Genetic hypogonadal (Gnrh1hpg) mouse model uncovers influence of reproductive axis on maturation of the gut microbiome during puberty.

The gut microbiome plays a key role in human health and gut dysbiosis is linked to many sex-specific diseases including autoimmune, metabolic, and neurological disorders. Activation of the hypothalamic-pituitary-gonadal (HPG) axis during puberty leads to sexual maturation and development of sex differences through the action of gonadal sex steroids. While the gut microbiome also undergoes sex differentiation, the mechanisms involved remain poorly understood. Using a genetic hypogonadal (hpg) mouse model, we sampled the fecal microbiome of male and female wild-type and hpg mutant mice before and after puberty to determine how microbial taxonomy and function are influenced by age, sex, and the HPG axis. We showed that HPG axis activation during puberty is required for sexual maturation of the gut microbiota composition, community structure, and metabolic functions. We also demonstrated that some sex differences in taxonomic composition and amine metabolism developed independently of the HPG axis, indicating that sex chromosomes are sufficient for certain sex differences in the gut microbiome. In addition, we showed that age, independent of HPG axis activation, led to some aspects of pubertal maturation of the gut microbiota community composition and putative functions. These results have implications for microbiome-based treatments, indicating that sex, hormonal status, and age should be considered when designing microbiome-based therapeutics.

The pedicled inferior paraumbilical perforator (I-PUP) flap for a volar wrist defect: a reconstructive solution across the ages.

Full-thickness soft-tissue defects overlying vital forearm or wrist structures frequently result from acute trauma or tumor ablation. These defects present reconstructive challenges, due to the thin pliable skin to be replaced and the non-graftable bed beneath. The authors discuss a case of a renal-transplant patient with a volar wrist SCC, in whom local vascular anatomy deemed microvascular free tissue transfer inappropriate. The authors present a successful novel reconstructive solution; the pedicled inferior paraumbilical perforator flap (I-PUP), a two-staged procedure that incorporates principles of distant flaps--which pre-date microsurgery--combined with techniques and lessons learned in the era of perforator flap surgery.

Elective spare parts free flap-calcaneal fillet of foot flap.

Severe lower limb trauma with significant soft tissue injury can be managed with reconstruction or, if this is impossible, amputation. If amputation is considered, below-knee amputation preserving limb length is optimal for long-term functional outcome. At times, soft tissue/bony injury can limit the ability to preserve limb length, particularly with proximal tibial injuries. We present a case of elective below-knee amputation where leg length and adequate soft tissue coverage was only possible by using an osteocutaneous fillet of foot and lower leg spare parts free flap, maintaining the tibial nerve pedicle for sensation and the posterior tibial artery for vascularity of the nerve. The procedure was technically challenging and required follow-up debulking operations. However, the technique provided the significant advantage of immediate sensation of robust glabrous distal stump cover and optimising leg length to enhance functional outcome.

Muscle-only intra-oral mucosal defect reconstruction.

Reconstructive requirements of medium to large sized oral mucosal defects following oncological resection include restoration of mucosal continuity with prevention of salivary leak and fistula formation, predictable soft tissue healing, and ensuring optimal oral function and cosmetic restoration. Such defects frequently mandate the use of microvascular free tissue transfer of fasciocutaneous flaps such as the radial forearm or anterolateral thigh flaps, or, for larger defects incorporating significant dead-space, muscle flaps such as rectus abdominis or latissimus dorsi. Commonly described techniques for re-establishing continuity of the epithelial component include using native mucosa, split skin graft, or a myocutaneous flap skin paddle. Few case series reports exist of non-epithelial reconstructive approaches. Here, the authors report a large series of muscle only flaps for oral defect reconstruction following oncologic resection. The current study demonstrates that mucosalised muscle is an effective additional method for intra-oral mucosal defect reconstruction.

The IMAP flap for pharygoesophageal reconstruction following stricture release.

Small-medium pharyngo-oesophageal or peri-tracheostoma defects represent a difficult reconstructive problem. Previous solutions included locoregional options such as the deltopectoral flap, or microvascular free tissue transfer. The authors present a novel application of the internal mammary artery perforator (IMAP) flap for reconstructing such defects. The IMAP flap may be mapped using pre-operative Doppler or CTA, and is raised on a single perforator. The relatively quick and simple flap raise provides robust fasciocutaneous tissue, may be tunneled subcutaneously to reach the neck and yields an inconspicuous donor site. The authors provide several cases demonstrating applications of the IMAP flap for reconstructing small-medium sized defects following release of annular pharyngoesophageal stricture, and studies documenting post-operative swallow. Overall, the pedicled IMAP fasciocutaneous flap is a useful technique to provide excellent composite tissue to reconstruct defects resulting from release of annular pharyngeal strictures. It is technically simple, and yields an inconspicuous anterior chest donor site.