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Global Translational Medicine Effect of leptin on aortic dissection

whether they contained information on the topic of assessment tool in this study. The Cochrane Quality Rating
interest. The reference lists of the articles with relevant Form contains a total of seven items, with each item
information were reviewed to identify citations to other given 1 point for “low risk” and 0 point for “high risk.”
studies on the same topic. Independent evaluations were made by the two researchers
and were then integrated. If there were any disagreements,
2.2. Inclusion and exclusion criteria another evaluation was made by the third researcher.
2.2.1. Inclusion criteria
2.3. Statistical analysis
To prevent bias, the inclusion criteria were as follows:
(i) The effect of leptin on AD tested in animal models; We separately pooled relative risk (RR) estimates from
(ii) sufficient data, such as the increase in artery diameter each study for each outcome using random effects meta-
and the comparison with animals receiving leptin or leptin analysis. The statistical heterogeneity of the RRs was
antagonist (LepA); and (iii) original data, independent of evaluated using the χ2 test, with significance set at P < 0.01,
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other studies. and the I statistic was calculated. To evaluate whether
there was publication bias in the included articles, we used
2.2.2. Exclusion criteria R software to draw funnel plots for qualitative analysis and
The pre-defined exclusion criteria were as follows: Egger’s test for quantitative analysis. If P < 0.05, it indicated
(i) Specific article types including case reports, abstracts, that there was publication bias. Low, moderate, and high
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reviews, editorials, and clinical trials; (ii) outcome variables degrees of heterogeneity corresponded to I values of
that were not caused by leptin or LepA; (iii) literature 25%, 50%, and 75%, respectively. Sensitivity analyses were
without full text or available review and main outcome conducted to evaluate whether the results could have been
indicators; and (iv) repetitive publications. markedly affected by a single study. All data (except age)
were expressed by x̄ ± s.
2.2.3. Data extraction and quality assessment
3. Results
The Chinese and English literature retrieved, according
to the retrieval strategy, were screened by two researchers 3.1. Search results
independently. The screening process was as follows: First, The references (n = 72) were retrieved by the original search
literature that were repeatedly searched were excluded; strategy or manual searches. The abstracts were reviewed,
second, titles and abstracts were read to eliminate irrelevant and eight articles were selected for full-text evaluation after
studies; full texts were read to identify studies that met the excluding repetitive literature and preliminary screening.
criteria, and data extraction was carried out; cross-checks After applying the inclusion and exclusion criteria, four
were carried out among researchers, and if there were any articles were included. The flowchart of the study inclusion
disagreements, a third researcher was consulted. process is shown in Figure 1.
The following research design details were extracted
from each study: (i) Year of publication, first author’s 3.2. Research quality assessment results
name, and experimental model; (ii) individual data of The Cochrane scoring system was used to evaluate the
each animal, including number, species, gender, etc.; quality of the included literature. The results showed that
(iii) treatment information, including treatment time, route of the lowest score was 6, while the highest was 10, with an
administration, and dosage; and (iv) result measurement and average of 4.25 ± 0.96, which was in the upper-middle level
evaluation time. For results that were obtained from animal (Figure 1).
studies at different time points, we extracted the data at the
time before killing. For data that were missing or presented 3.3. Meta-analysis of studies on aortic diameter
graphically, they were measured using a digital scale software. The changes in mouse aortic diameter were reported in four
In addition, we attempted to contact the author for more studies (inclusive of five animal experiments). The mice in
information or calculated on our own (if any); otherwise, the experimental group of three animal experiments were
we excluded it. For each comparison or each treatment and intervened with leptin. It is worth noting that the results
control group, we extracted data for the mean and its standard of two of these studies showed that there was a statistical
deviation. The time of the lesion was set to zero and the difference in the enlargement of aortic diameter compared
administration time was expressed relative to this. All data with the blank control group. However, one study reached
were extracted independently by two participants. the opposite conclusion, in which the diameter of the
Cochrane Handbook for Systematic Reviews of mouse aorta was smaller than that of the control group.
Interventions 4.2.6 (Higgins, 2006) was used as a quality The mice in the experimental group of the other two
[16]

Volume 1 Issue 2 (2022) 3 https://doi.org/10.36922/gtm.v1i2.85