AB0510 THE ROLE OF BONE SCINTIGRAPHY FOR THE FOLLOW-UP EVALUATION OF INFLAMMATORY ACTIVITY IN PATIENTS WITH SERONEGATIVE SPONDYLOARTHRITIS

Background:

The use of bone scintigraphy (Sc) in spondyloarthritis (SpA) as a technique for diagnosis, assessment of activity and treatment decision has been questioned by the scientific community. Due to its low cost compared to Magnetic Resonance Imaging - MRI (the gold standard)1, some studies proposed to evaluate Sc’s diagnostic accuracy. These studies have shown that Sc has a low diagnostic sensitivity of 50-55%2. Also, there is a poor correlation between symptoms and scintigraphic uptake3. We aimed to evaluate the use of Sc for management and follow-up of patients with SpA.

Objectives:

To determine if Sc activity correlates with patients’ complaints (peripheral and axial), inflammatory markers, disease activity scores and whether it influenced physicians’ treatment decisions during the follow-up of the disease.

Methods:

We performed a retrospective review of all patients at our department with SpA with at least one Sc from 2018 to 2020. The following variables were analyzed: demographic data, spondyloarthropathy subtype (ankylosing, enteropathic, psoriatic and undifferentiated SpA), axial or peripheral pain, Sc findings (inflammatory vs no-inflammatory activity), inflammatory markers (sedimentation rate - ESR and C-Reactive Protein - CRP), disease activity scores within one year since the Sc (Ankylosing Spondylitis Disease Activity Score with Erythrocyte Sedimentation Rate - ASDAS-ESR and Bath Ankylosing Spondylitis Disease Activity Index - BASDAI) and treatment at the time of the Sc (non-steroidal anti-inflammatory drugs, conventional synthetic disease-modifying antirheumatic drugs (DMARDs), target synthetic DMARDs and biologic DMARD. Treatment decisions (escalation, de-escalation or maintenance) in accordance to Sc results were also reviewed.

We used the non-parametric Mann-Whitney’s U test for comparisons between ordinal or numerical variables. For correlations between categorical variables we used the Fisher’s exact test and the χ2-independence test. Tests with p < 0.05 were statistically significant.

Results:

Fifty-five patients were reviewed, 75% women; median age of 48 years. Seventy-one percent had ankylosing SpA, 15% enteropathic SpA, 5% psoriatic SpA, 5% undifferentiated and 4% reactive SpA. Sixty-two percent of the patients had both axial and peripheral pain and 24% only axial complaints. Sixty-two percent of the patients had a Sc with no inflammatory changes, 27% had peripheral and 25% had axial inflammatory changes; 15% had evidence of both peripheral and axial inflammation. For ankylosing SpA, the median ASDAS-ESR was 2.89 and according to the BASDAI, 66% had active disease. The median CRP and ESR in patients with inflammatory vs a normal Sc was not different (p=0.02 vs p=0.36, respectively). Similarly, Sc findings were not correlated with patients’ axial (p=0.10) or peripheral pain (p=1.0), neither with the ASDAS-ESR (p=0.29) or the BASDAI (p=0.29). There was no correlation between inflammatory activity in Sc and the decision to maintain, escalate or de-escalate treatment (p=0.65), including the decision to start a biological DMARD (p=1.0) or to switch between biological DMARDs (p=0.19).

Conclusion:

There was no correlation between Sc findings and ESR, patients’ complaints, disease activity or treatment decisions. Considering previous research showing a low diagnostic sensitivity, our findings seem to support a limited role of bone Sc for the follow-up and management of patients with seronegative SpA.

References:

[1]Khmelinskii N, Regel A, Baraliakos X. The Role of Imaging in Diagnosing Axial Spondyloarthritis. Front Med. 2018;5. doi:10.3389/fmed.2018.00106

[2]Poddubnyy D. Classification vs diagnostic criteria: the challenge of diagnosing axial spondyloarthritis. Rheumatology. 2020;59(Supplement_4):iv6-iv17. doi:10.1093/rheumatology/keaa250

[3]Shim JS, Kim C, Ryu JJ, Choi SJ. Correlation between TM joint disease and rheumatic diseases detected on bone scintigraphy and clinical factors. Sci Rep. 2020;10(1):4547. doi:10.1038/s41598-020-60804-x

Disclosure of Interests:

None declared.

