Fecal microbiota in early rheumatoid arthritis.

OBJECTIVE: To compare the composition of intestinal microbiota of patients with early rheumatoid arthritis (RA) or fibromyalgia (FM), fecal samples were collected from 51 patients with RA and 50 with FM. METHODS: RA patients fulfilled the RA criteria of the American College of Rheumatology, and duration of their disease was < or = 6 months. Only nonhospitalized patients from outpatient care were included. Patients having extreme diets or previous disease modifying antirheumatic drug or glucocorticoid medication were excluded, as were those taking antibiotics or having gastroenteritis for at least 2 months prior to sampling. Fecal bacterial composition was analyzed with a method based on flow cytometry, 16S rRNA hybridization, and DNA-staining. A set of 8 oligonucleotide probes was used. RESULTS: In comparison to patients with FM, the RA patients had significantly less bifidobacteria and bacteria of the Bacteroides-Porphyromonas-Prevotella group, Bacteroides fragilis subgroup, and Eubacterium rectale--Clostridium coccoides group. Results from the 8 probes showed a significant overall difference between the 2 patient groups, indicating widespread microbial differences. CONCLUSION: These findings support the hypothesis that intestinal microbes participate in the etiopathogenesis of RA.

Bacterial components in the synovial tissue of patients with advanced rheumatoid arthritis or osteoarthritis: analysis with gas chromatography-mass spectrometry and pan-bacterial polymerase chain reaction.

OBJECTIVE: To study the presence of bacterial components in the synovial tissue (ST) of patients with advanced rheumatoid arthritis (RA). METHODS: ST was collected during joint surgery from 41 RA patients. Tissue from 39 patients with osteoarthritis (OA), 4 patients with undifferentiated inflammatory arthritis (UA), and 3 cases of accidental deaths served as controls. The pan-bacterial polymerase chain reaction (PCR) with primers for the 23S ribosomal RNA (rRNA) and 16S rRNA genes was used to detect bacterial DNA. In addition, synovial fluid (SF) samples from patients with chlamydial reactive arthritis (ReA) were also examined by the same method. The positive controls, bacterial DNA or ST spiked with different living bacteria, were analyzed alongside clinical samples. Most of the ST samples were also analyzed by gas chromatography-mass spectrometry (GC-MS) for determining the presence of bacteria-derived muramic acid. Strict precautions were followed in the clinics and the laboratory to prevent contamination. RESULTS: In GC-MS analysis, muramic acid was observed in the ST from 4 of 35 RA patients and from 2 of 14 OA patients, but not in ST from 2 patients with UA and 3 cadavers. Bacterial DNA was not detected by either one of the PCR primers used in ST from 42 patients with RA and 39 patients with OA. However, 5 of 15 SF samples from ReA patients were PCR positive. The sensitivity of GC-MS to detect muramic acid was 2 pg/injected amount (227 pg muramic acid/mg ST), and that of the pan-bacterial PCR was 2-20 bacteria colony forming units/reaction. CONCLUSION: These results indicate that a bacterial component, muramic acid, is detectable by GC-MS in ST from a few patients with advanced RA or OA. However, no bacterial DNA was detectable by PCR.

Effects of 6-hydroxydopamine on the development of the immune system in chickens.

It has been suggested that the sympathetic nervous system communicates with lymphocytes expressing cell surface receptors for neurotransmitters such as norepinephrine (NE), on the basis of the finding that neurotransmitters modify immune responses in mammalian species. We confirmed that chicken lymphocytes in the brusa of Fabricius, thymus and spleen expressed beta-adrenergic receptor (beta-AR) mRNA from embryonic day (E) 10 and that intracellular cAMP level was elevated by NE, suggesting that lymphocytes express functional beta-AR on their surface at an early embryonal stage. To clarify whether the nervous system is involved in the development of the immune system, the effects of 6-hydroxydopamine (6-OHDA), one of sympathectomizing agents, on chicken lymphocytes was investigated. A single injection of 6-OHDA at a dose of 400 microg into a chicken embryo was carried out at E7 or 14 (as referred to E7 group and E14 group, respectively). NE level and the relative proportion of Bu-1a(+), CD4(+) and CD8(+) cells in the spleen of 3-week-old chickens were not altered by 6-OHDA treatment. However, the proliferative responses and expression of IL-2 mRNA in spleen cells cultured with pokeweed mitogen were reduced in E7 group compared with those of control. Furthermore, in CD8(+) spleen cells of E14 group of 3-week-old chickens, the expression of beta-AR mRNA and the relative increase of intracellular cAMP stimulated with NE were significantly decreased. These results suggest that the sympathetic nervous system affects the development of the immune system.