Somatostatin receptor PET/MR imaging of large vessel inflammation in active compared with inactive vasculitis and atherosclerosis

Background

Use of 18F-FDG PET in large vessel vasculitis (LVV) is limited by non-specific uptake due to arterial remodelling and/or atherosclerosis leading to diagnostic uncertainty.

Purpose

To investigate somatostatin receptor 2 (SST2) as a novel inflammation-specific PET imaging target in LVV.

Methods

In a prospective observational cohort study, we tested the ability of PET/MRI using two somatostatin receptor tracers (68Ga-DOTATATE and 18F-FET-βAG-TOCA) to differentiate active from inactive LVV, and aortic atherosclerosis in patients with recent myocardial infarction. Ex vivo mapping of the imaging target was performed using immunofluorescence microscopy, imaging mass cytometry, and bulk, single-cell and single-nuclei RNA sequencing of temporal artery biopsies from LVV patients.

Results

Sixty-one participants were included (LVV, n=27; myocardial infarction ≤2 weeks, n=25; control subjects with an oncological indication for imaging, n=9). LVV patients (mean age 58 [SD 16] years; 78% female; 63% active or grumbling disease) had giant cell arteritis (n=13), Takayasu arteritis (n=13), or unspecified LVV (n=1). Baseline index vessel SST2 PET maximum tissue-to-blood ratio (TBRmax) was 61.8% (95% CI 31.5–99.0%, p<0.0001) higher in patients with active/grumbling LVV than inactive LVV, and 34.6% (95% CI 15.1–57.6%, p=0.0002) higher than recent myocardial infarction (Fig. 1a–c; arrow: PET signal; arrowhead: aortic thickening; asterisk: aortic atherosclerosis), with good diagnostic accuracy (AUC ≥0.86, p<0.001 for both). None of the control subjects without LVV or MI had increased arterial SST2 PET signal (Fig. 1d).

Mean aortic TBRmax was strongly correlated with Indian Takayasu Clinical Activity Score (r=0.82 [95% CI 0.46–0.95], p=0.001) and maximum wall thickness on MRI (r=0.68 [95% CI 0.31–0.87], p=0.002). SST2 PET/MRI was generally consistent with 18F-FDG PET/CT in LVV patients with contemporaneous scans (Fig. 1a, b), but with very low background signal in the brain and heart allowing for unimpeded assessment of nearby coronary, myocardial, and intracranial artery involvement. On follow-up imaging after a mean 9.3 (SD 3.2) months, clinically effective treatment for LVV was associated with a 0.49 ±SEM 0.24 (p=0.04; 22.3%) reduction in SST2 PET TBRmax, with good scan-scan repeatability in inactive LVV patients with no change in treatment (ICC 0.86, 95% CI 0.04–0.99).

SST2 localised to macrophages, pericytes, and perivascular adipocytes in inflamed arterial specimens (Fig. 2; a: H&E; b: imaging mass cytometry; arrow: SST2/CD68 co-staining). SSTR2-expressing macrophages co-expressed pro-inflammatory markers (S100A8, S100A9). Specific SST2 radioligand binding was confirmed by autoradiography in LVV specimens.

Conclusion

This is the first study to examine SST2 PET/MRI in LVV and to provide histological and gene expression data for validation. Here we show this novel approach holds major promise for diagnosis and therapeutic monitoring in LVV.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Wellcome Trust; Imperial NIHR Biomedical Research Centre

Substance Use During Pregnancy, Postpartum Depression and Child Outcomes: A Longitudinal Study

Introduction:

Although it is well know that the substance use during pregnancy has a negative impact on mother and child health, there are few data on pregnancy - related substance use as a risk factor for postpartum depression and child outcomes.

Aims: To determine maternal and child outcomes at 8 and 32 weeks postpartum of women who reported substance use during pregnancy.

Method:

This is a cohort study of 1804 Caucasian women in postpartum. Exclusion criteria: psychiatric disorders during pregnancy. Women were evaluated at 2-3 days, 8 and 32 weeks postpartum. Socio-demographic, obstetric, personal and family psychiatric history and substance use during pregnancy; the Edimburgh Postpartum Depression Scale (EPDS) were assessed. All women with EPDS>9 at 8 and 32 weeks were evaluated by a structured interview (DIGS) for DSM-III major depression.

Results:

The mean (SD) age was 31.7 (4.6). Forty-six percent of them were primiparous. Thirty-one percent has a family and 16% a psychiatry history. Fifty percent of women reported substance use during pregnancy: 42% caffeine, 21.6% nicotine, 8% alcohol and 0.6% cannabis. Incidence of major postpartum depression was: 12.7%. Incidence of: Apgar scores < 7 at 5 min after birth:0.4%, gestational age at delivery < 37 weeks:7.3%, birth weigt < 2.5 Kg:7.3%, and congenital malformations:1.4%.