Connective tissue disease-associated interstitial lung disease

BACKGROUND

Connective tissue diseases (CTD) are frequently associated with interstitial lung disease (ILD), significantly impacting their morbidity and mortality.

AIM

Analyze the experience of an autoimmune specialized unit on treating CTD-ILD and characterize the population based on most frequent diseases, imaging patterns, lung function tests results, serology and treatment. Assess mortality and mortality predictors in these patients.

METHODS

Retrospective, descriptive and statistical analysis of the CTD-ILD patients followed up at an autoimmune diseases unit during a 6-year period.

RESULTS

Over the study period, 75 patients with CTD-ILD were treated with a mean follow-up of 49 ± 31 months. The most frequent CTD were systemic sclerosis and rheumatoid arthritis. ILD was diagnosed prior to CTD in 8% of patients and concomitantly in 35%. Nonspecific interstitial pneumonia was the CT pattern in 60% and 35% had an isolated diminished DLCO on lung function tests. Pulmonary hypertension was present in 12% and it was the single most important mortality predictor (OR 14.41, p = 0.006). Corticosteroids are the mainstay of treatment but biologics were prescribed in 39% of the patients (mostly tocilizumab and rituximab). Two scleroderma patients were recently treated with nintedanib.

CONCLUSIONS

ILD is a potential complication of every CTD and can impose a dramatic burden on these patients. The clinical relevance of ILD together with their early expression in the course of the disease underlines the importance of the presence of chest physicians in these units.

Antiphospholipid antibodies are induced by in vitro fertilization and correlate with paraoxonase activity and total antioxidant capacity of plasma in infertile women

The objectives of this study were to determine whether antiphosholipid antibodies are associated with in vitro fertilization (IVF), and assess the potential biological effects of these antibodies. Sera from seventy infertile women (18 before IVF, 13 submitted to one IVF cycle and 39 after three cycles) and 28 healthy controls were collected. Anticardiolipin (anti-CL) and antiphosphatidylserine (anti-PS) antibodies, paraoxonase (PON) and Total Anti-oxidant Capacity of plasma (TAC) were measured. Anti-CL and anti-PS titres were significantly increased in treated patients compared with patients before treatment or controls ( P < 0.001). There were no differences regarding anti-CL and anti-PS titres between controls and untreated patients nor when different types of infertility were considered. PON activity and TAC were significantly reduced in treated patients when compared to untreated and controls ( P < 0.001; P < 0.002). PON correlated inversely with anti-CL and anti-PS IgG ( r = 20.734; P < 0.001) and directly with TAC ( r = 0.720, P < 0.001). In conclusion PON activity is decreased in women submitted to IVF treatment and is associated with the presence of antiphospholipid antibodies. These factors might contribute to the increased oxidative status found in these patients.

[Clock and molecular genetics in Drosophila]

Most living organisms possess a circadian clock (24 h period) which allows them to adapt to environmental conditions. Numerous studies in Drosophila allowed to discover various key clock genes, such as period and timeless. The powerful tools of drosophila genetics have shown that the molecular clock relies on negative feedback loops that generate oscillations of the clock genes mRNA. A delay between the accumulation of mRNAs and proteins is required for the feedback loop. It is generated by post-translational modifications as phosphorylations and ubiquitinations, which control protein stability and determine the period of their oscillations. Clock cells are present in brain as well as in multiple peripheric tissues where they run autonomously. The synchronisation of clock cells by light relies on cryptochrome in both brain and peripheral tissues. In the brain, synchronisation also involves the eye photoreceptors. The clock that drives sleep-wake rhythms is controlled by different groups of neurons in the brain. Each group has a distinct function in the generation of the behavioral rhythm and this function is modulated by environmental conditions.

Morning and evening peaks of activity rely on different clock neurons of the Drosophila brain

In Drosophila, a 'clock' situated in the brain controls circadian rhythms of locomotor activity. This clock relies on several groups of neurons that express the Period (PER) protein, including the ventral lateral neurons (LN(v)s), which express the Pigment-dispersing factor (PDF) neuropeptide, and the PDF-negative dorsal lateral neurons (LN(d)s). In normal cycles of day and night, adult flies exhibit morning and evening peaks of activity; however, the contribution of the different clock neurons to the rest-activity pattern remains unknown. Here, we have used targeted expression of PER to restore the clock function of specific subsets of lateral neurons in arrhythmic per(0) mutant flies. We show that PER expression restricted to the LN(v)s only restores the morning activity, whereas expression of PER in both the LN(v)s and LN(d)s also restores the evening activity. This provides the first neuronal bases for 'morning' and 'evening' oscillators in the Drosophila brain. Furthermore, we show that the LN(v)s alone can generate 24 h activity rhythms in constant darkness, indicating that the morning oscillator is sufficient to drive the circadian system.

