Biomedical subjects

Prem Puri

Publications and source records attributed to Prem Puri.

At least 37 records · Page 2Linked to original sources

PubMed2006

Subureteral dextranomer/hyaluronic acid injection as first line treatment in the management of high grade vesicoureteral reflux.

PURPOSE: Endoscopic correction of vesicoureteral reflux has become an established alternative to long-term antibiotic prophylaxis and ureteral reimplantation. A number of tissue augmenting substances have been used for the endoscopic correction of vesicoureteral reflux. We prospectively evaluated the effectiveness of dextranomer/hyaluronic acid copolymer (Deflux) as first line treatment for high grade vesicoureteral reflux. MATERIALS AND METHODS: Between 2001 and 2004, 692 children with a median age of 2.1 years (3 months to 13.7 years) with high grade vesicoureteral reflux underwent endoscopic subureteral injection of Deflux soon after the diagnosis of vesicoureteral reflux was made on the initial voiding cystourethrogram. Vesicoureteral reflux was unilateral in 283 patients and bilateral in 409. Of the 1,101 ureters vesicoureteral reflux was grade II to V in 35 (3.2%), 580 (52.7%), 457 (41.5%) and 29 (2.6%), respectively. The procedure was performed on an outpatient basis. Followup ultrasound and voiding cystourethrogram were performed 3 months after the procedure, and renal and bladder ultrasound was done annually. RESULTS: Reflux resolved after first, second and third endoscopic Deflux injections in 952 (86.5%), 130 (11.8%) and 19 ureters (1.7%), respectively. Followup ultrasound revealed no evidence of delayed vesicoureteral junction obstruction. Of the patients 18 (2.6%) had urinary tract infection during followup after successful vesicoureteral reflux correction. CONCLUSIONS: Endoscopic subureteral injection of Deflux is excellent first line treatment in children with high grade vesicoureteral reflux. This 15-minute outpatient procedure is safe and simple to perform, and it can be easily repeated in failed cases.

Adolescent↗

PubMed2006

Renal scarring in familial vesicoureteral reflux: is prevention possible?

PURPOSE: Detailed knowledge about risk factors for renal scarring in familial reflux is necessary to decide whether these factors could be influenced by early screening and treatment of siblings. We evaluated the prevalence of and risk factors influencing renal scarring in familial vesicoureteral reflux. MATERIALS AND METHODS: We reviewed the medical records and dimercapto-succinic acid scans of 306 children with familial vesicoureteral reflux. Scarring was classified as mild, moderate and severe. The impact of urinary tract infections, patient sex, reflux grade and age at diagnosis on renal scarring was evaluated. RESULTS: The prevalence of renal scarring was identical at 36% in 142 index patients and 74 siblings presenting with urinary tract infection but it was only 10% in 87 asymptomatic siblings (p <0.001) The difference between siblings with and without urinary tract infection was only statistically significant for mild scarring (23% vs 4.6%, p <0.001). It did not attain significance in those with moderate to severe scarring (13.5% vs 5.7%). Moderate to severe scarring was significantly more common in grade V than in grade IV refluxing units (43% vs 10%, p <0.0001) and in male than in female siblings (15.8% vs 3.4%, p = 0.012). Mild scarring was not significantly associated with reflux grade or patient sex. Children diagnosed before age 3 years showed significantly less scarring than patients diagnosed later (23% vs 41%, p <0.002). CONCLUSIONS: The development of mild renal scarring seems to mainly depend on urinary tract infections, while moderate and severe scarring are also associated with high grade reflux and male sex. Early detection and treatment may prevent further urinary tract infections as well as reflux related kidney damage.

Child, Preschool↗

PubMed2006

Endoscopic treatment for high grade vesicoureteral reflux in infants.

