Among the maternal organs affected by the Preeclampsia there are the mammary glands. As well as in the rest of the body, even at this level there could be changes in the endothelium and blood vessels: these would lead to a reduction in the development of the gland and changes in the mechanisms of production of milk[17]. It is also known that the children of preeclamptic mothers, exposed to intrauterine stress, may have special nutritional needs, in addition to a greater risk of complications[18][2]. In view of these considerations, it is interesting to evaluate the potential differences between HM of PE women and normotensive women, in the different lactation phases.
Our study is the first that provide data on the association between PE and HM Activin A levels. Our results showed the absence of significant differences between the different groups. Considering the importance of HM nutrition, previous studies have focused their attention on PE lactating mothers. Data showed an alteration in the levels of several components: macronutrients ( i.e. proteins, carbohydrates, lipids and energy metabolites) and pro- and anti-inflammatory cytokines, oxidative stress markers and antioxidant molecules[19][20][21][22][23][24][25]. Regarding neurotrophic factors, Dangat et al. examined the levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) [26][27]. At first, they evaluated the levels of milk neurotrophins only in colostrum and observed that milk NGF levels were similar, whereas milk BDNF levels were higher in the PE group as compared to controls[26]. In the second time, they extended the evaluation of these agents through the other phases of lactation and they found that the NGF concentrations at 1.5 and 3.5 months and BDNF levels at 1.5 months were lower in the PE group as compared to the control group [27].
However, our data show differences in Activin A concentration in the different lactation phases, with a significant decrease in levels from colostrum to mature milk, in mother having delivered also preterm and term of GA. Our results are in agreement with previous study that reported a similar decrease in Activin A levels from colostrum to mature milk of mother delivering at term GA[12]. In addition, this current study confirms the presence of Activin A also in HM of woman that delivered preterm[11] and our data do not show differences between term and preterm levels.
Anyway, these findings in Activin A levels herein reported warrants further consideration. In particular, Activin A probably acts in HM as a growth factor: previous studies demonstrated that Activin A plays a neurotrophic function in differentiations of many CNS target cell-types[13][28]. Moreover, It is useful in repairing neurotoxicity damage, in vitro and in vivo researches[29][30]. It seems to exert a role of CNS protection from antidepressant treatment side-effects[31].
It also performs, on the other hand, a biomarker function of damage, especially at the brain level, so it has also been suggested to use it as an early neonatal indicator of neurological insults, caused for example by asphyxia and intraventricular hemorrhage after birth[32]. In addition, a fairly large number of researchers have evaluated, in other types of samples (i.e blood, plasma, urine), the variation in the Activin A concentration in case of PE and many studies agree that there is a significant correlation between this pathology and Activin A blood levels [33].
Bearing in mind these considerations, the absence of differences in HM Activin A composition is an important finding: in fact, thanks to these data, it can be said that the beneficial properties of milk are maintained even in the event of the onset of PE. This is a very encouraging fact, especially considering the high vulnerability, already mentioned, of the children of hypertensive mothers.