Resolving Macrophages Counter Osteolysis by Anabolic Actions on Bone Cells

Progression of inflammatory osteolytic diseases, including rheumatoid arthritis and periodontitis, is characterized by increased production of proinflammatory mediators and matrix-degrading enzymes by macrophages and increased osteoclastic activity. Phenotypic changes in macrophages are central to the healing process in virtually all tissues. Using a murine model of periodontitis, we assessed the timing of macrophage phenotypic changes and the impact of proresolving activation during inflammatory osteolysis and healing. Proinflammatory macrophage activation and TNF-α overproduction within 3 wk after induction of periodontitis was associated with progressing bone loss. Proresolving activation within 1 wk of stimulus removal and markers of resolving macrophages (IL-10, TGF-β, and CD206) correlated strongly with bone levels. In vivo macrophage depletion with clodronate liposomes prevented bone resorption but impaired regeneration. Induction of resolving macrophages with rosiglitazone, a PPAR-γ agonist, led to reduced bone resorption during inflammatory stimulation and increased bone formation during healing. In vitro assessment of primary bone marrow-derived macrophages activated with either IFN-γ and LPS (proinflammatory activation) or IL-4 (proresolving activation) showed that IL-4-activated cells have enhanced resolving functions (production of anti-inflammatory cytokines; migration and phagocytosis of aged neutrophils) and exert direct anabolic actions on bone cells. Cystatin C secreted by resolving but not inflammatory macrophages explained, in part, the macrophage actions on osteoblasts and osteoclasts. This study supports the concept that therapeutic induction of proresolving functions in macrophages can recouple bone resorption and formation in inflammatory osteolytic diseases.

Suppression of luteal phase, but not midcycle, prolactin levels by chronic follicular phase opiate antagonism

OBJECTIVE

To investigate whether establishment and maintenance of chronic opioid blockade throughout the follicular phase of the menstrual cycle influences midcycle and luteal phase prolactin levels.

DESIGN

Randomized, double-blind, crossover study.

SETTING

Academic research environment.

PATIENT(S)

Volunteers, aged 21-35 years, with regular menstrual cycles.

INTERVENTION(S)

Naltrexone (50 mg) or placebo were administered on cycle days 2-14. Blood samples were obtained in the early follicular phase and in the periovulatory and midluteal phases of the menstrual cycle.

MAIN OUTCOME MEASURE(S)

Serum prolactin levels.

RESULT(S)

In the early follicular phase, serum prolactin levels were equivalent in naltrexone (12.0 +/- 2.7 microgram/L; mean +/- SE) and placebo (12.1 +/- 2.9 micrograms/L) cycles. A statistically significant increase in serum prolactin was observed on the day of the LH surge (naltrexone: 22.6 +/- 3.7 micrograms/L; placebo: 21.7 +/- 2.7 micrograms/L; P < 0.05 versus early follicular phase), but no difference between treatments was observed. However, midluteal prolactin levels were statistically significantly lower in naltrexone cycles compared with placebo cycles (12.6 +/- 3.3 versus 15.4 +/- 3.0 micrograms/L; P < 0.05).

CONCLUSION(S)

Chronic blockade of opioid activities during the follicular phase does not affect midcycle prolactin increments, but withdrawal of opioid blockade may enhance opioid effects on prolactin levels in the luteal phase.

Effects of chronic nocturnal opiate antagonism on the menstrual cycle

OBJECTIVE

Opioids generally suppress gonadotropin secretion. We investigated whether chronic opiate antagonism would affect the occurrence or timing of menstrual cycle events.

STUDY DESIGN

Opiate blockade was maintained in nine normal volunteers from cycle days 1 through 13 with naltrexone. A double-blind, placebo-controlled crossover design was used. Serum estradiol and progesterone were measured daily. Vaginal ultrasonography was performed daily beginning cycle day 10. Endometrial biopsies were performed 10 to 12 days after ovulation. Nonparametric paired data analysis was used.

RESULTS

No significant differences in the following menstrual cycle parameters were detected between naltrexone and placebo cycles: cycle length (25.4 +/- 0.9 vs 25.7 +/- 0.5 days), maximum follicle size (21.5 +/- 1.0 vs 20.8 +/- 1.1 mm), peak serum progesterone (15.8 +/- 1.8 vs 15.2 +/- 2.2 ng/ml), or integrated serum progesterone (108.1 +/- 12.8 vs 101.2 +/- 14.6 ng/ml/day). Histologic endometrial development was normal in all subjects during naltrexone cycles.

CONCLUSION

These data suggest that naltrexone-suppressible opioid activity does not play a significant role in the regulation of follicular events in normal women.

Captopril effect on non-diabetic glomerular albuminuria

In order to evaluate captopril effectiveness in the treatment of glomerular albuminuria in nondiabetic patients, an initial study was carried out in 16 patients with proteinuria greater than 1 gr/1, administering captopril, 50 mg/day during a 4 month follow-up period. During that time, urinary albumin levels significantly descended (p < 0.001), with a concomitant rise in serum albumin. We conclude that captopril can be effective as a part of the treatment of albuminuria associated with nephropathy of non diabetic origin.