Could use of Selective Serotonin Reuptake Inhibitors During Lactation Cause Persistent Effects on Maternal Bone?

Physiological adaptations in early-lactation cows result in differential responses to calcium perturbation relative to nonlactating, nonpregnant cows

The peripartal cow experiences a rapid change in calcium metabolism at the onset of lactation. Research has focused on understanding how mammary-derived factors, such as serotonin (5HT) and parathyroid hormone like hormone (PTHLH), aid in coordinating these calcemic adaptations to lactation. Therefore, the aim of our study was to determine how induced subclinical hypocalcemia influences physiological responses, specifically the 5HT-PTHLH-Ca axis, in lactating and nonlactating dairy cows to elucidate the potential contribution of the mammary gland. Twelve nonlactating, nonpregnant (NL) multiparous Holstein cows and 12 early-lactation (EL) multiparous Holstein cows received either (1) a continuous 24-h intravenous solution of 0.9% NaCl or (2) 5% ethylene glycol tetraacetic acid (EGTA) solution in 0.9% NaCl (n = 6 EL, n = 6 NL per treatment) with the aim of maintaining blood ionized calcium (iCa) less than 1.0 mM. Mammary gland biopsies were taken immediately after and 48 h after termination of infusion. Blood was sampled hourly during infusion and 4, 8, 12, 24, 48, and 72 h after termination of infusion. Infusion of EGTA successfully decreased blood iCa concentrations. However, EL EGTA-infused cows required increased rates of EGTA infusion to maintain iCa below 1.0 mM. Circulating and mammary serotonin concentrations were increased in EL relative to NL cows, with no difference as a result of EGTA infusion. Mammary PTHLH expression was increased in EL cows, with highest expression observed in EL EGTA-infused cows. Collectively, these data demonstrate the robust adaptations EL cows have to maintain Ca homeostasis and the supporting roles 5HT and PTHLH may play.

Graduate Student Literature Review: Serotonin and calcium metabolism: A story unfolding

The peripartum period is characterized by dynamic shifts in metabolic, mineral, and immune metabolism as the dairy cow adapts to the demands of lactation. Emphasis over the past decade has been placed on understanding the biology of the large shift in calcium metabolism in particular. Moreover, research has also focused on exploring the role of serotonin during the transition period and lactation and further unraveling its relationship with calcium. This review aimed to demonstrate the integration of calcium physiology during the peripartal period and throughout lactation. More specifically, we sought to discuss the knowledge gained in recent years on calcium metabolism, mammary calcium transport, serotonin metabolism, and the serotonin-calcium axis. Herein we also discuss the challenges and limitations of current research and where that leaves the present understanding of the serotonin-calcium axis as we seek to move forward and continue exploring this interesting relationship.

Evaluation of the increased risk of spine fracture in patients with mood disorder compared with matched controls: a longitudinal follow-up study using a national sample cohort in Korea

OBJECTIVE

To evaluate the risk of spine fracture in patients with mood disorder using a nationwide cohort.

DESIGN

A longitudinal follow-up study.

SETTING

Claims data for the population ≥20 years of age were collected from 2002 to 2013 for the Korean National Health Insurance Service-National Sample Cohort.

PARTICIPANTS

A total of 60 140 individuals with mood disorder were matched with 240 560 individuals (control group) for age, sex, income, region of residence and osteoporosis.

INTERVENTIONS

In both the mood disorder and control groups, the history of spine fracture was evaluated. The International Classification of Diseases 10th Revision codes for mood disorder (F31-F39) and spine fracture (S220 and S320) were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

The univariable and multivariable HRs and 95% CIs of spine fracture for patients with mood disorder were analysed using a stratified Cox proportional hazards model. Subgroup analyses were conducted according to the history of osteoporosis, age and sex.

RESULTS

Approximately 3.3% (2011/60 140) of patients in the mood disorder group and 2.8% (6795/240 560) of individuals in the control group had spine fracture (p<0.001). The mood disorder group demonstrated a higher adjusted HR for spine fracture than the control group (multivariable HR=1.10, 95% CI 1.04 to 1.15, p<0.001). The participants without osteoporosis showed a higher HR of mood disorder for spine fracture than the control participants (multivariable HR=1.25, 95% CI 1.14 to 1.37, p<0.001). According to age and sex, this result was consistent in subgroups of women aged 20-39 and 40-59 years and men aged ≥60 years.

CONCLUSION

The risk of spine fracture was increased in patients with mood disorder. The potential risk of spine fracture needs to be evaluated when managing patients with mood disorder.

Peripartum dietary supplementation of a small-molecule inhibitor of tryptophan hydroxylase 1 compromises infant, but not maternal, bone

Long-term effects of breastfeeding on maternal bone are not fully understood. Excessive maternal bone loss stimulated by serotonin signaling during lactation may increase bone fragility later in life. We hypothesized that inhibiting nonneuronal serotonin activity by feeding a small-molecule inhibitor of the rate-limiting enzyme in serotonin synthesis [tryptophan hydroxylase 1 (TPH1)] would preserve maternal bone postweaning without affecting neonatal bone. Chow supplemented with the small-molecule TPH1 inhibitor LP778902 (~100 mg/kg) or control chow was fed to C57BL/6 dams throughout pregnancy and lactation, and blood was collected on days 1 and 21 of lactation. Dams returned to a common diet postweaning and were aged to 3 or 9 mo postweaning. Pups were euthanized at weaning. The effect of TPH1 inhibition on dam and pup femoral bone was determined by micro-computed tomography. Peripartum dietary supplementation with LP778902 decreased maternal serum serotonin concentrations ( P = 0.0007) and reduced bone turnover, indicated by serum NH2-terminal propeptide of type I collagen ( P = 0.01) and COOH-terminal collagen cross-links ( P = 0.02) concentrations, on day 21 of lactation. Repressed bone turnover from TPH1 inhibition was not associated with structural changes in maternal femur at 3 or 9 mo postweaning. By contrast, neonates exposed to peripartum LP778902 demonstrated differences in trabecular and cortical femoral bone compared with pups from control dams, with fewer ( P = 0.02) and thinner ( P = 0.001) trabeculae as well as increased trabecular spacing ( P = 0.04). Additionally, cortical porosity was increased ( P = 0.007) and cortical tissue mineral density was decreased ( P = 0.005) in pups of LP778902-treated dams. Small-molecule TPH1 inhibitors should be carefully considered in pregnant and lactating women, given potential risks to neonatal bone development.