title: Association of circulating angiotensin converting enzyme activity with respiratory muscle function in infants.
abstract: BACKGROUND
  Angiotensin converting enzyme (ACE) gene contains a polymorphism, consisting of either the presence (I) or absence (D) of a 287 base pair fragment. Deletion (D) is associated with increased circulating ACE (cACE) activity. It has been suggested that the D-allele of ACE genotype is associated with power-oriented performance and that cACE activity is correlated with muscle strength. Respiratory muscle function may be similarly influenced. Respiratory muscle strength in infants can be assessed specifically by measurement of the maximum inspiratory pressure during crying (Pimax). Pressure-time index of the respiratory muscles (PTImus) is a non-invasive method, which assesses the load to capacity ratio of the respiratory muscles.The objective of this study was to determine whether increased cACE activity in infants could be related to greater respiratory muscle strength and to investigate the potential association of cACE with PTImus measurements as well as the association of ACE genotypes with cACE activity and respiratory muscle strength in this population.
  
  
  METHODS
  Serum ACE activity was assayed by using a UV-kinetic method. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pimean/Pimax) x (Ti/Ttot), where Pimean was the mean inspiratory pressure estimated from airway pressure, generated 100 milliseconds after an occlusion (P0.1), Pimax was the maximum inspiratory pressure and Ti/Ttot was the ratio of the inspiratory time to the total respiratory cycle time. Pimax was the largest pressure generated during brief airway occlusions performed at the end of a spontaneous crying effort.
  
  
  RESULTS
  A hundred and ten infants were studied. Infants with D/D genotype had significantly higher serum ACE activity than infants with I/I or I/D genotypes. cACE activity was significantly related to Pimax and inversely related to PTImus. No association between ACE genotypes and Pdimax measurements was found.
  
