Heat-Shock Protein 70 Overexpression in Adipose-Derived Stem Cells Enhances Fat Graft Survival

Heating Pretreatment of the Recipient Site Enhances Survival of Transplanted Fat in a Mouse Model

BACKGROUND

Despite several studies about the preparation of the recipient site in fat grafting, optimizing techniques with clinical usefulness is still necessary. Through previous animal studies reporting that heat can increase tissue vascular endothelial growth factor and vascular permeability, the authors hypothesize that pretreatment heating of the recipient site will increase retention of grafted fat.

METHODS

Twenty 6-week-old female BALB/c mice had two pretreatment sites on their back, one for the experimental temperatures (44°C and 48°C) and the other for the control. A digitally controlled aluminum block was used to apply the contact thermal damage. Human fat (0.5 mL) was grafted on each site and harvested on days 7, 14, and 49. The percentage volume and weight, histologic changes, and peroxisome proliferator-activated receptor gamma expression, a key regulator of adipogenesis, were measured by the water displacement method, light microscopy, and quantitative real-time polymerase chain reaction, respectively.

RESULTS

The harvested percentage volumes were 74.0% ± 3.4%, 82.5% ± 5.0%, and 67.5% ± 9.6% for the control, 44°C-pretreatment, and 48°C-pretreatment groups, respectively. The percentage volume and weight of the 44°C-pretreatment group was higher than the other groups ( P < 0.05). The 44°C-pretreatment group exhibited significantly higher integrity with fewer cysts and vacuoles than the other groups. Both heating pretreatment groups showed markedly higher rates of vascularity than the control group ( P < 0.017), and also increased the expression of peroxisome proliferator-activated receptor gamma over two-fold.

CONCLUSION

Heating preconditioning of the recipient site during fat grafting can increase the retention volume and improve the integrity, which is partly explained by increased adipogenesis in a short-term mouse model.

CLINICAL RELEVANCE STATEMENT

Tanning could be an alternative pretreatment for fat grafting.

Chronic heat treatment positively impacts metabolic profile of ovariectomized rats: association with heat shock response pathways

Low estrogen levels may predispose women to increased bodyweight and dyslipidemia. Previous studies from our laboratory suggest an involvement of depressed heat shock response (HSR) in this scenario because estrogen potently stimulates HSR. As heat treatment induces the expression of the anti-inflammatory heat shock proteins of the 70-kDa family (HSP70) and its accompanying HSR, we aimed to investigate whether chronic heat treatment promotes beneficial effects on biometric, lipid profile, oxidative stress, and HSR in ovariectomized rats. Wistar adult female rats (n = 32) were divided into four groups: control (C, n = 7), ovariectomized (OVX, n = 9), heat-treated (HT, n = 9), and heat-treated ovariectomized rats (OVX+HT, n = 7). HT and OVX+HT rats were anesthetized and submitted to heat treatment (once a week for 12 weeks) in a water bath (41 °C) to increase rats' rectal temperature up to 41 °C for 15 min, while C and OVX animals were submitted to a 36 °C water bath. HT attenuated the weight gain induced by OVX and increased HDL cholesterol and triglyceride serum levels. Also, OVX rats showed increased total cholesterol and LDL cholesterol levels that were not influenced by HT. Interestingly, it was found that an overall trend for HT to decrease tissue catalase and superoxide dismutase antioxidant activities was paralleled by a decrease in malondialdehyde levels (indicative of lower lipoperoxidation), especially in the skeletal muscle. Surprisingly, OVX was not able to depress intracellular HSP70 expression in the skeletal muscle, as expected, and this remained unchanged with HT. However, chronic HT did enhance intracellular HSP70 contents in white adipose tissue of OVX animals. As both glucose and insulin tolerance tests were not affected by OVX, which was not modified by HT, we suppose that estrogen absence alone is not sufficient to determine a state of insulin resistance associated with low intramuscular HSP70 content.

Oxidative Stress, Nutrition and Cancer: Friends or Foes?

The relationship between cancer and nutrition, as well as nutrition and oxidative stress, shares puzzling aspects that current research is investigating as the possible components of an intriguing regulating mechanism involving the complex interplay between adipose tissue and other compartments. Along the very recent biological evolution, humans underwent a rapid change in their lifestyles and henceforth the role of the adipocytes earned a much more complex task in the fine tuning of the tissue microenvironment. A lipidic signaling language probably evolved in association with the signaling role of reactive oxygen species, which gained a fundamental part in the regulation of cell stem and plasticity. The possible relationship with cancer onset might have some causative mechanism in the impairment of this complex task, usually deregulated by drastic changes in one's own lifestyle and dietary habit. This review tries to address this issue.

An lncRNA‑miRNA‑mRNA ceRNA network for adipocyte differentiation from human adipose‑derived stem cells

Human adipose tissue‑derived stromal stem cells (HASCs) represent a promising regenerative resource for breast reconstruction and augmentation. However, the mechanisms involved in inducing its adipogenic differentiation remain to be fully elucidated. The present study aimed to comprehensively investigate the expression changes in mRNAs, microRNAs (miRNAs) and long non‑coding (lnc)RNAs during the adipogenic differentiation of HASCs, and screen crucial lncRNA‑miRNA‑mRNA interaction axes using microarray datasets GSE57593, GSE25715 and GSE61302 collected from the Gene Expression Omnibus database. Following pretreatment, differentially expressed genes (DEGs), miRNAs (DE‑miRNAs) or lncRNAs (DE‑lncRNAs) between undifferentiated and differentiated HASCs were identified using the Linear Models for Microarray data method. A protein‑protein interaction (PPI) network was constructed for the DEGs based on protein databases, followed by module analysis. The 'lncRNA‑miRNA‑mRNA' competing endogenous RNA (ceRNA) network was constructed based on the interactions between miRNAs and mRNAs, lncRNAs and miRNAs predicted by the miRWalk and lnCeDB databases. The underlying functions of mRNAs were predicted using the clusterProfiler package. In the present study, 905 DEGs, 36 DE‑miRNAs and 577 DE‑lncRNAs were screened between undifferentiated HASCs and differentiated adipocyte cells. PPI network analysis demonstrated that LEP may be a hub gene, which was also enriched in significant module 5. LEP was predicted to be involved in the Janus kinase‑signal transducer and activator of transcription signaling pathway, and the regulation of inflammatory response. The upregulation of LEP was regulated by downregulated hsa‑miRNA (miR)‑130b‑5p and hsa‑miR‑23a‑5p (or hsa‑miR‑302d‑3p). These miRNAs also respectively interacted with RP11‑552F3.9 (or RP11‑15A1.7), ultimately forming the ceRNA axes. In conclusion, the present study revealed that the RP11‑552F3.9 (RP11‑15A1.7)‑hsa‑miR‑130b‑5p/hsa‑miR‑23a‑5p (hsa‑miR‑302d‑3p)‑LEP interaction axes may be crucial for inducing the adipogenic differentiation of HASCs via involvement in inflammation.