PURPOSE: Minimally invasive endoscopic treatment for vesicoureteral reflux has become an established alternative to long-term antibiotic prophylaxis and surgical intervention in children. We determined the long-term efficacy and safety of this treatment for high grade reflux in infants. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 411 consecutive infants who underwent endoscopic treatment of grade III to V vesicoureteral reflux between June 1985 and October 2004. A total of 29 patients (7%) were excluded from study because they were lost to followup or the medical records were incomplete. Of the remaining 382 infants, including 203 males, 274 had bilateral and 108 had unilateral vesicoureteral reflux. This represented 642 high grade refluxing units with grade III to V disease in 232, 339 and 71, respectively. A dimercapto-succinic acid scan performed in 312 infants revealed renal scarring in 88 (28%). The tissue augmenting substance used for endoscopic injection was polytetrafluoroethylene and dextranomer/hyaluronic acid copolymer in 432 and 210 ureters, respectively. Endoscopic treatment was done at a median age of 7 months (range 2 months to 1 year). Median followup in these patients was 7 years (range 6 months to 20 years). RESULTS: Complete resolution of vesicoureteral reflux after a single injection occurred in 443 ureters (69%), including 73% with dextranomer/hyaluronic acid copolymer and 65% with polytetrafluoroethylene. Of the 642 ureters 127 (20%) required more than 1 injection to correct vesicoureteral reflux. In 60 ureters vesicoureteral reflux was downgraded to grade I or II and no further treatment was given, while 12 ureters that failed to respond to endoscopic treatment required open surgical intervention. Only 1 ureter required reimplantation to treat vesicoureteral obstruction. CONCLUSIONS: Endoscopic correction is a safe, effective, minimally invasive outpatient procedure for high grade vesicoureteral reflux in infants. Early correction of vesicoureteral reflux may provide protection from reflux associated renal damage and prolonged antibiotic use.

Dextrans↗

PubMed2005

New insights into the pathogenesis of Hirschsprung's associated enterocolitis.

The management of Hirschsprung's disease (HD) has made dramatic strides over the last 20 years. Research into the embryological development and migration of ganglion cell has enabled a greater understanding of the pathogenesis of the disease. Coupled with new techniques in surgery, such as laparoscopy-assisted pull-through and the transanal pull-through, this knowledge has led to improved outcomes for children with HD. However, although our appreciation of Hirschsprung's associated enterocolitis and its aetiology has increased, there are continued references in the literature to a multitude of theories of pathogenesis. The purpose of this review is to delineate the theories and demonstrate the evidence supporting or otherwise contradicting each other.

Enterocolitis↗

PubMed2005

Modulation of immune cell function by polyunsaturated fatty acids.

The n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential dietary constituents. They are important as a source of energy, as structural components of cell membranes, and as signalling molecules. They have been demonstrated to be potent modulators of the immune response, and research has endeavoured to optimise the ratio of n-3 to n-6 PUFAs in the lipid component of total parenteral nutrition (TPN) to optimise their beneficial effects in the clinical setting. Critically ill neonates on TPN have an increased incidence of sepsis, and additional studies have determined that lipid emulsions depress various elements of cellular immune responses in monocytes, lymphocytes, and neutrophils. It has been proposed that PUFAs may mediate their manifold effects through the modification of eicosanoid production and by directly or indirectly modifying intracellular signal transduction pathways, including the alteration of gene transcription, in various tissues. They are susceptible to lipid peroxidation, and there is evidence that the products of this process may result in cell death by apoptosis, a nonphlogistic homeostatic process of cell deletion. PUFAs have been shown to induce apoptosis in primary lymphocytes, colonic mucosal cells, and various cell lines. Additionally, our laboratory has shown them to be potent inducers of apoptosis in neonatal monocytes. This may represent a novel mechanism whereby PUFAs may modify the immune response.

Animals↗

PubMed2005

Prepubertal unilateral spermatic vessel ligation decreases haploid cell population of ipsilateral testis postpubertally in rats.

