PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression in MIO mice

This study aims to investigate the effects and mechanisms of parathyroid hormone [1-34] (PTH1-34) on TNF-α-stimulated mice chondrocytes, as well as cartilage from a meniscus injury induced osteoarthritis (MIO) mice model. The C57BL/6J mice received medial meniscectomy, and then administrated with PTH1-34. The results showed that PTH1-34 administration decreased secondary allodynia and the pain-related transcripts. The IHC, ELISA, Micro-CT imaging and histopathology analysis revealed the significantly improved subchondral plate thickness and bone porosity, the reduced pro-inflammatory cytokines in serum and joint fluid. In vitro, mice chondrocyte was treated with TNF-α or co-cultured with synovial cells. The results showed that TNF-α markedly upregulated the MMP13 expression, and the ERK1/2, NF-κB or PI3K signaling pathway inhibitors could reverse the induction effect of TNF-α on expression of MMP13 in chondrocytes. PTH1-34 alone has no effect on the expression of MMP13 and NF-κB signaling pathways, but the PTH1-34 could reverse the induction effect of TNF-α on MMP13 expression and NF-κB signaling pathway activation in chondrocytes. In addition, PTH1-34 administration inhibited the expression of TNF-α and MMP13, and chondrocyte viability, while the PKA repressor reversed the effect of PTH1-34 in chondrocytes co-cultured with synovial cells. In conclusion, PTH1-34 has an obvious analgesic and anti-inflammatory effect, inhibits the matrix synthesis and alleviates the progression of osteoarthritis. In vitro, PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression via the PKA pathway and the NF-κB signaling pathways, respectively.

Participation of microglial p38 MAPK in formalin-induced temporomandibular joint nociception in rats

AIMS

To investigate nociceptive behavior and the immunoreactivity of microglia and phosphorylated-p38 (p-p38) mitogen-activated protein kinase (MAPK) following intracisternal administration of SB203580, a p38 MAPK inhibitor, or minocycline, a microglia inhibitor, in rats with temporomandibular joint (TMJ) inflammation.

METHODS

The number of nociceptive behavioral responses was recorded for nine successive 5-minute intervals following formalin injections into the left TMJ. SB203580 or minocycline was administered intracisternally 2 hours prior to the formalin injection. Statistical analysis used one-way analysis of variance followed by least significant difference post-hoc analysis.

RESULTS

The intra-articular injection of formalin increased the expression of p-p38 MAPK in the ipsilateral medullary dorsal horn. Most of the p-p38 MAPK co-localized with OX42, a microglial marker, but not with GFAP, an astrocyte marker. Intracisternal injections of SB203580 (0.5, 1, or 5 Μg) attenuated the number of nociceptive behavioral responses and the expression of p-p38 MAPK in the medullary dorsal horn. Intracisternal injections of minocycline (25 or 50 Μg) also attenuated the responses and the expression of OX42 and p-p38 MAPK in the medullary dorsal horn.

CONCLUSION

These findings suggest that p38 MAPK in microglia plays an important role in the central processing of inflammatory TMJ nociception in rats. The data further indicate that a targeted blockade of the microglial p38 MAPK pathway is a potentially important new treatment strategy for inflammatory TMJ nociception.

The expanding use of third-generation aromatase inhibitors: what the general internist needs to know

BACKGROUND

Breast cancer patients represent the largest group of adult cancer survivors in the US. Most breast cancers in women 50 years of age and older are hormone receptor positive. Third generation aromatase inhibitors (AIs) are the newest class of drugs used in treating hormone responsive breast cancer. It is often during start of adjuvant hormone therapy that the breast cancer patient establishes (or reestablishes) close follow-up with their general internist.

OBJECTIVE

Given the large numbers of breast cancer patients in the US and the increasing use of third generation AI's, general internists will need to have a clear understanding of these drugs including their benefits and potential harms. Currently there are three third generation aromatase inhibitors FDA approved for use in the US. All have been shown to be superior to tamoxifen in disease free survival (DFS) in the treatment of both metastatic and early breast cancers.

RESULTS

While the data on side effects is limited, AI (compared to tamoxifen) may result in higher rates of osteoporosis and fractures, more arthralgias, and increased vaginal dryness and dysparuenia. Limited information on their effects on the cardiovascular system and neuro-cognitive function are also available. Patient's receiving adjuvant hormone therapy are generally considered disease free or disease stable and require less intensive monitoring by their breast cancer specialist.

CONCLUSIONS

In situations where patients experience significant negative side effects from AI therapy, discussions to discontinue treatment (and switch to an alternative endocrine therapy) should involve the cancer specialist and take into consideration the patient's risk for breast cancer recurrence and the impact of therapy on their quality of life. In some cases, patients may choose to never initiate AI treatment. In other cases, patients may choose to prematurely discontinue therapy even if therapy is well tolerated. In both settings increased knowledge by the general internists will likely facilitate discussions of risks versus benefits of therapy and possibly improve compliance to adjuvant hormone therapy.

The discriminating value of serum lactate dehydrogenase levels in children with malignant neoplasms presenting as joint pain

OBJECTIVES

To determine if serum lactate dehydrogenase levels distinguish patients with malignant neoplasm presenting with musculoskeletal complaints from patients with juvenile rheumatoid arthritis who reported similar symptoms.

DESIGN

Retrospective case-comparison study.

SETTING

Tertiary care, outpatient clinics.

PATIENTS

Twelve patients with malignant neoplasms who presented with arthritis or arthralgias and normal complete blood cell counts and blood smears in whom rheumatologic diagnosis was initially made were compared with 24 children with a final diagnosis of juvenile rheumatoid arthritis. The patients with malignant neoplasms all had normal blood counts and elevated sedimentation rates at symptom onset.

INTERVENTIONS

None.

RESULTS

Serum lactate dehydrogenase levels were significantly higher in the cancer patients at 2.2 times the normal values vs 0.8 times high normal for patients with juvenile rheumatoid arthritis (P =.004, Mann-Whitney U test) No significant differences were observed in white blood cell counts, hemoglobin levels, platelet counts, erythrocyte sedimentation rate, or uric acid or aspartate aminotransferase levels at initial evaluation.

CONCLUSIONS

Serum lactate dehydrogenase values may distinguish patients with malignant neoplasms from those with rheumatic disease early in the course of illness when symptoms and other laboratory values are not helpful.