Objective: Hypertension is not only associated with cardiovascular diseases but also with alterations in bone quality. Hypertension therefore might be a risk factor for osseointegration. Preclinical studies suggest that losartan, an angiotensin II receptor blocker widely used to treat hypertension, has a beneficial effect in graft consolidation. Here, we determine the effect of hypertension and losartan on osseointegration. Methods:We used spontaneously hypertensive rats (SHR) and normotensive Wistar albinus rats receiving losartan (30 mg/kg, p.o.) or left untreated. After 1 week, titanium miniscrews were inserted into the tibia. Sixty days after implantation, implant stability was evaluated by removal torque measurement considered the primary endpoint. Microcomputed tomography and histomorphometric analysis were secondary endpoints.Results: Losartan increased the removal torque in the hypertensive SHR group to levels of the Wistar controls. While the cortical parameters of osseointegration remained unchanged, losartan increased medullary bone formation. Microcomputed tomography revealed a higher bone volume per tissue volume and trabecular thickness in the SHR rats treated with losartan. Histomorphometric analysis further showed that losartan significantly increased the thickness of newly formed bone in medullary area in hypertensive SHR rats. Losartan did not significantly alter the parameters of osseointegration in normotensive rats. Conclusions:The data presented suggest that the angiotensin II receptor antagonist losartan increases the medullary parameters of osseointegration in a tibia model of spontaneously hypertensive rats. Considering the study limitations, understanding the impact of hypertension and the respective drugs on osseointegration requires further research. K E Y W O R D Sbone, losartan, osseointegration, renin-angiotensin system, spontaneously hypertensive rats | 1127 MULINARI-SANTOS eT AL.
The association patterns between maternal age and foetal growth parameters as well as newborn size were analysed using a dataset of 4737 singleton term births taking place at the Viennese Danube hospital. Foetal growth patterns were reconstructed by the results of three ultrasound examinations carried out at the 11th/12th, 20th/21th and 32th/33thweek of gestation. In detail, crown-rump length, biparietal diameter, fronto-occipital diameter, head circumference, abdominal transverse diameter, abdominal anterior-posterior diameter, abdominal circumference, and femur length were determined. Birth weight, birth length and head circumference were measured immediately after birth. Young teenage mothers (≤15 years), older adolescent mothers (16-19 years), mothers of optimal age range (20-35 years) and mothers of advanced age (>35 years) differed significantly in body height, pre-pregnancy weight status and gestational weight gain. Surprisingly, the foetuses of young adolescent mothers were the largest ones during first trimester. During the second and third trimester however, the foetuses of mothers of optimal age range (20-35 years) and mothers older than 35 years showed larger biometric dimensions than adolescent mothers. According to multiple regression analyses, maternal age was significantly related to Foetal head size (ß =-0.04; 95% CI = -0,08 - 0.01; p=0.034) and abdominal dimensions (ß= 0.03; 95% CI = 0.01-0.05; p=0,011) during the second trimester and to birthweight (ß= -0.03; 95% CI= -4.40 - 0.04; p=0.050). The associations however, are quite weak and the statistical significance is maybe due to the large sample size. At the time of birth, offspring of mothers of optimal age range (20 to 35 years) is significantly larger than that of adolescent mothers and mothers of advanced age. Mothers of advanced age showed the significantly highest (p=<0.0001) prevalence (5.6%) of SGA newborns (<2500g). The small size of newborn among young adolescent mothers may be due to a competition over nutrients between the still growing mothers and the foetuses during the third trimester, while placental ageing may be responsible for smaller size of offspring among mothers of advanced age.
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