  
  CONCLUSIONS
  These results suggest that a relation in cACE activity and respiratory muscle function may exist in infants. In addition, an association between ACE genotypes and cACE activity, but not respiratory muscle strength, was demonstrated.
authors.affiliation: Neonatal Intensive Care Unit, Department of Pediatrics, University of Patras Medical School, Rio, Patras, Greece. gdimitriou@med.upatras.gr
authors.forename: Gabriel
authors.initials: G
authors.lastname: Dimitriou
authors.forename: Despina
authors.initials: D
authors.lastname: Papakonstantinou
authors.forename: Eleana F
authors.initials: EF
authors.lastname: Stavrou
authors.forename: Sotirios
authors.initials: S
authors.lastname: Tzifas
authors.forename: Aggeliki
authors.initials: A
authors.lastname: Vervenioti
authors.forename: Anny
authors.initials: A
authors.lastname: Onufriou
authors.forename: Aglaia
authors.initials: A
authors.lastname: Athanassiadou
authors.forename: Stefanos
authors.initials: S
authors.lastname: Mantagos
mesh_terms: D015415:Biomarkers / Q000097:blood; D003448:Crying; D005260:Female; D005838:Genotype; D006115:Greece; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D001239:Inhalation; D008297:Male; D008471:Meconium Aspiration Syndrome / Q000201:enzymology* / Q000235:genetics / Q000503:physiopathology; D053580:Muscle Strength; D007703:Peptidyl-Dipeptidase A / Q000097:blood* / Q000235:genetics; D010641:Phenotype; D011312:Pressure; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000201:enzymology* / Q000235:genetics / Q000503:physiopathology; D012132:Respiratory Muscles / Q000503:physiopathology*; D012893:Sleep Wake Disorders / Q000201:enzymology* / Q000235:genetics / Q000503:physiopathology; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D007703:Peptidyl-Dipeptidase A
references.citation: Nature. 1998 May 21;393(6682):221-2
references.pmid: 9607758
references.citation: J Appl Physiol (1985). 1987 Feb;62(2):768-75
references.pmid: 3104298
references.citation: J Clin Invest. 1990 Oct;86(4):1343-6
references.pmid: 1976655
references.citation: Pediatr Pulmonol. 1989;6(1):14-8
references.pmid: 2704577
references.citation: Am J Hum Genet. 1992 Jul;51(1):197-205
references.pmid: 1319114
references.citation: J Appl Physiol (1985). 1986 Jun;60(6):2040-7
references.pmid: 3722070
references.citation: Lancet. 1979 Jul 28;2(8135):196
references.pmid: 89302
references.citation: Chest. 2001 Jun;119(6):1755-60
references.pmid: 11399702
references.citation: Am J Physiol Endocrinol Metab. 2001 Jan;280(1):E150-9
references.pmid: 11120669
references.citation: J Cardiovasc Pharmacol. 1992;19 Suppl 6:S80-8
references.pmid: 1382170
references.citation: Med Sci Sports Exerc. 2006 Jun;38(6):1074-81
references.pmid: 16775548
references.citation: PCR Methods Appl. 1993 Oct;3(2):120-1
references.pmid: 8268786
references.citation: Int J Biochem Cell Biol. 2003 Jun;35(6):855-66
references.pmid: 12676172
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1982 Jan;52(1):64-70
references.pmid: 7061279
references.citation: Am Rev Respir Dis. 1984 Mar;129(3):497-8
references.pmid: 6703506
references.citation: Am J Hum Genet. 1996 Jun;58(6):1268-78
references.pmid: 8651305
references.citation: Am Rev Respir Dis. 1985 Jun;131(6):811-5
references.pmid: 4003928
references.citation: Curr Pharm Des. 2006;12(16):2057-64
references.pmid: 16787247
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1982 Nov;53(5):1190-5
references.pmid: 7174413
references.citation: J Clin Pharmacol. 1990 Dec;30(12):1106-11
references.pmid: 2273083
references.citation: J Appl Physiol (1985). 1986 May;60(5):1599-604
references.pmid: 3710979
references.citation: Med Sci Sports Exerc. 2005 Jun;37(6):944-8
references.pmid: 15947718
references.citation: Am Rev Respir Dis. 1984 Mar;129(3):396-402
references.pmid: 6422814
references.citation: Pediatr Res. 1983 Sep;17(9):707-9
references.pmid: 6225986
references.citation: Am J Cardiol. 1999 Nov 1;84(9):1038-43
references.pmid: 10569660
references.citation: Circulation. 1995 Sep 15;92(6):1387-8
references.pmid: 7664416
references.citation: Early Hum Dev. 2000 Feb;57(2):149-56
references.pmid: 10735461
references.citation: J Appl Physiol (1985). 1985 Jun;58(6):2054-61
references.pmid: 3924888
references.citation: N Engl J Med. 1995 Mar 16;332(11):706-11
references.pmid: 7854377
references.citation: Int J Sports Med. 2008 Jan;29(1):40-4
references.pmid: 17614015
references.citation: Hum Genet. 1998 Jul;103(1):48-50
references.pmid: 9737775
references.citation: Clin Genet. 2003 Feb;63(2):139-44
references.pmid: 12630962
references.citation: Hum Genet. 2001 Mar;108(3):230-2
references.pmid: 11354635
references.citation: Exerc Sport Sci Rev. 2002 Oct;30(4):184-90
references.pmid: 12398116
references.citation: Ann Intern Med. 1989 Jan 1;110(1):17-23
references.pmid: 2908830
references.citation: Eur J Appl Physiol. 2004 Jul;92(3):267-74
references.pmid: 15083369
references.citation: Am J Respir Crit Care Med. 2002 Aug 15;166(4):518-624
references.pmid: 12186831
references.citation: J Appl Physiol (1985). 1995 Feb;78(2):646-53
references.pmid: 7759435
references.citation: Am J Hypertens. 1992 May;5(5 Pt 1):276-80
references.pmid: 1533768
references.citation: Eur J Pediatr. 1983 Oct;141(1):3-7
references.pmid: 6315441
references.citation: N Engl J Med. 1985 Aug 15;313(7):420-4
references.pmid: 3860734
references.citation: Am J Physiol. 1997 Dec;273(6):H2659-63
references.pmid: 9435601
references.citation: Med Sci Sports Exerc. 2004 Aug;36(8):1314-20
references.pmid: 15292738
references.citation: J Physiol. 1996 Sep 1;495 ( Pt 2):573-86
references.pmid: 8887767
references.citation: Am J Respir Crit Care Med. 2002 Aug 1;166(3):362-6
references.pmid: 12153971
references.citation: J Lab Clin Med. 1991 Jan;117(1):33-9
references.pmid: 1846167
references.citation: Am J Physiol. 1996 Jul;271(1 Pt 1):E96-103
references.pmid: 8760086
references.citation: Clin Chest Med. 1988 Jun;9(2):195-210
references.pmid: 3292123
references.citation: Exp Physiol. 2000 Sep;85(5):575-9
references.pmid: 11038409
references.citation: J Appl Physiol (1985). 1999 Oct;87(4):1313-6
references.pmid: 10517757