The abstract does not describe the study and the results accurately. The study involved carrying out a research to determine whether exercise would alleviate some of the cardiac complications that accompany diabetes type-2. It focused on defects occurring in cardiomyocytes from mice with type-2 diabetes. The authors did not give enough details of the study in the abstract. For instance, they did not mention how the study took place and under what conditions. Additionally, they failed to describe the methods used clearly. However, they gave clearer results and informative discussion in the abstract. They did not provide enough information in the abstract especially on methods used.
The purpose of this study was to determine whether exercise would restore cardiomyocyte calcium ions cycling and excitation-contraction (EC) coupling defects in cardiomyocytes from mice with type-2 diabetes (db/db). The authors adequately indicated their reasons for carrying out the study. The reasons were to establish the role of exercise in reducing EC coupling defects and increasing cardiac performance by activation of Ca2+ – calmodulin-dependent protein kinase (CaMKIIδ).
The background information provided was enough to understand the objectives of the study. For instance, they noted that diabetic mellitus cases would reach pandemic levels in the next 2 decades and cardiovascular mortality was approximately 2 to 4 fold higher in diabetic than in non-diabetic patients. Moreover, Stølen and colleagues (2009) have indicated that diabetics are 2.5 times more likely to develop congestive heart failure compared to non-diabetics. These fears of increasing diabetes mellitus cases prompted the authors to carry out this study. The db/db diabetic mouse model develops cardiomyopathy in the same manner as humans and this justifies their choice of mice.
The methods used to collect data included, observations, experiments and use of judgmental samples. They describe the methods with sufficient details applicable for others to repeat or extend the study. The tools used to analyze the data, as one-way ANOVA is standard in research work. In carrying out western blot and real time PCR (RT-PCR), they used standardized protocols renormalized to house keeping genes and proteins. These protocols are universal and applicable in repeating or extending the study because they are standardized.
The authors indicated why they used some procedures in this study. For instance, they noted that to determine maximal oxygen uptake, they let mice run until exhaustion in a customized treadmill. This is because together with others, they had previously demonstrated the efficiency and relevancy of this exercise through clinical trials and experimental studies.
Nevertheless, they did not indicate potential problems with the procedures they used. They should have done so to avoid misconceptions that the results obtained were final and perfect. Things keep on changing and any results obtained in scientific research are subject to further investigations. Quoting the limitations of the procedures used would open a chance for other researchers to investigate and correct their work in future if need be.
They specified the statistical methods and procedures used. For statistical analysis, they used one-way ANOVA with Conferring posthoc test corrected for multiple comparisons. Other procedure used was western blot and real-time quantitative PCR (RT-PCR) using interchangeable protocols and tempered house keeping genes and proteins to quantify the cardiomyocytes.
The experiments done were appropriate to achieve the objectives of the study. One of the objectives was to determine whether exercise improved aerobic capacity in diabetic mice. The results indicated that exercise improved aerobic capacity to 13% higher in exercised db/db mice compared to sedentary db/db mice.
Tables and figure clearly presented the collected data. The authors employed the use of tables, charts, bar graphs and line graphs well. They inserted pictures that fit well in presenting the data. Legends accompany every illustration and this helps a greatly in explaining the illustrations.
These were the results of the study: it established that exercise improved aerobic capacity by 13% in db/db mice. Exercise also improved left ventricular function by improving fractional shortening and stroke volume in these mice. Exercised db/db mice had lower plasma levels of free fatty acids, triglycerides and insulin compared to sedentary db/db mice. Sedentary diabetic mice had impaired fractional shortening but this improved remarkably after training.
There was a lower twitch Ca2+ release in sedentary but not in exercised diabetic mice. Exercise training increased SR Ca2+ load in sedentary db/db mice demonstrated by reduced caffeine-induced Ca2+ release. Sedentary diabetic mice had increased sarcoplasmic reticulum calcium ions (SR Ca2+) leak compare to its world type counterpart. In wild type sedentary mice, Ca2+ release along the cardiomyocyte release had reduced synchrony.
Protein expression was higher in sedentary wild type mice than in sedentary db/db mice but exercise normalized these levels of expression. Inhibition of protein kinase A, had more pronounced effects that inhibition of CaMKII.
The team achieved the aims of this study. This is because they established that exercise restored cardiomyocyte calcium ions cycling and excitation-contraction coupling defects in diabetic mice. Inferring that, exercise will achieve the same effects in diabetic patients.
The authors discussed their results in relation to previous researches. A good example is pointing out that increased diastolic SR Ca 2+ leak and subsequent increase in Ca2+ waves’ frequency was concurred to findings from previous studies. They also interpreted the data adequately. They used graphs and charts in interpreting the data. Legends accompanied each illustration to give more insights about the data represented in the illustration. They drew inferences from the data and this formed the basics of their discussion.
Nevertheless, they did not discuss the limitations of this study. The limitations included failure to use methods that are more elaborate in data collection. The number of subjects involved in this study is also a limiting factor. They used only 20 characters in each case, that is, 20 exercised and 20 sedentary mice. This is a limiting number and a larger population would reduce assumptions reached because of studying smaller populations.
The ‘take home’ message in this paper is that exercise help in reducing cardiomyopathy complications common in diabetic patients. To make the paper more interesting, the authors would consider using human beings in place of mice. This will improve the relevance of this study in relation to human beings.
The ultimate purpose of any research should be to solve human problems thus incorporating diabetic patients in the study would make it more interesting. In the next set of experiments, the authors would consider looking for volunteers and liaising with hospitals to incorporate patients in the study. They would also consider giving sufficient information in the abstract and remain focused on the objectives mentioned in their study.
Citation of reference papers for comments made was average. Citing more papers would be fine to recognize the writers of those papers.
Works cited
Stølen, Tomas, Høydal, Morten, Kemi, Ole Johan, Catalucci, Daniele, Ceci, Marcello Ellen, Larsen, Aasum, Rolim, Natale, Condorelli, Gianluigi, Smith, Godfrey, and Wisløff, Ulrik. “Interval Training Normalizes Cardiomyocyte Function, Diastolic Ca2+ Control, and SR Ca2+ Release Synchronicity in a Mouse Model of Diabetic Cardiomyopathy”. Circulation Research 105(2009): 527-536.