Message-Passing Interface (MPI) has become a standard for parallel applications in high-performance computing. Within a single cluster node, MPI implementations benefit from the shared memory to speed-up intra-node communications while the underlying network protocol is exploited to communicate between nodes. However, it requires the allocation of additional buffers leading to a memory-consumption overhead. This may become an issue on future clusters with reduced memory amount per core. In this article, we propose an MPI implementation built upon the MPC framework called MPC-MPI reducing the overall memory footprint. We obtained up to 47% of memory gain on benchmarks and a real-world application.