Evaluation of urinary protein precipitation protocols for the multidisciplinary approach to the study of chronic pelvic pain research network

Relationship Between Blood Cytokine Levels, Psychological Comorbidity, and Widespreadness of Pain in Chronic Pelvic Pain

Background: Low-grade inflammation has been implicated in the etiology of depression, long-term fatigue and chronic pain. TNFα and IL-6 are perhaps the most studied pro-inflammatory cytokines in the field of psychoneuroimmunology. The purpose of our study was to further investigate these relationships in patients with chronic pelvic pain specifically. Using plasma samples from a large, well-described cohort of patients with pelvic pain and healthy controls via the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network, we examined the relationship between TNFα and IL-6 and comorbid psychological symptoms. We also investigated the relationship between IL-8 and GM-CSF, and widespreadness of pain. Methods: We included baseline blood samples in the analyses, 261 patients (148 women) and 110 healthy controls (74 women). Fourteen pro- and anti-inflammatory or regulatory cytokines were analyzed in a Luminex^® xMAP^® high-sensitivity assay. We used regression models that accounted for known factors associated with the outcome variables to determine the relationship between cytokine levels and clinical measures. Results: There were no statistical differences in cytokine levels between patients and healthy controls when controlling for age. In patients, TNFα was significantly associated with levels of fatigue (p = 0.026), but not with pain intensity or depression. IL-6 was not significantly related to any of the outcome variables. Women with pelvic pain showed a negative relationship between IL-8 and widespreadness of pain, while men did not (p = 0.003). For both sexes, GM-CSF was positively related to widespreadness of pain (p = 0.039). Conclusion: Our results do not suggest low-grade systemic inflammation in chronic pelvic pain. Higher TNFα blood levels were related to higher fatigue ratings, while higher systemic GM-CSF levels predicted more widespread pain. Our study further suggests a potentially protective role of IL-8 with regard to with regard to the widepreadness of pain in the body, at least for women.

Association of Longitudinal Changes in Symptoms and Urinary Biomarkers in Patients with Urological Chronic Pelvic Pain Syndrome: A MAPP Research Network Study

PURPOSE

We analyzed a series of novel noninvasive urinary biomarkers for their ability to objectively monitor the longitudinal clinical status of patients with urological chronic pelvic pain syndrome.

MATERIALS AND METHODS

Baseline, 6 and 12-month urine samples were collected (216) and used to quantify vascular endothelial growth factor, vascular endothelial growth factor (VEGF) receptor 1 (R1), neutrophil gelatinase associated lipocalin (NGAL), matrix metalloproteinase-2, matrix metalloproteinase (MMP)-9, and MMP-9/NGAL complex by enzyme-linked immunosorbent assays. Patient symptom changes were classified as improved, stable or worse using a functional clustering algorithm. Proportional odds models were used to evaluate the association between symptom change and urinary biomarkers.

RESULTS

Across all sampled participants, longitudinal decreases in normalized VEGF concentration (pg/μg) were associated with pain severity improvement, and decreases in MMP-9, NGAL and VEGF-R1 concentration (pg/ml) as well as NGAL normalized concentration were associated with improved urinary symptoms. Longitudinal decreases in normalized VEGF-R1 were associated with pain improvement in patients with moderate widespreadness, no bladder symptoms and no painful filling. Lower baseline normalized VEGF-R1 concentration was associated with pain improvement in patients with pelvic pain only. Higher baseline MMP-9/NGAL levels were associated with pain and urinary improvement across all participants. Moreover, longitudinal increases in MMP-2 concentration was associated with improved pain in men and patients with painful filling.

CONCLUSIONS

Our results suggest these urinary biomarkers may be useful in monitoring urological chronic pelvic pain syndrome symptom changes with respect to both urinary severity and pain severity. With further testing, they may represent objective biological measures of urological chronic pelvic pain syndrome progression and/or resolution while also providing insight into the pathophysiology of urological chronic pelvic pain syndrome.