Factors That Influence Substance Use Among American Indian/Alaskan Native Youth: A Systematic Mixed Studies Review

BACKGROUND

The American Indian/Alaskan Native (AI/AN) mortality rate from illicit drug use was 22.7%, double that of the general population between 2007 and 2009. Fifteen percent of AI/AN youth reported receiving treatment for substance use compared with 10% of non-AI/AN peers.

OBJECTIVE

The purpose was to explore the factors that influence substance use among AI/AN youth.

METHOD

We performed a systematic review using a results-based convergent synthesis design. Eight electronic databases were searched for articles published between 2014 and 2019 using the search terms "Native American youth," "Native American adolescent," "Native Youth," "substance use," "substance misuse," and "substance abuse." The Mixed Methods Appraisal Tool was used to appraise the studies.

RESULTS

Forty-seven studies met the inclusion criteria (44 quantitative, one qualitative, and two mixed-methods studies). The results were organized using the ecological systems model and included evaluation of both protective and risk factors related to AI/AN youth substance use. Three system levels were found to influence substance use: individual, micro- and macrosystems. The individual systems-level coping mechanisms played a key role in whether AI/AN youth initiated substance use. Family, school, and peer factors influence the microsystem level. At the macrosystem level, community environmental factors were influential.

CONCLUSION

The major factor linking all the systems was the influence of a connected relationship with a prosocial adult who instilled future aspirations and a positive cultural identity. Findings of this systematic mixed studies review will assist in intervention development for AI/AN youth to prevent substance misuse.

Progelatinase A mRNA expression in cell lines derived from tumors in patients with metastatic renal cell carcinoma correlates inversely with survival

OBJECTIVES

Tumors are thought to metastasize by a process involving tumor cell attachment to extracellular matrix, degradation of matrix components by tumor-associated proteases, and cellular movement into the area modified by protease activity. Type IV collagen comprises the major element tumor cells must degrade to gain access to the rest of the body. Renal cancer cell line progelatinase A (E.C. 3.4.24.24; 72-kDa type IV collagenase; MMP-2) mRNA expression was correlated with patient survival.

METHODS

Total cellular mRNA was extracted from tumor cell lines derived from patients with metastatic renal cell carcinoma. The results of the densitometric analysis of Northern blots were correlated with patient survival. Formalin-fixed, paraffin-embedded tissue sections of primary renal cancers were examined for immunohistochemical expression of MMP-2.

RESULTS

Cell lines established from 23 primary renal tumors and six metastatic sites in 26 patients with metastatic renal carcinoma were studied. Variable expression of progelatinase A, relative to A2058 melanoma cells (mean +/- SEM, 0.60 +/- 0.21; median, 0.082; range, 0 to 4.78), was found. There was a significant inverse association between patient survival and the log of the MMP-2 expression (P = 0.045 by the Cox proportional-hazards model). Using a cutoff value of 0.10, the closest round number to the median expression of MMP-2, a significant difference between survival of patients with lower and higher MMP-2 expression in their primary renal cell line was found (P = 0.0054). Cell lines with low, intermediate, and high expression of MMP-2 mRNA all had primary tumors with high tissue immunohistochemical expression of MMP-2.

CONCLUSIONS

These studies demonstrate an inverse relationship between renal cancer cell line MMP-2 mRNA expression and patient survival. Immunohistochemical studies of the primary tumors from which the cell lines were derived uniformly showed high MMP-2 expression. Previous work suggests local renal factors upregulate cellular expression of MMP-2 in the primary tumor, and are not active at extrarenal sites.