DNA flow cytometry is a sensitive and rapid technique to evaluate the germ cell maturation of testis. The haploid cell population of testis specifically denotes testicular maturation. High ligation of spermatic vessels (HLSV) and low ligation of spermatic vessels (LLSV) have been described in the surgical treatment of high undescended testis. Estimation of germ cell population of testis after these maneuvers has not been performed so far by DNA flow cytometry; hence this study was designed. Thirty male rats, aged 30 days, were randomized into three groups. Group I underwent sham surgery; group II underwent unilateral HLSV-ligation and division of main spermatic vessels, similar to the Fowler-Stephens technique; and group III underwent unilateral LLSV-ligation and division of main spermatic vessels close to the testis, similar to the Koff and Sethi technique. Thirty days later, the ipsilateral testes were harvested, and haploid, diploid, and tetraploid cells were counted by DNA flow cytometry. The mean (+/-SD) percentage of the haploid cell population was 68.7+/-4.8, 49.3+/-6.5, and 50.8+/-6.4 in groups I, II, and III, respectively. There was a significant (p<0.05) decrease in haploid cell population between groups I and II and between groups I and III. However, there was no significant difference between groups II and III. In conclusion, prepubertal HLSV as well as LLSV decreases the haploid cell population of ipsilateral testis in rats. LLSV has no advantage over HLSV.

Animals↗

PubMed2005

Effect of nitric oxide on the development of nitrofen-induced fetal hypoplastic lung explants.

BACKGROUND/PURPOSE: Nitric oxide (NO) is an important cell-signaling molecule, and its generators, nitric oxide synthases, are expressed temporospatially in fetal rat lung. Recently, NO has been reported to modulate branching of the fetal rat lung lobe in vitro. We designed this study to evaluate the effect of NO on the morphogenesis of hypoplastic lung using nitrofen-induced rat lung explant model. METHODS: A hypoplastic fetal lung model and a normal control lung model were induced by feeding a pregnant rat with nitrofen (100 mg) or olive oil on day 9.5 of gestation, respectively. Fetal lungs were harvested on day 13.5 and placed in organ culture containing serum-free medium Dulbecco modified Eagle medium. An NO donor, DETA NONOate (DETA/NO), was added daily in the culture medium. The lung cultures were divided into 4 groups: group 1 (n = 8), normal controls without DETA/NO; group 2 (n = 22), normal controls with DETA/NO; group 3 (n = 13), hypoplastic lungs without DETA/NO; group 4 (n = 22), hypoplastic lungs with DETA/NO. The fetal lungs were incubated for 48 hours at 37 degrees C with 5% CO2. Lung bud count and area of the specimens were measured under computer-assisted digital tracings. The rate of increase in bud count and lung area was calculated as the ratio of each value at 48 hours minus each value at 0 hour, divided by the value at 0 hour. RESULTS: The lung bud count was significantly increased in group 2 compared with group 1 at a concentration of 50 micromol/L DETA/NO (P < .05). In the nitrofen group, the lung bud count was significantly increased in group 4 compared with group 3 at 100 micromol/L DETA/NO added (P < .05). There was no significant difference in the rate of increase in whole lung area among the 4 groups. The peak increase rates of lung area and bud count were significantly lower in group 4 compared with group 2. CONCLUSIONS: This study demonstrates that the NO donor, DETA/NO, promotes branching of the nitrofen-induced hypoplastic fetal lung explant. These data suggest that NO may modulate the development of the nitrofen-induced hypoplastic lung.

Animals↗

PubMed2005

The role of oxygen tension in the regulation of embryonic lung development.

BACKGROUND/PURPOSE: Oxygen tension is an important physiologic mediator of embryonic and fetal development. In vitro studies have demonstrated that the proper embryonic development is dependent upon low oxygen tension and even short exposure to normoxic environments (21%) can be detrimental to embryonic development. We hypothesized that low oxygen tension promotes lung growth in embryonic organ culture and therefore designed this study to investigate embryonic lung growth in normoxic and hypoxic conditions using simple closed chamber. METHODS: Fetal rat lungs were harvested on day 13.5 and placed in organ culture containing serum-free Dulbecco's modified Eagle's medium with antibiotics. The lung cultures were divided into normoxic group, with a 21% oxygen concentration (n = 15), and hypoxic group (n = 15). Hypoxic condition (6% oxygen) was achieved using Oxoid Campygen in a closed chamber. The lungs were placed in 5% carbon dioxide, 37 degrees C incubator for 48 hours. Media were not changed during the incubation period. The morphometric analysis was measured at 0 hour and at 48 hours by counting total terminal buds and entire epithelial contour using Image J software. The fold increase in branching was calculated as the ratio of buds present at 48 hours minus the buds present at 0 hour divided by the number of buds at 0 hour. The increase in entire epithelial contour over 48 hours was calculated in exactly the same way as described above. RESULTS: There was no significant difference in the increase in total terminal buds count in the hypoxic group (2.06 +/- 0.19) compared with the normoxic group (2.59 +/- 0.21), and no significant difference in the increase in entire epithelial contour in the hypoxic group (1.45 +/- 0.11) compared with the normoxic group (1.63 +/- 0.11). CONCLUSIONS: Although hypoxia has been reported to be an important regulator of murine vascular development, our data show that the embryonic lung growth in whole lung organ culture under hypoxic condition is not significantly different from that in normoxic condition.

