Investigating the relationship between serum 11-deoxycortisol levels and blood pressure

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Investigating the relationship between serum
11-deoxycortisol levels and blood pressure

• Helen Turner
• MSc Project

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Do levels of 11-deoxycortisol affect blood
pressure in a normal population?

• Objectives
• To optimise and validate a novel method for
• the measurement of serum 11-deoxycortisol.
• To establish the relationship between serum
• 11-deoxycortisol and blood pressure in an
• adult population.

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Hypertension

• Without treatment
• increased risk of cardiovascular and renal
  complications
• Can be split into essential or secondary
  hypertension
• 95 of patients have essential hypertension
• which can be attributed to both environmental and
  genetic factors
• 5 have secondary hypertension
• Where the cause is known, and if treated will
  alleviate the symptoms

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Steroids Hypertension

• Supportive evidence
• Abnormal steroid production can lead to
  hypertension-e.g in PA, CAH, Cushings GSH
• Male presenting with hypertension, may have
  elevated glucocorticoid metabolites in their
  urine
• Alterations in the 11-deoxycortisol cortisol
  ratio has been seen in hypertensive patients

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Cholesterol
17-OH Pregnenolone
DHEA
Pregnenolone
Progesterone
Androstenedione
17-OH Progesterone
Deoxycorticosterone
11-Deoxycortisol
Corticosterone
Cortisol
18-OH Corticosterone
21ß-Hydroxylase
Aldosterone
11ß-Hydroxylase
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11-deoxycortisol and 11ß hydroxylase

• Mutations in CYB11B1 alter 11ß hydroxylase
  activity
• 11ß hydroxylase deficient patients have increased
  levels of 11-deoxycortisol
• Present with hypertension
• Therefore
• could slight changes in 11ß hydroxylase
  activity, cause slight variations in blood
  pressure?

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Method

• Extraction
• 400ul sample 100ul assay buffer, add to 2.5mls
  CCL4
• Discard aqueous layer
• Drying down
• 1ml extract dried under low pressure N2 _at_37ªC
• Reconstitution
• With 200ul assay buffer, _at_RT for 30mins
• DELFIA
• Dissociation enhanced lanthanide
  fluoroimmunoassay

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DELFIA Set up
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Validation

• Recovery 113
• Cross reactivity 11 17OHP
• lt0.1 other steroids
• Lower limit of Detection 0.9nmol/L
• Precision within assay 16
• between assay 20
• Comparison to RIA r0.72 plt0.0001

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Materials

• Patient samples
• From MRC Hertfordshire study
• 271 patients 140males and 131 females
• Born between 1931 and 1939 in Hertfordshire
• No major medical conditions
• Clinics between June 2003 and June 2004
• Blood Pressure
• Recorded at clinics
• Lying and seated positions

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Results Females
r0.01, p0.9348
r-0.01, p0.8837
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Results Males
r0.01, p0.8949
r-0.01, p0.2280
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Conclusions

• We produced a simple method for measuring
  11-deoxycortisol in serum
• There is no relationship between 11-deoxycortisol
  and blood pressure in a normal adult population

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Future Work

• Measure cortisol
• To compare 11deoxycortisol in the hypertensive
  patient to normal patients
• Measure 11-deoxycortisol in a greater age range

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Acknowledgements

• Pete Wood
• Christine Glenn
• MRC- Southampton
• Karen Jameson
• Martyn Egerton (Epsom and St Helier Hosptial)

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Cross Reactivity
Steroid Cross reactivity ()
Cortisone 0.37
Progesterone 0.6
Prednisone 0.39
21-deoxycortisol lt0.1
Aldosterone lt0.1
Adione lt0.1
Cortisol 0.6
17 OHP 14
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Precision
Intra Assay Variation
Inter Assay Variation
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Hypertension
Stage Systolic BP (mmHg) Diastolic BP (mmHg)
Normal lt120 lt80
Pre-hypertensive 120-139 80-89
Stage 1 140-159 90-99
Stage 2 160gt 100gt
6th report of the Joint National Committee on the
Prevention, Detection, Evaluation and treatment
of Blood Pressure
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Steroids Hypertension 2

• Non- supportive evidence
• No significant correlation between cortisol
  levels in plasma and the degree of hypertension
• Deoxycorticosterone levels shows no correlation
  with blood pressure
• The metabolites of deoxycorticosterone, are
  potent mineralocorticoids but require
  11-hydroxylase for their production

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• Lower Limit of Detection
• 0.9nmol/L
• Recovery
• Mean recovery 113