Prenatal Malnutrition-Induced Changes in Blood Pressure

Abstract

Abstract-A link between prenatal malnutrition and hypertension in human populations has recently been proposed. Rat models of prenatal malnutrition have provided major support for this theory on the basis of tail-cuff measurements. However, this technique requires restraint and elevated temperature, both potential sources of stress. To determine the effect of prenatal protein malnutrition on blood pressure under nonstress conditions, 24-hour radiotelemetric measurements were taken in the home cage. Male rats born to dams fed a 6% casein diet for 5 weeks before mating and throughout pregnancy were studied in early adulthood (from 96 days of age). During the waking phase of their cycle but not the sleep phase, prenatal malnutrition gave rise to small but significant elevations of diastolic blood pressure and heart rate compared with well-nourished controls. Direct effects of stress on blood pressure responses were determined in a second experiment using an olfactory stressor. Prenatally malnourished rats showed a greater increase in both systolic and diastolic pressures compared with well-nourished controls during the first exposure to ammonia. A different pattern of change of cardiovascular responses was also observed during subsequent presentations of the stressor. These findings of a small baseline increase in diastolic pressure consequent to prenatal malnutrition, but an augmented elevation of both systolic and diastolic pressures after first exposure to stress, suggest the need to reevaluate interpretation of the large elevations in blood pressure previously observed in malnourished animals using the stressful tail-cuff procedure. (Hypertension. 1998;32:108-114.)

Prenatal Exposure to Dexamethasone in the Mouse Alters Cardiac Growth Patterns and Increases Pulse Pressure in Aged Male Offspring

“…This suggests elevations in blood pressure following DEX exposure may only be apparent in slightly “stressed” animals, which may be due in part to alterations in the hypothalamic-pituitary-adrenal axis (HPA). Certainly, in studies in the maternal protein restriction rat model it has been shown, when telemetry was used to measure blood pressure, that there were no differences in blood pressure in the intrauterine-growth restricted offspring but the offspring did demonstrate an elevated blood pressure in response to a restraint stress [28], [29]. This could account for the reported elevations in blood pressure in this model when blood pressure was measured using the tail-cuff method in unconditioned restrained rats.…”

“…The development of hypertension in adult life after prenatal exposure to glucocorticoids is a common finding [18], [26], [36], [43], [51], although this is not always the case [27], [52], [53]. In this regard, it is important to note that the use of methods such as tail-cuff plethysmography or carotid cannulation to measure blood pressure, may elicit a stress response and thus not truly reflect elevations in basal blood pressure [28], though repeated handling and conditioning of the animal through multiple, repeated measurements made by experienced experimenters may minimize the effects of these stresses and still yield valuable data. Other factors such as recovery from anesthesia, or preheating of the tail have the potential to lead to physiological alterations in the animal's cardiovascular system and a subsequent a rise in blood pressure.…”

Childhood malnutrition and maltreatment are linked with personality disorder symptoms in adulthood: Results from a Barbados lifespan cohort

“…Preclinical data from our laboratory have demonstrated increased behavioral reactivity under stressful conditions in prenatally malnourished rats nutritionally rehabilitated after birth (Duran et al, 2006; Rosene et al, 2004; Tonkiss et al, 1998). Further, in our study of early immediate genes, exposure to restraint stress resulted in a significantly greater number of c-Fos positive neurons in the medial prefrontal and anterior cingulate cortices of adult rats with histories of early protein malnutrition relative to well-nourished controls (Rosene et al, 2004).…”

Sex differences in primary hypertension

“…A study in normotensive WKY and hypertensive SHR showed that SBP was approximately 30 mm Hg higher when measured by tail-cuff [WKY, 162 ± 5; SHR, 207 ± 5, mm Hg] than by telemetry [WKY, 131 ± 1; SHR, 178 ± 6, mm Hg] [85]. A study in prenatally malnourished rats showed that the blood pressure increase induced by a noxious odor was augmented by the stress of the tail-cuff procedure itself [86]. The stress from tail-cuff can also affect the response to drugs.…”

“…The stress from tail-cuff can also affect the response to drugs. Hydralazine had an approximately 2-fold greater hypotensive effect on the SBP when measured by tail-cuff compared to telemetry, indicating that the antihypertensive effects of some drugs may be influenced by the level of stress the animal is experiencing [86]. Sullivan et al [87] showed that female endothelin B receptor-deficient rats maintained on a HS (8%) diet for two weeks had 12 mm Hg higher SBP than males when measured by tail-cuff; however, in a later study when radiotelemetry was used to measure MAP in these animals, the females no longer had higher blood pressure than the males (David M. Pollock, personal communication).…”