Hallo,
Although I do not know you I am sorry to hear of your troubles. I have just seen your website pictures and am saddened that there is not a viable market for your images at the moment. Perhaps as you hint, the US market is not currently "in tune" with your vision.
Whilst I have no experience of the US art market scene - so feel free to ignore this - perhaps going out of business could be rephrased?
People (companies/institutions) change all the time; restructuring, relocating, repositioning in the market etc. Rather than "closing down" could this not be "spun" or presented as a relocation for personal reasons/artistic endeavour (whatever) - at least on the website. Could you keep one good (perhaps your best/favourite) gallery in the US? This would keep you with a physical prescence in the US market, that may sell some of your work or at least keep it visible to potential US buyers and perhaps a place people could be directed to physically view your work? They might/should/could be willing to work internationally with someone - work can be physically sent by courier etc (and returned) for not that much cost.
Perhaps gallery representation could be found in Italy/Europe on your return, then you might have a presence in two continents.
I suppose that there might not be a viable market for your work anywhere but you currently have something that a lot of people would work really hard for - gallery representation. I think that your physical location (i.e. moving back to Italy) should have little bearing in continuing that representation - providing you feel that you want to contine to support/promote your work in that territory.
Just my thoughts. Whatever you do, I wish you all the best & I hope you will be continuing to photograph whereever you reside.
Sim2.