Preliminary Study on the Cytoarchitecture of the Human Parabrachial/Kölliker-Fuse Complex, with Reference to Sudden Infant Death Syndrome and Sudden Intrauterine Unexplained Death

Abstract

The parabrachial/Kölliker-Fuse complex has been defined, in different animal species, to lie in the dorsolateral part of the pontine tegmentum and to be subdivided into three well-defined regions: the medial parabrachial nucleus, the lateral parabrachial nucleus, and the Kölliker-Fuse nucleus. Experimental studies have shown that the parabrachial/Kölliker-Fuse complex is involved in a variety of functional activities and above all plays an important role in respiratory modulation. In human brainstem, the cytoarchitecture and physiology of this complex have not yet been fully characterized. The aim of the present study was to examine fetal and infant human brainstems in order to define the precise morphology of the three nuclei of the parabrachial/Kölliker-Fuse complex, and to determine whether this nervous center shows morphologic alterations in sudden infant death syndrome (SIDS) and in sudden intrauterine unexplained death (SIUD). In serial sections of 31 brainstems of subjects aged from 32 gestational wk to 10 months of life, we studied, by morphologic and morphometric analyses, the cytoarchitecture and the extension of the three nuclei of the parabrachial/Kölliker-Fuse complex. All the morphometric parameters were very similar in SIUD and SIDS cases to those of the respective control group, as shown by the absence of significant statistical differences between the two fetus and infant groups. We observed that the features of both the lateral and the medial parabrachial nuclei are largely consistent with those reported in experimental studies. In contrast, the Kölliker-Fuse nucleus appears to be more developed in human beings than in other animal species, showing a greater extension and a more complex structure, as well as subdivision into two subnuclei (compactus and dissipatus).

Study of the human hypoglossal nucleus: Normal development and morpho-functional alterations in sudden unexplained late fetal and infant death

“…These include, in particular in the brainstem, hypoplasia of the arcuate nucleus, pre-Bö tzinger nucleus, tractus solitarius nucleus, parafacial complex and parabrachial/ Kö lliker-Fuse complex [1][2][3][4][5][6][7]. The present study was performed with the purpose to deepen our knowledges by evaluating the development and the involvement in these pathologies even of the hypoglossal nucleus (HGN), a nucleus of the dorsal part of the medulla oblongata that, even if not generally included among the so defined vital centers, takes part in specific phases of breathing.…”

“…Therefore, we aimed to start from these works to evaluate if the HGN shows morpho-functional alterations not only in SIDS but also in sudden unexplained perinatal deaths, like the alterations in nuclei and/or structures of the brainstem and cerebellum checking vital functions, previously observed by us in these pathologies [1][2][3][4][5][6][7][21][22][23].…”

Unexplained stillbirth versus SIDS: Common congenital diseases of the autonomic nervous system—pathology and nosology

“…A more in-depth description of the neuropathologic findings and the related illustrations can be found in our previous works [12][13][14][15][16][17][18]. In the medulla oblongata hypoplasia of the arcuate nucleus was present in over 50% of the sudden perinatal deaths and SIDS victims.…”

“…Instead, the Kölliker-Fuse nucleus was found to be hypodeveloped particularly in sudden intra-partum deaths; it has an important function during intrauterine life, inhibiting the response of central and peripheral chemoreceptors (which are already fully formed and potentially functional in the last weeks of pregnancy) and therefore any respiratory reflex. After birth, the Kölliker-Fuse abruptly reduces its inhibitory effects and becomes active as a respiratory center able to coordinate the pulmonary motor responses to hematic oscillations of pO 2 , pCO 2 and pH [15].…”

Sudden unexpected postnatal collapse at 20 hours from birth during skin-to-skin care related to brainstem developmental alterations – a case report

“…oscillations of pO 2 , pCO 2 and pH [5][6][7][8]. This activity is also sustained by the chemo receptor nuclei, to which the retrotrapezoid nucleus and the raphe obscurus nucleus belong [3,9].…”