Animals↗

PubMed2005

Notable sequential alterations in notochord volume during development in the Adriamycin rat model.

BACKGROUND/PURPOSE: The Adriamycin rat model (ARM) is a well-established model of the vertebral, anorectal, cardiac, tracheoesophageal, renal, and limb association. An important finding in the ARM is that Adriamycin induces abnormal notochord morphology in the region of the foregut. Having recently demonstrated notochord hypertrophy in ARM embryos, the authors designed this study to assess notochord volume sequentially from gestational days 10 to 14 (E10-E14) to test the hypothesis that notochord hypertrophy occurs maximally soon after Adriamycin administration. METHODS: Adriamycin (1.75 mg/kg) was administered intraperitoneally to pregnant rats on E7, E8, and E9. Control animals were given saline. Embryos were recovered at E10, E11, E12, E13, and E14 and embedded in paraffin. Quantitative morphology using the Cavalieri technique was performed on hematoxylin and eosin-stained transverse serial sections to determine total embryo and total notochord volume. RESULTS: The percentage volume of notochord per embryo was significantly increased (P < .05) in Adriamycin-treated embryos at all gestational time frames from E10 to E14 when compared with equivalent controls. This increased volume of notochord was found to be maximal at E11. CONCLUSIONS: These data support the authors' previous finding that Adriamycin induces notochord hypertrophy and suggest that notochord volume is increased relative to embryo volume soon after Adriamycin administration and is maximal on E11. The abnormal increase in notochord volume during the critical phase of development may interfere with organogenesis, resulting in the vertebral, anorectal, cardiac, tracheoesophageal, renal, and limb association.

Abnormalities, Drug-Induced↗

PubMed2005

Long-term clinical outcome in patients with Hirschsprung's disease and associated Down's syndrome.

BACKGROUND/PURPOSE: Down's syndrome (DS) is the most common chromosomal abnormality associated with Hirschsprung's disease (HD). The purpose of this study was to review the long-term clinical outcome in patients with HD and associated DS. METHODS: Between 1975 and 2003, 39 (15%) of the 259 patients with HD had been associated with DS. Follow-up was carried out by means of examination of patient's records and personal/telephone interviews with the patient's parents or guardians. RESULTS: Twenty-six (67%) patients presented in the newborn period and 13 (33%) after the neonatal period. Twenty-eight (72%) patients had rectosigmoid HD, 10 long segment, and 1 total colonic aganglionosis. Thirty-two patients had other associated anomalies, 24 of these having cardiac anomalies. Definitive pull-through operation was performed in 33 patients. Parents of 1 child refused surgical intervention and parents of 2 children decided against pull-through operation after colostomy. Three children died before pull through. Thirteen patients had one or more episodes of enterocolitis after pull-through operation. At the time of follow-up (6 months to 28 years), 3 patients were found to have reverted to stoma because of poor bowel control or recurrent enterocolitis. Of the remaining 30 patients, 3 were lost to follow-up and 4 were too young to be assessed for bowel control. Assessment of bowel function in 23 patients revealed normal control in 8 (4 of these soiled for 6-17 years after definitive surgery), soiling in 8, and constipation requiring enemas or laxatives in 7. CONCLUSIONS: The vast majority of patients with HD associated with DS continue to have disturbances of bowel function after definitive pull-through operation.

Abnormalities, Multiple↗

PubMed2005

Effect of nitric oxide on fibroblast growth factor-10 and bone morphogenetic protein 4 expressions in the branching morphogenesis of fetal rat lung explants.

