Abstract 108: Stroke Amplifies Cerebrovascular Matrix Metalloproteinase-3 (MMP3) Activity In Diabetes: Potential Sex Differences And Impact On Endothelial To Mesenchymal Transition (EndMT)

Both female sex and diabetes increase the risk of poor stroke recovery, but underlying mechanisms are unclear. We reported that inhibition of MMP3 with UK356618 prevents hemorrhagic transformation (HT) in male diabetic rats, and female diabetic rats develop greater HT than males. Emerging evidence suggests that MMP3 may contribute to the regulation of EndMT, a process associated with scarring and impaired healing. We tested the hypotheses that: 1) MMP3 activity is amplified to a greater extent in the cerebrovasculature of female diabetic rats, especially after stroke; 2) EndMT occurs in female brain endothelial cells (BMVECs), and 3) MMP3 inhibition in stroke and diabetes-like conditions improves cell integrity/survival in female BMVECs.

Methods: Cerebral microvascular homogenates were prepared from control and diabetic male and female rats subjected to sham or 60-min middle cerebral artery occlusion. MMP3 expression/activity was measured. EndMT /endothelial integrity were assessed by immunoblotting in male and female BMVECs cultured in normal, diabetes or ischemia-like conditions.

Results (Table): Cerebrovascular MMP3 expression/activity is higher in females. TGF-β, a major EndMT inducer, significantly decreased VE-Cadherin and increased EndMT markers αSMA and p-SMAD2 to a greater extent in female cells. Ongoing studies suggested that MMP3 inhibitor UK356618 improved the expression of tight junction protein occludin and cell survival, which was associated with a decrease in transforming growth factor receptor-1 (TGFβR1).

Conclusions: The impact of long-term MMP3 inhibition on EndMT, neurovascular restoration, and post-stroke recovery in females and diabetes needs to be further explored.

Exercise improves angiogenic function of circulating exosomes in type 2 diabetes: Role of exosomal SOD3

Exosomes, key mediators of cell-cell communication, derived from type 2 diabetes mellitus (T2DM) exhibit detrimental effects. Exercise improves endothelial function in part via the secretion of exosomes into circulation. Extracellular superoxide dismutase (SOD3) is a major secretory copper (Cu) antioxidant enzyme that catalyzes the dismutation of O₂^•- to H₂ O₂ whose activity requires the Cu transporter ATP7A. However, the role of SOD3 in exercise-induced angiogenic effects of circulating plasma exosomes on endothelial cells (ECs) in T2DM remains unknown. Here, we show that both SOD3 and ATP7A proteins were present in plasma exosomes in mice, which was significantly increased after two weeks of volunteer wheel exercise. A single bout of exercise in humans also showed a significant increase in SOD3 and ATP7A protein expression in plasma exosomes. Plasma exosomes from T2DM mice significantly reduced angiogenic responses in human ECs or mouse skin wound healing models, which was associated with a decrease in ATP7A, but not SOD3 expression in exosomes. Exercise training in T2DM mice restored the angiogenic effects of T2DM exosomes in ECs by increasing ATP7A in exosomes, which was not observed in exercised T2DM/SOD3^-/- mice. Furthermore, exosomes overexpressing SOD3 significantly enhanced angiogenesis in ECs by increasing local H₂ O₂  levels in a heparin-binding domain-dependent manner as well as restored defective wound healing and angiogenesis in T2DM or SOD3^-/- mice. In conclusion, exercise improves the angiogenic potential of circulating exosomes in T2DM in a SOD3-dependent manner. Exosomal SOD3 may provide an exercise mimetic therapy that supports neovascularization and wound repair in cardiometabolic disease.

8 Improving Management for Acute Cholecystitis and Biliary Pancreatitis – the ‘Hot Gallbladder Pathway’

Aim

There is a wide variation between National Health Service (NHS) hospitals in the management of patients with acute cholecystitis and biliary pancreatitis. 20–33% of patients will make repeat visits to hospital with gallstone-related symptoms before any surgical intervention performed. We established a ‘Hot Gallbladder Pathway’ with the aim for improving outcome and decreasing complications of these patients. The aim of this quality improvement project was to assess if a district general hospital (DGH) could provide a safe and effective ‘hot gallbladder’ service with a clear pathway.

Method

Quality improvement methods were used to integrate the ‘hot gallbladder pathway’ to manage patients with acute calculous cholecystitis and biliary pancreatitis. A prospective observational study with strict inclusion/ exclusion criteria and secure online data was conducted during a 13-month period. The data were then compared against existing National Institute for Health and Clinical Excellence (NICE) guidelines and further changes were recommended.

Results

We achieved almost 70% of the patients undergoing emergency laparoscopic cholecystectomy in both group of patients who met the pathway criteria within the expected time frame, compared with the pre-implementation result of 23% and national average of only 16% in England. None of the patients suffered from intraoperative complications or 30-day mortality.

Conclusions

A clear ‘hot gall bladder pathway’ is effective at improving care for patients requiring emergency laparoscopic cholecystectomy and potentially useful for other acute Trusts which their standard is below the NICE guideline.

14 NICE CG188; Hot Gall Bladder Pathway in Emergency General Surgery - Are We Following the Guidelines?

Aim

1 - To compare the current standard of practice to existing guidelines and to make appropriate changes. 2 - To set a clear pathway for referring patients to the ‘hot laparoscopic cholecystectomy’ pathway. 3 - Avoid inappropriate booking for laparoscopic Cholecystectomy for patients who are not fulfilling the criteria of Hot Gall Bladder Pathway. 4 - Avoid unnecessary delay in performing Laparoscopic Cholecystectomy in patient with Acute Cholecystitis and mild Biliary Pancreatitis.

Method

It was a retrospective audit of all the patients who underwent Laparoscopic Cholecystectomy through Hot Gall Bladder Pathway between 1st February 2019 to 1st March 2020.

We screened a total of 134 patients who had been included in this pathway, 36 patient excluded.

1- Acute cholecystitis with no associated organ dysfunction 63 patients

2- Mild Acute Biliary Pancreatitis 35 patients

Results

Mild Acute Biliary Pancreatitis who underwent Laparoscopic Cholecystectomy within index admission or within 2 weeks of diagnosis 69 % (25/35).

Acute cholecystitis with no associated organ dysfunction (mild or moderate; Tokyo guideline grade I or II) who underwent Laparoscopic Cholecystectomy within week of diagnosis 68.2 % (43/63).

Conclusions