Blood pressure during nocturnal sleep in headache.

AIM: Interactions between blood pressure control, sleep and headache have been largely studied, although not well understood. We designed a study trying to simultaneously evaluate all three aspects in the same subjects. We particularly concentrated on the observation of physiological blood pressure circadian rhythm, and the presence of cutaneous allodynia correlated to headache. Objective of the study was to investigate blood pressure during nocturnal sleep in patients that underwent a blood pressure 24 hours monitoring, and at the same time the presence of headache and of sleep behavioural alterations. METHODS: Blood pressure 24 hours monitoring was performed by an ambulatory blood pressure (ABP) monitor (Space Labs) with its ad hoc software. Headache diagnosis was made according to ICHD-II criteria. Presence of allodynia and sleep behavior were evaluated through semi-structured ad hoc questionnaires. RESULTS: A total of 195 subjects were included, of which 122 without headache (mean age 60.4±11.6 years, 78 men and 44 women) and 73 with history of headache, (mean age 54.2±12.5 years, 18 men and 55 women). Fifty-one headache patients had migraine (mean age 52.6±11.7 years, 11 men and 40 women) and 22 tension type headache (TTH - mean age 58.0±13.5 years, 7 men and 15 women). Allodynia was found in 30 out of 73 headache patients: 23 out of 51 in the migraine group and in 7 out of 22 in the tension-type one. The physiological reduction of blood pressure during night (dipping) was more conserved among headache patients (34 dippers out of 73 subjects, 46,6%) with respect to subjects without headache (40 dippers out of 122, 32,8%) and that this border-line difference was more strongly significant comparing allodynic subjects (19 dippers out of 30, 63.3%) with both non-headache (40 dippers out of 122, 32.8%, P<0.001) and non-allodynic (15 out of 43, 34.9%, P<0.05) ones. No significant difference was observed between headache patients and subjects without headache in terms of mean systolic and diastolic pressure, neither between migraine and TTH. CONCLUSION: Allodynic headache patients seem to maintain a more physiologic pressure circadian rhythm. While considering the possibility of selection bias, the hypothesis of an allostatic function of headache and allodynia in patients with unbalanced blood pressure could be made.

Possible correlations between blood pressure, primary headaches and cutaneous allodynia.

Following an allostatic perspective, episodic migraine (M) may be considered as an adaptive behavioural response to endogenous or exogenous stressors, while its progression to a daily or nearly daily form (chronic migraine) may represent the failure of adaptive strategies. Multiple factors may enhance the progression/chronification of M, and among these the presence of cutaneous allodynia (CA) as well as alterations in blood pressure and in sleep. The working hypothesis of the study was that subjects with M, and particularly those with CA, could show a tendency towards high blood pressure levels and/or to alterations in the circadian rhythm of blood pressure. We studied 235 subjects consecutively attending a centre for blood pressure control for a blood pressure 24 h monitoring. Headache diagnosis was made according to the ICHD-II criteria. The presence of CA was evaluated through a semi-structured ad hoc questionnaire. Blood pressure 24 h monitoring was performed by an ambulatory blood pressure monitor (Space Labs) with its ad hoc software. Seventy-eight subjects had a history of headache (mean age 54.0 ± 12.4 years, 18 men and 60 women); 56 of them had M, 22 had tension-type headache; among them, CA was found in 24/56 subjects with M, and in 6/22 with tension-type headache; 157 subjects did not suffer from headache (mean age 60.5 ± 11.5 years, 99 men and 58 women). No significant difference was observed between headache subjects and subjects without headache in terms of mean systolic and diastolic pressure, neither in the M nor in tension-type subgroups. With regard to the circadian rhythm of blood pressure, the physiological reduction during night (dipping) was more evident among headache subjects than in subjects without headache; this border-line difference was more strongly significant in subjects with CA than both non-headache (p = 0.003) and non-CA (p = 0.05) ones. The difference between allodynic and non-allodynic subjects was present also in the M sub-group (7 dippers out of 32 non-allodynic migraineurs vs. 12 dippers out of 24 allodynic migraineurs, p = 0.03) notwithstanding the reduction of the sample size. Despite the initial hypothesis, subjects with primary headaches did not show differences in terms of mean blood pressure values and they showed a more physiologic blood pressure daily rhythm than those without headaches. Also the presence of CA, a marker of progression to chronic headache forms, was associated neither with hypertension nor with increased frequency of loss of dipping. M, particularly when associated with allodynia, may improve breathing during nocturnal sleep and consequently counteract possible blood pressure alterations, suggesting an allostatic function of allodynic headache.

