43. [PMID: 22099478 DOI: 10.1016/j.jpurol.2011.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Accepted: 09/12/2011] [Indexed: 01/15/2023]
Abstract
AIM To investigate the effect of increased intra-abdominal pressure (IAP) on the fetal urinary system. MATERIALS AND METHODS Pregnant rabbits (15-day gestation) were used. Control (n = 5) and experimental (EG, n = 4) groups underwent intraperitoneal catheter placement. The IAP was increased by intraperitoneal air insufflations during the third trimester in the EG. At term, organ weight and organ weight/body weight (BW) ratios were noted, histological examination of the urinary system organs was performed, and the apoptotic indexes were calculated. RESULTS BW and total renal weight were significantly increased in the EG (38.65 ± 8.34 g vs 49.36 ± 8.81 g, p = 0.008; and 0.406 ± 0.132 g vs 0.531 ± 0.129 g, p = 0.02). Total renal weight/BW ratio did not differ between groups (0.0103 ± 0.001 vs 0.0107 ± 0.001; p = 0.33). Bladder weight and bladder weight/BW ratio was also significantly increased in the EG (0.067 ± 0.014 g vs 0.114 ± 0.026 g, p = 0.00; and 0.00175 ± 0.00026 vs 0.00229 ± 0.00036, p = 0.001). Immature glomeruli and collecting tubules, and a thin and underdeveloped muscular layer in the ureter and bladder were encountered in the EG, and the apoptotic cell index was significantly increased (p < 0.05). CONCLUSION Increased IAP has an adverse effect on fetal urinary system development, and may play a role in the pathogenesis of various congenital abnormalities of the urinary system.
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Affiliation(s)
- Ibrahim Karnak
- Hacettepe University Faculty of Medicine, Departments of Pediatric Surgery, 06100 Sıhhiye, Ankara, Turkey.
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Sarafidis K, Tsepkentzi E, Agakidou E, Diamanti E, Taparkou A, Soubasi V, Papachristou F, Drossou V. Serum and urine acute kidney injury biomarkers in asphyxiated neonates. Pediatr Nephrol 2012; 27:1575-82. [PMID: 22532328 DOI: 10.1007/s00467-012-2162-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 02/29/2012] [Accepted: 03/01/2012] [Indexed: 01/22/2023]
Abstract
BACKGROUND We evaluated serum (s) cystatin C (CysC) and neutrophil gelatinase-associated lipocalin (NGAL) and urine (u) CysC, NGAL and kidney injury molecule-1 (KIM-1) as markers of acute kidney injury (AKI) in asphyxiated neonates. METHODS AKI biomarkers were measured in 13 asphyxiated neonates born at ≥ 36 weeks gestational age (eight with AKI and five without AKI) and 22 controls. AKI was defined as serum creatinine ≥ 1.5 mg/dl for >24 h or rising values >0.3 mg/dl from day of life (DOL) 1. Biomarkers were measured on DOL 1, 3, and 10. RESULTS Asphyxiated neonates had significantly higher sCysC on DOL 1 as well as sNGAL and uCysC and uNGAL (standardized to urine creatinine and absolute values) than controls at all time points. Compared to controls, significantly higher sNGAL, uCysC, and uNGAL values were observed in the asphyxia-AKI and asphyxia-no AKI subgroups. Regarding uKIM-1, only the absolute values were significantly higher in asphyxiated neonates (DOL 10). sNGAL, uCyst, and uNGAL had a significant diagnostic performance as predictors AKI on DOL 1. CONCLUSIONS sNGAL, uCysC, and uNGAL are sensitive, early AKI biomarkers, increasing significantly in asphyxiated neonates even in those not fulfilling AKI criteria. Their measurement on DOL 1 is predictive of post-asphyxia-AKI.
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Affiliation(s)
- Kosmas Sarafidis
- 1st Department of Neonatology, Medical School, Aristotle University of Thessaloniki, Kostantinoupoleos 49, 54642, Thessaloniki, Greece.