Conclusions:

In the presentation, the maternal and child perinatal outcomes of women exposed to licit and ilicit drugs will be summarize and will include a discussion of the future clinical and research implications. This work has been done in part with Grants: GO3/184;FIS:PI04178;PI041635,PI041783,PI041779,PI041758,PI041761,PI041791,PI041766,PI041782,RD06/0001/1009; CIBER-SAM.

[Detection of syncytial respiratory virus in clinical samples using a RT-PCR technique]

From November 2000 to May 2001, 208 clinical samples were analyzed for respiratory infection. Parallel to the detection of the syncytial respiratory virus (SRV) by solid phase immunoassay (EIA) and rapid culture in shell-vial or conventional tube, a reverse transcription polymerase chain reaction (RT-PCR) technique was developed. The procedures were complimentary and useful in the diagnosis of respiratory infections due to SRV, both in children and adults.

Newborn universal immunisation against hepatitis B: immunogenicity and reactogenicity of simultaneous administration of diphtheria/tetanus/pertussis (DTP) and oral polio vaccines with hepatitis B vaccine at 0, 2 and 6 months of age

The reactogenicity and immunogenicity of the administration of recombinant vaccine against hepatitis B simultaneously (but at separate sites) with diphtheria/tetanus/pertussis (DTP) and oral polio vaccines were examined. Six hundred and twenty-six children (group I) were given hepatitis B vaccine at 0, 2 and 6 months of age; the other vaccines were administered at 2, 4 and 6 months of age. A control group of 731 children (group II) received only DTP and oral polio vaccines. The results showed that 93% of the infants in group I had anti-HBs titres above the protective level ( > or = 10 mIU ml-1) after vaccination. There were no differences in the immune responses for DTP and polio between the two study groups. The vaccine efficacy against poliomyelitis was 96% for serotype I, 100% for serotype II and 97-98% for serotype III. Of the infants in both groups, 97% had antibodies against B. pertussis; all children were positive for tetanus and diphtheria. There were no differences in the incidences of general reactions between groups. Local swelling and redness were reported following 4.2 and 4.4%, respectively, of all injections of hepatitis B vaccine. These reactions were reported following 31 and 33%, respectively, of all doses of DTP vaccine. It can be concluded that the simultaneous administration of hepatitis B vaccine with the DTP and polio vaccines is well-tolerated; hepatitis B vaccine remained highly immunogenic and did not interfere with the immune response to the other antigens.

[Varicella pneumonia in the adult]

In the adult, the primary infection by the varicella-zoster virus acquires an unusual severity due to several complications, the most frequent of them being pneumonia. The authors analyze the clinical, epidemiological, serological and radiological data of the only two cases of varicellous pneumonia in the adult at a general hospital during the past 5 years. They highlight as the main characteristics: easiness of diagnosis, dissociation between clinical and radiological signs and the excellent therapeutical response to the early administration of intravenous Aciclovir. They comment as well the risk factors of this complication and the criteria for hospitalization.

Isolation and distribution of Streptococcus suis capsular types from diseased pigs in Spain

A total of 65 isolates of Streptococcus suis was recovered from various tissues of diseased pigs. Almost 96% of all these isolates could be categorized as one of capsular types 1 to 22 and 1/2. Capsular type 2 was the most prevalent and represented 53.8% of all isolates, followed by capsular types 1 (9.2%), 1/2 (7.7%) and 8 (4.6%). Brain-meninges, multiples tissues and lungs were the source of the majority of the isolates. A total of 37% of S. suis isolates, mainly from brain-meninges, were found in pure culture. The antimicrobial susceptibility pattern of S. suis isolates was determined.

[Intestinal infections caused by Aeromonas]

We have identified 38 instances of intestinal infection by Aeromonas and 4 by Plesiomonas in 16,184 coprocultures carried out during a 4 year period in the HCU of Zaragoza. The low prevalence can be related with the fact that specific media for the recovery of these organisms were not used. The species Aeromonas sobria (47.36%) and A. caviae (39.47%) were more common than A. hydrophila (13.15%). Aeromonas were isolated from patients with and without intestinal disease. The occurrence of gastrointestinal disease was independent from the type of Aeromonas species isolated (p greater than 0.1). We did not find significant differences when we compared patients with and without diarrhea, the rates of the strains that produced gas from glucose, and those of the strains that did not produce arabinose acid. The rates of positivity for lysine decarboxylase and Voges-Poskauer were significantly more common in the strains isolated from symptomatic patients. The sensitivity to cephalothin (MIC less than or equal to 8 micrograms/ml) can be an adequate marker to differentiate A. sobria from the other two species (p less than 0.01).