Effects of serum storage on the determination of cholesterol.

Cholesterol determined by 4 different enzymatic commercial kits and by the dry chemistry Reflotron system was higher in serum stored at 4 degrees C and at -20 degrees C than in fresh serum. The effects of storage seem to be temperature-dependent. In fact, cholesterol values significantly increased only after 2h of freezing. The prolongation of freezing up to 2 weeks was not followed by further significant changes. In serum stored at 4 degrees C the increase in cholesterol was slower than in frozen serum. Both free and esterified cholesterol underwent an increase after storage. When cholesterol was determined by a chemical method (sulfuric acid-ferric chloride) after extraction with ethyl acetate and ethanol, no difference was observed in fresh and stored serum. Cholesterol, triglycerides and apoproteins A-I and B underwent parallel changes after storage both in whole serum and fractionated lipoproteins. Our findings strongly suggest that in serum stored at positive or negative temperature there is an alteration of the lipoprotein molecules which allows an easier availability of cholesterol for the enzyme-substrate reaction than in fresh serum. Current enzymatic methods underestimate (about 10%) cholesterol when the analysis is performed on fresh serum.

Cholesterol distribution between HDL subfractions. A study of 498 subjects.

In 498 subjects (205 normolipidemics and 293 hyperlipidemics) of both sexes, the cholesterol content of high density lipoprotein (HDL) subfractions has been determined. The serum concentration of total HDL-cholesterol appears to be more strictly related to the cholesterol content of HDL2 than to that of HDL3. This latter one, however, gives a contribution to the variability of HDL-cholesterol so that the value of HDL-cholesterol cannot be assumed as a reliable estimate of the serum level of the more anti-atherogenic HDL2 subfraction. The cholesterol content of HDL and its subfractions is higher in women than in men and decreases with increasing serum VLDL-cholesterol level and body weight. Both HDL2- and HDL3-cholesterol appear to largely depend from the metabolism of triglyceride-rich lipoproteins in accordance with the data of experimental studies.

Relationship of serum triglyceride concentration to lipoprotein composition and concentration in normolipidemic and hyperlipidemic subjects.

In a series of 438 subjects (184 normolipidemics and 254 hyperlipidemics) the relationship among serum concentration of triglycerides, lipoprotein lipids and apoproteins A-I and B has been evaluated. The results show that as serum triglyceride level increases, VLDL rise and become enriched in triglycerides. The increase of VLDL is associated with a reduction of serum levels of LDL and HDL which appear to be rich in triglycerides and poor in cholesterol. The decrease in serum HDL level is mainly due to a reduction in serum concentration of the HDL2 subfraction. The triglyceride content of HDL2 and HDL3 rises with increasing serum triglycerides. The increase in serum triglyceride concentration seems then to be associated with a complex metabolic derangement which involves all the lipoprotein fractions.

Changes in serum and lipoprotein lipids, and apolipoprotein B and A-I, in patients with different types of primary hyperlipoproteinaemia treated with gemfibrozil.

Gemfibrozil was given at the dose of 600 mg twice daily to 16 type IIa, 13 type IIb and 11 type IV hyperlipoproteinaemic patients for four months. At the end of the fourth month of therapy low-density lipoprotein (LDL) cholesterol decreased on the average by 18% in type IIa, by 11% in type IIb and increased by 37% in type IV patients. Very-low-density lipoprotein (VLDL) cholesterol and triglycerides fell by 57% in type IIb and by 58% and 76% respectively in type IV subjects. High-density lipoprotein (HDL) cholesterol rose in all groups of patients owing to the increase of the HDL2 subfraction. However, in type IIa the change did not reach the level of statistical significance. Apoprotein B decreased in type IIa and in type IIb patients and apoprotein A-I significantly increased in type IIb and IV patients. The individual changes in total VLDL and LDL lipids and in apoprotein B could be related to their pretreatment level. The cholesterol triglyceride ratio significantly increased in LDL and HDL fractions and the effect was greater in the subgroup of patients with the greatest abnormality in lipoprotein lipid composition. On the whole the differential effects of gemfibrozil on serum lipoprotein concentration and composition in the various types of hyperlipoproteinaemia can be regarded as a trend toward a normalization and may be explained by the multiple effects of the drug on lipid metabolism.