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Bellini C, Hennekam RCM. Non-immune hydrops fetalis: a short review of etiology and pathophysiology. Am J Med Genet A 2012; 158A:597-605. [PMID: 22302731 DOI: 10.1002/ajmg.a.34438] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 10/31/2011] [Indexed: 01/16/2023]
Abstract
Hydrops fetalis is an excessive accumulation of fetal fluid. Hydrops is traditionally classified into either immune or non-immune hydrops (NIHF), but in practice, nowadays in the Western world >90% of hydrops is of non-immune origin. The basis of the disorder is an imbalance in the regulation of fetal fluid movement between the vascular and interstitial space. We previously suggested a diagnostic flow-chart for NIHF. In this short review we describe the main mechanisms leading to NIHF.
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Affiliation(s)
- Carlo Bellini
- Neonatal Intensive Care Unit, Department of Paediatrics, Gaslini Institute, University of Genoa, Genova, Italy.
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Wassink G, Bennet L, Booth LC, Jensen EC, Wibbens B, Dean JM, Gunn AJ. The ontogeny of hemodynamic responses to prolonged umbilical cord occlusion in fetal sheep. J Appl Physiol (1985) 2007; 103:1311-7. [PMID: 17656627 DOI: 10.1152/japplphysiol.00396.2007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is evidence that preterm fetuses have blunted chemoreflex-mediated responses to hypoxia. However, the preterm fetus has much lower aerobic requirements than at term, and so moderate hypoxia may not be sufficient to elicit maximal chemoreflex responses; there are only limited quantitative data on the ontogeny of chemoreflex and hemodynamic responses to severe asphyxia. Chronically instrumented fetal sheep at 0.6 (n = 12), 0.7 (n = 12), and 0.85 (n = 8) of gestational age (GA; term = 147 days) were exposed to 30, 25, or 15 min of complete umbilical cord occlusion, respectively. At all ages, occlusion was associated with early onset of bradycardia, profoundly reduced femoral blood flow and conductance, and hypertension. The 0.6-GA fetuses showed a significantly slower and lesser fall in femoral blood flow and conductance compared with the 0.85-GA group, with a correspondingly reduced relative rise in mean arterial blood pressure. As occlusion continued, the initial adaptation was followed by loss of peripheral vasoconstriction and progressive development of hypotension in all groups. The 0.85-GA fetuses showed significantly more sustained reduction in femoral conductance but also more rapid onset of hypotension than either of the younger groups. Electroencephalographic (EEG) activity was suppressed during occlusion in all groups, but the degree of suppression was less at 0.6 GA than at term. In conclusion, the near-midgestation fetus shows attenuated initial (chemoreflex) peripheral vasomotor responses to severe asphyxia compared with more mature fetuses but more sustained hemodynamic adaptation and reduced suppression of EEG activity during continued occlusion of the umbilical cord.
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Affiliation(s)
- Guido Wassink
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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O'Connell AE, Boyce AC, Kumarasamy V, Douglas-Denton R, Bertram JF, Gibson KJ. Long-term effects of a midgestational asphyxial episode in the ovine fetus. ACTA ACUST UNITED AC 2006; 288:1112-20. [PMID: 16952168 DOI: 10.1002/ar.a.20381] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We and others have shown previously that fetuses at midgestation can survive 30 min of complete umbilical cord occlusion, although hydrops fetalis (or gross fetal edema) results. To investigate whether this hydrops resolves by late gestation and if there are any long-term consequences of the asphyxial insult on the heart and kidneys, eight fetuses were subjected to 30 min of complete umbilical cord occlusion at 0.6 gestation (90 days; term 150 days) and were compared to a sham group (n = 10). During the occlusion period, fetuses became severely hypoxemic, hypercapnemic, and acidotic, with both blood pressure and heart rate decreasing. Most variables had returned to normal by 2-hr recovery. At 129 +/- 1 days of gestation, approximately 40 days post occlusion, some fetuses were still slightly hydropic as skin fold measurements were increased (P < 0.01), although fetal body weight was not different from the sham group. The two groups had similar heart and kidney weights, ventricular cardiac myocyte nucleation, and glomerular number. By contrast, brain weight was reduced by 37% (P < 0.001) and the cerebral lateral ventricles were grossly dilated. Lungs were 50% smaller than in sham fetuses (P < 0.001). Thus, the hydrops that develops at midgestation as a result of a severe asphyxial episode can, but does not always, fully resolve by late gestation. Also, while fetuses at midgestation can survive this asphyxial episode with no long-term impact in renal or cardiac size, nephron number, or cardiomyocyte nucleation, the brain and lungs are severely affected.