PURPOSE: Nitric oxide (NO) can accelerate branching morphogenesis of fetal rat lung explants in vitro, whereas its exact mechanism remains unclear. In this study, we investigate the effect of NO on the expression of fibroblast growth factor-10 (FGF10) and bone morphogenetic protein-4 (BMP4), which plays an important role in bud formation. METHODS: Fetal rat lungs harvested on day 13.5 of gestation were cultured in serum-free medium for 72 hours with 0, 50, 100, and 200 micromol/L of an NO donor, DETA NONOate (DETA/NO) (n = 4, 3, 6, and 5). The ratio of bud increment of each cultured lung was calculated, and the FGF10 and BMP4 mRNA expression levels were analyzed by real-time reverse transcription polymerase chain reaction. RESULTS: Bud increment ratio was significantly increased in 50, 100, and 200 micromol/L DETA/NO (3.3 +/- 0.2, 3.0 +/- 0.3, and 3.5 +/- 0.5) compared to controls (1.9 +/- 0.3) (P < .05). There was a significant increase in BMP4 mRNA expression in 100 micromol/L DETA/NO (190% +/- 20%) compared to controls (100% +/- 30%) (P < .05), whereas FGF10 mRNA expression was not significantly different between each DETA/NO group and controls. CONCLUSION: The NO donor not only promotes branching of fetal lung explants but also upregulates expression of BMP4, which is an important regulator of branching morphogenesis.

Animals↗

PubMed2005

Controversies concerning diagnostic guidelines for anomalies of the enteric nervous system: a report from the fourth International Symposium on Hirschsprung's disease and related neurocristopathies.

Intestinal Dysganglionoses (IDs) represent a heterogeneous group of Enteric Nervous System anomalies including Hirschsprung's disease (HD), Intestinal Neuronal Dysplasia (IND), Internal Anal Sphincter Neurogenic Achalasia (IASNA) and Hypoganglionosis. At present HD is the only recognised clinico-pathological entity, whereas the others are not yet worldwide accepted and diagnosed. This report describes the areas of agreement and disagreement regarding definition, diagnosis, and management of IDs as discussed at the workshop of the fourth International Meeting on "Hirschsprung's disease and related neurochristopathies." The gold standards in the preoperative diagnosis of IDs are described, enlighting the importance of rectal suction biopsy in the diagnostic workup. The most important diagnostic features of HD are the combination of hypertrophic nerve trunks and aganglionosis in adequate specimens. Acetylcholinesterase staining is the best diagnostic technique to demonstrate hypertrophic nerve trunks in lamina propia mucosae, but many pathologist from different centers still use H&E staining effectively. Moreover, the importance of an adequate intraoperative pathological evaluation of the extent of IDs to avoid postoperative complications is stressed. Although it is not clear whether IND is a separate entity or some sort of secondary acquired condition, it is concluded that both IND and IASNA do exist. Other interesting conclusions are provided as well as detailed results of the discussion. Further investigation is needed to resolve the many controversies concerning IDs. The fourth International Conference in Sestri Levante stimulated discussion regarding these entities and led to the International guidelines to serve the best interest of our patients.

Child↗

PubMed2005

Uroplakin III is not a major candidate gene for primary vesicoureteral reflux.

Vesicoureteral reflux (VUR) is the retrograde flow of urine from the bladder into the ureter and towards the kidneys. VUR is the most common cause of end stage renal failure in both children and adults and it is a major cause of severe hypertension in children. VUR is seen in approximately 1-2% of newborn Caucasians. Substantial evidence exists that VUR is a genetic disorder. Uroplakins are integral membrane proteins found in the bladder wall. Knockout studies in mice have suggested uroplakin III (UPK3) as a candidate gene for VUR. We have used parametric and nonparametric linkage analysis and tests for association, to investigate this possibility in a cohort of 126 sibling pairs affected with primary VUR. None of the analyses showed any substantial evidence for linkage or association of markers at the UPK3 locus to VUR. Our results do not support a role for UPK3 in primary VUR.

Child↗

PubMed2005

Megacystis microcolon intestinal hypoperistalsis syndrome.