The F-box protein slimb controls the levels of clock proteins period and timeless

The Drosophila circadian clock is driven by daily fluctuations of the proteins Period and Timeless, which associate in a complex and negatively regulate the transcription of their own genes. Protein phosphorylation has a central role in this feedback loop, by controlling Per stability in both cytoplasmic and nuclear compartments as well as Per/Tim nuclear transfer. However, the pathways regulating degradation of phosphorylated Per and Tim are unknown. Here we show that the product of the slimb (slmb) gene--a member of the F-box/WD40 protein family of the ubiquitin ligase SCF complex that targets phosphorylated proteins for degradation--is an essential component of the Drosophila circadian clock. slmb mutants are behaviourally arrhythmic, and can be rescued by targeted expression of Slmb in the clock neurons. In constant darkness, highly phosphorylated forms of the Per and Tim proteins are constitutively present in the mutants, indicating that the control of their cyclic degradation is impaired. Because levels of Per and Tim oscillate in slmb mutants maintained in light:dark conditions, light- and clock-controlled degradation of Per and Tim do not rely on the same mechanisms.

Defining the role of Drosophila lateral neurons in the control of circadian rhythms in motor activity and eclosion by targeted genetic ablation and PERIOD protein overexpression

The ventral lateral neurons (LNvs) of the Drosophila brain that express the period (per) and pigment dispersing factor (pdf) genes play a major role in the control of circadian activity rhythms. A new P-gal4 enhancer trap line is described that is mostly expressed in the LNvs This P-gal4 line was used to ablate the LNvs by using the pro-apoptosis gene bax, to stop PER protein oscillations by overexpressing per and to block synaptic transmission with the tetanus toxin light chain (TeTxLC). Genetic ablation of these clock cells leads to the loss of robust 24-h activity rhythms and reveals a phase advance in light-dark conditions as well as a weak short-period rhythm in constant darkness. This behavioural phenotype is similar to that described for disconnected1 (disco1) mutants, in which we show that the majority of the individuals have a reduced number of dorsally projecting lateral neurons which, however, fail to express PER. In both LNv-ablated and disco1 flies, PER cycles in the so-called dorsal neurons (DNs) of the superior protocerebrum, suggesting that the weak short-period rhythm could stem from these PDF-negative cells. The overexpression of per in LNs suppresses PER protein oscillations and leads to the disruption of both activity and eclosion rhythms, indicating that PER cycling in these cells is required for both of these rhythmic behaviours. Interestingly, flies overexpressing PER in the LNs do not show any weak short-period rhythms, although PER cycles in at least a fraction of the DNs, suggesting a dominant role of the LNs on the behavioural rhythms. Expression of TeTxLC in the LNvs does not impair activity rhythms, which indicates that the PDF-expressing neurons do not use synaptobrevin-dependent transmission to control these rhythms.

In vivo HIV-1 frameshifting efficiency is directly related to the stability of the stem-loop stimulatory signal

In many retroviruses, the expression of reverse transcriptase, protease, and integrase is dependent upon a -1 frameshift event. The frameshift signal is composed of a slippery sequence where the ribosome shifts, and a downstream stimulatory sequence. In most cases, the stimulatory sequence is a pseudoknot, but in some viruses, such as human immunodeficiency virus type 1 (HIV-1), a single stem-loop is involved. Here, we analyzed the precise role of the stem-loop thermodynamic stability. We tested the frameshifting stimulatory activity of a series of HIV-1-derived sequences showing a stepwise increment of the estimated deltaG degrees. These sequences were introduced at the junction of a lacZ-luc fusion gene cloned on a versatile expression vector, and the different constructs were tested in Saccharomyces cerevisiae and in mouse NIH3T3 cells. The results showed that the frameshifting efficiency was correlated directly to the stem stability between deltaG degrees = -2.5 kcal mol(-1) and deltaG degrees = -19.4 kcal mol(-1). This demonstrates the essential role of the stability of the stem-loop and does not support the involvement of a specific RNA-binding protein target sequence. However, increasing further the stem stability led to a diminution of frameshifting efficiency, suggesting that the stem-loop acts through a precise kinetic of pausing. Because the same pattern was observed in both yeast and mouse cells, it is likely that the stimulatory mechanism is conserved through evolution.

