BackgroundHereditary angioedema (HAE) resulting from C1-inhibitor deficiency is characterized by attacks of subcutaneous and submucosal edema. Many factors have been presumed to induce edema. Our study analyzed these factors in a fairly large patient population.MethodsIn the first stage of our study, we analyzed the data recorded by 92 subjects in their patient diaries over seven years. The second phase included 27 HAE patients, who had been completing the diary entry ‘Trigger factors’ every day for seven months whether or not they had experienced an attack.ResultsDuring the initial stage, 91% of the subjects described some factor possibly related to the onset of an attack. They could identify a trigger factor – most commonly (21%) mental stress – in 30% of the 3176 attacks. We found a significant (p < 0.001) difference in the distribution of the trigger factors of the edematous attacks of different locations. The 27 participants of the second phase identified 882 potential trigger factors and recorded 365 attacks. Of these, 246 (67%) occurred on days when the patients identified a potential trigger factor. The likelihood of edema-formation associated with the latter was as follows: menstruation – 63%, infection – 38%, mental stress – 26%, physical exertion – 25%, meteorological changes – 21%, fatigue – 17%.ConclusionThis analysis of the trigger factors explored, for the first time, their potential role in inducing HAE attacks. Our findings might open new perspectives in extending the indications for edema-prophylaxis, and could contribute to a better understanding of the pathomechanism of HAE attacks.

STP reduces the number of postprocedural edematous episodes. C1-INH concentrate is safe and effective for prophylaxis. When this agent is not available, danazol is a potential alternative for prophylaxis before elective medical interventions.

SUMMARY Nursing has important physiological and psychological consequences on mothers during the postpartum period. Tuberoinfundibular peptide of 39 residues (TIP39) may contribute to its effects on prolactin release and maternal motivation. Since TIP39-containing fibers and the receptor for TIP39, the parathyroid hormone 2 receptor (PTH2 receptor) are abundant in the arcuate nucleus and the medial preoptic area, we antagonized TIP39 action locally to reveal its actions. Mediobasal hypothalamic injection of a virus encoding an antagonist of the PTH2 receptor markedly decreased basal serum prolactin levels and the suckling-induced prolactin release. In contrast, injecting this virus into the preoptic area had no effect on prolactin levels, but did dampen maternal motivation judged by reduced time in a pup-associated cage during a place-preference test. In support of an effect of TIP39 on maternal motivation, we observed that TIP39 containing fibers and terminals had the same distribution within the preoptic area as neurons expressing Fos in response to suckling. Furthermore, TIP39 terminals closely apposed the plasma membrane of 82% of Fos-ir neurons. Retrograde tracer injected into the arcuate nucleus and the medial preoptic area labeled TIP39 neurons in the posterior intralaminar complex of the thalamus (PIL), indicating that these cells but not other groups of TIP39 neurons project to these hypothalamic regions. We also found that TIP39 mRNA levels in the PIL markedly increased around parturition and remained elevated throughout the lactation period, demonstrating the availability of the peptide in postpartum mothers. Furthermore, suckling, but not pup exposure without physical contact, increased Fos expression by PIL TIP39 neurons. These results indicate that suckling activates TIP39 neurons in the PIL that affect prolactin release and maternal motivation via projections to the arcuate nucleus and the preoptic area, respectively.

Oxytocin is released from neurons in the paraventricular hypothalamic nucleus (PVN) in mothers upon suckling and during adult social interactions. However, neuronal pathways that activate oxytocin neurons in social contexts are not yet established. Neurons in the posterior intralaminar complex of the thalamus (PIL), which contain tuberoinfundibular peptide 39 (TIP39) and are activated by pup exposure in lactating mothers, provide a candidate projection. Innervation of oxytocin neurons by TIP39 neurons was examined by double labeling in combination with electron microscopy and retrograde tract-tracing. Potential classic neurotransmitters in TIP39 neurons were investigated by in situ hybridization histochemistry. Neurons activated after encounter with a familiar conspecific female in a familiar environment were mapped with the c-Fos technique. PVN and the supraoptic nucleus oxytocin neurons were closely apposed by an average of 2.0 and 0.4 TIP39 terminals, respectively. Asymmetric (presumed excitatory) synapses were found between TIP39 terminals and cell bodies of oxytocin neurons. In lactating rats, PIL TIP39 neurons were retrogradely labeled from the PVN. TIP39 neurons expressed vesicular glutamate transporter 2 but not glutamic acid decarboxylase 67. PIL contained a markedly increased number of c-Fos-positive neurons in response to social encounter with a familiar conspecific female. Furthermore, the PIL received ascending input from the spinal cord and the inferior colliculus. Thus, TIP39 neurons in the PIL may receive sensory input in response to social interactions and project to the PVN to innervate and excite oxytocin neurons, suggesting that the PIL-PVN projection contributes to the activation of oxytocin neurons in social contexts.