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare and the most severe form of functional intestinal obstruction in the newborn. The major features of this congenital and usually lethal anomaly are abdominal distension, bile-stained vomiting, and absent or decreased bowel peristalsis. Abdominal distension is a consequence of the distended, unobstructed urinary bladder with or without upper urinary tract dilation. Most patients with MMIHS are not able to void spontaneously. This article reviews the pathogenesis of MMIHS as well as the clinical, radiological, surgical and histological findings in all reported cases of this syndrome.

Colon↗

PubMed2005

Association of transforming growth factor-beta1 gene polymorphism with reflux nephropathy.

PURPOSE: Reflux nephropathy (RN) is recognized as a major cause of end stage renal failure in children and young adults. Transforming growth factor-beta1 (TGF-beta1) is a potent proinflammatory and fibrogenetic cytokine known to have a key role in the regulation of renal tissue fibrosis. We investigate genotype frequencies for polymorphisms of the TGF-beta1 gene at position -509, codon 10 and 25, and examine circulating levels of TGF-beta1 in patients with reflux nephropathy. MATERIALS AND METHODS: Renal scaring was evaluated with 99technetium dimercapto-succinic acid renal scan. Genotyping was performed in 123 patients with severe to moderate reflux nephropathy and 58 controls for the position -509, the coding region at position 10 and 25 of the TGF-beta1 gene polymorphisms by polymerase chain reaction, gel analysis and appropriate restriction digest. TGF-beta1 serum levels were measured with standard ELISA technique. RESULTS: The genotype distribution of -509-CT was significantly increased in the RN group compared to controls, (82% vs 37%). Similarly, there was a significant increase in the CC Lue(10)-->Pro (codon 10) genotype (77% vs 27.5%, p <0.05), while TC Lue(10)-->Pro was significantly lower (7.3% vs 43%, p <0.05) in patients compared to controls. There was no significant difference in the Arg(25)-->Pro (codon 25) TGF-beta1 genotypes distribution between patients and controls. There were no statistically significant differences in the serum levels of TGF-beta1 in children with RN (4.2 +/- 0.3 mIU/ml) compared to controls (3.9 +/- 0.4 mIU/ml) (p >0.05). CONCLUSIONS: Patients with TGF-beta1 -509 and Lue(10)-->Pro gene polymorphisms may be at higher risk for reflux nephropathy.

Adolescent↗

PubMed2004

Altered expression of angiotensin II receptor subtypes and transforming growth factor-beta in the heart of nitrofen-induced diaphragmatic hernia in rats.

The renin-angitensin system (RAS) plays an important role as a growth factor in cardiac development. Angiotensin converting enzyme is involved in converting angiotensin I to angiotensin II (Ag-II). The effects of Ag-II are mediated by two primary receptors, type 1 (AT1) and type 2 (AT2). Ag-II stimulates transforming growth factor-beta1(TGF-beta1) and acts as a potent stimulant of myocyte growth and fetal contractile protein gene transcription. The aim of this study was to determine the expression of Ag-II receptor subtypes and TGF-beta1 in the hypoplastic heart of nitrofen-induced congenital diaphragmatic hernia (CDH). CDH was induced in pregnant rats following administration of 100 mg nitrofen on day 9.5. The fetuses were divided into three groups: normal controls (n=16), nitrofen-treated without CDH (n=16), and nitrofen-induced CDH (n=16). Reverse transcriptase-polymerase chain reaction was performed to evaluate mRNA expression of AT1, AT2, and TGF-beta1. Levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin. AT1 and AT2 mRNA expressions were significantly decreased in CDH heart compared with controls (0.43+/-0.33 vs. 1.0+/-0.48 and 0.62+/-0.23 vs. 1.4+/-0.43, respectively). TGF-beta1 mRNA expressions were also significantly decreased in CDH heart compared with controls (0.38+/-0.17 vs. 0.72+/-0.26). No significant difference was found between the hearts of controls and nitrofen-treated rats without CDH. The decreased expression of AT1, AT2, and TGF-beta1 mRNA in the hypoplastic heart suggests that the downregulation of RAS may be involved in the pathogenesis of cardiac hypoplasia in nitrofen-induced CDH.

