Hypercalcemia in the etiology of puerperal psychosis

An Analysis of Cellular Communication Network Factor Proteins as Candidate Mediators of Postpartum Psychosis Risk

Postpartum (or puerperal) psychosis (PP) is a severe psychiatric condition associated with hallucinations, delusions, cognitive disorganization, and mood problems, which affects approximately 1-2 out of every 1,000 mothers shortly after childbirth. While the risk factors for, and co-morbidities of, PP are relatively well-defined, currently, the pathophysiology underlying the disorder is very poorly-specified. Here, I argue, on the basis of multiple lines of new evidence, that altered expression of the Cellular Communication Network (CCN) factor proteins (and of the heterodimerizing CCN2 and CCN3 proteins in particular), may be associated with, and possibly causal for, increased PP risk. Future preclinical and clinical studies should aim to test this hypothesis as empirical support for it would provide much-needed clues regarding the biological substrates of PP, and could point to predictive biomarkers for the condition.

A pharmacological mouse model suggests a novel risk pathway for postpartum psychosis

Postpartum psychosis (PP) is a severe psychiatric disorder affecting a small proportion of new mothers shortly after childbirth. The molecular pathophysiology underlying the disorder is currently poorly understood, and there are no amenable animal models for the condition; maternal deficiency for the enzyme steroid sulfatase has been proposed as a potential risk mechanism. Here we show that inhibition of steroid sulfatase with 667-COUMATE (10mg/kg p.o.) in new mouse mothers results in behavioural abnormalities that can be partially alleviated by the administration of the clinically-efficacious antipsychotic ziprasidone (0.3-1.0mg/kg i.p.). The pattern of behavioural abnormalities in 667-COUMATE-treated mice implicated a genetic substrate at 21-23cM on chromosome 15; of the 17 genes within this chromosomal interval, only one (Nov/Ccn3) was significantly differentially expressed in the brains of vehicle and 667-COUMATE-treated mice. Two additional members of the Ccn family (Ccn2/Ctgf and Ccn4/Wisp1) were also significantly differentially expressed between the two groups, as were three further genes co-expressed with Nov/Ccn3 in brain (Arhgdig) or previously implicated in disorder risk by clinical studies (Adcy8 and Ccl2). The expression of Nov/Ccn3, but not of the other differentially-expressed genes, could be normalised by ziprasidone administration (1.0mg/kg). NOV/CCN3 lies directly under a linkage peak for PP risk at 8q24, and the associated protein possesses numerous characteristics that make it an excellent candidate mediator of PP risk. Our data suggest the 667-COUMATE-treated mouse as a model for PP with some degree of face, construct, and predictive validity, and implicate a novel, and biologically-plausible, molecular risk pathway for PP.

A chapter in the unity of variety—calcium is the sole author?

Efforts to elucidate the pathomechanism of Alzheimer's disease and other neurodegenerative disorders have yielded an increasing pile of hypotheses. When analyzing thousands of scientific papers, the involvement of the central secondary messenger, calcium, becomes apparent. Here, we demonstrate that disturbed calcium homeostasis might be a common underlying factor in brain pathologies. By targeting calcium, this new information promises to broaden our understanding of health and illness and the approaches we take to treating disease.

Dopamine supersensitivity and hormonal status in puerperal psychosis

BACKGROUND

We examine the dopamine receptor supersensitivity hypothesis of puerperal psychosis, and explore puerperal changes in the functional sensitivity of this receptor system.

METHOD

Dopamine receptor sensitivity was estimated using growth hormone (GH) response to apomorphine challenge following delivery in 37 control women, and 11 deliveries in 10 women at 'high risk' of puerperal psychosis (previous history of puerperal affective or non-puerperal manic psychosis). Tests were on days 4 or 5, 11 or 12 and at six weeks postpartum.

RESULTS

Three women developing puerperal psychosis had subsensitive GH responsiveness on day 4. GH response to 67 challenge tests (in control and 'high risk' women) increased between days 4 or 5 and six weeks postpartum (P < 0.05). GH response at six weeks correlated with free thyroxine levels (P < 0.01).

CONCLUSIONS

These three cases do not support the stated hypothesis. Hypothalamic dopamine receptor sensitivity increases during the puerperium; thyroxine might influence this.

Post-pregnancy osteoporosis associated with hypercalcaemia

A lactating 31-year-old woman who developed four vertebral fractures 1-2 months after the delivery of her first child is described. She was hypercalcaemic (serum calcium up to 2.99 mmol/l), and urinary excretion of both calcium and hydroxyproline (an index of bone resorption) were markedly elevated. Serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D were suppressed, but parathyroid hormone-related peptide was above normal. There was severe axial osteopenia, as assessed by dual-energy X-ray absorptiometry. The biochemical abnormalities were reversed within 2 weeks of weaning, with the exception of the parathyroid hormone-related peptide concentration, which declined more gradually. This appears to be the first description of the abnormalities in calcium metabolism and bone density from early in the course of post-pregnancy osteoporosis and it indicates that this condition is associated with high levels of osteolysis which return to normal after weaning. This rapid reversal of the metabolic abnormalities accounts for the inconclusive nature of previous descriptions of post-pregnancy osteoporosis, in which investigations were more delayed. It also emphasizes the importance of weaning in the management of women presenting with this condition. A possible aetiological role for parathyroid hormone-related peptide is discussed.