A novel glial fibrillary acidic protein mRNA lacking exon 1

Glial fibrillary acidic protein (GFAP) is the major intermediate filament protein in the mature astrocytes. We have assayed for the presence of GFAP mRNA gene in mouse tissues outside the nervous system. Nuclease S1 protection experiments show that RNAs lacking exon 1 are transcribed in bone marrow. From a mouse bone marrow cDNA library we isolated GFAP cDNAs which start in the 3' part of intron 1 and contain all the downstream GFAP exons. The new GFAP mRNAs, which we call GFAP gamma mRNAs, are already present in the brain at embryonic day 15 and in adult forebrain and cerebellum. Their presence in astrocytic cell lines suggests that astrocytes may be the site of in vivo expression of these mRNAs. In addition we have detected GFAP gamma mRNAs in mouse spleen. Furthermore in human an analogous GFAP mRNA containing the 3' part of intron 1 and lacking the exon 1 is also present in adult brain. These results suggest a new regulation of the GFAP gene expression.

Identification of new human myelin basic protein transcripts in the immune and central nervous systems

Five new myelin basic protein (MBP) transcripts were identified which each have preferential sites of expression in adult human brain and immune system. They contain a novel 5' coding region which presents extensive sequence similarity to the mouse 0' region. One of these ribonucleic acid (RNA) species, HMBPR1, is found essentially, if not only, in haemopoietic and immune cells. Two alternatively spliced transcripts called MBP2a and c are only expressed in the central nervous system (CNS). In addition, the two other transcripts are expressed in both immune and nervous systems. Thus, the MBP locus can generate multiple forms of RNA, whose start sites and splicing depend on the tissue in which they are expressed. The presence of an MBP transcript specifically expressed in the adult human immune system suggests previously unsuspected functions related to the pathogenesis of multiple sclerosis.

A new family of transcripts of the myelin basic protein gene: expression in brain and in immune system

A cDNA clone (MBP2) corresponding to a novel mouse myelin basic protein (MBP) mRNA has been isolated from an adult mouse bone marrow cDNA library. It contains the MBP exons 1a-7 except exon 5. Using PCR experiments we have determined that this MBP2 mRNA belongs to a new MBP mRNA family initiated upstream from exon 1b. Their 5' end extends into exon 1a and/or the region 0' previously described. These mRNAs are generated by alternative splicing of the primary transcript involving excision of exon 1a, 1b, 2, 5, or 6. Thus, these new mRNAs are produced from a promoter(s) located upstream from the major promoter 1b. They are expressed in brain (at least from embryonic day 15), in bone marrow, and in other hemolymphopoietic tissues, particularly in macrophage cells. As their expression is not restricted to myelinating cells, the function of these novel MBP mRNAs and putative proteins might not be related to myelination.

A novel transcript overlapping the myelin basic protein gene

Myelin basic protein (MBP) is a major constituent of myelin synthesized by oligodendrocytes and Schwann cells. We have investigated the expression of mouse MBP RNAs outside the nervous system. Nuclease protection experiments indicate that RNAs containing exon 1 and not the six downstream exons of the MBP gene are transcribed in various hemopoietic tissues. We have isolated a hemopoietic MBP-related (HMBPR) cDNA clone from a mouse bone marrow cDNA library screened with an MBP cDNA probe. This clone contains exons 1a and 1b and a part of intron 1 of the MBP gene. An additional 5' region, encoded by at least three unidentified exons, lies upstream of exon 1a. The HMBPR clone corresponds to a 5-kb RNA expressed in bone marrow, spleen, thymus, and macrophagic cells. This transcript is expressed at a similar level in brain, although at a lower level than the classical 2-kb mRNA. These data indicate that a new transcript, overlapping the MBP transcription unit and controlled by a distinct promoter, is expressed in hemopoietic tissues. This RNA might encode a 21-kDa protein sharing a common domain with MBP.