Animals↗

PubMed2004

Expression of vasoactive mediators during mechanical ventilation in nitrofen-induced diaphragmatic hernia in rats.

The high mortality in patients with congenital diaphragmatic hernia (CDH) has been attributed to pulmonary hypoplasia and persistent pulmonary hypertension (PPH). Endothelin-1 (ET-1), nitric oxide (NO), and calcitonin gene-related peptide (CGRP) have been reported to be important vasoactive mediators in the perinatal pulmonary circulation. The exact mechanism by which these vasoactive mediators interact to regulate the perinatal pulmonary vascular tone in CDH with PPH is not fully understood. We hypothesized that the altered pulmonary vascular reactivity in CDH is due to imbalance in vasoactive mediators. This study was designed to investigate mRNA expression of ET-1, eNOS, and CGRP in CDH lung in the perinatal period. A CDH model was induced in pregnant rats following administration of nitrofen. In control animals, the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The newborn rats were intubated and ventilated, and ventilation was continued for 1-6 h. Left lungs were collected from both groups at 0, 1, and 6 h after ventilation (n=8 in each group). Reverse transcriptase-polymerase chain reaction on lung tissue was performed to evaluate the relative level of ET-1, eNOS, and CGRP mRNA expression. The results showed a significant increase in ET-1 mRNA in CDH lung at 1 and 6 h after ventilation compared with controls. In CDH lung, eNOS mRNA and CGRP mRNA levels were significantly increased at 1 h but were similar to control values at 6 h after ventilation. The increased expression of vasoconstrictor ET-1 mRNA and vasodilators eNOS mRNA and CGRP mRNA in the CDH lung at 1 h after ventilation suggests that pulmonary vascular tone is rapidly changing after birth. An imbalance in the production of vasoconstrictors and vasodilators by the CDH lung may contribute to high pulmonary vascular resistance.

Animals↗

PubMed2004

Decreased expression of voltage-gated K+ channels in pulmonary artery smooth muscles cells in nitrofen-induced congenital diaphragmatic hernia in rats.

The newborn with congenital diaphragmatic hernia (CDH) is at high risk of developing persistent pulmonary hypertension (PPH). Recently, smooth muscle K(+) channels have been implicated in hypoxic pulmonary vasoconstriction in adults. We hypothesized that the hyperreactivity of the newborn pulmonary vasculature in CDH might reflect a relatively low level of smooth muscle K(+) channel activity because of hypoxemia, which could give rise to excessive smooth muscle cell depolarisation and lead to failure of the pulmonary vasculature to adapt to extrauterine life. We therefore investigated K(+) channel subunits in pulmonary artery smooth muscle cells (PASMC) in the nitrofen-induced CDH lung in rats. The CDH model was induced in pregnant rats after administration of 100 mg nitrofen on day 9.5 of gestation (term = 22 days). Dexamethasone (0.25 mg/kg) was given on days 18.5 and 19.5 of gestation. Cesarean section was performed on day 21. Fetuses were divided into three groups: group I, normal control; group II, nitrofen-induced CDH; and group III, nitrofen-induced CDH with antenatal dexamethasone treatment. Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the relative amount of the potassium channels Kv1.2, Kv2.1, and KvCa mRNA. Indirect immunohistochemistry was performed using a laser scanning confocal microscope with anti-Kv1.2, -Kv2.1, and -KvCa antibodies. In the CDH lung, Kv1.2, Kv2.1, and KvCa immunoreactivity was markedly decreased in PASMC compared with controls. Relative mRNA levels of potassium channel anti-Kv1.2, -Kv2.1, and -KvCa were significantly decreased in the CDH lung compared with controls (p<0.05). Dexamethasone treatment increased Kv1.2, Kv2.1, and KvCa immunoreactivity and mRNA levels in the CDH lung. Changes in voltage-gate K(+) channel subunits expression in the CDH lung suggest that potassium channels may play an important role in the development of pulmonary hypertension. Antenatal dexamethasone may modulate pulmonary vascular tone in the CDH hypoplastic lung by selectively upregulating local expression of Kv1.2, Kv2.1, and KvCa.

Analysis of Variance↗