Decreased reuptake of serotonin in human platelets after surgery

Preoperative SSRI use increases perioperative transfusion need in patients undergoing surgical procedures on the hip joint

PURPOSE

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for psychiatric conditions. Previous studies have shown that SSRIs can increase bleeding risk by affecting platelet aggregation. However, their impact on perioperative outcomes in hip surgery remains uncertain. This case-control study examines the link between preoperative SSRI use and perioperative transfusion requirements in hip surgery patients.

METHODS

Data from the M161Ortho dataset of Pearl Diver patient records database were utilized. Patients who underwent hip joint surgery between 2010 and 2022 and had documented preoperative SSRI use within one month prior to surgery were included. Patients with coagulopathy disorders or coagulopathy medication use were excluded. Perioperative transfusion need was defined as receiving red blood cell or whole blood transfusions on the same date or within 10 days following the surgery.

RESULTS

A total of 75,374 patients with preoperative SSRI use were matched with an equal number of non-SSRI users. Preoperative SSRI use was associated with an increased risk of requiring perioperative transfusion (5.7% vs. 5.1%, P < 0.001). Subgroup analysis demonstrated increased transfusion risk in patients undergoing pinning (2.6% vs. 1.8%, P = 0.02), open reduction with internal fixation (ORIF) (8.9% vs. 8.2%, P = 0.007), and total hip arthroplasty (THA) (3.8% vs. 3.4%, P < 0.001), but no significant difference was observed in patients undergoing hemiarthroplasty.

CONCLUSION

Clinicians should be aware of the potential risk of increased perioperative transfusion requirements in hip surgery patients using SSRIs, especially during pinning, ORIF, and THA procedures. It is essential to consider this when managing patients on SSRIs before hip surgery.

Examining the Association Between Serotonergic Antidepressants and Blood Transfusion Requirements in Orthopaedic Surgery: A Comprehensive Analysis

AIM

The study aimed to investigate the association between the use of serotonergic antidepressants and blood transfusion requirements in orthopedic surgical patients.

METHODOLOGY

A retrospective follow-up study was conducted at Kota Trauma Hospital, Kota, Rajasthan focusing on patients who underwent orthopedic surgeries between November 2021 through December 2022. Patients were categorized into two groups: users of serotonergic antidepressants and users of other antidepressants (non-selective serotonergic antidepressants). The requirement for blood transfusion for both groups was assessed. Covariate factors, such as medication use and comorbidities (e.g., diabetes mellitus, cardiovascular diseases), were examined to control potential confounding variables.

RESULT

A total of 170 subjects with complete medical records were included in the study. The results presented a significant association between the usage of serotonergic antidepressants and blood transfusion requirements (p=0.001). While no significant differences between the two groups were observed in perioperative hemoglobin levels and fluid infusion, there was a significant difference in blood loss and postoperative drainage.

CONCLUSION

Serotonergic antidepressant usage was correlated with increased blood transfusion requirements in orthopedic surgery patients on antidepressants. The study underscores the importance of considering medication factors in perioperative management and highlights potential implications for patient care strategies.

Tail biting in pigs: blood serotonin and fearfulness as pieces of the puzzle?

Tail biting in pigs is a widespread problem in intensive pig farming. The tendency to develop this damaging behaviour has been suggested to relate to serotonergic functioning and personality characteristics of pigs. We investigated whether tail biting in pigs can be associated with blood serotonin and with their behavioural and physiological responses to novelty. Pigs (n = 480) were born in conventional farrowing pens and after weaning at four weeks of age they were either housed barren (B) or in straw-enriched (E) pens. Individual pigs were exposed to a back test and novel environment test before weaning, and after weaning to a novel object (i.e. bucket) test in an unfamiliar arena. A Principal Component Analysis on behaviours during the tests and salivary cortisol (novel object test only) revealed five factors for both housing systems, labeled ‘Early life exploration’, ‘Near bucket’, ‘Cortisol’, ‘Vocalizations & standing alert’, and ‘Back test activity’. Blood samples were taken at 8, 9 and 22 weeks of age to determine blood platelet serotonin. In different phases of life, pigs were classified as tail biter/non-tail biter based on tail biting behaviour, and as victim/non-victim based on tail wounds. A combination of both classifications resulted in four pig types: biters, victims, biter/victims, and neutrals. Generally, only in phases of life during which pigs were classified as tail biters, they seemed to have lower blood platelet serotonin storage and higher blood platelet uptake velocities. Victims also seemed to have lower blood serotonin storage. Additionally, in B housing, tail biters seemed to consistently have lower scores of the factor ‘Near bucket’, possibly indicating a higher fearfulness in tail biters. Further research is needed to elucidate the nature of the relationship between peripheral 5-HT, fearfulness and tail biting, and to develop successful strategies and interventions to prevent and reduce tail biting.