Analysis of the 5' region of the human tyrosine hydroxylase gene: combinatorial patterns of exon splicing generate multiple regulated tyrosine hydroxylase isoforms

A single human gene has been described to encode multiple tyrosine hydroxylase (TH) mRNAs. The study of this variation has been extended by S1 mapping experiments and by analysis of the 5' region of the TH gene. Four different mRNAs were found to originate solely from alternative splicing of two exons. Comparison of the 5' flanking regions of human and rat genes discloses several highly conserved segments, likely to play an important role in the regulation of TH gene expression.

Cloning of quail tyrosine hydroxylase: amino acid homology with other hydroxylases discloses functional domains

A cDNA clone containing the entire coding region of quail tyrosine hydroxylase (TH) has been isolated and analyzed. Comparison with rat and human THs and phenylalanine hydroxylases reveals several highly conserved domains. Two of them, shared by all these hydroxylases, are localized in the central and C-terminal parts of the molecules, and most probably include the active site. Two others are found only in the TH molecules. One contains putative sites of phosphorylation and is implicated in the posttranslational regulation of the enzyme. The second highly preserved domain, consisting of a stretch of 21 amino acids, is presumably associated with an important feature of the enzyme that remains to be identified.

A single human gene encoding multiple tyrosine hydroxylases with different predicted functional characteristics

Catecholaminergic systems in discrete regions of the brain are thought to be important in affective psychoses, learning and memory, reinforcement and sleep-wake cycle regulation. Tyrosine hydroxylase (TH) is the first enzyme in the pathway of catecholamine synthesis. Its importance is reflected in the diversity of the mechanisms that have been described which control its activity; TH levels vary both during development and as a function of the activity of the nervous system. Recently, we deduced the complete amino-acid sequence of rat TH from a complementary DNA clone encoding a functional enzyme. Here we demonstrate that, in man, TH molecules are encoded by at least three distinct messenger RNAs. The expression of these mRNAs varies in different parts of the nervous system. The sequence differences observed are confined to the 5' termini of the messengers and involve alternative splicing events. This variation has clear functional consequences for each putative form of the enzyme and could represent a novel means of regulating catecholamine levels in normal and pathological neurons.

Molecular genetics of catecholamines as an approach to the biochemistry of manic-depression

Manic depressive illness has been clearly established to exhibit a strong genetic component and is therefore amenable to linkage analysis using random DNA markers. In view of the catecholamine hypothesis of this disorder, the gene encoding tyrosine hydroxylase (TH) the limiting enzyme in catecholamines is a good candidate to investigate. This gene has been localized to chromosome 11 in close linkage with Harvey-ras-1. The various transcriptional and post-transcriptional mechanisms that modulate short and long-term TH activity are discussed. Human tyrosine hydroxylase is coded by at least three distinct mRNAs derived from a single gene. This variation has clear functional consequences and could represent a novel mode of regulating catecholamines levels in normal and pathological neurons.

Isolation of a rat pineal gland cDNA clone homologous to tyrosine and phenylalanine hydroxylases

A rat pineal gland cDNA expression library has been probed with an antiserum raised against rat tryptophan hydroxylase. A clone has been isolated and its sequence reveals a high degree of homology with those of tyrosine and phenylalanine hydroxylases.

Cloning and sequence analysis of the cDNA encoding a snake neurotoxin precursor

A recombinant plasmid has been constructed containing a sequence of 186 nucleotides encoding a potent neurotoxin found in the venom of the sea-snake Laticauda semifasciata and designated as erabutoxin a. This sequence is flanked, in the upstream region, by a sequence of 60 nucleotides encoding a hydrophobic peptide fragment presumably involved in the secretion process of the neurotoxin. The sequence coding for the toxin ends with a termination codon which is followed by a 3'-untranslated sequence of approximately 240 nucleotides (excluding the poly(A) tract).

Complete coding sequence of rat tyrosine hydroxylase mRNA

Several clones specific for tyrosine hydroxylase [tyrosine 3-monooxygenase, L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] have been identified from a rat PC12 library by using the previously characterized clone pTH-1. The most complete of these, pTH-51, is 1758 base pairs long and covers most of the length of the mRNA, including the entire coding and 3' untranslated region. The polypeptide has an estimated molecular weight of 55,903 and some of its characteristic features are discussed.