Immunosuppression with a Combination of Triptolide and Cyclosporin A in Rat Vascularized Groin Flap Allotransplantation:

From replantation to transplantation: The evolution of orthoplastic extremity reconstruction

For more than six decades, the use of the operating microscope for extremity surgery has led to remarkable advances in the management of orthopedic trauma, tumors, infections, and congenital differences. The microsurgical reconstructive ladder ascends from basic microsurgical procedures such as a digital artery or nerve repair to more complex procedures such as autologous tissue transplantation. Functional muscle transfers, toe-to-hand transfers, and recently vascularized composite allotransplantation are the highest rungs on this ladder that help restore extremity function. The development of the orthoplastic approach over the last three decades simultaneously integrates the principles and practices of both orthopedic surgery and plastic surgery for optimal care and salvage of extremities. Clinical, anatomic, and basic science research in reconstructive microsurgery has resulted in significant improvements in extremity salvage, reconstruction, and restoration.

A systematic review of immunomodulatory strategies used in skin-containing preclinical vascularized composite allotransplant models

BACKGROUND

Acute rejection remains a vexing problem in vascularized composite allotransplantation (VCA). Available immunosuppressive regimens are successful at minimizing alloimmune response and allowing VCA in humans. However, repeated rejection episodes are common, and systemic side effects of the current standard regimen (Tacrolimus, MMF, Prednisone) are dose limiting. Novel immunomodulatory approaches to improve allograft acceptance and minimize systemic toxicity are continuously explored in preclinical models. We aimed to systematically summarize past and current approaches to help guide future research in this complex field.

METHODS

We conducted a systematic review of manuscripts listed in the MEDLINE and PubMed databases. For inclusion, articles had to primarily investigate the effect of a therapeutic approach on prolonging the survival of a skin-containing preclinical VCA model. Non-VCA studies, human trials, anatomical and feasibility studies, and articles written in a language other than English were excluded. We followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines.

RESULTS

The search retrieved 980 articles of which 112 articles were ultimately included. The majority of investigations used a rat model. An orthotopic hind limb VCA model was used in 53% of the studies. Cell and drug-based approaches were investigated 58 and 52 times, respectively. We provide a comprehensive review of immunomodulatory strategies used in VCA preclinical research over a timeframe of 44 years.

CONCLUSION

We identify a transition from anatomically non-specific to anatomical models mimicking clinical needs. As limb transplants have been most frequently performed, preclinical research focused on using the hind limb model. We also identify a transition from drug-based suppression therapies to cell-based immunomodulation strategies.

Anti-inflammatory abietanes diterpenoids isolated from Tripterygium hypoglaucum

Tripterygium hypoglaucum (H. Lév.) Hutch. has been used to remedy rheumatoid arthritis, however, it shows frequent toxicity to the body. In this study, liquid chromatograph-mass spectrometer (LC-MS) was guided to characterize abietanes diterpenoids with anti-inflammatory activity from the stem of T. hypoglaucum. Thirteen undescribed abietanes diterpenoids were isolated and purified, and their chemical structure was identified using various spectroscopic methods. These compounds belonged to abietanes with splitting C ring, abietanes with benzenoid rings, diterpene quinoids, diterpene quinoids with lactone rings, and abietanes with benzenoid and lactone rings, respectively. Lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages was used to evaluate anti-inflammatory activity of the compounds. The results indicated that hypoglicin B-G and hypoglicin J-M exhibited inhibitory activity of NO production with the IC₅₀ values of 6.01, 25.21, 8.29, 3.63, 0.72, 0.89, 36.91, 0.82, 2.85, 11.92 μM, respectively. Among these compounds, compound hypoglicin L showed high anti-inflammatory activity and low toxicity (SI = 5.02 × 10⁴). Further QPCR analysis revealed that hypoglicin D and hypoglicin L can inhibit the mRNA expression of iNOS in LPS-stimulated RAW264.7 cells at doses of 12.5 and 3.13 μM, respectively. Taken together, ten anti-inflammatory diterpenoids were found from T. hypoglaucum in this study.

A novel animal model for skin flap prelamination with biomaterials

Several animal models of skin flap construction were reported using biomaterials in a way similar to prefabrication. However, there are few animal model using biomaterials similar to prelamination, another main way of clinical skin flap construction that has been proved to be reliable. Can biomaterials be added in skin flap prelamination to reduce the use of autogenous tissues? Beside individual clinical attempts, animal model is needed for randomized controlled trial to objectively evaluate the feasibility and further investigation. Combining human Acellular Dermal Matrix (hADM) and autologous skin graft, we prelaminated flaps based on inguinal fascia. One, two, three and four weeks later, hADM exhibited a sound revascularization and host cell infiltration. Prelaminated skin flaps were then raised and microsurgically transplanted back to groin region. Except for flaps after one week of prelamination, flaps from other subgroups successfully reconstructed defects. After six to sixteen weeks of transplantation, hADM was proved to being able to maintain its original structure, having a wealth of host tissue cells and achieving full revascularization.To our knowledge, this is the first animal model of prelaminating skin flap with biomaterials. Success of this animal model indicates that novel flap prelamination with biomaterials is feasible.

Catalytic Asymmetric Formal Total Synthesis of (-)-Triptophenolide and (+)-Triptolide

Catalytic asymmetric formal synthesis of (-)-Triptophenolide and (+)-Triptolide have been achieved. Key reaction involves Palladium catalyzed asymmetric conjugate addition of aryl boronic acid to 3-methyl cyclohexe-1-none to form quaternary carbon. Claisen rearrangement and subsequent aldol reaction furnished trans-decaline key intermediate, which assured a formal total synthesis of (-)-Triptophenolide and (+)-Triptolide.