Does acute tryptophan depletion affect peripheral serotonin metabolism in the intestine?

BACKGROUND

Serotonin (5-hydroxytryptamine; 5-HT), a tryptophan metabolite, plays an important regulatory role in the human central nervous system and in the gastrointestinal tract. Acute tryptophan depletion (ATD) is currently the most widely established method to investigate 5-HT metabolism.

OBJECTIVE

The aim of this study was to assess the effect of an acute decrease in the systemic availability of tryptophan on intestinal 5-HT metabolism and permeability.

DESIGN

Thirty-three healthy volunteers (17 with ATD, 3 of whom dropped out; 16 placebo) participated in this randomized placebo-controlled study. Plasma and duodenal mucosal concentrations of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), and kynurenic acid (KA) were measured by HPLC-mass spectrometry. Intestinal barrier function was assessed with a multisugar plasma test, and analysis of tight junction transcription was performed in duodenal biopsy samples obtained by gastroduodenoscopy.

RESULTS

Mucosal 5-HT, 5-HIAA, and KA concentrations remained unaltered by ATD. In contrast, ATD significantly decreased plasma 5-HT (P < 0.05) and 5-HIAA (P < 0.0001) concentrations. After endoscopy, a significant increase in plasma 5-HT concentrations was observed in the placebo group (P = 0.029) compared with the ATD group. Moreover, a significant increase in plasma KA concentrations over time was found in the placebo group (P < 0.05). No changes in intestinal barrier function were observed.

CONCLUSIONS

An acute decrease in precursor availability does not affect mucosal concentrations of serotonergic metabolites, in contrast with systemic concentrations. ATD alters biochemical responses to acute stress from the endoscopic examination reflected by lower 5-HT concentrations. Changes in 5-HT concentrations were paralleled by alterations in KA concentrations, which suggest competition between the 2 metabolic pathways for the mutual precursor. This trial was registered at clinicaltrials.gov as NCT00731003.

Peri-operative decreased cAMP levels in long-term alcoholic patients

Long-term alcoholic patients have a five-fold higher risk of post-operative bleeding complications compared with nonalcoholic individuals. Serotonin increases and cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) decrease platelet aggregation. We examined the platelet-rich plasma levels of these substances and agonist-induced platelet aggregation in long-term alcoholic patients before and after surgery. Thirty-three consecutive patients (13 long-term alcoholics and 20 non-alcoholics) scheduled for tumour resections of the upper digestive tract were included in the study. The levels of cAMP were significantly decreased before and after surgery in long-term alcoholic patients, but there were no significant differences in cGMP and serotonin levels in alcoholic compared with non-alcoholic patients. In contrast to previous studies, no significantly altered aggregation responses in long-term alcoholics were found. A possible explanation is decreased inhibition through diminished cAMP levels; cGMP and serotonin do not seem to influence peri-operative haemostasis.

Serotonin transport kinetics correlated between human platelets and brain synaptosomes

RATIONALE

Blood platelets have been used extensively as a model system for investigating the role of the serotonin transporter (SERT) in various psychiatric disorders, especially depression. However, to date, it is not known whether platelet serotonin (5-HT) transport would be related to that in brain.

OBJECTIVES

We examined 5-HT transport kinetics simultaneously in human blood platelets and human cortical brain synaptosomes to determine whether they were correlated.

METHODS

Blood platelets and synaptosomes were obtained from 25 patients undergoing epileptic surgery. Synaptosomes were obtained from normal margins of surgical neuropathology specimens of anterotemporal cortex.

RESULTS

Platelet SERT V(max) was significantly correlated with brain SERT V(max) on linear regression (r=0.58, p<0.005), after controlling for the confounding effects of gender (t=-2.4, p=0.025) and time of day (t=2.1, p<0.05). Consistent with previous observations, there was a negative correlation between the maximum velocity (V(max)) of platelet 5-HT transport and pO2 (r=-0.52, p<0.01). Females had a significantly higher pO2 than males (F=4.9, p<0.05). After accounting for gender differences, addition of pO2 did not add further strength to the regression, given the aforementioned gender differences in pO2. The correlation between unadjusted values for platelet vs brain SERT V(max) was r=0.3, p=0.06.

CONCLUSIONS

These results suggest that a relationship may exist between 5-HT transport in platelets and cortical synaptosomes, when appropriate controls for confounding factors are employed.