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Affiliation(s)
- Amanda E O'Connell
- Department of Physiology and Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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Kitagawa H, Pringle KC, Koike J, Zuccollo J, Sato Y, Sato H, Aoba T, Seki Y, Wakisaka M, Nakada K. Fetal hydrops in experimental obstructive uropathy resolves after vesicostomy formation: is this cause and effect? Pediatr Surg Int 2005; 21:25-8. [PMID: 15459778 DOI: 10.1007/s00383-004-1257-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The association of obstructive uropathy and hydrops is rare but often fatal. Hydrops has been observed in our fetal lamb model with obstructive uropathy. We created a vesicoamniotic shunt 21 days after creating the obstruction to explore the effect of relieving the obstruction on the hydrops. Fetal lambs underwent urethral and urachal ligation at 60 days gestation. We created a vesicostomy (female) or urethrostomy (male) in 12 lambs to release the pressure 21 days after creating the obstruction. The fetuses were delivered at term (145 days), and the urinary tract was removed for histological examination. Six fetuses had severe hydrops at the time of the vesicostomy (group A), and six had no hydrops (group B). Only two lambs from group A survived (33%), and four lambs survived from group B (66%). Three lambs miscarried, and one was stillborn from group A. Two lambs from group B miscarried. In our fetal lamb model, hydrops appears to be associated with massive urinary ascites. We hypothesize that a connection exists between urinary ascites and hydrops. Vesicostomy, by bypassing the obstruction, may allow the lambs to recover from their hydrops. However, it is possible that by 21 days after creation of the obstruction, the damage created by the hydrops is irreversible.
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Affiliation(s)
- Hiroaki Kitagawa
- Division of Pediatric Surgery, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, 216-8511 Kawasaki, Japan.
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Quaedackers JS, Roelfsema V, Hunter CJ, Heineman E, Gunn AJ, Bennet L. Polyuria and impaired renal blood flow after asphyxia in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2003; 286:R576-83. [PMID: 14604846 DOI: 10.1152/ajpregu.00592.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Renal impairment is common in preterm infants, often after exposure to hypoxia/asphyxia or other circulatory disturbances. We examined the hypothesis that this association is mediated by reduced renal blood flow (RBF), using a model of asphyxia induced by complete umbilical cord occlusion for 25 min (n = 13) or sham occlusion (n = 6) in chronically instrumented preterm fetal sheep (104 days, term is 147 days). During asphyxia there was a significant fall in RBF and urine output (UO). After asphyxia, RBF transiently recovered, followed within 30 min by a secondary period of hypoperfusion (P < 0.05). This was mediated by increased renal vascular resistance (RVR, P < 0.05); arterial blood pressure was mildly increased in the first 24 h (P < 0.05). RBF relatively normalized between 3 and 24 h, but hypoperfusion developed again from 24 to 60 h (P < 0.05, analysis of covariance). UO significantly increased to a peak of 249% of baseline between 3 and 12 h (P < 0.05), with increased fractional excretion of sodium, peak 10.5 +/- 1.4 vs. 2.6 +/- 0.6% (P < 0.001). Creatinine clearance returned to normal after 2 h; there was a transient reduction at 48 h to 0.32 +/- 0.02 ml.min(-1).g(-1) (vs. 0.45 +/- 0.04, P < 0.05) corresponding with the time of maximal depression of RBF. No renal injury was seen on histological examination at 72 h. In conclusion, severe asphyxia in the preterm fetus was associated with evolving renal tubular dysfunction, as shown by transient polyuria and natriuresis. Despite a prolonged increase in RVR, there was only a modest effect on glomerular function.
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Affiliation(s)
- J S Quaedackers
- The Liggins Institute, The University of Auckland, Auckland, New Zealand
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